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What niacin used for: Niacin (Vitamin B3) : Benefits, Dosage, Sources, Risks

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Niacin – Mayo Clinic

Overview

Niacin is a B vitamin that’s made and used by your body to turn food into energy. It helps keep your nervous system, digestive system and skin healthy.

Niacin (vitamin B-3) is often part of a daily multivitamin, but most people get enough niacin from the food they eat. Foods rich in niacin include yeast, milk, meat, tortillas and cereal grains.

People use prescription niacin (Niacor, Niaspan) to help control their cholesterol.

The recommended daily amount of niacin for adult males is 16 milligrams (mg) a day and for adult women who aren’t pregnant, 14 mg a day.

Evidence

Research on the use of oral niacin to treat specific conditions shows:

  • High cholesterol. Prescription niacin is used to increase high-density lipoprotein (HDL) cholesterol — the “good” cholesterol that helps remove low-density lipoprotein (LDL), the “bad” cholesterol, from your bloodstream. Despite niacin’s ability to raise HDL, research suggests that niacin therapy isn’t linked to lower rates of death, heart attack or stroke.
  • Niacin deficiency (pellagra). Niacin and a related nutrient called niacinamide are used to treat or prevent niacin deficiency. This condition isn’t common in the United States.

Niacin deficiency has been linked to birth defects. A study in mice suggested that niacin supplementation during gestation prevented birth defects. Research is needed to prove a similar benefit in humans.

Our take

Generally safe

Prescription niacin might benefit people with high cholesterol who aren’t able to take statins or haven’t been able to control their cholesterol levels through use of a statin, diet and exercise. Don’t take prescription niacin for high cholesterol if you’re pregnant.

Safety and side effects

When taken orally in appropriate amounts, niacin appears to be safe.

High doses of niacin available via prescription can cause:

  • Severe skin flushing combined with dizziness
  • Rapid heartbeat
  • Itching
  • Nausea and vomiting
  • Abdominal pain
  • Diarrhea
  • Gout
  • Liver damage
  • Diabetes

Serious side effects are most likely if you take between 2,000 to 6,000 mg of niacin a day. If you think you might have overdosed on niacin, seek medical attention immediately.

If you have liver disease, peptic ulcer disease or severe low blood pressure (hypotension), don’t take large amounts of niacin. The supplement has been linked with liver damage, can cause hypotension and might activate a peptic ulcer.

Taking niacin also might worsen allergies, gallbladder disease and symptoms of certain thyroid disorders. If you have diabetes, niacin can interfere with blood glucose control. Use niacin with caution if you have the complex form of arthritis gout. Niacin can cause an excess of uric acid in the blood (hyperuricemia), putting you at risk of gout.

If you’re pregnant, don’t take prescription niacin for high cholesterol. However, if needed to prevent or treat niacin deficiency, niacin is likely safe to take during pregnancy and in breast-feeding women when used in recommended amounts.

Interactions

Possible interactions include:

  • Alcohol. Taking niacin with alcohol might increase the risk of liver damage and worsen niacin side effects, such as flushing and itching.
  • Allopurinol (Zyloprim). If you’re taking niacin and have gout, you might need to take more of this gout medicine to control your gout.
  • Anticoagulant and anti-platelet drugs, herbs and supplements. These types of drugs, herbs and supplements reduce blood clotting. Taking niacin with them might increase your risk of bleeding.
  • Blood pressure drugs, herbs and supplements. Niacin might have an additive effect when you take blood pressure drugs, herbs or supplements. This could increase your risk of low blood pressure (hypotension).
  • Chromium. Taking niacin with chromium might lower your blood sugar. If you have diabetes and take niacin and chromium, closely monitor your blood sugar levels.
  • Diabetes drugs. If you have diabetes, niacin can interfere with blood glucose control. You might need to adjust the dose of your diabetes drugs.
  • Hepatotoxic drugs, herbs and supplements. These drugs, herbs and supplements, like niacin, cause liver damage.
  • Statins. Research indicates that taking niacin with these cholesterol medications offers little additional benefit when compared with statins alone, and might increase the risk of side effects.
  • Zinc. Taking zinc with niacin might worsen niacin side effects, such as flushing and itching.

Nov. 12, 2020

Show references

  1. Shi H, et al. NAD deficiency, congenital malformations and niacin supplementation. New England Journal of Medicine. 2017;377:544.
  2. Schandelmaier S, et al. Niacin for primary and secondary prevention of cardiovascular events. Cochrane Database of Systematic Reviews. http://onlinelibrary.wiley.com/doi/10.1002/14651858.CD009744.pub2/full. Accessed Aug. 9, 2017.
  3. Niacin. Micromedex 2.0 Healthcare Series. http://www.micromedexsolutions.com. Accessed Aug. 9, 2017.
  4. Niacin (B3; nicotinic acid) oral. Facts & Comparisons eAnswers. http://www.wolterskluwercdi.com/facts-comparisons-online/. Accessed Aug. 9, 2017.
  5. Melmed S, et al. Disorders of lipid metabolism. In: Williams Textbook of Endocrinology. 13th ed. Philadelphia, Pa.: Elsevier; 2016. https://www.clinicalkey.com. Accessed Aug. 9, 2017.
  6. Pazirandeh S. Overview of water-soluble vitamins. https://www.uptodate.com/contents/search. Accessed Aug. 9, 2017.
  7. Niacin. Natural Medicines. https://naturalmedicines.therapeuticresearch.com. Accessed Aug. 21, 2017.


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Niacin – Consumer

What is niacin and what does it do?

Niacin (also called vitamin B3) helps turn the food you eat into the energy you need. Niacin is important for the development and function of the cells in your body.

How much niacin do I need?

The amount of niacin you need depends on your age and sex. Average daily recommended amounts are listed below in milligrams (mg) of niacin equivalents (NE) (except for infants in their first 6 months).

The mg NE measure is used because your body can also make niacin from tryptophan, an amino acid in proteins. For example, when you eat turkey, which is high in tryptophan, some of this amino acid is converted to niacin in your liver. Using mg NE accounts for both the niacin you consume and the niacin your body makes from tryptophan. Infants in their first six months do not make much niacin from tryptophan.













Life StageRecommended Amount
Birth to 6 months2 mg
Infants 7–12 months4 mg NE
Children 1–3 years6 mg NE
Children 4–8 years8 mg NE
Children 9–13 years12 mg NE
Teen boys 14–18 years16 mg NE
Teen girls 14–18 years14 mg NE
Adult men 19+ years16 mg NE
Adult women 19+ years14 mg NE
Pregnant teens and women18 mg NE
Breastfeeding teens and women17 mg NE

What foods provide niacin?

Niacin is found naturally in many foods, and is added to some foods. You can get recommended amounts of niacin by eating a variety of foods, including the following:

  • Animal foods, such as poultry, beef, pork, and fish
  • Some types of nuts, legumes, and grains
  • Enriched and fortified foods, such as many breads and cereals

What kinds of niacin dietary supplements are available?

Niacin is found in multivitamin/multimineral supplements. It is also available in B-complex dietary supplements and supplements containing only niacin. The two main forms of niacin in dietary supplements are nicotinic acid and nicotinamide.

Niacin (in the form of nicotinic acid) is also available as a prescription medicine used to treat high blood cholesterol levels.

Am I getting enough niacin?

Most people in the United States get enough niacin from the foods they eat. Niacin deficiency is very rare in the United States. However, some people are more likely than others to have trouble getting enough niacin:

What happens if I don’t get enough niacin?

You can develop niacin deficiency if you don’t get enough niacin or tryptophan from the foods you eat. Severe niacin deficiency leads to a disease called pellagra. Pellagra, which is uncommon in developed countries, can have these effects:

  • Rough skin that turns red or brown in the sun
  • A bright red tongue
  • Vomiting, constipation, or diarrhea
  • Depression
  • Headaches
  • Extreme tiredness
  • Aggressive, paranoid, or suicidal behavior
  • Hallucinations, apathy, loss of memory

In its final stages, pellagra leads to loss of appetite followed by death.

What are some effects of niacin on health?

Scientists are studying niacin to better understand how it affects health. Here is an example of what this research has shown.

Cardiovascular disease

Scientists have studied the use of large doses of niacin in the form of nicotinic acid to help reduce the risk of heart attack and stroke in people with atherosclerosis. They found that prescription-strength nicotinic acid (more than 100 times the recommended dietary allowance) can lower blood levels of LDL (bad) cholesterol, raise levels of HDL (good) cholesterol, and lower levels of triglycerides. But these favorable effects on blood lipids (fats) don’t affect the risk of having a cardiovascular event, such as heart attack, sudden cardiac death, or stroke. In addition, experts do not recommend high doses of nicotinic acid for people taking a statin medication.

Your healthcare provider should approve and supervise any use of very high doses of nicotinic acid (in the thousands of milligrams) to treat atherosclerosis.

Can niacin be harmful?

The niacin that food and beverages naturally contain is safe. However, dietary supplements with 30 mg or more of nicotinic acid can make the skin on your face, arms, and chest turn red and burn, tingle, and itch. These symptoms can also lead to headaches, rashes, and dizziness.

If you take nicotinic acid as a medication in doses of 1,000 or more mg/day, it can cause more severe side effects. These include:

  • Low blood pressure (which can increase the risk of falls)
  • Extreme tiredness
  • High blood sugar levels
  • Nausea, heartburn, and abdominal pain
  • Blurred or impaired vision and fluid buildup in the eyes

Long-term treatment, especially with extended-release forms of nicotinic acid, can cause liver problems, including hepatitis and liver failure.

Niacin in the form of nicotinamide has fewer side effects than nicotinic acid. However, at high doses of 500 mg/day or more, nicotinamide can cause diarrhea, easy bruising, and can increase bleeding from wounds. Even higher doses of 3,000 mg/day or more can cause nausea, vomiting, and liver damage.

The daily upper limits for niacin from dietary supplements are listed below.








AgesUpper Limit
Birth to 12 monthsNot established
Children 1–3 years10 mg
Children 4–8 years15 mg
Children 9–13 years20 mg
Teens 14–18 years30 mg
Adults 19+ years35 mg

 

Does niacin interact with medications or other dietary supplements?

Niacin dietary supplements can interact or interfere with certain medicines that you take, and some medicines can lower niacin levels in your body. Here are some examples:

  • Tuberculosis drugs (such as isoniazid and pyrazinamide) interfere with the body’s ability to convert tryptophan to niacin. This interference can lower niacin levels in your body.
  • High doses of nicotinic acid (1,500 mg/day or more) can raise blood sugar levels and interfere with the effectiveness of diabetes medications. These doses can even raise blood sugar levels in people who don’t have diabetes.

Tell your doctor, pharmacist, and other healthcare providers about any dietary supplements and prescription or over-the-counter medicines you take. They can tell you if the dietary supplements might interact with your medicines. They can also tell you if the medicines might interfere with how your body absorbs, uses, or breaks down niacin and other nutrients.

Niacin and healthful eating

People should get most of their nutrients from food and beverages, according to the federal government’s Dietary Guidelines for Americans. Foods contain vitamins, minerals, dietary fiber, and other components that benefit health. In some cases, fortified foods and dietary supplements are useful when it is not possible to meet needs for one or more nutrients (e.g., during specific life stages such as pregnancy). For more information about building a healthy dietary pattern, see the Dietary Guidelines for Americans and the U.S. Department of Agriculture’s MyPlate.

Where can I find out more about niacin?

  • For general information on niacin:
  • For more information on food sources of niacin:
  • For more advice on choosing dietary supplements:
  • For information about building a healthy dietary pattern:

Disclaimer

This fact sheet by the Office of Dietary Supplements (ODS) provides information that should not take the place of medical advice. We encourage you to talk to your healthcare providers (doctor, registered dietitian, pharmacist, etc.) about your interest in, questions about, or use of dietary supplements and what may be best for your overall health. Any mention in this publication of a specific product or service, or recommendation from an organization or professional society, does not represent an endorsement by ODS of that product, service, or expert advice.


Updated: March 22, 2021 History of changes to this fact sheet

Niacin – Consumer

What is niacin and what does it do?

Niacin (also called vitamin B3) helps turn the food you eat into the energy you need. Niacin is important for the development and function of the cells in your body.

How much niacin do I need?

The amount of niacin you need depends on your age and sex. Average daily recommended amounts are listed below in milligrams (mg) of niacin equivalents (NE) (except for infants in their first 6 months).

The mg NE measure is used because your body can also make niacin from tryptophan, an amino acid in proteins. For example, when you eat turkey, which is high in tryptophan, some of this amino acid is converted to niacin in your liver. Using mg NE accounts for both the niacin you consume and the niacin your body makes from tryptophan. Infants in their first six months do not make much niacin from tryptophan.













Life StageRecommended Amount
Birth to 6 months2 mg
Infants 7–12 months4 mg NE
Children 1–3 years6 mg NE
Children 4–8 years8 mg NE
Children 9–13 years12 mg NE
Teen boys 14–18 years16 mg NE
Teen girls 14–18 years14 mg NE
Adult men 19+ years16 mg NE
Adult women 19+ years14 mg NE
Pregnant teens and women18 mg NE
Breastfeeding teens and women17 mg NE

What foods provide niacin?

Niacin is found naturally in many foods, and is added to some foods. You can get recommended amounts of niacin by eating a variety of foods, including the following:

  • Animal foods, such as poultry, beef, pork, and fish
  • Some types of nuts, legumes, and grains
  • Enriched and fortified foods, such as many breads and cereals

What kinds of niacin dietary supplements are available?

Niacin is found in multivitamin/multimineral supplements. It is also available in B-complex dietary supplements and supplements containing only niacin. The two main forms of niacin in dietary supplements are nicotinic acid and nicotinamide.

Niacin (in the form of nicotinic acid) is also available as a prescription medicine used to treat high blood cholesterol levels.

Am I getting enough niacin?

Most people in the United States get enough niacin from the foods they eat. Niacin deficiency is very rare in the United States. However, some people are more likely than others to have trouble getting enough niacin:

What happens if I don’t get enough niacin?

You can develop niacin deficiency if you don’t get enough niacin or tryptophan from the foods you eat. Severe niacin deficiency leads to a disease called pellagra. Pellagra, which is uncommon in developed countries, can have these effects:

  • Rough skin that turns red or brown in the sun
  • A bright red tongue
  • Vomiting, constipation, or diarrhea
  • Depression
  • Headaches
  • Extreme tiredness
  • Aggressive, paranoid, or suicidal behavior
  • Hallucinations, apathy, loss of memory

In its final stages, pellagra leads to loss of appetite followed by death.

What are some effects of niacin on health?

Scientists are studying niacin to better understand how it affects health. Here is an example of what this research has shown.

Cardiovascular disease

Scientists have studied the use of large doses of niacin in the form of nicotinic acid to help reduce the risk of heart attack and stroke in people with atherosclerosis. They found that prescription-strength nicotinic acid (more than 100 times the recommended dietary allowance) can lower blood levels of LDL (bad) cholesterol, raise levels of HDL (good) cholesterol, and lower levels of triglycerides. But these favorable effects on blood lipids (fats) don’t affect the risk of having a cardiovascular event, such as heart attack, sudden cardiac death, or stroke. In addition, experts do not recommend high doses of nicotinic acid for people taking a statin medication.

Your healthcare provider should approve and supervise any use of very high doses of nicotinic acid (in the thousands of milligrams) to treat atherosclerosis.

Can niacin be harmful?

The niacin that food and beverages naturally contain is safe. However, dietary supplements with 30 mg or more of nicotinic acid can make the skin on your face, arms, and chest turn red and burn, tingle, and itch. These symptoms can also lead to headaches, rashes, and dizziness.

If you take nicotinic acid as a medication in doses of 1,000 or more mg/day, it can cause more severe side effects. These include:

  • Low blood pressure (which can increase the risk of falls)
  • Extreme tiredness
  • High blood sugar levels
  • Nausea, heartburn, and abdominal pain
  • Blurred or impaired vision and fluid buildup in the eyes

Long-term treatment, especially with extended-release forms of nicotinic acid, can cause liver problems, including hepatitis and liver failure.

Niacin in the form of nicotinamide has fewer side effects than nicotinic acid. However, at high doses of 500 mg/day or more, nicotinamide can cause diarrhea, easy bruising, and can increase bleeding from wounds. Even higher doses of 3,000 mg/day or more can cause nausea, vomiting, and liver damage.

The daily upper limits for niacin from dietary supplements are listed below.








AgesUpper Limit
Birth to 12 monthsNot established
Children 1–3 years10 mg
Children 4–8 years15 mg
Children 9–13 years20 mg
Teens 14–18 years30 mg
Adults 19+ years35 mg

 

Does niacin interact with medications or other dietary supplements?

Niacin dietary supplements can interact or interfere with certain medicines that you take, and some medicines can lower niacin levels in your body. Here are some examples:

  • Tuberculosis drugs (such as isoniazid and pyrazinamide) interfere with the body’s ability to convert tryptophan to niacin. This interference can lower niacin levels in your body.
  • High doses of nicotinic acid (1,500 mg/day or more) can raise blood sugar levels and interfere with the effectiveness of diabetes medications. These doses can even raise blood sugar levels in people who don’t have diabetes.

Tell your doctor, pharmacist, and other healthcare providers about any dietary supplements and prescription or over-the-counter medicines you take. They can tell you if the dietary supplements might interact with your medicines. They can also tell you if the medicines might interfere with how your body absorbs, uses, or breaks down niacin and other nutrients.

Niacin and healthful eating

People should get most of their nutrients from food and beverages, according to the federal government’s Dietary Guidelines for Americans. Foods contain vitamins, minerals, dietary fiber, and other components that benefit health. In some cases, fortified foods and dietary supplements are useful when it is not possible to meet needs for one or more nutrients (e.g., during specific life stages such as pregnancy). For more information about building a healthy dietary pattern, see the Dietary Guidelines for Americans and the U.S. Department of Agriculture’s MyPlate.

Where can I find out more about niacin?

  • For general information on niacin:
  • For more information on food sources of niacin:
  • For more advice on choosing dietary supplements:
  • For information about building a healthy dietary pattern:

Disclaimer

This fact sheet by the Office of Dietary Supplements (ODS) provides information that should not take the place of medical advice. We encourage you to talk to your healthcare providers (doctor, registered dietitian, pharmacist, etc.) about your interest in, questions about, or use of dietary supplements and what may be best for your overall health. Any mention in this publication of a specific product or service, or recommendation from an organization or professional society, does not represent an endorsement by ODS of that product, service, or expert advice.


Updated: March 22, 2021 History of changes to this fact sheet

Niacin – Consumer

What is niacin and what does it do?

Niacin (also called vitamin B3) helps turn the food you eat into the energy you need. Niacin is important for the development and function of the cells in your body.

How much niacin do I need?

The amount of niacin you need depends on your age and sex. Average daily recommended amounts are listed below in milligrams (mg) of niacin equivalents (NE) (except for infants in their first 6 months).

The mg NE measure is used because your body can also make niacin from tryptophan, an amino acid in proteins. For example, when you eat turkey, which is high in tryptophan, some of this amino acid is converted to niacin in your liver. Using mg NE accounts for both the niacin you consume and the niacin your body makes from tryptophan. Infants in their first six months do not make much niacin from tryptophan.













Life StageRecommended Amount
Birth to 6 months2 mg
Infants 7–12 months4 mg NE
Children 1–3 years6 mg NE
Children 4–8 years8 mg NE
Children 9–13 years12 mg NE
Teen boys 14–18 years16 mg NE
Teen girls 14–18 years14 mg NE
Adult men 19+ years16 mg NE
Adult women 19+ years14 mg NE
Pregnant teens and women18 mg NE
Breastfeeding teens and women17 mg NE

What foods provide niacin?

Niacin is found naturally in many foods, and is added to some foods. You can get recommended amounts of niacin by eating a variety of foods, including the following:

  • Animal foods, such as poultry, beef, pork, and fish
  • Some types of nuts, legumes, and grains
  • Enriched and fortified foods, such as many breads and cereals

What kinds of niacin dietary supplements are available?

Niacin is found in multivitamin/multimineral supplements. It is also available in B-complex dietary supplements and supplements containing only niacin. The two main forms of niacin in dietary supplements are nicotinic acid and nicotinamide.

Niacin (in the form of nicotinic acid) is also available as a prescription medicine used to treat high blood cholesterol levels.

Am I getting enough niacin?

Most people in the United States get enough niacin from the foods they eat. Niacin deficiency is very rare in the United States. However, some people are more likely than others to have trouble getting enough niacin:

What happens if I don’t get enough niacin?

You can develop niacin deficiency if you don’t get enough niacin or tryptophan from the foods you eat. Severe niacin deficiency leads to a disease called pellagra. Pellagra, which is uncommon in developed countries, can have these effects:

  • Rough skin that turns red or brown in the sun
  • A bright red tongue
  • Vomiting, constipation, or diarrhea
  • Depression
  • Headaches
  • Extreme tiredness
  • Aggressive, paranoid, or suicidal behavior
  • Hallucinations, apathy, loss of memory

In its final stages, pellagra leads to loss of appetite followed by death.

What are some effects of niacin on health?

Scientists are studying niacin to better understand how it affects health. Here is an example of what this research has shown.

Cardiovascular disease

Scientists have studied the use of large doses of niacin in the form of nicotinic acid to help reduce the risk of heart attack and stroke in people with atherosclerosis. They found that prescription-strength nicotinic acid (more than 100 times the recommended dietary allowance) can lower blood levels of LDL (bad) cholesterol, raise levels of HDL (good) cholesterol, and lower levels of triglycerides. But these favorable effects on blood lipids (fats) don’t affect the risk of having a cardiovascular event, such as heart attack, sudden cardiac death, or stroke. In addition, experts do not recommend high doses of nicotinic acid for people taking a statin medication.

Your healthcare provider should approve and supervise any use of very high doses of nicotinic acid (in the thousands of milligrams) to treat atherosclerosis.

Can niacin be harmful?

The niacin that food and beverages naturally contain is safe. However, dietary supplements with 30 mg or more of nicotinic acid can make the skin on your face, arms, and chest turn red and burn, tingle, and itch. These symptoms can also lead to headaches, rashes, and dizziness.

If you take nicotinic acid as a medication in doses of 1,000 or more mg/day, it can cause more severe side effects. These include:

  • Low blood pressure (which can increase the risk of falls)
  • Extreme tiredness
  • High blood sugar levels
  • Nausea, heartburn, and abdominal pain
  • Blurred or impaired vision and fluid buildup in the eyes

Long-term treatment, especially with extended-release forms of nicotinic acid, can cause liver problems, including hepatitis and liver failure.

Niacin in the form of nicotinamide has fewer side effects than nicotinic acid. However, at high doses of 500 mg/day or more, nicotinamide can cause diarrhea, easy bruising, and can increase bleeding from wounds. Even higher doses of 3,000 mg/day or more can cause nausea, vomiting, and liver damage.

The daily upper limits for niacin from dietary supplements are listed below.








AgesUpper Limit
Birth to 12 monthsNot established
Children 1–3 years10 mg
Children 4–8 years15 mg
Children 9–13 years20 mg
Teens 14–18 years30 mg
Adults 19+ years35 mg

 

Does niacin interact with medications or other dietary supplements?

Niacin dietary supplements can interact or interfere with certain medicines that you take, and some medicines can lower niacin levels in your body. Here are some examples:

  • Tuberculosis drugs (such as isoniazid and pyrazinamide) interfere with the body’s ability to convert tryptophan to niacin. This interference can lower niacin levels in your body.
  • High doses of nicotinic acid (1,500 mg/day or more) can raise blood sugar levels and interfere with the effectiveness of diabetes medications. These doses can even raise blood sugar levels in people who don’t have diabetes.

Tell your doctor, pharmacist, and other healthcare providers about any dietary supplements and prescription or over-the-counter medicines you take. They can tell you if the dietary supplements might interact with your medicines. They can also tell you if the medicines might interfere with how your body absorbs, uses, or breaks down niacin and other nutrients.

Niacin and healthful eating

People should get most of their nutrients from food and beverages, according to the federal government’s Dietary Guidelines for Americans. Foods contain vitamins, minerals, dietary fiber, and other components that benefit health. In some cases, fortified foods and dietary supplements are useful when it is not possible to meet needs for one or more nutrients (e.g., during specific life stages such as pregnancy). For more information about building a healthy dietary pattern, see the Dietary Guidelines for Americans and the U.S. Department of Agriculture’s MyPlate.

Where can I find out more about niacin?

  • For general information on niacin:
  • For more information on food sources of niacin:
  • For more advice on choosing dietary supplements:
  • For information about building a healthy dietary pattern:

Disclaimer

This fact sheet by the Office of Dietary Supplements (ODS) provides information that should not take the place of medical advice. We encourage you to talk to your healthcare providers (doctor, registered dietitian, pharmacist, etc.) about your interest in, questions about, or use of dietary supplements and what may be best for your overall health. Any mention in this publication of a specific product or service, or recommendation from an organization or professional society, does not represent an endorsement by ODS of that product, service, or expert advice.


Updated: March 22, 2021 History of changes to this fact sheet

Niacin (Vitamin B3): Benefits & Side Effects

Vitamin B3, also called niacin, is one of the eight B-complex water-soluble vitamins. Niacin has a wide range of uses in the body, helping functions in the digestive system, skin and nervous system. Niacin, a name coined from nicotinic acid vitamin, comes in several forms, including niacinamide (nicotinamide) and inositol hexanicotinate. Each of these forms has various uses as well. 

Food sources of niacin include yeast, meat, fish, milk, eggs, nuts, green vegetables, beans and enriched breads and cereals. The human body can also make niacin from the amino acid tryptophan, according to the National Institutes of Health (NIH). 

Benefits

Like other B vitamins, niacin helps the body break down carbohydrates, fats and proteins into energy, according to the University of Maryland Medical Center. In addition, it plays a role in gland and liver function. “Niacin has a role in producing certain hormones in the adrenal glands and helps remove harmful chemicals from the liver,” Dr. Sherry Ross, women’s health expert at Providence Saint John’s Health Center in Santa Monica, California, told Live Science.

Niacin also can play a part in improving health. According to NIH, it is also used for treating migraine headaches, circulation problems and dizziness, and to reduce the diarrhea associated with cholera. 

Some studies have found the taking niacin may help stroke patients. When rats with ischemic stroke were given niacin, their brains grew new blood vessels, according to researchers at Henry Ford Hospital in Detroit, Michigan. Ischemic stroke is caused by an obstruction within a blood vessel supplying blood to the brain and accounts for 87 percent of all cases. A 2000 study published in the journal Stroke also used rats and found that treatment with nicotinamide may repair damage to the brain caused by strokes.  

Vitamin B3 may also be helpful to cancer patients. A recent study found that nicotinamide significantly reduces the incidence of nonmelanoma skin cancers in those with a history of basal cell carcinoma or squamous cell carcinoma.

It may be good for other skin conditions, too. In a double-blind trial by the State University of New York, the topical application of a 4 percent niacinamide gel twice a day for two months resulted in a similar acne improvement when compared to 1 percent clindamycin gel. 

Those who have intimacy problems may also benefit from niacin. According to a study published in the Journal of Sexual Medicine, vitamin B3 was found to improve the ability to maintain an erection in men with moderate to severe erectile dysfunction. 

A recent animal study suggested that niacin may be helpful in preventing inflammatory bowel disease and colitis. The 2017 study, published in Scientific Reports, found that rats that were given niacin and then induced with colitis saw less colonic damage than those who did not receive niacin. The authors attribute this protection to niacin’s anti-inflammatory and anti-angiogenic effects. (Angiogenic means the formation and development of blood vessels.)

Niacin and cholesterol

Niacin is known for lowering LDL (bad) cholesterol and triglycerides in the blood. Additionally, the Mayo Clinic reported that niacin could raise HDL (good) cholesterol by more than 30 percent. Therefore, niacin has been a major part of treating high cholesterol for at least 50 years. But a large-scale 2014 study has caused some health professionals to revisit that view. 

The study, published in The New England Journal of Medicine, examined 50- to 80-year-olds with cardiovascular disease. They were already taking statin medication, which was combined with extended-release niacin and laropiprant, which reduces face flushing associated with niacin, for four years. Niacin did not result in the hypothesized reduced heart attacks and strokes. It also was associated with a higher risk of death from all causes and serious side effects, including liver problems, excess bleeding, infections, loss of blood sugar control in diabetics, gout and the development of diabetes. The authors of the study conclude that doctors should take these adverse effects into consideration when prescribing niacin and perhaps niacin should only be used to treat severe patients. 

A 2017 article in the Journal of Clinical-Lipidology, however, cited previous studies that saw reductions in cardiovascular events in patients that combined niacin with statins. The authors of the article state that more research is needed before niacin ends its term as a cholesterol therapy mainstay. 

Niacin flush

One side effect of taking niacin supplements is mild flushing. Ross described it as a feeling of warmth, itching, redness or a tingly feeling under the skin. The flushing is harmless and usually subsides within one or two hours, according to the British Columbia Drug and Poison Information Center (DPIC). Some over-the-counter niacin tablets deliver the dose in a short burst, which makes the reaction more intense. Timed-release tablets deliver the vitamin more slowly, which reduces the intensity of the flushing. However, this type of niacin may cause liver damage in some people, according to the DPIC. 

Other side effects can include stomach upset, intestinal gas, dizziness and pain in the mouth, the NIH reported. 

Deficiency and dosage

In the United States and other developed countries, niacin deficiency is rare and is typically found in alcoholics. According to the University of Maryland Medical Center, symptoms of mild niacin deficiency include fatigue, canker sores, vomiting, depression, poor circulation and indigestion. More severe niacin deficiency can cause a condition called pellagra. The symptoms of pellagra include digestive problems, inflamed or flakey skin, diarrhea and mental impairment.

The normal recommended daily allowance (RDA) of niacin is dependent on age, gender, health conditions and reproductive status. For women and men, the average RDA is 14 to 16 milligrams a day, according to the NIH. Those taking medications or those that have medical conditions should contact a medical professional before taking niacin due to drug interactions and side effects.

Getting too much niacin is possible, even for healthy individuals. “When taking it, you need to check for interactions with other meds and make sure your labs tests are normal,” said Dr. Kristine Arthur, internist at Orange Coast Memorial Medical Center in Fountain Valley, California. “If you take too much you can have side effects including nausea, stomach upset, abnormal liver tests, muscle breakdown and flushing — usually with over 1 to 2 grams per day.” 

Many doctors advise against self-medicating with niacin and suggest that in many cases supplementation isn’t needed. “The water soluble vitamins, such as C and B complex, are much harder to reach toxic levels from over-ingestion, but does this mean we need to procure them from a supplement regularly? In most cases, the answer is no,” said Dr. David Greuner, director and co-founder of NYC Surgical Associates. Most people are able to get plenty of niacin through a healthy diet. 

Additional reporting by Jessie Szalay, Live Science contributor.

Additional resources

Vitamin B3 (Niacin) Information | Mount Sinai

AIM-HIGH Investigators. The role of niacin in raising high-density lipoprotein cholesterol to reduce cardiovascular events in patients with atherosclerotic cardiovascular disease and optimally treated low-density lipoprotein cholesterol Rationale and study design. The Atherothrombosis Intervention in Metabolic syndrome with low HDL/high triglycerides: Impact on Global Health outcomes (AIM-HIGH). Am Heart J. 2011 Mar;161(3):471-477.e2.

Bissett DL, Oblong JE, Berge CA, et al. Niacinamide: A B vitamin that improves aging facial skin appearance. Dermatol Surg. 2005;31:860-865; discussion 865.

Boden WE, Sidhu MS. Toth PP. The therapeutic role of niacin in dyslipidemia management. J Cardiovasc Pharmacol Ther. 2014;19(2):141-58.

Brown BG, Zhao XQ, Chalt A, et al. Simvastatin and niacin, antioxidant vitamins, or the combination for the prevention of coronary disease. N Engl J Med. 2001;345(22):1583-1592.

Cumming RG, Mitchell P, Smith W. Diet and cataract: the Blue Mountains Eye Study. Ophthalmology. 2000;107(3):450-456.

Draelos ZD, Ertel K, Berge C, et al. Niacinamide-containing facial moisturizer improves skin barrier and benefits subjects with rosacea. Cutis. 2005;76:135-141.

Elam M, Hunninghake DB, Davis KB, et al. Effects of niacin on lipid and lipoprotein levels and glycemic control in patients with diabetes and peripheral arterial disease: the ADMIT study: a randomized trial. Arterial Disease Multiple Intervention Trial. JAMA. 2000;284:1263-1270.

Garcia-Closas R. et al. Food, nutrient and heterocyclic amine intake and the risk of bladder cancer. Eur J Cancer. 2007;43(11):1731-1740.

Ginsberg HN, reyes-Soffer G. Niacin: a long history, but a questionable future. Curr Opin Lipidol. 2013;24(6):475-9.

Goldberg A, Alagona P, Capuzzi DM, et al. Multiple-dose efficacy and safety of an extended-release form of niacin in management of hyperlipidemia. Am J Cardiol. 2000;85:1100-1105.

Guyton JR. Niacin in cardiovascular prevention: mechanisms, efficacy, and safety. Curr Opin Lipidol. 2007 Aug;18(4):415-420.

Jacques PF, Chylack LT Jr, Hankinson SE, et al. Long-term nutrient intake and early age related nuclear lens opacities. Arch Ophthalmol. 2001;119(7):1009-1019.

Jones KW. Do patients on statins also need niacin? JAAPA. 2013;26(7):9-10.

Kuzniarz M, Mitchell P, Cumming RG, Flood VM. Use of vitamin supplements and cataract: the Blue Mountains Eye Study. Am J Ophthalmol. 2001;132(1):19-26.

Mittal MK, Florin T, Perrone J, Delgado JH, Osterhoudt KC. Toxicity from the use of niacin to beat urine drug screening. Ann Emerg Med. 2007;50(5):587-590.

Nutrients and Nutritional Agents. In: Kastrup EK, Hines Burnham T, Short RM, et al, eds. Drug Facts and Comparisons. St. Louis, MO: 2000;4-5.

Raja R, Thomas JM, Greenhill-Hopper M, Ley SV, Almeida Paz FA. Facile, one-step production of niacin (vitamin B3) and other nitrogen-containing pharmaceutical chemicals with a single-site heterogeneous catalyst. Chemistry. 2008;14(8):2340-2348.

Sahebkar A. effect of niacin on endothelial function: a systematic review and meta-analysis of randomized controlled trials. Vasc Med. 2014;19(1):54-66.

Sanyal S, Karas RH, Kuvin JT. Present-day uses of niacin: effects on lipid and non-lipid parameters. Expert Opin Pharmacother. 2007 Aug;8(11):1711-17.

Song WL, FitzGerald GA. Niacin, an old drug with a new twist. J Lipid Res. 2013;54(10):2486-94.

Surjana D. Damian DL. Nicotinamide in dermatology and photoprotection. Skinmed. 2011;9(6):360-365.

Torkos S. Drug-nutrient interactions: a focus on cholesterol-lowering agents. Int J Integrative Med. 2000;2(3):9-13.

Villines TC, Kim AS, Gore RS, Taylor AJ. Niacin: the evidence, clinical use, and future directions. Curr Atheroscler Rep. 2012;14(1):49-59.

Wolerton: Comprehensive Dermatalogic Drug Therapy. 2nd ed. Philadelphia, PA: Elsevier Saunders; 2007.

Zhang XM, Jing YP, Jia MY, Zhang L. Negative transcriptional regulation of inflammatory genes by group B3 vitamin nicotinamide. Mol Biol Rep. 2012;39(12):1036-1071.

Zhao H, Yang X, Zhou R, Yang Y. Study on vitamin B1, vitamin B2 retention factors in vegetables. Wei Sheng Yan Jiu. 2008;37(1):92-96.

Health Benefits and Uses of Niacin

Niacin is a B vitamin found in a number of foods and sold in supplement form. Sometimes referred to as vitamin B3, niacin is also produced naturally by the body.

Known to play a key role in converting food into energy, niacin is considered essential to the function of the digestive system, skin, and nerves. Although niacin deficiency is very rare, some people use niacin supplements to help with certain health conditions.

Uses 

In alternative medicine, niacin supplements are often touted as a natural remedy for the following health problems:

  • acne
  • Alzheimer’s disease
  • arthritis
  • blood pressure
  • cataracts
  • diabetes
  • high cholesterol
  • migraines
  • motion sickness
  • memory problems
  • premenstrual syndrome

Additionally, niacin is used to slow the effects of aging, reduce stress, improve digestion, and stimulate circulation.

Benefits 

Here’s a look at the science behind the health benefits of niacin:

High Cholesterol

Taking niacin is likely effective in lowering cholesterol, according to the National Institutes of Health (NIH). In fact, some niacin supplements are approved by the U.S. Food and Drug Administration as prescription medications for high cholesterol.

A number of clinical trials have indicated that niacin may help raise levels of HDL (“good”) cholesterol and reduce levels of LDL (“bad”) cholesterol. However, in a recent study from the New England Journal of Medicine, researchers found that adding niacin to statin therapy had no cardiovascular benefit for patients with heart disease. Published in 2011, the study involved 3,414 people with heart disease and atherosclerosis.

If you’re considering the use of niacin in the treatment of high cholesterol, talk to your doctor before starting your supplement regimen.

Alzheimer’s Disease

Increasing your dietary intake of niacin may protect against Alzheimer’s disease, according to a 2004 study from the Journal of Neurology, Neurosurgery, and Psychiatry. Analyzing six years of dietary data and cognitive assessments of 3,718 older adults, the study’s authors found that niacin intake appeared to protect against the development of Alzheimer’s disease. In addition, higher food intake of niacin was associated with a slower rate of cognitive decline.

Diabetes

A number of studies show that niacin may benefit people with diabetes. In a 2000 study from the Journal of the American Medical Association, for instance, researchers found that niacin helped protect against the low levels of HDL cholesterol that typically accompany diabetes. Although the study also found that niacin led to modest increases in blood sugar levels, the authors conclude that “niacin can be safely used in patients with diabetes.”

Other Benefits 

Although preliminary research suggests that niacin may help reduce pain in people with osteoarthritis and aid in the treatment of cataracts, more studies need to be conducted before niacin can be recommended for either condition.

Sources 

Niacin is found in many foods, including:

  • dairy products
  • eggs
  • fish
  • lean meats
  • legumes
  • nuts
  • poultry

In addition, niacin can be found in enriched bread and cereals.

Caveats

While niacin is likely safe for most people, the NIH cautions that niacin may trigger certain side effects (including burning, tingling, itching, and reddening of the skin). In some cases, niacin may also cause headache, stomach upset, dizziness, and gas.

Additionally, niacin supplements may be harmful to people with certain health conditions (including liver disease, kidney disease, gallbladder disease, and ulcers) and people taking certain medications (including blood pressure drugs, anti-diabetes drugs, and statins).

Given these health concerns, it’s important to seek medical advice if you’re considering the use of niacin supplements.

Using It for Health

If you’re considering using niacin, talk to your doctor first. Keep in mind that alternative medicine should not be used as a substitute for standard care. Self-treating a condition and avoiding or delaying standard care may have serious consequences.

Where to Find Them

Widely available for purchase online, niacin supplements are also available in most drugstores, grocery stores, and stores specializing in dietary supplements.

90,000 Niacin for people with and without cardiovascular disease

Review question

We reviewed the evidence for the effectiveness of niacin in preventing death and cardiovascular disease.

Relevance

Myocardial infarction and stroke are the most common causes of death, morbidity, disability and reduced quality of life in developed countries.

Niacin (nicotinic acid, vitamin B3) has been considered as a cardiovascular prevention agent because it is known to lower blood cholesterol, a major risk factor.Thus, it was assumed that long-term use of niacin can reduce the risk of myocardial infarction and stroke. We have evaluated the benefits of niacin in clinical trials.

Research characteristics

We found 23 studies involving 39,195 people. They compared niacin to placebo. The evidence is current to August 2016. Most of the participants averaged 65 years of age, and many had suffered myocardial infarction.Participants took niacin or a placebo for periods ranging from six months to five years. Seventeen of the 23 studies were funded in whole or in part by drug manufacturers who had a commercial interest in the research results.

Highlights

The use of niacin did not lead to a decrease in the number of deaths, myocardial infarctions or strokes. Many people (18%) were forced to stop taking niacin due to side effects.The results did not differ between participants who had myocardial infarction before taking niacin and those who did not have myocardial infarction before. There was no difference in results between participants who took statins (other medicines to prevent heart attacks and strokes) and did not take them. The overall quality of the evidence ranged from moderate to high.

Thus, we did not find any evidence of benefit from taking niacin.

Focus on niacin | DSD de Luxe Treatment and cosmetic line for hair and scalp

Author:
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TO.MD, endocrinologist, dermatologist, trichologist (Moscow)
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Certified IAT course instructor.

History of the discovery of niacin

In 1867, scientist Huber oxidized nicotine with chromic acid and obtained an unknown early substance. Six years later, the scientist Weidel obtained the same substance in a different way, also oxidizing nicotine, but this time with nitric acid.He also assigned the name to this substance – nicotinic acid.

But neither Huber nor Weidel knew anything about the biological role of the substance they discovered.

At the same time, in many regions of the world, especially in those where food was mainly limited to corn, epidemics of a serious disease – pellagra – raged.

The classic name of pellagra – “disease of three D” – diarrhea, dermatitis, dementia (in English literature sometimes add the fourth “D” – death, from the English.Death).

The disease usually begins in the spring or summer. On areas of the skin not covered with clothing (the back of the hands and feet, wrist, neck, face), somewhat less often – on the chest, forearms, legs, rashes appear in the form of erythema of various shades (the color of smoked meat, dark brown, raspberry, dark -red).

Most patients with pellagra (78%) are characterized by a decrease in the intensity of sweating, dry rough skin. Large blisters (pemphigus pellagrosus) appear on the dorsum of the hands and feet in more than 10% of cases.The defeat of the pellagra in the neck area was called “Casal’s collar”. In most cases, before the appearance of skin lesions on the mucous membrane of the mouth and tongue, aphthae occurs. There is a burning sensation and dryness in the mouth. The tongue becomes crimson-red, often longitudinal and transverse deepened grooves (“checkerboard”) tongue are formed on it. Gustatory sensations disappear in patients. Along with this, there is flatulence, diarrhea; often – severe salivation. Hair loss is a common symptom of pellagra.Damage to the nervous system is manifested by such disorders as severe weakness, dizziness, convulsions, visual impairment, anorexia, stomach pain, neurological and mental disorders, paralysis of the limbs, confusion, depression (up to suicidal attempts), dementia. Loud music, bright light, rich colors irritate the sick. Usually, within 4-5 years if untreated, the disease ends with the death of the patient.

Pellagra is still common in South America and Africa, but it can be found everywhere, especially among chronic alcoholics.

American professor Joseph Goldberger (Goldberger) in 1916 decided to establish whether pellagra is an infectious disease, or it belongs to vitamin deficiency. To do this, Goldberger and fifteen of his colleagues put the experience on themselves. They took material from patients with pellagra – blood, discharge from the nose and mouth, skin scales – and mixed it with their food for a month. None of the doctors fell ill with pellagra, which refuted the opinion about its infectious nature. In addition, Goldberger ran a series of experiments on 11 healthy volunteers and discovered that he could induce pellagra by altering their diet.He concluded that this disease is caused by the absence of a certain substance that is not found in corn, but is present in meat and milk. Even without knowing this substance, it has already been given the name – factor PP – “pellagra-preventing factor” (preventing pellagra).


Patients with pellagra

The knowledge was not cheap: Goldberger suffered from dengue yellow fever during his life and almost died of typhus. Ultimately, Goldberger was nominated for the Nobel Prize.It was only in 1937 that the mysterious “pellagra-preventing factor” was found to be nicotinic acid by the American biochemist Konrad Arnold Elvehjem. Elvehiem caused the development of black tongue in dogs by feeding them the Goldberger diet and then treating the disease with niacin. He also isolated the PP factor from active liver extracts, showing that this factor is niacin.

In 1938, in the USSR, pellagra was already successfully treated with nicotinic acid.

Later, the name “nicotinic acid” was replaced by “niacin” in order to eliminate confusion with nicotine. Niacin is also known as vitamin B3, as it was the third most water-soluble vitamin identified.

Thus, the names – vitamin PP, niacin, nicotinic acid, vitamin B3 – belong to one substance. But this “multifaceted” vitamin has one more feature – it is … not a vitamin. Unlike B vitamins, it can be produced in the body from tryptophan, has a chemical formula characteristic of an amino acid, and is metabolized in quantities more characteristic of amino acids.Thus, it would be more correct to classify vitamin B3 as an amino acid.

Biological Effects of Niacin

The range of action of niacin is too wide. It participates in the metabolism of proteins, carbohydrates, lipids, has hypotensive, antianemic, anti-sclerotic, vasodilating action. The processes of glucose metabolism, amino acids, biosynthesis of fatty acids, prostaglandins, steroids are associated with vitamin PP. The possibility of synthesizing niacin from the amino acid tryptophan has been established, which, therefore, along with vitamin PP, is a precursor of NAD (P) -coenzymes.NAD reduced is a component of the mitochondrial respiratory chain with the highest negative potential. The oxidation of reduced NAD is accompanied by the release of energy, which is cumulated in the form of a high-energy chemical bond of ATP.

It has now become apparent that the various physiological effects of niacin are realized through interaction with hormones of the pituitary-adrenal system.

An important practical property of nicotinic acid is the ability to dilate blood vessels, influence blood microcirculation, and coagulation processes are obviously carried out by activating the kinin system – biologically active peptides.

Currently, the anti-lipidemic effect of nicotinic acid has been proven. Nicotinamide, a metabolite of nicotinic acid, has similar functions, but unlike nicotinic acid, it has no pharmacological significance in lowering lipid levels. In 1955, it was noted that nicotinic acid lowers the level of total cholesterol and low-density lipoprotein cholesterol (LDL-C), increases the level of high-density lipoprotein cholesterol (HDL-C) [Altschuletal.1955]. Relatively small doses of niacin (1.5-2.0 g per day) cause a significant increase in HDL cholesterol (by about 15-40%), making it the most effective drug for raising “good cholesterol” levels. In contrast, at least 3.0–4.5 g / day of niacin is needed to lower LDL levels by about 15% [Knopp, 1999]. In addition, nicotinic acid was shown to reduce serum triglycerides by 20-50% and lipoprotein (a) by about 20% [Carlson et al.1989]. Recently it was found that it is able to activate the GPR109A (G-protein – coupled receptor), located on the membranes of adipose tissue cells (adipocytes), thereby causing a sharp restriction of the release of free fatty acids from these cells into the blood.

Since the GPR109A receptor is found not only in adipose cells, but also in some other tissues, in particular, in immune cells (neutrophils and monocyte macrophages), its activation by niacin leads to a decrease in the intensity of inflammation.The fact that immune cells (macrophages) play an important role in the formation of the atherosclerotic process, and nicotinic acid affects their activity, easily explains the sharp decrease in the rate of formation of atherosclerotic plaques on the walls of blood vessels under the influence of niacin. It is suggested that in high doses, niacin may help cure or prevent ulcerative colitis, colorectal cancer, Crohn’s disease, and familial adenomatous polyposis.

By acting on the HM74A receptor, niacin induces the release of prostaglandin D2 (PGD2) and has a vasodilating effect when administered in high doses, which is noticeable by reddening of the skin.Flash (flash – vasodilation) develops within 20 minutes after oral administration and lasts about 20-60 minutes. A small proportion of people experience a “hot flush” as a result of taking 25 mg, most from 50 mg and most from 100 mg. The flash begins in the forehead and travels down the body, rarely reaching the toes. The higher the initial dose, the more pronounced the initial hyperemia. The capillaries expand and blood flow through the organs increases. The blood flow increases, including in the skin. Patients should be warned in advance of the possibility of a vascular reaction.Low-dose niacin is recommended until redness occurs. Then the dose of niacin can be gradually increased. With each dose, the reaction is repeated to a much lesser extent. If niacin is not taken for more than a day, the flush returns, but when niacin is resumed, it will not be as intense as the initial flush. Since the production of prostaglandins requires the activity of the enzymes cyclooxygenase (COX), the production of prostaglandins from niacin may be partially reduced due to the effects of COX inhibitors such as aspirin.Drugs that block cyclooxygenase or the DP1 receptor can help avoid a pronounced vasodilator effect.

Nicotinic acid stimulates the release of histamine, which leads to increased gastric motility and increased production of hydrochloric acid.

There are many reports in the literature on the hepatotoxicity of niacin. Here is what they write about this in the widely known book Niacin: The Real Story by famous scientists and doctors who have devoted decades of research on the effects of niacin – Abram Hoffer, Andrew W.Saul, Harold D. Foster: “An observation that is still controversial is that niacin increases liver function tests in some patients. It is mistakenly believed that an increase in liver function tests (ALS, AST) indicates that this organ is affected by a certain painful process. The Mayo Clinic used electron microscopy to examine the livers of their niacin-treated patients undergoing treatment for dyslipidemia. They found no evidence of pathology.This was reported by Dr.William Parsons. Parsons emphasizes that elevated liver enzymes are not indicative of liver disease. In most patients with elevated liver function tests, values ​​return to normal within a few days, even if niaicin has not been withdrawn. More than 40 years ago, there were reports of liver damage from taking niacin and / or niacinamide. It has now become apparent that these events were associated with the intake of substandard sustained-release forms of modified niacin.This information had nothing to do with standard niacin. I (Harold D. Foster) have used niacin in daily dosages of 2000-3000 mg to lower cholesterol and treat schizophrenic patients since 1953 – have cured thousands of people. Only one patient who cured schizophrenia with niacin developed jaundice. When niacin was stopped, the illness disappeared, but schizophrenia returned. As soon as the niacin supplementation was continued, the schizophrenia disappeared again and the jaundice did not recur. I have not seen any cases of jaundice in the past 20 years.But there is a possibility that liver function test results may be elevated as a result of methyl depletion. According to Dr. David Capuzzi, a diabetes, metabolic and endocrinologist based in Philadelphia and one of the leading experts on niacin and cholesterol, the problem can be solved before it occurs by giving 2,400 milligrams of lecithin twice a day. Betaine can also help. ”

Chronic high-dose niacin use is known to decrease insulin sensitivity, but its intake has not been associated with a marked change in blood glucose levels.This can be explained by a compensatory increase in insulin production, as a result of which the blood glucose level remained practically unchanged. Activation of the niacin receptor (HM73A) by some other agonists appears to rapidly lower blood glucose levels in diabetics, restoring insulin sensitivity or improving glucose uptake rates. This indicates that niacin receptors themselves may have beneficial effects on glucose metabolism, and niacin-induced insulin resistance is not enhanced by HM74A activation.Although chronic high-dose niacin use decreases insulin sensitivity, compensatory increases in insulin levels keep glucose levels virtually unchanged in healthy individuals.

Abram Hoffer testifies that an increase in glucose, even if it occurs, is insignificant and does not worsen the health of patients: “I found that in 1/3 of my patients with diabetes mellitus there was a need for a slight increase in insulin, in 1/3 there was a need for it. lowering, the rest did not require any changes. “

Adequate cellular levels of NAD are important for the activation of stress-responsive proteins, including the p53 protein, which helps to suppress the development of tumors in response to DNA damage. The relationship between changes in the cellular level of NAD and the response to genotoxic stress with the use of niacin suggests a possible role in the prevention of cancer. Most of this evidence comes from in vitro and animal studies. So more research is needed to understand the relevance of the data obtained.

Effects of niacin on skin

The 2013 study included 60 women with acne. The participants were divided into two groups. The first group used the nicotinamide gel, the second – the clindamycin gel for 8 weeks. In both groups, by the end of the study, there was a marked improvement, while there was no statistically significant difference between the two groups. In another study by Seiberg M et al. evaluated the effect of 5% niacinamide cream on rosacea.The results indicated significant suppression of acne after 12 weeks of treatment, although there was no improvement in the first 4-8 weeks.

Osborne R et al. in 2013, it was found that the use of a complex containing niacinamide made it possible to significantly increase the total content of NAD levels in skin fibroblasts of adults. And mild wrinkles (“crow’s feet”) are reduced with the use of 5% niacinamide face cream. At the same time, after 4 weeks of applying the cream, the effect is not yet noticeable, but by the 8th week it becomes significant.The use of 5% niacinamide cream for 12 weeks also improves skin elasticity compared to placebo control.

Nicotinamide can help lighten the skin while having a local anti-inflammatory effect. While niacin causes redness by acting on the HM74A receptor, nicotinamide does not activate this receptor and does not cause skin redness. Japanese researchers led by Hakozaki T concluded that applying 5% niacinamide cream to the face of women with brown skin pigmentation caused a reduction in hyperpigmentation after just 4 weeks.In women who visually appeared tanned, 2% niacinamide cream also showed a skin lightening effect.

Effects of niacin on hair

Niacin stimulates the release of prostaglandin D2 (PGD2). Although it is known that PGD2 receptors are involved in the development of male pattern baldness, long-term practical experience with the use of niacin and nicotinamide in trichology indicates its extremely positive effect on hair growth.

It should be noted that niacin and its compounds are capable of penetrating hair follicles when applied topically.In a study by Davis et al. a mixture of caffeine, nicotinamide, panthenol, dimethicone was applied externally. The study of hair thickness using laser scanning micrometry showed a significant increase in hair diameter.

In 2005, a pilot, double-blind, placebo-controlled study of the effect of topically applied nicotinic acid derivatives in female androgenetic alopecia was carried out. 40 women applied the active drug, 20 women received placebo. The first group showed a statistically significant improvement.

A common “folk” recipe for improving hair growth is the external use of nicotinic acid, sold in ampoules and intended for injection. But since this remedy does not meet the necessary requirements for external use, many are faced with side effects, the most frequent of which are: itching, dandruff, dry skin and other manifestations of dermatitis.

It is obvious that the presence of nicotinic acid in modern specialized complex preparations for stimulating hair growth remains a relevant solution.

  1. acobson EL1, Shieh WM, Huang AC. Mapping the role of NAD metabolism in prevention and treatment of carcinogenesis. Mol Cell Biochem. (1999).
  2. J Res Med Sci. 2013 Feb; 18 (2): 115-7.Comparison of topical 5% nicotinamid gel versus 2% clindamycin gel in the treatment of the mild-moderate acne vulgaris: A double-blinded randomized clinical trial. Shahmoradi Z 1 , Iraji F, Siadat AH, Ghorbaini A.
  3. Seiberg M1, et al.Inhibition of melanosome transfer results in skin lightening. J Invest Dermatol 2000.
  4. Osborne R1, et al. Practical application of cellular bioenergetics to the care of aged skin. Br J Dermatol. (2013).
  5. Hakozaki T1, et al. The effect of niacinamide on reducing cutaneous pigmentation and suppression of melanosome transfer. Br J Dermatol. (2002)
  6. Davis MG, et al. A novel cosmetic approach to treat thinning hair.Br J Dermatol (2011)
  7. J Cosmet Dermatol. 2005 Dec; 4 (4): 258-61. A pilot study evaluating the efficacy of topically applied niacin derivatives for treatment of female pattern alopecia. Draelos ZD, Jacobson EL, Kim H, Kim M, Jacobson MK.

THE FULL TEXT OF THE ARTICLE IS AVAILABLE IN
JOURNAL TRICHOLOGY (No. 2, 2015)


DSD de Luxe preparations containing niacin and other nicotinic acid derivatives:

Fresh Cells DeLuxe Concentrate 3.4.3 B (maximum content)

Dixidox DeLuxe Forte Lotion 3.4

Krexepil DeLuxe forte lotion 3.4.1

90,000 Vitamin B3 – nicotinamide, plasma (Vitamin PP, niacin, Vitamin B3 – Nicotinamide, Niacinamide, plasma)

Method of determination
HPLC-MS (high performance liquid chromatography with mass selective detection).

Study material
Blood plasma (EDTA)

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Synonyms: Nicotinic acid; Vitamin PP; Antipellagric factor; 3-pyridinecarboxylic acid.

Niacin; Vitamin B3; Nicotinicacid; Vitamin PP; Pyridine-3-carboxylicacid; 3-pyridinecarboxylicacid; Apelagrin; Pellagrin.

Brief characteristics of the analyte Vitamin B3 – nicotinamide

Vitamin B3 includes two main forms – nicotinamide and nicotinic acid. In the course of metabolic processes in the body, they are converted into nicotinamide adenine dinucleotide (NAD, nicotinamide adenine dinucleotide – NAD) and nicotinamide adenine dinucleotide phosphate (NADP, nicotinamide adenine dinucleotide phosphate – NADP) – coenzymes of many oxidative-reduction metabolism important for the cell.

Nicotinamide is important for the development and functioning of the central nervous system (CNS). Nicotinamide is thought to play an important role in neuronal protection against traumatic injury, ischemia, and stroke, and may be involved in the pathogenesis of the three most common neurodegenerative conditions: Alzheimer’s, Parkinson’s, and Huntington’s. A key factor in this is the bioavailability of nicotinamide, a low concentration of which can lead to neurological deficits and dementia, and a high concentration – to potential neurotoxicity.B3 deficiency in its classic form is pellagra, and one of the common names for this vitamin “PP” comes from pellagra prevention. Clinical manifestations of this disease include bilateral symmetrical dermatitis in areas of the skin exposed to sunlight; extensive inflammation of the mucous membranes, manifested by diarrhea, achlorhydria, glossitis, stomatitis, vaginitis; mental manifestations, including fatigue, insomnia, apathy, in severe cases – encephalopathy with disorientation, hallucinations, memory loss, psychosis and dementia.

The main food sources of vitamin B3 are foods containing yeast, lean meat, liver, poultry meat. Smaller amounts of this vitamin (but sufficient to avoid deficiency) are found in milk, various green leafy vegetables, and canned salmon. In some plant foods, especially cereals (corn, wheat), niacin is bound to peptides and sugars and is less readily available for absorption. Up to two-thirds of the required amount of vitamin B3 in adults can be formed in the body itself through the metabolism of tryptophan.

Nutritional deficiency of B3 is associated with a shortage of protein foods and is rarely observed in developed countries; it can more often occur when maize (maize) predominates in the diet, which is poor in both niacin and tryptophan. Pellagra can sometimes be a secondary manifestation of carcinoid syndrome, in which up to 60% of tryptophan is catabolized to 5-OH-tryptophan and serotonin; and Hartnup’s disease, a genetic disorder accompanied by malabsorption of amino acids, including tryptophan.

Alcoholism and the effect of certain medications can lead to vitamin deficiency.A complicating factor may be the deficiency of vitamins B2, B6 and iron, which are involved in the conversion of tryptophan to niacin.

What is the purpose of determining the level of vitamin B3 in the blood

The test is used to assess the status of vitamin B3 in the body.

Vitamin B3 preparations are used in medical practice, including nicotinamide, in the treatment of pellagra, carcinoid syndrome, Hartnup’s disease, nicotinic acid – in lipid-lowering therapy, using the spectrum of its effects on lipid metabolism.Although the intake of vitamin B3 in its natural form with food is not associated with any toxic effects, however, pharmacological doses of niacin can have side effects. More often it is manifested by redness and tingling sensation of the face, hands, chest. Other possible side effects of the use of high doses of niacin are itching, gastritis, sometimes hepatotoxicity, deterioration of carbohydrate metabolism, increased uric acid levels, which limits the use of this drug.

Literature

Main literature:

  1. Litvitsky P.F. Vitamin metabolism disorders. Questions of modern pediatrics. 2014; 13 (4): 40-47.
  2. Tietz Clinical Guide on Laboratory Tests. 4th ed. (ed. by Alan G.B. Wu). – M .: Ed. “Labo”. 2013: 1279.
  3. Fricker R.A., Green E.L., Jenkins S.I., Griffin S.M. The Influence of Nicotinamide on Health and Disease in the Central Nervous System.International Journal of Tryptophan Research. 2018; 11: 1178646918776658. doi: 10.1177 / 1178646918776658. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5966847/
  4. Johnson L.E. Niacin (Nicotinic Acid). In: MSD Manual Professional Version. www.msdmanuals.com
  5. Tietz Textbook of Clinical Chemictry and Molecular Diagnostics (Ed. Burtis C. A., Ashwood E. R., Bruns D. E.), 5th ed., Elseivier. 2012: 2238.

90,000 Niacin, or Vitamin B3 | Tervisliku toitumise informatsioon

Niacin is the general name for nicotinic acid, nicotinamide and its derivatives, which are manifested in the biological activity of nicotinamine.

Ready-made niacin is found in foods such as meat, fish and legumes, and in the body it can be synthesized from the amino acid tryptophan, which is found in proteins. Therefore, the recommended daily dose is expressed in milligram equivalent.

Niacin is needed:
  • for the metabolism of fats and carbohydrates, as well as for the synthesis of proteins,
  • for the functioning of the nervous and muscular systems, for the correct formation and maintenance of tissues of the skin, tongue and digestive tract, as well as for improving the scar tissue of the skin,
  • to improve the circulation of cholesterol in the body and to lower the level of cholesterol and triglycerides in the blood,
  • for the “respiration” of cells,
  • for the prevention of pellagra.

Signs of a niacin deficiency can include skin damage, diarrhea and other digestive problems, and general fatigue. With prolonged niacin deficiency, pellagra (rough skin) may develop. Niacin deficiency does not occur with normal and varied mixed diets.

The synthetic form of niacin, nicotinamide, can cause depression in some people. It is also known that liver damage can occur if the daily dosage is exceeded. Therefore, it should only be taken under medical supervision as a dietary supplement.

The best sources of niacin are nuts, seeds, poultry, yeast, pork and beef, Kama flour, eggs, whole grain rice, fish, cottage cheese, and cottage cheese.

Recommended daily intake of 15-18 mg of niacin is provided by the following products:
  • 90 g of peanuts,
  • 100 g of heat-treated liver,
  • 100 g of canned tuna or heat-treated poultry meat,
  • 260 g of Kama flour ,
  • 300 g cheese,
  • 350 g whole grain bread,
  • 550 g (10 pcs.) boiled eggs.

Clinical Study Mitochondrial Myopathies: Niacin – Clinical Research Registry

Executive Summary

The most common form of mitochondrial disorder in adults is mitochondrial myopathy, often manifested by progressive external ophthalmoplegia (PEO), progressive muscle weakness and exercise intolerance. Mitochondrial myopathy is often caused by single deletions of heteroplasmic mitochondrial DNA (mtDNA) or multiple deletions of mtDNA, the former being sporadic and the latter caused by mutations in nuclear-encoded mtDNA proteins.maintenance. There is currently no cure for this disease. However, the NAD + precursor of vitamin B3 has been shown to empower diseased mitochondria in animal studies by increasing intracellular levels of NAD +, an important cofactor required for cellular energy metabolism. Vitamin B3 comes in several forms: nicotinic acid (niacin), nicotinamide, and nicotinamide riboside. Nicotinamide riboside has been shown to prevent and improve disease symptoms in several mouse models of mitochondrial myopathy.In addition, researchers have previously observed that treatment with another form of vitamin B3, niacin, improved NAD + deficiency and muscle activity in patients with mitochondrial myopathy.

In this study, a form of vitamin B3, niacin, is used to activate dysfunctional mitochondria. and to address the signs of mitochondrial myopathy in early-stage patients. The vitamin B3 form is niacin, because it has been used in high doses to treat patients with hypercholesterolemia and has proven to be safe in humans.Phenotypically similar patients with mitochondrial myopathy are being studied, as previous experience of the researcher indicates that similar phenotypes presented predict uniform physiological and clinical manifestations. responses to interventions despite different genetic origins. Patients with mitochondrial myopathy usually have a sporadic deletion of a single mtDNA or a mutation in the nuclear mtDNA serving gene that causes multiple deletions of mtDNA. In addition, data from healthy controls from the primary NiaMIT study (ID ClinicalTrials.gov: NCT03973203) are used to analyze the collected data. Clinical examinations and muscle biopsy collection are performed at 0 and 10 months. Fasting blood samples are collected every second week for up to 1.5 months, every fourth week for up to 4 months, and thereafter every six weeks until the end of the study. The effects of niacin on disease markers, muscle mitochondrial biogenesis, muscle strength, and whole body metabolism are being studied in patients and healthy individuals.

The hypothesis is that the precursor of NAD +, niacin, increases intracellular levels of NAD +, improves mitochondrial biogenesis, and already alleviates the symptoms of mitochondrial myopathy in the early stages of the disease.

Intervention

Intervention type:

Food supplement

Intervention name:
Niacin

Description:

The dosage for the slow-release form of niacin will be 500-1000 mg / day. The daily niacin dose of 250 mg / day is gradually increased by 250 mg / month, so that the full dose is reached after 2 months. The intervention time with a full dose of niacin is 8 months, followed by a total intervention time of 10 months.

Arm Group label:

Niacin in patients with early mitochondrial myopathy

Another name:

A nicotinic acid

Eligibility

Criteria:

Inclusion criteria:

1.Early stage genetically diagnosed mitochondrial myopathy without any other serious symptoms or manifestations caused by single or multiple deletions of mtDNA

2. Agreed to avoid vitamin supplements or foods with forms of vitamin B3. 14 days before enrollment and during training

3. Written informed consent to participate in the study.

Exclusion Criterion:

1. Failure to follow the study protocol.

2. Pregnancy or breastfeeding at any stage of the study.

3. Malignant neoplasm requiring constant treatment.

4. Unstable heart disease.

5. Severe kidney disease requiring treatment.

6. Severe encephalopathy.

7. Regular use of intoxicants.

Floor:

Everything

Minimum age:

17 years

Maximum age:

There is no data

Healthy volunteers:

Not

References

problendo Endocrinology Problems 0375-96602308-1430 Endocrinology Research Center 10.14341 / probl11329Research Article Niacin status of the organism in experimental diabetes mellitus; Influence of protein level in the diet 150219944014143

Niacin (vitamin PP) is an unusual vitamin because it can be synthesized in the body from tryptophan, and thus is not a strictly necessary component of the diet.The conversion of tryptophan to niacin, which is important in a healthy body, can be impaired in pathological conditions. It has been established that in diabetes mellitus, the activity of many enzymes of tryptophan metabolism changes, resulting in a decrease in the conversion of this amino acid into niacin and, accordingly, in a decrease in the excretion of 1-methylnicotinamide, a product of niacin metabolism. At the same time, numerous studies indicate that this vitamin and its coenzyme forms play an important role in the onset and progression of insulin-dependent diabetes mellitus.The diabetogenic effect of streptozotocin is etiologically associated with a decrease in the level of NADPH in cells. Niacin deficiency increases the sensitivity to the action of streptozotocin, and the administration of nicotinamide both before and after the administration of streptozotocin gives a protective effect against its damaging action, restores the activity of enzymes of tryptophan metabolism along the niacin pathway to a level characteristic of healthy animals. Nicotinamide is used as a hypolipidemic and sugar-reducing agent in the treatment of patients with diabetes mellitus.

In recent years, there have been reports of an effective protective effect of a high-protein diet in the development of streptozotocin diabetes in rats, but its mechanism remains unclear. Since dietary protein can serve as a source of niacin, we hypothesized that one of the mechanisms of the protective effect of a high-protein diet could be realized precisely through the synthesis of niacin from dietary protein. This work is devoted to testing this assumption.

DiabetesMellitusThe conversion of tryptophan to niacin, which is important in a healthy body, can be impaired in pathological conditions. It has been established that diabetes mellitus changes the activity of many enzymes of tryptophan metabolism, which results in a decrease in the conversion of this amino acid into niacin [9, 11, 13] and, accordingly, in a decrease in the excretion of 1-methylnicotinamide, a product of niacin metabolism [1, 2]. At the same time, numerous studies indicate that this vitamin and its coenzyme forms play an important role in the onset and progression of insulin-dependent diabetes mellitus.The diabetogenic effect of streptozotocin is etiologically associated with a decrease in the level of NADPH in cells [4, 7, 12]. Niacin deficiency increases the sensitivity to the action of streptozotocin [14], and the introduction of nicotinamide both before and after the administration of streptozotocin gives a protective effect against its damaging action [4, 8], restores the activity of enzymes of tryptophan metabolism along the niacin pathway to a level characteristic of healthy animals [13]. Nicotinamide is used as a hypolipidemic and sugar-reducing agent in the treatment of patients with diabetes mellitus [1, 2].

In recent years, there have been reports of the effective protective effect of a high-protein diet in the development of streptozotocin diabetes in rats [5, 6], but its mechanism remains unclear. Since dietary protein can serve as a source of niacin, we assumed that

Table 1

Influence of nicotinamide and protein level in the diet on the course of alloxan diabetes in rats (M ± m, n = 5)

that one of the mechanisms of the protective action of high-protein diet can be realized precisely by synthesizing niacin from dietary protein.This work is devoted to testing this assumption.

Materials and Methods

Male Wistar rats with an initial body weight of about 160 g were used in the experiment; they received the diet of the vivarium of the Institute of Nutrition of the Russian Academy of Medical Sciences for 7 days.

Experiment 1. Alloxan diabetes. After the adaptation period, the animals were transferred to semisynthetic isocaloric diets with different contents of protein, fat, and carbohydrates. At the same time, the content of a mixture of minerals (0.8 g / day), a mixture of water-soluble vitamins (0.2 g / day), choline chloride (0.04 g / day), vitamin A (300 IU / day) and vitamin D (20 IU / day) remained the same.The diet of the 1st group of animals contained 9% casein, the 2nd-4th groups – 18%, the 5th and 6th groups – 50%.

Alloxan (“Spofa”, CSFR) was simultaneously injected subcutaneously in all animals at a dose of 200 mg per 1 kg of body weight.

14 days after the administration of alloxan, the animals of the 3rd group began daily subcutaneous injections of insulin at a dose of 20 IU per 1 kg of body weight, the animals of the 4th and 6th groups were daily subcutaneously injected with a solution of nicotinamide at a dose of 300-400 mg per 1 kg of body weight.

On the 28th day, the animals were decapitated.

Experiment 2. Streptozotocin diabetes mellitus was induced by double intraperitoneal administration of streptozotocin (Serva, Germany) in 0.1 M citrate buffer pH 4.5 at a dose of 60 and 30 mg per 1 kg of body weight with an interval of 3 days. After 7 days, the animals were determined by the glucose content in the blood and urine. The experiment included animals in which the blood glucose level exceeded 15 mmol / L and glucosuria was found.

The animals were divided into 2 groups, which received for 28 days a semi-synthetic isocaloric diet containing a full set of vitamins and minerals, with different amounts of proteins, fats and carbohydrates.The protein component was represented by animal proteins casein and milk whey protein concentrate (CSB-UV) in a 2: 1 ratio. The lipid component was represented by corn and sunflower oil (1: 1). The animals received corn starch as a carbohydrate component.

Animals of the 1st group (control) received a balanced diet containing (in g per 100 g of diet) protein – 17.8, vegetable oil – 24.2, starch – 57.5. Animals of the 2nd group received a diet (in g per 100 g), containing protein – 50, vegetable oil – 14.2, starch – 35.8.After 14 days. feeding animals with diets with varying amounts of protein, they were placed in metabolic cages to collect urine, depriving them of food and providing water without restriction. 1-Methylnicotinamide in urine was determined by the fluorescence method [3].

On the 35th day after the administration of streptozotocin, the animals were decapitated and the content of nicotinamide coenzymes in the liver was determined [3]. In the blood serum of rats, insulin was determined by radioimmunoassay (set “Ria-ins-12’ I-M ”, produced by the Institute of Bioorganic Chemistry of the Academy of Sciences of Belarus), glucose by glucose oxidase, radioimmunoassay methods, tryptophan and serotonin using high performance liquid chromatography (4 |.0.05) decrease in glycemia by 33% (Table 1). Nicotinamide had the same pronounced sugar-lowering effect (lowering glycemia by 35%) with a protein content in the diet of 18% (group 4). An increase in the protein content in the diet to 50% and a corresponding increase in the tryptophan content in the diet from 2.5 to 7 g per 1 kg of diet at the recommended intake for rats of 1.3-1.4 g / kg (4) also led to a decrease in glucose levels in the blood by 35%, which is comparable to the effect of insulin and nicotinamide.At the same time, the concentration of tryptophan in the blood did not increase compared to that in animals receiving 18% protein, and the concentration of serotonin, a product of the oxidative metabolism of tryptophan along the serotonin pathway, even significantly decreased ( cm.tab. one). If, nevertheless, we assume that an increase in the protein level in the diet of rats leads to an intensification of the metabolism of tryptophan along the niacin pathway, then this should be accompanied by an increase in the content of nicotinamide coenzymes in the body, since it is known that an increase in the content of tryptophan in the diet is accompanied by the induction of tryptophan dioxygenase, an enzyme that limits the rate of niacin the pathways of tryptophan oxidation, and almost linear

Table 2

Metabolic parameters of tryptophan and vitamin PP in rats with streptozotocin diabetes mellitus with different protein content in the diet (Af ± m, l = 4-6)

by an increase in the amount of NADP in the liver , heart and spleen (10].This was confirmed in experiment 2 with streptozotocin diabetes. With a constant concentration of tryptophan and serotonin in the blood plasma, the content of oxidized and reduced nicotinamide coenzymes in the liver of rats with experimental diabetes fed a diet with an increased protein quota, as follows from Table. 2 did tend to increase compared to animals fed a diet with optimal protein levels. The excretion of 1-methylnicotinamide, the end product of tryptophan metabolism by the niacin pathway, also tended to increase.

Thus, these data support the above assumption about the intensification of endogenous synthesis of niacin from dietary protein.

Another argument in favor of this assumption may be the lack of additivity of the effects of increased levels of protein in the diet and nicotinamide when used together (see Table 1). The decrease in blood glucose levels in this case is 28% and thus does not exceed the effect of exposure to nicotinamide (by 22%) or increased protein levels (by 42%) (groups 4, 5, 6).This can be regarded as evidence that the mechanism of action of nicotinamide and an increased level of protein in the diet is the same, i.e., the sugar-lowering effect of an increased protein quota is realized through endogenous synthesis of nicotinamide from tryptophan. Otherwise, the effects of nicotinamide and increased protein levels would have to add up.

Conclusions

References Zelinsky B. A., Zelinsky S. U … Goncharov L. I., Vernigorodsky V. S. // Endocrinology. Kiev, 1981. Vol. 11, – S.19-22. Podorozhniy P. G., Berezin P. K- // Actual problems of physiology, biochemistry and pathology of the endocrine system. – M., 1972. Theoretical and clinical aspects of nutritional science, – M., 1987. – T. 8 Bender DA, Bender AE // Nutr. Abstr. Rev. Ser. A. – 1986, – Vol. 56, – ​​P. 695-719. Eizirik D. L., Boschero A. C., Migliorini R. H. // Brazilian J. med. biol. Res. – 1985, – Vol. 18, P. 233-235. Eizirik D. L., Germane C. M., Migliorini R. H. // Acta diabetol. lat. – 1988, – Vol. 25, – P. 117-126. Ho Ch.-K., Hashim S.11 Diabetes. 1972. Vol. 21. P. 789-793. Masiello P., Bergamini E. // Experientia. 1977. Vol. 33. — P. 1246-1247. McDaniel E. G. Hundley J. M., Sebrell W. H. 11 J. Nutr.— i966. — Vol. 59, P. 407-423. Powanda M. C., Wannemacher R. W. // Ibid. 1970. Vol. 100, P. 1471-1478 Sanada H., Miyazaki M., Takahashi T. // J. Nutr. Sci. Vitam. 1980, Vol. 26, P. 449-459, Schein P., Loftus S. // Cancer Res. 1968. Vol. 28. – P. 1501 – 1506.Shibata K. // Agricut. biol. Chem. 1987. Vol. 51. — P. 811-816. Wright J.R., Mendola J. Lacy P. E. // Experientia. – 1988, – Vol. 44, – P. 38.90 000 Niacin – Niacin – qaz.wiki

organic compound and form of vitamin B3

This article is about the nutrient. For the neo-fusion group, see Niacin (group).

Niacin
Names
Pronunciation aɪ ə c ɪ n /
Preferred IUPAC name

Pyridine-3-carboxylic acid

Other names

  • Nicotinic acid (INN)
  • Bionic
  • Vitamin B 3
  • Vitamin PP
Identifiers
3D model (JSmol)
3DMet
109591
CHEBI
CHAMBL
ChemSpider
DrugBank
ECHA InfoCard 100.000.401
EU number
3340
KEGG
MeSH Niacin
RTECS number
UNII
  • InChI = 1S / C6H5NO2 / c8-6 (9) 5-2-1-3-7-4-5 / h2-4H, (H, 8.9) Y
    Key: PVNIIMVLHYAWGP-UHFFFAOYSA-N Y
  • InChI = 1 / C6H5NO2 / c8-6 (9) 5-2-1-3-7-4-5 / h2-4H, (H, 8.9)

    Key: PVNIIMVLHYAWGP-UHFFFAOYAA

Specifications
C 6 H 5 N O 2
Molar mass 123.111 g mol -1
Appearance White translucent crystals
Density 1.473 g cm −3
Melting temperature 237 ° C; 458 ° F; 510 C
18 g l -1
magazine P 0.219
Acidity (p K a ) 2.0, 4.85
Isoelectric point 4.75
1.4936
0.1271305813 D
Thermochemistry
-344.9 kJ mol −1
−2.73083 MJ mol −1
Pharmacology
C04AC01 (WHO) C10BA01 (WHO) C10AD02 (WHO) C10AD52 (WHO)
License data
Intramuscularly, inside
Pharmacokinetics:
20–45 min.
Hazards
GHS pictograms
Signal word GHS Warning
h419
P264 , P280 , P305 + 351 + 338 , P337 + 313 , P501
NFPA 704 (fire diamond)
Flash point 193 ° C (379 ° F; 466 K)
365 ° C (689 ° F; 638 K)
Y check (what is there?)
Y N
Links to infoboxes

Chemical compound

Niacin , also known as nicotinic acid , is an organic compound and form of vitamin B 3 , an essential nutrient for humans.Plants and animals can produce it from the amino acid tryptophan. Niacin is found in diets from a variety of whole and processed foods, with most in fortified packaged foods, meat, poultry, red fish such as tuna and salmon, and lower in nuts, legumes, and seeds. Niacin is a dietary supplement used to treat pellagra, a disease caused by niacin deficiency. Signs and symptoms of pellagra include skin and mouth lesions, anemia, headaches, and fatigue.Many countries require it to be added to wheat flour or other grains, thereby reducing the risk of pellagra.

The amide derivative of nicotinamide (niacinamide) is a component of the coenzymes nicotinamide adenine dinucleotide (NAD) and nicotinamide adenine dinucleotide phosphate (NADP +). Although niacin and nicotinamide (niacinamide) are identical in their vitamin activity, nicotinamide does not have the same pharmacological, lipid-modifying effects or side effects as niacin, that is, when niacin is taken from the -amide group, it does not lower cholesterol and does not causes flushing.Nicotinamide is recommended for treating niacin deficiency because it can be administered in therapeutic amounts without causing hot flashes, which is considered a side effect.

Niacin is also available as a prescription. Amounts far in excess of the recommended dietary intake for vitamin functions will lower blood triglycerides and low-density lipoprotein cholesterol (LDL-C) and raise blood high-density lipoprotein cholesterol (HDL-C, often called “good” cholesterol).There are two forms of niacin: immediate release and sustained release. Initial prescription doses are 500 mg / day, which are increased over time until a therapeutic effect is achieved. Immediate-release doses can be as high as 3000 mg / day; sustained release up to 2000 mg / day. Despite the proven lipid changes, niacin has not been shown to be beneficial in reducing the risk of cardiovascular disease in those already on statins.A 2010 review concluded that niacin is effective as monotherapy, but a 2017 review of twice as many trials concluded that prescription niacin, while affecting lipid levels, does not reduce mortality from all causes, cardiovascular mortality, myocardial infarction and is not fatal. or non-fatal strokes. Prescription niacin has been shown to cause hepatotoxicity and increase the risk of type 2 diabetes.Niacin prescriptions in the United States peaked at 9.4 million in 2009, and had dropped to 1.3 million by 2017.

Niacin has the formula C
6 HOUR
5 NO
2 and belongs to the pyridinecarboxylic acid group. As a precursor for nicotinamide adenine dinucleotide (NAD) and nicotinamide adenine dinucleotide phosphate (NADP), niacin is involved in DNA repair.

Definition

Niacin is at the same time a vitamin, i.e.E. An essential nutrient sold as a dietary supplement and a prescription drug in the United States. As a vitamin, it is a precursor of the coenzymes nicotinamide adenine dinucleotide (NAD) and nicotinamide adenine dinucleotide phosphate (NADP). These compounds are coenzymes of many dehydrogenases involved in many hydrogen transfer processes. NAD plays an important role in the catabolism of fats, carbohydrates, proteins and alcohol, as well as in cellular signaling and DNA repair, while NADP is mainly involved in anabolic reactions such as the synthesis of fatty acids and cholesterol.The vitamin intake recommendations made by several countries are that doses of 14–18 mg / day are sufficient to meet the needs of healthy adults. Niacin or nicotinamide (niacinamide) is used to prevent and treat pellagra, a condition caused by vitamin deficiency. When niacin is used as a medicine to treat high cholesterol and triglycerides, daily doses range from 500 to 3000 mg / day. Nicotinamide in high doses does not have this therapeutic effect.

Vitamin deficiency

A man with pellagra caused by a chronic lack of vitamin B 3 in the diet.

Severe dietary niacin deficiency causes pellagra, characterized by diarrhea, sun-sensitive dermatitis accompanied by hyperpigmentation and thickening of the skin (see image), inflammation of the mouth and tongue, delirium, dementia and, if left untreated, death. Common psychiatric symptoms include irritability, poor concentration, anxiety, fatigue, memory loss, anxiety, apathy, and depression.The biochemical mechanism (s) of the observed deficiency-induced neurodegeneration is not well understood, but may be based on: A) the need for nicotinamide adenine dinucleotide (NAD +) to suppress the formation of neurotoxic tryptophan metabolites, B) inhibition of mitochondrial ATP generation, resulting in cell damage; C) activation of the poly (ADP-ribose) polymerase (PARP) pathway, since PARP is a nuclear enzyme involved in DNA repair, but in the absence of NAD + can lead to cell death; D) decreased synthesis of neuroprotective neurotrophic factor of the brain or its receptor kinase B, tropomyosin receptor; or E) altering genome expression directly due to niacin deficiency.

Niacin deficiency is rare in developed countries and is more commonly associated with poverty, malnutrition or malnutrition secondary to chronic alcoholism. It also tends to occur in less developed regions where people eat corn (maize) as their staple food, as corn is the only grain low in digestible niacin. A cooking technique called nyxtamalization, or pretreatment with alkaline ingredients, increases the bioavailability of niacin in corn flour / flour production.For this reason, people who eat corn tortillas or rootlets have a lower risk of niacin deficiency.

For the treatment of deficiency, the World Health Organization (WHO) recommends prescribing niacinamide instead of niacin to avoid the redness side effect commonly caused by niacin. The guidelines suggest using 300 mg / day for three to four weeks. Dementia and dermatitis improve within a week. Because deficiencies in other B vitamins may be present, WHO recommends taking a multivitamin in addition to niacinamide.

Hartnup’s disease is an inherited nutritional disorder resulting in niacin deficiency. It is named after an English family with a genetic disorder that resulted in an inability to metabolize the essential amino acid tryptophan, which is a precursor to niacin synthesis. Symptoms are similar to pellagra, including a red scaly rash and sensitivity to sunlight. Oral niacin or niacinamide is prescribed to treat the condition in doses of 50 to 100 mg twice daily with a good prognosis if identified and treated early.Niacin synthesis is also insufficient in carcinoid syndrome due to a metabolic abnormality of its precursor tryptophan to produce serotonin.

Measurement of vitamin status

Plasma concentrations of niacin and niacin metabolites are not useful markers of niacin status. Urinary excretion of the methylated metabolite N1-methylnicotinamide is considered reliable and sensitive. A 24-hour urine collection is required for measurement. For adults, a value of less than 5.8 μmol / day corresponds to a niacin deficiency, and a value of 5.8 to 17.5 μmol / day corresponds to a low level.According to the World Health Organization, an alternative means of expressing N1-methylnicotinamide in urine is the concentration of creatinine in mg / g in a 24-hour urine collection, while the deficit is defined as <0.5, low 0.5-1.59, acceptable 1, 6-4.29 and high> 4.3 Niacin deficiency occurs before signs and symptoms of pellagra appear. Erythrocyte nicotinamide adenine dinucleotide (NAD) concentrations are potentially another sensitive indicator of niacin depletion, although definitions of “insufficient”, “low” and “adequate” have not been established.Finally, plasma tryptophan levels decrease with a low niacin diet as tryptophan is converted to niacin. However, low tryptophan levels can also be caused by a diet low in this essential amino acid, so it is not specific for confirmation of vitamin status.

Diet Guidelines

Dietary Advice

90,838 RDI for Niacin (mg NE / day)

Australia and New Zealand
Age group Upper reception level
Infants 0-6 months 2 mg / day of pre-prepared niacin * ND
Infants 7-12 months 4 mg / day NE *
1-3 6 10
4-8 8 15
9-13 12 20
14-18 30
19+ 35 year
Women 14+ 14
Men 14+ 16
Pregnant women aged 14-50 18
Pregnant women aged 14-18 30
Pregnant women 19-50 years old 35 year
Breastfeeding females 14-50 years old 17
Breastfeeding females 14-18 years old 30
Breastfeeding females 19-50 years old 35 year
* Adequate intake for infants
Canada
Age group (years) Recommended Daily Allowance for Niacin (mg NE / day) Allowable upper consumption level
0-6 months 2 mg / day of pre-prepared niacin * ND
7-12 months 4 mg / day NE *
1-3 6 10
4-8 8 15
9-13 12 20
Women aged 14-18 14 30
Men 14-18 years old 16
Women 19+ 14 35 year
Men 19+ 16
Pregnant women <18 years old 18 30
Pregnant women 18-50 years old 18 35 year
Breastfeeding females <18 years old 17 30
Breastfeeding females 18-50 years old 17 35 year
European Food Safety Agency
Floor Adequate intake (mg N.e. / MJ)
Females 1.3
Males 1.6
Age (years) Tolerable upper limit of niacin (mg / day) Tolerable upper limit of nicotinamide (mg / day)
1-3 2 150
4-6 3 220
7-10 4 350
11-14 6 500
15-17 8 700
United States
Age group Recommended Daily Allowance for Niacin (mg NE / day) Allowable upper consumption level
Infants 0-6 months 2 * ND **
Infants 6-12 months 4 *
1-3 6 10
4-8 8 15
9-13 12 20
Women aged 14-18 14 30
Men 14-18 years old 16 30
Women 19+ 14 35 year
Men 19+ 16 35 year
Pregnant women aged 14-18 18 30
Pregnant women 19-50 years old 18 35 year
Breastfeeding females 14-18 years old 17 30
Breastfeeding females 19-50 years old 17 35 year
* Adequate intake for babies, as RDA has not yet been established
** Unable to establish; the source of intake should be only mixture and food

The US Institute of Medicine (renamed National Academy of Medicine in 2015) updated the Estimated Average Requirements (EAR) and Recommended Dietary Allowances (RDA) for niacin in 1998, as well as Tolerable Upper Intake Levels (UL).Instead of RDA, Adequate Intake (AIs) is defined for populations for which there is insufficient evidence to determine a dietary intake level sufficient to meet the nutritional needs of most people. (see table).

The European Food Safety Authority (EFSA) refers to a collective set of information as Dietary Reference Values ​​(DRV), with a Population Reference Intake (PRI) instead of RDA, and Average Demand instead of EAR.For the EU, AI and UL have the same definition as in the US, except that the units are milligrams per megajoule (MJ) of energy consumed, not mg / day. For women (including pregnant and lactating women), men and children, the PRI is 1.6 mg per megajoule. Since the conversion is 1 MJ = 239 kcal, an adult consuming 2390 kcal should consume 16 mg of niacin. This compares to the US RDA (14 mg / day for adult women, 16 mg / day for adult men).

UL

is established by determining the amount of vitamins and minerals that cause adverse effects and then selecting the upper limit of the amount that is “the maximum daily intake that is unlikely to cause adverse health effects.” Regulators from different countries do not always agree. In the US: 30 or 35 mg for teens and adults, less for children. The UL EFSA for adults is set at 10 mg / day, which is about one-third of that in the US.For all UL government officials, this term applies to niacin as a supplement consumed in a single dose and is intended as a limit to avoid a flushing reaction. This explains why the Recommended Daily Intake for EFSA may be higher than the UL.

Both DRI and DRV describe the amounts required as niacin equivalents (NE), calculated as 1 mg NE = 1 mg niacin or 60 mg tryptophan essential amino acid. This is because the amino acid is used to synthesize the vitamin.

For US food and supplement labeling purposes, the amount per serving is expressed as a percentage of the Daily Value (% DV). For labeling purposes, niacin 100% DV is 16 mg. Until May 27, 2016, it was 20 mg, revised to align with the RDA. Compliance with the updated labeling rules was required by January 1, 2020 for manufacturers with annual food sales of USD 10 million or more, and by January 1, 2021, for manufacturers with lower food sales volumes.A table of old and new daily values ​​for adults is given in the section “Reference daily intake”.

Sources

Niacin is found in a variety of whole and processed foods, including fortified packaged foods, meats from a variety of animal sources, seafood, and spices. In general, animal products contain about 5-10 mg of niacin per serving, although dairy and eggs are low.Some plant foods, such as nuts and grains, contain about 2-5 mg of niacin per serving, although this naturally occurring niacin is heavily bound to polysaccharides and glycopeptides, making it only about 30% bioavailable. Fortified food ingredients like wheat flour contain niacin, which is bioavailable. Whole foods with the highest niacin content per 100 grams are:

Source Amount
(mg / 100 g)
Beef, depending on which part, how it is cooked 4-8
Pork, depending on which part, how it is cooked 4-8
Sunflower seeds 7.0
Tuna, white, canned 5.8
Almond 3.6
White mushrooms 3.6
Cod 2.5
Rice, brown 2.5
Hot Dogs 2.0
Source Amount
(mg / 100 g)
Avocado 1.7
Baked potatoes with skin 1.four
Corn (corn) 1.0
Rice, white 0.5
Cabbage 0.4
Eggs 0.1
Milk 0.1
Cheese 0.1
Tofu 0.1

Vegetarian and vegan diets can provide adequate amounts if foods such as nutritional yeast, peanuts, peanut butter, tahini, brown rice, mushrooms, avocados, and sunflower seeds are included.Fortified foods and nutritional supplements can also be consumed to ensure adequate intake.

Cooking

Niacin, naturally found in food, is susceptible to degradation during frying, especially in the presence of sour foods and sauces. It is soluble in water, so it can also be removed from products cooked in water.

Food fortification

Countries are fortifying food with nutrients to address known deficiencies.As of 2020, 54 countries required wheat flour fortification with niacin or niacinamide; 14 also require corn meal fortification and 6 require rice fortification. In different countries, niacin fortification ranges from 1.3 to 6.0 mg / 100 g.

As a dietary supplement

In the United States, niacin is sold as an over-the-counter nutritional supplement in amounts ranging from 100 to 1000 mg per serving. These products often carry an FDA-cleared health statement.An example would be “Maintains a healthy blood lipid profile.” The American Heart Association strongly discourages substituting niacin for a prescription drug with niacin because of the potentially serious side effects, which means that niacin should only be used under the supervision of a healthcare professional, and because the production of niacin in dietary supplements is not necessary. is well regulated by the FDA as a prescription niacin. Consuming more than 30 mg of niacin as a dietary supplement may cause skin redness.The skin of the face, hands and chest becomes reddish due to the expansion of small subcutaneous blood vessels, accompanied by a sensation of warmth, tingling and itching. These signs and symptoms are usually temporary and last from a few minutes to hours; they are considered unpleasant rather than poisonous.

As a lipid-modifying drug

In the United States, prescription immediate and slow release niacin is used to treat primary hyperlipidemia and hypertriglyceridemia.It is used either as monotherapy or in combination with other lipid-modifying drugs. Dosages start at 500 mg / day and are often gradually increased to 3000 mg / day for immediate release or 2000 mg / day for slow release (also called sustained release) to achieve targeted lipid changes (lowering LDL-C). and triglycerides, and higher HDL-C). Prescriptions peaked in the United States in 2009, when it was 9.4 million, and by 2017 it had dropped to 1.3 million.At the end of 2017, Avondale, having bought the rights to Niakor from Upsher Smith, raised the price of the drug by more than 800%.

Systematic reviews found no effect of prescription niacin on all-cause mortality, cardiovascular mortality, myocardial infarction, or fatal or non-fatal strokes despite elevated HDL cholesterol. Reported side effects include an increased risk of new-onset type 2 diabetes.

Mechanisms

Niacin reduces the synthesis of low-density lipoprotein cholesterol (LDL-C), very low-density lipoprotein cholesterol (VLDL-C), lipoproteins (a) and triglycerides, and also increases high-density lipoprotein cholesterol (HDL-C).The lipid-therapeutic effects of niacin are mediated in part by the activation of G-protein coupled receptors, including the hydroxycarboxylic acid receptor 2 (HCA 2 ) and the hydroxycarboxylic acid receptor 3 (HCA 3 ), which are highly expressed in body adipose tissue. HCA 2 and HCA 3 inhibit the production of cyclic adenosine monophosphate (cAMP) and thus suppress the release of free fatty acids (FFA) from fatty deposits, reducing their availability to the liver for synthesis of the considered lipids circulating in the blood.A decrease in the amount of free fatty acids also suppresses the expression in the liver of apolipoprotein C3 and coactivator-1b PPARg, thereby increasing VLDL-C turnover and decreasing its production. Niacin also directly inhibits the action of diacylglycerol-O-acyltransferase 2 (DGAT2), a key enzyme in triglyceride synthesis.

The mechanism underlying niacin, which increases HDL-C levels, is not fully understood, but appears to be different. Niacin increases levels of apolipoprotein A1 by inhibiting the breakdown of this protein, which is a component of HDL cholesterol.It also inhibits the uptake of HDL-C by the liver by suppressing the production of the cholesterol ester transfer protein (CETP) gene. It stimulates the ABCA1 transporter in monocytes and macrophages and activates the gamma receptor, which is activated by the peroxisome proliferator, resulting in reverse cholesterol transport.

In combination with statins

Sustained release niacin was combined with lovastatin, trade name Advicor, and simvastatin, trade name Simcor, as prescription drug combinations.Advicor was approved by the US Food and Drug Administration (FDA) in 2001. Simcor was approved in 2008. Subsequently, large outcome studies using these therapies with niacin and statins have failed to demonstrate an additional benefit of niacin compared to statin-only therapy. The FDA withdrew approval for both drugs in 2016. Reason given: “Based on the collective evidence from several large studies of cardiovascular outcomes, the Agency concluded that the body of scientific evidence no longer supports the conclusion that drug-induced reductions in triglyceride levels and / or increased HDL cholesterol levels in patients on statins. lead to a decrease in the risk of cardiovascular events ”.The pharmaceutical company has stopped taking drugs.

Contraindications.

Immediate-release niacin (Niacor) and extended-release niacin (Niaspan) is contraindicated in people with active or history of liver disease because both, but especially Niaspan, have been associated with cases of severe, sometimes fatal, liver failure. Both products are contraindicated in people with pre-existing peptic ulcers or other bleeding problems, as niacin lowers platelet count and prevents blood from clotting.Both products are also contraindicated in women who are pregnant or planning to become pregnant, as safety during pregnancy has not been evaluated in human trials. These foods are contraindicated in breastfeeding women because niacin is known to be excreted in breast milk, but the number and likelihood of side effects in a nursing infant is unknown. Women are advised to either not breastfeed or stop taking the drug. High-dose niacin has not been tested or approved for use in children under 16 years of age.

Side effects

The most common side effects of medicinal niacin (500-3000 mg) are redness (eg, warmth, redness, itching, or tingling) of the face, neck and chest, headache, abdominal pain, diarrhea, dyspepsia, nausea, vomiting, rhinitis, skin itching and rash. They can be minimized by starting therapy with low doses, gradually increasing the dose, and avoiding fasting.

Acute side effects of high-dose niacin therapy (1-3 grams per day), which is commonly used in the treatment of hyperlipidemias, may also include hypotension, fatigue, glucose intolerance and insulin resistance, heartburn, blurred or impaired vision, and macular edema.With long-term use, side effects of high-dose niacin therapy (750 mg daily) also include liver failure (associated with fatigue, nausea, and loss of appetite), hepatitis, and acute liver failure; These hepatotoxic effects of niacin are more likely to occur with sustained release dosage forms. Long-term use of nicotinic acid at greater than or equal to 2 g per day also significantly increases the risk of cerebral hemorrhage, ischemic stroke, gastrointestinal ulceration and bleeding, diabetes, dyspepsia and diarrhea.

Flushing

Hot flashes – a short-term expansion of the arterioles of the skin causing a reddish color of the skin – usually lasts 15 to 30 minutes, although it can sometimes persist for several weeks. The face is usually affected, but the reaction can spread to the neck and upper chest. The reason is the expansion of blood vessels due to an increase in the level of prostaglandin GD 2 (PGD2) and serotonin. Hot flashes were often thought to be histamine-related, but histamine has not been shown to be involved in the response.Redness is sometimes accompanied by a tingling or itching sensation, especially in areas covered by clothing.

To prevent hyperemia, it is necessary to change or block the pathway mediated by prostaglandins. Aspirin, taken half an hour before niacin, prevents redness, just like ibuprofen. Taking niacin with meals can also help reduce this side effect. Acquired tolerance will also help reduce flushing; after a few weeks of taking a constant dose, most people no longer have hot flashes.To reduce these side effects, slow or “sustained” release forms of niacin have been developed.

Liver damage

Niacin at drug doses may cause moderate elevations in serum transaminase and unconjugated bilirubin, both biomarkers of liver damage. The increase usually goes away even with continued medication. Less commonly, however, the sustained-release form of the drug can lead to severe hepatotoxicity, which manifests itself within days or weeks.Early symptoms of severe liver damage include nausea, vomiting, and abdominal pain, followed by jaundice and itching. The mechanism is thought to be the direct toxicity of elevated serum niacin levels. Reducing the dose or switching to an immediate-release form may resolve symptoms. In rare cases, the injury is severe and progresses to liver failure.

Diabetes mellitus

High doses of niacin, used to treat hyperlipidemia, have been shown to increase fasting blood glucose levels in people with type 2 diabetes.Long-term niacin therapy has also been associated with an increased risk of new-onset type 2 diabetes.

Other side effects

High doses of niacin can also cause niacin maculopathy, macular and retinal thickening, resulting in blurred vision and blindness. This maculopathy is reversible after discontinuation of niacin. Niaspan, a slow-release product, was associated with a decrease in platelet count and a moderate increase in prothrombin time.

Pharmacology

Pharmacodynamics

Niacin and nicotinamide are converted to the coenzyme NAD. NAD is converted to NADP by phosphorylation in the presence of the enzyme NAD + kinase. NAD and NADP are coenzymes for many dehydrogenases involved in many hydrogen transfer processes. NAD plays an important role in the catabolism of fats, carbohydrates, proteins and alcohol, as well as in cellular signaling and DNA repair, while NADP is mainly involved in anabolic reactions such as the synthesis of fatty acids and cholesterol.Organs with high energy requirements (brain) or high turnover rates (intestines, skin) are usually most susceptible to energy deficiencies.

Activation of HCA 2 has other effects besides lowering serum cholesterol and triglyceride concentrations: antioxidant, anti-inflammatory, antithrombotic, improvement of endothelial function and plaque stability, all this counteracts the development and progression of atherosclerosis.

Niacin inhibits the cytochrome P450 enzymes CYP2E1, CYP2D6 and CYP3A4.Niacin causes an increase in serum unconjugated bilirubin levels in normal people and in people with Gilbert’s syndrome. However, in Gilbert syndrome, the increase in bilirubin levels is higher and its clearance is delayed longer than in normal people. One test used to diagnose Gilbert’s syndrome involves intravenous administration of nicotinic acid (niacin) at a dose of 50 mg over 30 seconds.

Pharmacokinetics.

Both niacin and niacinamide are rapidly absorbed from the stomach and small intestine.The absorption is facilitated by sodium-dependent diffusion, and at higher consumption, by passive diffusion. Unlike some other vitamins, the percentage of absorption does not decrease with increasing dose, so that even with an amount of 3-4 grams, absorption is almost complete. At a dose of one gram, peak plasma concentrations of 15 to 30 μg / ml are reached within 30-60 minutes. Approximately 88% of an oral pharmacological dose is excreted by the kidneys as unchanged niacin or nicotinuric acid, its main metabolite.The plasma half-life of niacin is 20 to 45 minutes.

Niacinamide is the main form in the bloodstream. In the liver, niacinamide is converted to the storage nicotinamide adenine dinucleotide (NAD). If necessary, NAD is hydrolyzed in the liver to niacinamide and niacin for transport to tissues, where it is converted back to NAD to serve as a cofactor for the enzyme. Excess niacin is methylated in the liver to N 1 -methylnicotinamide (NMN) and is excreted in the urine as such or as an oxidized metabolite N 1 -methyl-2-pyridone-5-carboxamide (2-pyridone).Decreased urinary levels of these metabolites are indicative of niacin deficiency.

Production

Biosynthesis

In addition to absorbing niacin from food, niacin can be synthesized from the essential amino acid tryptophan in a five-step process, the penultimate compound of which is quinolinic acid (see figure). Some bacteria and plants use aspartic acid in a pathway that also converts to quinolinic acid.For humans, conversion efficiency is estimated as the need for 60 mg of tryptophan to produce 1 mg of niacin. This requires riboflavin, vitamin B 6 and iron. Pellagra is a consequence of a corn-dominated diet because the niacin in corn is poorly bioavailable and corn proteins are low in tryptophan compared to wheat and rice proteins.

Industrial synthesis

Nicotinonitrile is obtained by ammoxidation of 3-methylpyridine.The nitrile hydratase is then used to convert nicotinonitrile to nicotinamide, which can be converted to niacin. Alternatively, ammonia, acetic acid, and paraldehyde are used to produce 5-ethyl-2-methylpyridine, which is then oxidized to niacin.

Industrial demand includes animal feed and food fortification for human consumption. According to Ullmann’s Encyclopedia of Industrial Chemistry, in 2014, 31,000 tons of nicotinamide were sold worldwide.

Chemistry

This colorless, water-soluble solid is a pyridine derivative with a carboxyl group (COOH) at the 3-position. Other forms of vitamin B 3 include the corresponding nicotinamide amide (niacinamide) in which the carboxyl group has been replaced by a carboxamide group (CONH
2 ).

Preparations

Niacin is found in a multivitamin and is sold as a one-component dietary supplement.The latter can be immediate or slow release.

Nicotinamide (niacinamide) is used to treat niacin deficiency because it does not cause the hot flush side effects seen with niacin. Nicotinamide can be toxic to the liver at doses exceeding 3 g / day for adults.

Prescription drugs can be immediate release (Niacor, 500 mg tablets) or extended release (Niaspan, 500 and 1000 mg tablets).Niaspan has a film coating that delays the release of niacin, resulting in absorption within 8-12 hours. This reduces vasodilation and the side effects of hot flashes, but increases the risk of hepatotoxicity compared to immediate-release drugs.

Niacin in combination with statins (discontinued) is described above. The combination of niacin and laropiprant was approved for use in Europe and marketed as Tredaptive. Laropiprant is a prostaglandin D2 binding drug that has been shown to reduce niacin-induced vasodilation and the side effects of hot flushes.A clinical trial showed no additional efficacy of Tredaptive in lowering cholesterol when used with other statins, but did show an increase in other side effects. The research resulted in the withdrawal of Tredaptive from the international market.

One form of dietary supplement sold in the United States is inositol hexanicotinate (IHN), also called inositol nicotinate. It is inositol that is esterified with niacin at all six alcohol groups of inositol.IHN is commonly sold as “no wash” or “no wash” niacin in units of 250, 500, or 1000 mg / tablet or capsule. It is marketed as an over-the-counter drug in the US and is often marketed and labeled as niacin, which misleads consumers into thinking they are receiving the active form of the drug. While this form of niacin does not cause the redness associated with immediate-release products, there is insufficient evidence to recommend an IHN for the treatment of hyperlipidemia.

History

Niacin was first described as a chemical compound by chemist Hugo Weidel in 1873 in his research on nicotine, but this predates the concept of food components other than proteins, fats and carbohydrates, which are essential for life for many years.The original nomenclature of vitamins was alphabetical, and Elmer McCollum called these fat-soluble A and water-soluble B. Over time, eight chemically different water-soluble B vitamins were isolated and numbered, with niacin designated as vitamin B 3 .

Corn (corn) has become a staple food in the southeastern United States and parts of Europe. The disease, which was characterized by dermatitis of the skin exposed to sunlight, was described in Spain in 1735 by Gaspar Casal.He attributed the reason to poor nutrition. In northern Italy it was named “pellagra” from the Lombard language ( Agra = holly-like or whey-like; Pella = leather). Over time, the disease was more closely related to corn. In the United States, Joseph Goldberger was assigned to study pellagra by the United States Surgeon General. His research confirmed the corn diet was the culprit, but he did not identify the root cause.

Nicotinic acid was extracted from the liver by biochemist Konrad Elvehj in 1937.He later identified the active ingredient as “pellagra prevention factor” and “anti-black tongue factor.” It was also called “PP vitamin”, “PP vitamin” and “PP factor”, all of which are derived from the term “pellagra prevention factor.” In the late 1930s, research by Tom Douglas Spice, Marion Blankenhorn, and Clark Cooper confirmed that niacin cured pellagra in humans. As a result, the prevalence of the disease has decreased significantly.

In 1942, when the fortification of flour with nicotinic acid began, the headline in the popular press read “Tobacco in Your Bread.”In response, the Food and Nutrition Board of the American Medical Association approved the Food and Nutrition Board’s new names niacin and niacin amide primarily for use by non-scientists. It was considered appropriate to choose a name to separate nicotinic acid from nicotine in order to avoid the perception that vitamins or niacin-rich foods contain nicotine or that cigarettes contain vitamins. As a result, the name niacin was derived from ni cotinic ac id + Vitam to .In 1951, Carpenter discovered that niacin in corn was biologically unavailable and could only be released in highly alkaline lime water at pH 11. This explains why a Latin American culture that used alkaline corn flour to make tortilla was not at risk of niacin contamination. deficit.

In 1955, Altshul and colleagues described large amounts of niacin as having lipid-lowering properties. Thus, niacin is the oldest known lipid-lowering agent.Lovastatin, the first statin drug, first hit the market in 1987.

Explore

In animal models and in vitro , niacin has a marked anti-inflammatory effect in a variety of tissues, including the brain, gastrointestinal tract, skin and vascular tissue, by activating the hydroxycarboxylic acid 2 (HCA2) receptor, also known as the niacin receptor. 1 (NIACR1). Unlike niacin, nicotinamide does not activate NIACR1; however, both niacin and nicotinamide activate the G protein coupled estrogen receptor (GPER) in vitro .

References

external links

  • Niacin.