Physiology, Glucose Metabolism – StatPearls

Introduction

Glucose is central to energy consumption. Carbohydrates, lipids, and proteins all ultimately break down into glucose, which then serves as the primary metabolic fuel of mammals and the universal fuel of the fetus. It serves as the major precursor for the synthesis of different carbohydrates like glycogen, ribose, and deoxyribose, galactose, glycolipids, glycoproteins, and proteoglycans. On the contrary, in plants, glucose is synthesized from carbon dioxide and water (photosynthesis) and stored as starch. At the cellular level, most often, glucose is the final substrate that enters the tissue cells and converts to ATP (adenosine triphosphate).

ATP is the energy currency of the body and is consumed in multiple ways including the active transport of molecules across cell membranes, contraction of muscles and performance of mechanical work, synthetic reactions that help to create hormones, cell membranes, and other essential molecules, nerve impulse conduction, cell division and growth, and other physiologic functions. [1]

Issues of Concern

The average fasting blood glucose concentration (no meal within the last 3 to 4 hours) is between 80 to 90 mg/dl. On average, postprandial blood glucose may rise to 120 to 140 mg/dl, but the body’s feedback mechanism returns the glucose to normal within 2 hours. During starvation, the liver provides glucose to the body through gluconeogenesis: synthesizing glucose from lactate and amino acids.

We can summarize blood glucose regulation and its clinical significance in the following ways:

After a meal, there is a rise in blood glucose levels, which raises insulin secretion from the pancreas simultaneously. Insulin causes glucose to deposited in the liver as glycogen; then, during the next few hours, when blood glucose concentration falls, the liver releases glucose back into the blood, decreasing fluctuations. 

Clinical significance: During severe liver disease, it is impossible to maintain blood glucose concentration.

High blood glucose causes insulin secretion, which concomitantly lowers blood glucose levels as glucose in driven from extracellular to intracellular. Conversely, a fall in blood glucose stimulates glucagon secretion, which in turn raises blood glucose levels.

Clinical significance: Impaired and insufficient insulin secretion leads to diabetes mellitus.

Low blood glucose level is sensed by hypothalamus leading to activation of the sympathetic nervous system to maintain glucose level and avoid severe hypoglycemia.

Prolonged hypoglycemia for hours and days leads to the secretion of growth hormone and cortisol that maintain blood glucose level by increasing fat utilization and decreasing the rate of glucose utilization by cells.[2]

Cellular Level

Following are the critical steps in the utilization of glucose at the cellular level-

For glucose to be utilizable in most tissue cells, it needs to be transported across the cell membrane into the cytoplasm. Glucose cannot readily diffuse through because of the high molecular weight. Transport is made possible through protein carrier molecules; this is known as facilitated diffusion, and it takes place down the gradient from high concentration to low concentration.  

There is an exception for the gastrointestinal tract and renal tubules. Here, glucose is transported actively by sodium-glucose co-transport against the concentration gradient.

The rate of glucose/carbohydrate utilization is under the control of the rate of insulin secretion from the pancreas. Normally, the amount of glucose that can diffuse in the cells is limited except for liver and brain cells. This diffusion is significantly increased by insulin to 10 times or more.

As soon as glucose enters the cell, it becomes phosphorylated to glucose-6-phosphate. This reaction is mediated by glucokinase in the liver and hexokinase in most other cells. This phosphorylating step serves to capture glucose inside the cell. It is irreversible mostly except in liver cells, intestinal epithelial cells, and renal tubular epithelial cells where glucose phosphatase is present in these locations, which is reversible.

This glucose can then either be utilized immediately for the release of energy through glycolysis, a multi-step procedure to release energy in the form of ATP, or can be stored as glycogen(polysaccharide). Liver cells and muscle cells store large amounts of glycogen, for later utilization to release glucose by glycogenolysis, i.e., breakdown of glucose.[3]

Development

In a developing fetus, regulated glucose exposure is imperative to normal growth because glucose is the primary energy form used by the placenta. In late-gestation, fetal glucose metabolism is essential to the development of skeletal muscles, fetal liver, fetal heart, adipose tissue. Three components that are crucial to fetal glucose metabolism are maternal serum glucose concentration, maternal glucose transport to the placenta, which is impacted by the amount of glucose the fetus uses, and finally, fetal pancreas insulin production.

Fetal insulin secretion gradually increases during the gestational period. Pulsatile peaks in glucose level are beneficial to insulin secretion; however, constant hyperglycemia down-regulates insulin sensitivity and glucose tolerance.[4] In mothers with elevated serum glucose levels, adverse fetal impacts include congenital abnormalities, fetal macrosomia, and stillbirth. [5] 

Organ Systems Involved

• Nervous System: The pancreas performs autonomic function through the sympathetic and parasympathetic innervation of the pancreas. The brain itself also houses insulin receptors in multiple regions, including the hypothalamus, cerebellum, hippocampus, among other areas.

• Pancreas: The pancreas is in the right upper quadrant of the abdomen, behind the stomach. The endocrine functionality of the pancreas regulates glucose homeostasis.

• Liver: Glycogenesis and gluconeogenesis are the storing and releasing of glucose, respectively. These processes occur using insulin, glucagon, and hepatocyte derived factors.

• Gut: Hormones in the gut are released in response to the ingestion of nutrients. These hormones are involved in appetite, glucose production, gastric emptying, and glucose removal.

• Adipocytes: Adipose tissue secretes adipokines, which regulate insulin release through their involvement in glucose metabolism, control of food intake, and insulin gene expression. [6]

Function

Glucose metabolism involves multiple processes, including glycolysis, gluconeogenesis, and glycogenolysis, and glycogenesis. Glycolysis in the liver is a process that involves various enzymes that encourage glucose catabolism in cells. One enzyme, in particular, glucokinase, allows the liver to sense serum glucose levels and to utilize glucose when serum glucose levels rise, for example, after eating. During periods of fasting, when there is no glucose consumption, for example, overnight while asleep, the process of gluconeogenesis takes place.

Gluconeogenesis happens when there is glucose synthesis from non-carbohydrate components in the mitochondria of liver cells. Additionally, during fasting periods, the pancreas secretes glucagon, which begins the glycogenolysis process. In glycogenolysis, glycogen, the stored form of glucose, is released as glucose. The process of synthesizing glycogen is termed glycogenesis and occurs when excess carbohydrates exist in the liver. [7] 

Glucose tolerance is regulated with the circadian cycle. In the morning, humans typically have their peak glucose tolerance for metabolism. Afternoon and evenings are a trough for oral glucose tolerance. This trough likely occurs because pancreatic beta-cells are also most responsive in the morning—similarly, glycogen storage components peak in the evening. Adipose tissue is most sensitive to insulin in the afternoon. The varied timings of fuel utilization throughout the day compose the cycle of glucose metabolism.[8] 

Mechanism

Glycolysis is the most crucial process in releasing energy from glucose, the end products of which are two molecules of pyruvic acid. It occurs in 10 successive chemical reactions, leading to a net gain of two ATP molecules from one molecule of glucose. 

The overall efficiency for ATP formation is only approximately forty-three percent, with the remaining 57 percent is lost in the form of heat. The next step is the conversion of pyruvic acid to acetyl coenzyme A, this reaction utilizes coenzyme A, releasing two molecules of carbon dioxide and four hydrogen atoms. No ATP forms at this stage, but the four released hydrogen atoms participate in oxidative phosphorylation, later releasing six molecules of ATP. The next step is the breakdown of acetyl coenzyme A and release of energy in the form of ATP in the Kreb’s cycle or the tricarboxylic acid cycle, taking place in the cytoplasm of the mitochondrion.[9]

Related Testing

• HbA1c. The HbA1C value indicates a 2 to 3 month average of a patient’s glycemic control. Since the HbA1C value summarizes long-term glycemic control, it is frequently used to evaluate patients with long-standing hyperglycemia, as seen in patients with diabetes, and to forecast the risk of diabetic complications.[10]

• Fasting Plasma Glucose. Plasma blood glucose level is measured after a period of fasting, typically at least 8 hours. A value greater than 126 mg/dL is associated with diabetes.[11]

• Random Plasma Glucose. A random plasma glucose measurement is sampled sometime after dietary intake was last ingested. A value greater than 200 mg/dL is highly suggestive of diabetes.[12]

• Oral Glucose Tolerance Test. All pregnant women should receive gestational diabetes mellitus (GDM) screening through an orally consumed glucose challenge and subsequent plasma blood glucose measurement.[13] 

• C-Peptide. C-peptide is a quantitative measurement of beta-cell function in an individual’s pancreas. Measured via urine or serum samples, a C-peptide value aids in the evaluation and management of diabetes.[14]

• Autoantibody. Presence of autoantibodies, including islet autoantibody, insulin autoantibody, insulinoma-associated antigen-2 autoantibodies, anti-glutamic acid decarboxylase (GAD) autoantibodies, among others are suggestive of auto-immune response as is seen in type 1 diabetes.[15][16]

Pathophysiology

Although not completely understood, Type 1 and Type 2 diabetes differ in their pathophysiology. Both are considered polygenic diseases, meaning multiple genes are involved, likely with multifactorial environmental influences including gut microbiome composition and environmental pollutants, among others. Type 1 diabetes is the autoimmune destruction of the body’s pancreatic beta cells, which produce insulin hormone. Without the insulin hormone, the body is unable to regulate blood glucose control. Type 1 diabetes more commonly presents in childhood and persists through adulthood, equally affects males and females, and has the highest prevalence of diagnosis in European White race individuals. Life expectancy for an individual with Type 1 diabetes is reduced by an estimated 13 years.

Type 2 diabetes results when pancreatic beta cells cannot produce enough insulin to meet metabolic needs. Additionally, as adipose cells are deposited in the patient’s liver and muscle, insulin resistance becomes a prominent feature of Type 2 diabetes. Therefore, individuals with more adipose deposition, typically with higher body fat content and an obese BMI, more commonly have type 2 diabetes.

Type 2 diabetes is more common, as 95% of individuals with overall diabetes have Type 2 Diabetes. Type 2 diabetes is more common among adult and older adult populations; however, youth are demonstrating rising rates of type 2 diabetes. Type 2 diabetes is slightly more common in males (6.9%) than in females (5.9%). It is also more common in individuals of Native American, African American, Hispanic, Asian, and Pacific Islander race or ethnicity.[17]

Clinical Significance

Poor glucose metabolism leads to diabetes mellitus. According to the American Diabetes Association, the prevalence of diabetes in the year 2015 was 9.4%, with people aging 65 and older forming the largest group. Every year, 1.5 million Americans receive a diagnosis of diabetes. As the seventh-highest cause of mortality in the United States, diabetes mellitus poses a concerning healthcare challenge with large amounts of yearly expenditures, morbidity, and death.

Diabetes classifies into two types-

Type 1 DM- due to deficient insulin secretion. Key features of this type are-

• Immune-mediated in over 90% cases.

• It can occur in any age group, but it is most common in children and young adults.

• Circulating insulin is virtually absent, leading to a catabolic state with exogenous insulin required for treatment.

Type 2 DM- due to insulin resistance with a defect in compensatory insulin secretion. Key features of this type are-

• This condition occurs predominantly in adults but now also increasingly presents in children and adolescents.

• Genetic and environmental factors combine, leading to both insulin resistance and beta-cell loss.

• Treatment entails lifestyle changes and oral anti-diabetic drugs.

Uncontrolled diabetes poses a significantly increased risk of developing macrovascular disease, especially coronary, cerebrovascular, and peripheral vascular disease. It also increases the chances of microvascular disease, including retinopathy, nephropathy, and neuropathy.[18]

Review Questions

• Access free multiple choice questions on this topic.

• Comment on this article.

Figure

Diagram of the relationship between the processes of carbohydrate metabolism, including glycolysis, gluconeogenesis, glycogenesis, glycogenolysis, fructose metabolism, and galactose metabolism. Contributed by Wikimedia User: Eschopp, CC BY-SA 4.0 https://creativecommons.org/licenses/by-sa/4.0, (more…)

References

1.

Jaiswal N, Gavin MG, Quinn WJ, Luongo TS, Gelfer RG, Baur JA, Titchenell PM. The role of skeletal muscle Akt in the regulation of muscle mass and glucose homeostasis. Mol Metab. 2019 Oct;28:1-13. [PMC free article: PMC6822261] [PubMed: 31444134]

2.

Chen Y, Zhao X, Wu H. Metabolic Stress and Cardiovascular Disease in Diabetes Mellitus: The Role of Protein O-GlcNAc Modification. Arterioscler Thromb Vasc Biol. 2019 Oct;39(10):1911-1924. [PMC free article: PMC6761006] [PubMed: 31462094]

3.

Taneera J, Dhaiban S, Mohammed AK, Mukhopadhyay D, Aljaibeji H, Sulaiman N, Fadista J, Salehi A. GNAS gene is an important regulator of insulin secretory capacity in pancreatic β-cells. Gene. 2019 Oct 05;715:144028. [PubMed: 31374326]

4.

Hay WW. Placental-fetal glucose exchange and fetal glucose metabolism. Trans Am Clin Climatol Assoc. 2006;117:321-39; discussion 339-40. [PMC free article: PMC1500912] [PubMed: 18528484]

5.

Schaefer-Graf U, Napoli A, Nolan CJ., Diabetic Pregnancy Study Group. Diabetes in pregnancy: a new decade of challenges ahead. Diabetologia. 2018 May;61(5):1012-1021. [PMC free article: PMC6448995] [PubMed: 29356835]

6.

Röder PV, Wu B, Liu Y, Han W. Pancreatic regulation of glucose homeostasis. Exp Mol Med. 2016 Mar 11;48(3):e219. [PMC free article: PMC4892884] [PubMed: 26964835]

7.

Han HS, Kang G, Kim JS, Choi BH, Koo SH. Regulation of glucose metabolism from a liver-centric perspective. Exp Mol Med. 2016 Mar 11;48(3):e218. [PMC free article: PMC4892876] [PubMed: 26964834]

8.

Poggiogalle E, Jamshed H, Peterson CM. Circadian regulation of glucose, lipid, and energy metabolism in humans. Metabolism. 2018 Jul;84:11-27. [PMC free article: PMC5995632] [PubMed: 29195759]

9.

Tozzi M, Hansen JB, Novak I. Pannexin-1 mediated ATP release in adipocytes is sensitive to glucose and insulin and modulates lipolysis and macrophage migration. Acta Physiol (Oxf). 2020 Feb;228(2):e13360. [PubMed: 31400255]

10.

Schnell O, Crocker JB, Weng J. Impact of HbA1c Testing at Point of Care on Diabetes Management. J Diabetes Sci Technol. 2017 May;11(3):611-617. [PMC free article: PMC5505423] [PubMed: 27898388]

11.

Eun YM, Kang SG, Song SW. Fasting plasma glucose levels and coronary artery calcification in subjects with impaired fasting glucose. Ann Saudi Med. 2016 Sep-Oct;36(5):334-340. [PMC free article: PMC6074322] [PubMed: 27710985]

12.

Barasch A, Gilbert GH, Spurlock N, Funkhouser E, Persson LL, Safford MM., DPBRN Collaborative Group. Random plasma glucose values measured in community dental practices: findings from the dental practice-based research network. Tex Dent J. 2013 Apr;130(4):291-7. [PubMed: 23767158]

13.

Garrison A. Screening, diagnosis, and management of gestational diabetes mellitus. Am Fam Physician. 2015 Apr 01;91(7):460-7. [PubMed: 25884746]

14.

Leighton E, Sainsbury CA, Jones GC. A Practical Review of C-Peptide Testing in Diabetes. Diabetes Ther. 2017 Jun;8(3):475-487. [PMC free article: PMC5446389] [PubMed: 28484968]

15.

Regnell SE, Lernmark Å. Early prediction of autoimmune (type 1) diabetes. Diabetologia. 2017 Aug;60(8):1370-1381. [PMC free article: PMC5491594] [PubMed: 28550517]

16.

Pippitt K, Li M, Gurgle HE. Diabetes Mellitus: Screening and Diagnosis. Am Fam Physician. 2016 Jan 15;93(2):103-9. [PubMed: 26926406]

17.

Skyler JS, Bakris GL, Bonifacio E, Darsow T, Eckel RH, Groop L, Groop PH, Handelsman Y, Insel RA, Mathieu C, McElvaine AT, Palmer JP, Pugliese A, Schatz DA, Sosenko JM, Wilding JP, Ratner RE. Differentiation of Diabetes by Pathophysiology, Natural History, and Prognosis. Diabetes. 2017 Feb;66(2):241-255. [PMC free article: PMC5384660] [PubMed: 27980006]

18.

Zhang N, Jiang H, Bai Y, Lu X, Feng M, Guo Y, Zhang S, Luo Q, Wu H, Wang L. The molecular mechanism study of insulin on proliferation and differentiation of osteoblasts under high glucose conditions. Cell Biochem Funct. 2019 Jul;37(5):385-394. [PubMed: 31140646]

Disclosure: Mihir Nakrani declares no relevant financial relationships with ineligible companies.

Disclosure: Robert Wineland declares no relevant financial relationships with ineligible companies.

Disclosure: Fatima Anjum declares no relevant financial relationships with ineligible companies.

SugarScience.UCSF.edu | Metabolizing Sugar

Share:

SugarScience Blog

By Royal Society of New Zealand

Sugar metabolism is the process by which energy contained in the foods that we eat is made available as fuel for the body. The body’s cells can use glucose directly for energy, and most cells can also use fatty acids for energy. Glucose and fructose are metabolised differently, and when they are consumed in excess they may have different implications for health.

Looking at glucose first – when food is consumed, there is a corresponding rise and subsequent fall in blood glucose level, as glucose is absorbed from the gastrointestinal tract into the blood and then taken up into the cells in the body.

Glucose in the blood stimulates the pancreas to release insulin, which then triggers uptake of glucose by cells in the body (e.g. muscle cells) causing blood glucose to return to base levels. Insulin will turn off fat burning and promote glucose burning as the body’s primary fuel source. Any excess glucose ends up being stored as glycogen in the muscles, and it can also be stored as lipid in the fat tissue.

Fructose is also taken up into the blood from the gut, but in this case, the liver serves as a pre-processing organ that can convert fructose to glucose or fat. The liver can release the glucose and fat into the blood or store it as glycogen or fat depots, which, if sugars are consumed in excess, may lead to fatty liver disease and also increase risk for diabetes and cardiovascular disease.

There are also some noted interaction effects between glucose and fructose, in that glucose enables fructose absorption from the gut, while fructose can accelerate glucose uptake and storage in the liver.

If the sugar comes with its inherent fibre (as with whole fruit) then up to 30% of this sugar will not be absorbed. Instead, it will be metabolised by the microbes in the gut, which may improve microbial diversity and help prevent disease. The fibre will also mean a slower rise in blood glucose, which has shown to have positive health effects.

It is easy to over-consume sugar

It is easy to over-consume sugar in juice and sweet drinks, as they contain mostly water and sugar. One glass of orange juice can contain concentrated sugar from five or six whole oranges. And while it is easy to drink that much sugar, you would be less likely to eat that many oranges in one go.

Fizzy drinks do not make you feel full as quickly as foods do. This makes them easy to over-consume. And a small fizzy drink contains nine teaspoons of added sugar, so drinking just one can means that you have almost reached your recommended maximum intake for that whole day.

more: 

http://www.royalsociety.org.nz/expert-advice/papers/yr2016/sugar/sugar-metabolism/

Liver disease

A broad term meaning any bodily process in which the liver is injured or does not work as it is supposed to. In this website we focus on liver diseases in which the diet hurts the liver

SugarScience Glossary

Added sugar

Any sugar added in preparation of foods, either at the table, in the kitchen or in the processing plant. This may include sucrose, high fructose corn syrup and others.

SugarScience Glossary

Diabetes mellitus

Usually shortened to just diabetes. Sometimes called sugar diabetes. Look at Type 1 Diabetes and Type 2 Diabetes for more information

SugarScience Glossary

Fatty acids

A type of fat in our body and our food. Three fatty acids are combined with another chemical called glycerol to form a triglyceride.

SugarScience Glossary

Sugars

Sugars are chemicals made of carbon, hydrogen, and oxygen found which taste sweet and are found in food. They are an important part of what we eat and drink and of our bodies. On this site, sugar is used to mean simple sugars (monosaccharides) like fructose or glucose, and disaccharides like table sugar (sucrose). Sucrose is two simple sugars stuck together for example (see Table sugar). Sugars are a type of carbohydrate. Carbohydrates are energy sources for our bodies Sugars enter the blood stream very quickly after being eaten.

SugarScience Glossary

Glucose

Glucose is a sugar we eat. It is found in starch. It is the main fuel for our bodies. It is the sugar measured when we have a blood test to measure the blood sugar.

SugarScience Glossary

Pancreas

The pancreas is an internal organ that helps us digest our food by making insulin and other chemicals.

SugarScience Glossary

Fat

One of the three major groups of nutrients we eat. Much of this website is related to problems associated with too much fat storage in the body. Each gram of fat produces 9 calories of energy if burned by the body as fuel. Fat can be stored in many places in the body. We generally think of fat as under the skin (subcutaneous), but the fat that may be most damaging to us is the fat stored in the liver and around the organs of the abdomen (intrahepatic and visceral or abdominal or intra-abdominal)

SugarScience Glossary

Fructose

A sugar that we eat. Also called fruit sugar. Most fructose comes in sucrose (table sugar, cane sugar, beet sugar), or from high-fructose corn syrup.

SugarScience Glossary

Liver

The largest internal organ. It weighs about three to four pounds and is located under the lower edge of the ribs on the right side. It helps us digest our food and remove toxins from our blood. “Hepat” in a word means liver, so an “hepato-toxin” is a liver poison or something that can cause damage to the liver

SugarScience Glossary

Insulin

Insulin is a messenger released from the pancreas after eating, which shunts energy (glucose or triglycerides) from the blood into fat cells for storage. Insulin is given to some people with diabetes to lower the blood glucose; it leaves the blood and enters the fat cell for storage.

SugarScience Glossary

SugarScience is the authoritative source for evidence-based, scientific information about sugar and its impact on health.

Recent Articles

• Compulsive About Sugar? Workplace Sugary Beverage Sales Ban Doesn’t Help Everyone Equally
• State Preemption: An Emerging Threat to Local Sugar-Sweetened Beverage Taxation
• Transnational corporations, obesity and planetary health
• Cost-Effectiveness Of A Workplace Ban On Sugar-Sweetened Beverage Sales
• City Visions: Are sugary drinks a public health hazard?

Archives

• June 2021

• April 2021

• March 2021

• July 2020

• October 2019

• August 2019

• March 2019

• January 2019

• September 2018

• March 2018

• February 2018

• November 2017

• October 2017

• September 2017

• August 2017

• April 2017

• January 2017

• December 2016

• November 2016

• October 2016

• September 2016

• August 2016

• July 2016

• March 2016

• January 2016

• December 2015

• October 2015

• July 2015

• June 2015

• May 2015

• April 2015

• March 2015

• February 2015

• January 2015

• December 2014

• November 2014

• October 2014

• June 2014

• March 2014

SugarScience Facts

Growing scientific evidence shows that too much added sugar, over time, is linked to diabetes, heart disease and liver disease.

SugarScience Facts

Overconsumption of added sugar is linked to type 2 diabetes, a disease affecting 26 million Americans.

Truth and myths about the benefits and dangers of milk, is it true that milk causes excess weight, acne and digestive problems

Once upon a time, milk was perceived as an exceptionally healthy product. No wonder it was given to employees of hazardous industries. Today, many nutritionists and nutritionists argue that milk threatens with excess weight, digestive problems and skin problems. We decided to figure out together with experts what is more in a glass of milk – harm or benefit.

Tags:

health

food

Rules of Life

Contents of the article

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.

What is lactose?

Weight and nutrition watchers know that sugar can often be found in places we would not expect to find it at all – in sausage, bread, canned peas, etc. But this is not enough – sugar can be not only added. Dairy products contain a carbohydrate called lactose, which is often referred to as “milk sugar”. It consists of glucose and galactose, together they create a pleasant, slightly sweet taste. It is because of it that some people find it difficult to give up dairy products. But perhaps it is not necessary to do this?

What is lactose intolerance?

“In our body, a special enzyme is formed to break down lactose with a very similar name – lactase,” explains Angelina Vodolazkaya, preventive medicine doctor, endocrinologist, nutritionist, nutritionist at the Biogena Clinic. – For various reasons, this enzyme may not be formed or formed in insufficient quantities, then a condition occurs, which is called lactose intolerance. It can be congenital or acquired.”

There is a theory that our distant ancestors did not have an enzyme that metabolizes milk sugar. Its appearance is a genetic mutation. It arose when people began to actively domesticate cows, goats and eat dairy products. Another interesting fact is that children up to a year digest milk sugar well, and then less and less lactase is produced and the enzyme becomes less active.

“Studies have shown that 45 to 85% of people in different countries have problems with lactose in the form of intolerance or allergy to it,” says nutritionist Anastasia Venza. – This is mainly due to the absence or insufficient amount of lactase. When lactose is not metabolized, it becomes food for disease-causing bacteria in the gut. This can lead to abdominal discomfort and skin problems.”

“Lactose intolerance can be suspected if dyspeptic symptoms (bloating, colic, stool disturbance) appear within two hours after consuming dairy products,” says Angelina Vodolazka. “But it’s not worth diagnosing yourself. There are a number of methods to refine it.”

How can I test for lactose intolerance?

“There are several ways to do this in any laboratory,” says Anastasia Venza. – Let’s focus on two of them. The first method is the hydrogen breath test. The procedure does not take much time. The test involves the consumption of a large portion of milk or products based on it in a controlled environment. Then the concentration of hydrogen in your breath is measured. If you are lactose intolerant, the concentration of hydrogen in your breath will be higher than normal. The second method is a genetic test for the presence of mutations in the genes responsible for the production of lactase. The results will show which genotype a person is a carrier of. The CC genotype indicates a possible risk of early development of lactase deficiency, and the TT genotype indicates a low probability of lactase deficiency.”

Is it true that milk causes extra weight and mucus in the lungs?

Two of the most common dairy-free horror stories are stories of mucus and weight gain from dairy. The weight myth is very easy to debunk. We do not get fat from a certain group of foods, but when we consume more calories than we burn. In other words, the point is not cheese and cottage cheese, but their quantity and the energy value of the portion eaten.

Yes, lactose is a carbohydrate, but the glycemic index of milk is 31, which is considered low. But the insulin index of milk is really high – 90. In other words, it causes a sharp jump in insulin, therefore, with diabetes and insulin resistance, it is better to exclude milk. But you can eat cheese, especially aged hard cheese, it has a low insulin index.

You can also find articles on the Internet claiming that milk promotes the secretion and accumulation of mucus in the lungs and stomach. However, scientific research has not confirmed this.

Should we cut out dairy products completely?

Our experts urge you not to give up dairy completely without good reason. Milk protein contains twenty amino acids, of which ten are essential, that is, the human body cannot produce them on its own and can only get them from food.

“Dairy products are a valuable source of protein, vitamins, amino acids and calcium,” says Angelina Vodolazka. — And fermented milk products have a positive effect on the microbiota. Therefore, without good reason to refuse them is not worth it. Studies confirm the beneficial effects of dairy products on bone mineral density, the state of the immune system, and a number of other body parameters. With partial lactose intolerance, it is possible to help digestion in small volumes by taking the enzyme lactase. As a rule, it is produced in the form of a biologically active food supplement. Lactose absorption is also facilitated by the intake of probiotics such as Lactobacillus spp., Bifidobacterium longum or Bifidobacterium animalis, which produce lactase in the intestine.”

What can replace dairy products?

First, you should pay attention to lactose-free products and products with a reduced lactose content. Secondly, it is important to know that the higher the fat content of a dairy product, the less lactose it contains. In other words, there is less of it in cheese, butter or cream than in ordinary milk. These foods can usually be afforded in moderation even if you are lactose intolerant. “Fermented dairy products, such as yogurt and kefir, are also usually well digested, even for lactose intolerant people. The cultures of bacteria in these products decompose lactose, which makes them easier to digest,” reminds Anastasia Venza.

And even for those who need to completely give up dairy products (for example, because of an allergy to the milk protein casein), today there is an alternative – plant-based substitutes. But choosing them, you need to carefully study the composition. “Sugar, sweeteners and preservatives are often added to plant-based milk,” says Anastasia Venza. – There may also be unwanted effects associated with allergic reactions to ingredients. For example, oat and rice milk contain gluten, while almond and hazelnut milk should not be used if you are allergic to nuts. The rest can be guided by taste preferences. I recommend starting the use of milk substitutes with a small amount. You can try mixing different types to get the right taste and nutritional value.”

3 natural sugar substitutes to try in baking

Sugar is bad! But love for him, sadly, is inherent in us from birth. Scientists have discovered that the sweet taste acts as a pain reliever and sedative for babies at the same time! What can we say about us adults who don’t have to wait for mom to get the coveted dessert! How to be – especially on the eve of the New Year holidays, when there are so many sweet temptations on store shelves? Many chefs are wondering if, in honor of our Grandfather Frost, we should test recipes with insidious sugar substitutes? And which of them, in this case, can be added to desserts and pastries? Yes! If not every day, then it is possible, because doctors do not recommend abusing such experiments. However, for diabetics, this is generally a real salvation.

Xylitol

Chemically, it is a sugar alcohol found in small amounts in some vegetables, fruits and berries, such as strawberries and raspberries. And most of all it is in birch bark – now it is clear why birch sap is sold so successfully in our country?

In the food industry, xylitol is registered as food additive E967 and is not only a sweetener, but also an emulsifier and water-retaining agent. This means that in addition to the taste properties, this substance can add a little more friability and volume to the dough. Another important plus is that the calorie content of xylitol is almost half that of sugar, and it has a low glycemic index. Recall: this index shows how quickly carbohydrates from foods are absorbed by the body, raising blood sugar levels. So, pure glucose has 100 units, refined sugar has 70, and xylitol has about 10.

Because the body does not metabolize xylitol as sugar, it does not affect insulin levels, and some research suggests that it may also prevent cavities and possibly improve bone and dental health. And, according to some studies, it helps fight fungal diseases and ear infections.

Why can’t such a good product replace all the bad sugar in the world? But because he has some unpleasant features . .. For example, he, like other sugar alcohols, causes bloating, flatulence and diarrhea – therefore, the daily dose should not exceed 40 grams. The fact is that 50-75% of the xylitol that has entered the body is consumed by intestinal bacteria, which convert it, among other things, into gases (hydrogen, methane and carbon dioxide). And one more important fact: xylitol is toxic to human four-legged friends, so dog owners should store it in a pet-proof container and never allow animals to try baking with such a sweetener.

How to cook with it? Unlike some other sweeteners, xylitol bakes well and can be used as a 1:1 substitute for white sugar, so it can be adapted to any recipe. If you have a tendency to indigestion, try pairing it with other sweeteners like stevia first.

Erythritol

Like xylitol, erythritol is a sugar alcohol naturally found in grapes, pears, mushrooms, and other fruits and vegetables, but is most commonly made from corn. It has a super low glycemic index – one unit, and only 0. 2 calories per gram (per 95% less than sugar). Due to these properties, erythritol does not affect blood sugar levels, and also does not cause tooth decay and may even contribute to the remineralization of teeth. Unlike other sugar alcohols, erythritol is primarily absorbed into the bloodstream before it reaches the intestines and appears to resist fermentation by intestinal bacteria. Thus, it is less likely to cause indigestion.

What can you cook? For example, chocolate mint whipped cream mousse: Blend 3 large ripe avocados in a blender with 1/2 cup unsweetened cocoa powder and 3/4 cup heavy cream or coconut milk. Add mint extract, a little erythritol and salt to taste, cool (from 30 minutes to 1 hour), serve with whipped cream, to which add fresh mint leaves.

Stevia

Various varieties of this plant have been known to the indigenous people of Brazil for centuries under the name “sweet herb”. The Indians added it to teas – mainly medicinal ones, with tart and bright notes. Because, frankly, even the modern food industry cannot eradicate the characteristic bitter aftertaste from this sugar substitute, which many compare to licorice.

Compounds found in stevia plant material are approximately 300 times sweeter than sugar. They have no calories, which means there is no effect on insulin levels in the blood. In the early days of research, some scientists suggested that the plant extract, if used frequently, could contribute to infertility and even cause cancer! (Let’s note in brackets – perhaps those authors were simply paid, for example, by the producers of refined sugar … because the alarming data was soon massively refuted). The latest scientific papers prove otherwise: Stevia compounds can fight cancer! This, in particular, is evidenced by the test results of the “Center for Research and Development of Health Sciences” of one of the universities of Mexico. According to the results of experiments there, it was found that prostate cancer cells slow down their growth in the presence of an extract of the root of a plant from the genus Stevia.

How to cook with it… First, save money: 1/2 teaspoon of stevia replaces a whole glass of sugar for sweetness. A crushed dry plant (this is also sold) is not suitable for baking: it leaves a too strong aftertaste. But tablets and powder have less aftertaste and are suitable for puddings, ice cream or smoothies. Secondly, experienced chefs also recommend mixing stevia with erythritol or xylitol.

Why is it not worth replacing sugar with sweeteners forever?

According to numerous modern studies, the abuse of sweeteners can be harmful to health, so for many of them there is a recommended daily dose. Researchers from the United States, for example, found that sweet lovers who consume half a liter of store-bought drinks daily with sweeteners have an increased risk of stroke, coronary heart disease and vascular problems. The hope that artificial sweeteners will help in the fight against obesity has not materialized either. It turned out that in many subjects they cause increased appetite! What to do?

You can, for example, quite imperceptibly for taste, reduce the dosage of sweets in recipes with the help of berries, citrus fruits and spices.