Vitamin D and Calcium | Johns Hopkins Medicine

What are Vitamin D and Calcium?

Vitamin D (a hormone) and calcium (a mineral) are nutrients that sustain healthy bones. They are also needed for:

• Muscle movement

• Nerve communication

• Absorption of calcium and phosphorous (vitamin D)

• Immune system responses (vitamin D)

• Signaling between cells (calcium)

• Hormonal secretion (calcium)

• Blood vessel flow (calcium)

Without enough vitamin D or calcium, your parathyroid glands compensate by producing too much of their hormone, a condition called hyperparathyroidism. That can lead to bone weakening (osteoporosis) and increased fracture risk.
Other problems from calcium and vitamin D deficiencies include:

Given the crucial role of both nutrients in bone health, The Endocrine Society and the Institute of Medicine recommend certain consumption levels based on age and health. They have not yet found, however, that taking vitamin D provides cardiovascular protection.

How Much Vitamin D and Calcium Do You Need?

The Endocrine Society and The Institute of Medicine have suggested recommended daily allowances (RDA) for vitamin D and calcium, as well as maximum daily consumption amounts that you should not exceed for your safety:

The recommendations come with two precautions:

How Do You Get Vitamin D and Calcium?

Your body makes Vitamin D when your skin is exposed to sun, but several factors limit its creation:

• Aging, which changes absorption ability

• The amount of sun you would need to achieve normal blood vitamin D levels is probably more than is safe for your skin, so most people may need supplements to achieve a normal vitamin D level.

Either form of vitamin D (D2 or D3) benefits the body, but very few foods naturally contain the nutrient or are fortified with it. That’s why doctors recommend supplements to make up the difference. Foods containing vitamin D include:

• Cod liver oil: 400-1,000 IU per teaspoon

• Wild caught salmon: 600-1,000 IU per 3.5 oz

• Farmed salmon: 100-250 IU per 3.5 oz

• Canned salmon: 300-600 IU per 3.5 oz

• Canned sardines: 300 IU per 3.5 oz

• Canned mackerel: 250 IU per 3.5 oz

• Canned tuna: 236 IU per 3.5 oz

• Fresh shitake mushrooms: 100 IU per 3.5 oz

• Sundried shitake mushrooms: 1,600 IU per 3.5 oz

• Egg yolk: 20 IU per yolk

Milk, orange juice, infant formula, yogurt, margarine, butter, cheese and breakfast cereals are often fortified with vitamin D.

Calcium is found in:

Vitamin D Deficiency

A lack of vitamin D can cause serious problems, and doctors typically prescribe larger doses for 6-8 weeks to those with a diagnosed deficiency. Patients should make sure their labs are following Endocrine Society and Institute of Medicine thresholds when getting tested.

Neither group recommends universal screening for a vitamin D deficiency. Certain medical conditions, ethnicities and medications put people at risk and make them candidates for testing:

• Hyperparathyroidism

• Some lymphomas

What roles do calcium and vitamin D play in the body?

Calcium is an essential nutrient needed by all living creatures, including humans. Vitamin D is a prohormone that helps the body absorb calcium, which is essential for bone health.

Bones and teeth contain 99% of the body’s calcium.

Many different foods contain calcium. Manufacturers may also fortify certain food products with calcium and vitamin D. Getting enough sunlight is the best way to help the body create vitamin D.

This article looks at the roles of calcium and vitamin D and their benefits. It also looks at the effects of too much or too little calcium or vitamin D. Finally, it identifies dietary sources of calcium and vitamin D and supplementation options.

Calcium is crucial for bone development and growth in children. It is also responsible for the maintenance of strong bones in adults.

As well as its role in bone health, calcium aids in muscle contraction. When a signal arrives at the muscle, calcium is released, helping the muscle to contract. As calcium leaves the muscle, the muscle relaxes.

Calcium also plays a role in effective blood clotting.

According to the National Institutes of Health (NIH), the recommended daily amount of calcium by age group is:

• 0–6 months: 200 milligrams (mg)
• 7–12 months: 260 mg
• 1–3 years: 700 mg
• 4–8 years: 1,000 mg
• 9–18 years: 1,300 mg
• 19–70 years: 1,000 mg (1,200 mg for women 51–70 years)
• over 70 years: 1,200 mg

Research suggests that vitamin D also plays a vital role in bone health, as it regulates calcium in the blood. Without vitamin D, the kidneys would excrete too much calcium.

There is growing interest in the role of vitamin D in reducing allergic response and protecting against certain cancers, including colorectal and breast cancer.

Vitamin D also plays an important role in:

• supporting lung function and good cardiovascular health
• insulin regulation and glucose metabolism
• brain, immune, and nervous system health

According to the NIH, the recommended daily amount of vitamin D by age group is:

• 0–12 months: 10 micrograms (mcg), or 400 international units (IU)
• 1–13 years: 15 mcg (600 IU)
• 14–18 years: 15 mcg (600 IU)
• 19–70 years: 15 mcg (600 IU)
• over 70 years: 20 mcg (800 IU)
• pregnant and breastfeeding women: 15 mcg (600 IU)

As well as its crucial role in bone health, calcium may also reduce the risks associated with high blood pressure.

A 2019 article in the journal Nutrients suggests that calcium may help lower blood pressure. Another study from 2020, involving 136,249 participants, suggests that calcium has a protective effect against colorectal cancer. However, research on this is still in the early stages.

Appropriate levels of calcium and vitamin D can also support a healthy pregnancy. A recent review shows an association between higher vitamin D levels and lower risk of preeclampsia and premature birth.

Due to its role in insulin regulation and glucose metabolism, vitamin D can support effective diabetes management.

Too much calcium may cause constipation. High levels of calcium can also interfere with iron and zinc absorption.

High calcium levels rarely come from dietary sources. They are most likely due to excessive supplementation.

High levels of calcium from supplementation may increase a person’s risk of kidney stones.

Some studies show a link between high levels of calcium and increased risk of heart disease, but others found no association.

Some studies also show that high levels of calcium may increase prostate cancer risk.

Too little calcium in the body is known as hypocalcemia. Over time, a calcium deficiency may result in the following symptoms:

• muscle aches, pains, and cramps
• tingling or numbness in the hands, arms, legs, feet, and around the mouth
• fatigue
• insomnia
• brain fog
• dry skin, nails, and hair
• alopecia
• skin conditions such as eczema and psoriasis
• severe PMS
• dental problems
• depression

Those most at risk from low levels of calcium include:

• post-menopausal people
• people of childbearing age with amenorrhea
• people who do not consume dairy products, such as vegans or ovo-vegetarians
• people with lactose intolerance who avoid dairy

Long-term deficiency in calcium or vitamin D can result in osteoporosis, where the bones become more fragile and prone to breaking.

Some studies show a link between increased risk of depression and low levels of vitamin D. However, there is no evidence to show vitamin D supplementation prevents depression or reduces its symptoms.

People at higher risk of low levels of vitamin D include:

• breastfed infants
• people who rarely expose their skin to the sun
• people with darker skin tones
• older adults
• people with conditions that limit fat absorption, such as Crohn’s disease
• people with obesity or who have undergone gastric bypass surgery

Too much vitamin D can be harmful. However, a person cannot get too much vitamin D from sunlight, only from excessive supplementation.

High levels of vitamin D may result in:

• nausea
• vomiting
• muscle weakness
• confusion
• pain
• loss of appetite
• dehydration
• excessive urination and thirst
• kidney stones

Extremely high levels of vitamin D can result in kidney failure, irregular heartbeat, and death.

Calcium is present in several foods. Good dietary sources of calcium include:

• dairy products, such as milk, yogurt, and cheese
• fortified dairy alternatives, such as soy milk
• green leafy vegetables, such as kale, Chinese cabbage, and broccoli
• canned sardines and salmon
• tofu
• fortified products, including breakfast cereals and fruit juices
• nuts and seeds
• legumes

Most grain-based foods, such as bread and pasta, are not rich in calcium. However, they can add a large amount of dietary calcium if consumed regularly and in large amounts.

There are limited dietary sources of vitamin D.

Most dietary sources of vitamin D come from fortified foods. Most milk producers in the United States fortify milk with vitamin D. Manufacturers often add vitamin D to plant-based milk, such as soy, almond, or oat milk.

Manufacturers may also add vitamin D to breakfast cereals, orange juice, yogurt, and margarine.

The following foods provide a limited natural source of vitamin D:

• fatty fish, such as trout, salmon, and mackerel
• beef liver
• egg yolks
• cheese
• mushrooms

Calcium and vitamin D supplements are available in tablet, chewable, and liquid forms.

Calcium supplements usually contain either calcium carbonate or calcium citrate. People should take calcium carbonate with food.

People can take calcium citrate with or without food. Those with absorption issues or conditions such as inflammatory bowel disease should choose calcium citrate.

Some people may experience gastrointestinal issues with calcium supplementation. Taking a supplement with meals and spreading the dose throughout the day may help with these issues.

Vitamin D supplements contain either vitamin D2 (ergocalciferol) or vitamin D3 (cholecalciferol). Both forms are effective, though D3 appears to result in higher levels in the blood.

Supplement manufacturers extract D2 from yeast. D3 can come from:

• lanolin, which comes from wool
• fish oil
• algae oil

People following a vegan diet should check the source of supplements containing D3 or choose supplements containing D2. They should consult with a doctor before taking an over-the-counter supplement.

If someone is very low in vitamin D, they may need a clinical-grade prescription.

Calcium and vitamin D play a crucial role in bone health and have several other health benefits.

High levels of calcium and vitamin D in the body are rare and likely to come from excessive supplementation. Calcium and vitamin D deficiencies are more common and can have a negative effect on health, including causing osteoporosis.

There are many dietary sources of calcium. The primary source of vitamin D is sunlight. People can obtain additional calcium and vitamin D from supplements.

How vitamin D and calcium work and why it is better to use them in pairs

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Do not self-medicate! In our articles, we collect the latest scientific data and the opinions of authoritative health experts. But remember: only a doctor can diagnose and prescribe treatment.

Advertisements urge us to buy and drink vitamin D and calcium supplements and assure us that this will solve many health problems. Is this true, or is the general obsession with these elements just the result of successful pharmaceutical marketing? Larisa Gennadievna Bavykina, an endocrinologist and nutritionist, a geneticist at the Atlas Medical Center , answers a controversial question.

What is Vitamin D? Pediatricians at the beginning of the 20th century began to recommend spending at least 15 minutes a day in the sun and consuming cod liver oil regularly.

At the beginning of the 21st century, numerous studies were carried out that contributed to the popularization of vitamin D. Scientists have found that it has an unusual structure for vitamins and affects many processes in the body. In addition, vitamin D is similar to a hormone in that it has receptors in various organs and tissues. For example, in osteoblasts (young bone cells). And vitamin D receptors in the gut help absorb calcium.

The basis of vitamin D is cholesterol, so this vitamin can penetrate into all cells of the body.

Production methods

• Direct sunlight. The arms should be bare to the middle of the shoulder, the face and neck should be open. If these conditions are met for 5-15 minutes 2-3 times a week in the morning or evening, you will provide the body with vitamin D in the summer. But the abuse of sunlight – sunburn – is already harmful to health and increases the risk of skin cancer.
• Vitamin D fortified milk or fish oil. Milk is irradiated on a conveyor belt with an ultraviolet lamp, and a precursor of vitamin D is formed from cholesterol. Fish oil is obtained from cod liver, which is naturally rich in this vitamin.
• Preparations. Aqueous and oil solutions of vitamin D. This is a priority method of obtaining this vitamin in our time in the autumn, winter and spring periods.

Vitamin deficiency

You should not prescribe this vitamin yourself, especially since the symptoms of its deficiency are nonspecific and may indicate other pathologies.

Ask an endocrinologist or general practitioner to prescribe the drug in late summer – early autumn, if possible, take an analysis for vitamin D levels. The doctor will determine what dose of this vitamin to prescribe – preventive or saturating.

In addition, according to recent studies, the absorption of vitamin D is influenced by certain genes, more precisely, the genes “supervise” the work of various enzymes involved in the absorption of vitamin D. Thus, the DHCR7 gene regulates the work of the enzyme 7-dehydrocholesterol reductase, which is necessary for the synthesis vitamin D precursor. The CYP2R1 gene is responsible for liver enzymes involved in vitamin D metabolism. The GC gene regulates the activity of a protein that binds and transports this vitamin and its metabolites in the liver. Because of this complex system, it turns out that people under the same living conditions have different levels of vitamin D, which depends on genetic characteristics.

Vitamin D has a positive effect on the immune system, helps maintain bone density and prevents osteoporosis.

Benefits of calcium

Calcium is involved in a variety of body processes:

• important for bone metabolism;
• supports bone strength;
• helps melatonin formation;
• provides muscle contractions and conduction of nerve impulses.

To prevent calcium deficiency, fermented milk products should be consumed, and products marked “fortified with calcium” are also acceptable. With a lack of calcium, the body “takes” it from the bones, and they become “leaky”, the risk of fractures increases and osteoporosis develops.

Where to look for calcium

Calcium and vitamin D are interconnected: milk and dairy products contain bioavailable calcium, but it is well absorbed only when there is enough vitamin D in the body. Only in commonwealth of these two elements reduce the risk of developing osteoporosis.

Calcium is found not only in dairy products, but also in nuts, nut milk, green vegetables (spinach, broccoli, etc.). The problem is that 100 g of hard cheese contains the same amount of calcium as 1 kg of broccoli and 15 kg of spinach. Therefore, it is easier to get the necessary element from fermented milk products or medicines prescribed by a doctor.

What is vitamin D for

Science has known about vitamin D for a long time, it was discovered back in 1922 by the American scientist McCollum and was initially considered only as a vitamin, but now it is classified as a group of hormone-like substances.

What is vitamin D

Vitamin D is fat-soluble, it is best absorbed with fatty foods and accumulates in adipose tissue. A large amount of vitamin D is found mainly in animal foods: fatty fish (salmon, catfish, mackerel, sardines, tuna), fish caviar, egg yolk and dairy products. Also, a small amount of it is found in red caviar, oysters, wild mushrooms and seeds.

It is unique in that it is the only vitamin that is produced in the body on its own under the influence of UV sunlight.

Benefits of Vitamin D

Its main role is to help absorb calcium and phosphorus from food. In babies, vitamin D prevents the development of rickets, a disease associated with impaired bone development and softening. In adolescents and adults, vitamin D prevents the development of caries and gum pathologies, protects against osteoporosis (softening of bone tissue due to a lack of calcium), and accelerates the healing of fractures. Vitamin D also increases resistance to viral diseases, which is extremely important, especially when your baby first went to kindergarten and began to get sick often.

Why vitamin D deficiency is dangerous

Vitamin D deficiency causes calcium and phosphorus to be washed out of the bones. In childhood, against the background of vitamin D deficiency, rickets develops, in adults – softening of bone tissue (osteomalacia) and rarefaction of bone tissue (osteoporosis). Vitamin deficiency is especially dangerous in the first year of a child’s life, when there is a rapid growth of bone tissue.

Currently, scientists are suggesting the impact of vitamin D deficiency on the development of cancer, as well as autoimmune, infectious, viral and cardiovascular diseases.

How to get vitamin D

It would seem simpler than simple: you need good nutrition and stay outdoors under the sun’s rays, and the issue is resolved!

However, there are pitfalls here.

Studies have shown that the amount of vitamin D in foods is an unstable value. For example, during the examination of milk from the same manufacturer, the content of vitamin D in different batches fluctuated and could be less than declared within 20 IU. That is why in some countries manufacturers additionally enrich milk and dairy products with vitamin D.

In order for the body to produce enough vitamin, it is necessary to be with the face and limbs open to sunlight in the midday sun (between 10 am and 3 pm) twice a week. Fair-skinned people need five minutes, dark-skinned people should be in the sun for at least half an hour.

However, for some children, to compensate for the deficiency of vitamin D in the body, it is not enough just to fully nourish sunbathing. Toddlers suffering from diseases of the gastrointestinal tract, overweight, living in regions where there is little sunlight, children who move little, with dark skin, as well as children who do not want to be in the sun – they are all at risk. for lack of vitamin D.

Prevention of vitamin D deficiency

Non-specific prophylaxis should be comprehensive and begin even before the birth of the child.

The expectant mother needs to spend a lot of time outdoors, it is enough to move, observe the regime of work and rest, monitor the nature of the diet (take more vegetables, fruits, protein foods). In the last 3-4 months of pregnancy, calcification of the bones of the fetal skeleton begins, therefore, the need for calcium increases, and, consequently, for vitamin D. Pregnant women are recommended to take multivitamin preparations from the first weeks, and starting from the third trimester, take an additional 500-1500 IU vitamin A.

It is very important to support and maintain breastfeeding for as long as possible. It is necessary to properly organize the daily routine of a nursing mother and a good diet containing meat, dairy products, fish, and vegetables. Also, a kind of prevention for a growing baby is the introduction of complementary foods, daily walks in the air with an open face and limbs, therapeutic exercises, general massage courses.

Children who are formula-fed should be given vitamin D. When choosing a mixture, it is necessary to take into account the presence of this vitamin and lactose in it, which is necessary for its absorption. But despite the fact that almost all adapted mixtures contain a vitamin, there is an opinion that its absorption from them is not active enough.

Vitamin D specific prophylaxis

In our country, regardless of the nature of feeding, from 4 weeks of age, specific prevention of vitamin D deficiency is carried out for all children. Full-term children are prescribed a prophylactic dose of 500 IU of an aqueous or oily solution of vitamin D daily, while children at risk – 1000 IU. Recently, many researchers and practitioners have supported the opinion that it is necessary to carry out the prevention of rickets for all children of the first three years of life without a break for the summer period, provided that the child is in his region, while children from 3 to 5 years old should be given vitamin D in autumn. – spring months.

Also, there is currently an active practice of prescribing vitamin D for a long time, not only for growing babies, but also for adolescents, adults, and the elderly.

Vitamin D overdose

Vitamin D is not only useful, but if used incorrectly and excessively, it can harm the baby. Vitamin D must be given carefully, as some children are hypersensitive to the vitamin and even at low doses, a condition called hypervitaminosis can develop. Signs of hypervitaminosis – loss of appetite, anxiety, muscle weakness, sleep disturbance, constipation, may be nausea and even vomiting. Therefore, with long-term use of vitamin D, especially adolescents and adults, it is necessary to periodically examine the level of the vitamin in the blood serum. You need to know that vitamin D is an important and useful component in the development of your baby, but, as in any business, a reasonable approach and following the recommendations of the attending doctor are important.

Many diseases and pathological conditions are associated with hyper- and hypovitaminosis. If you suspect a deficiency or excess of some vitamins in the body, consult an endocrinologist or endocrinologist-nutritionist. The doctor will ask you in detail about the symptoms, if necessary, prescribe laboratory tests.