Metabolism refers to the set of changes that substances undergo from the moment they enter the digestive tract to the formation of final breakdown products excreted from the body. That is, metabolism in all organisms, from the most primitive to the most complex, including the human body, is the basis of life.

Characteristics of anabolic and catabolic processes in the body

In the process of life, continuous changes occur in the body: some cells die, others replace them. In an adult, they die within 24 hours; others replace them. In an adult, 1/20 of the skin epithelial cells and half of all epithelial cells of the digestive tract, about 25 g of blood, etc. die and are replaced within 24 hours.

During the growth process, renewal of the body's cells is possible only when the body continuously receives O2 and nutrients, which are the building materials from which the body is built. But for the construction of new cells of the body, their continuous renewal, as well as for a person to perform some kind of work, energy is needed. The human body receives this energy through decay and oxidation in metabolic processes (metabolism). Moreover, metabolic processes (anabolism and catabolism) are finely coordinated with each other and occur in a certain sequence.

Anabolism is understood as a set of synthesis reactions. Catabolism is a set of breakdown reactions. It must be taken into account that both of these processes are continuously connected. Catabolic processes provide anabolism with energy and starting substances, and anabolic processes provide the synthesis of structures, the formation of new tissues in connection with the growth processes of the body, the synthesis of hormones and enzymes necessary for life.

Throughout individual development, the most significant changes are experienced by the anabolic phase of metabolism and, to a lesser extent, by the catabolic phase.

According to their functional significance in the anabolic phase of metabolism, the following types of synthesis are distinguished:

1) growth synthesis - an increase in the protein mass of organs during the period of increased cell division (proliferation) and growth of the organism as a whole.

2) functional and protective synthesis - the formation of proteins for other organs and systems, for example, the synthesis of blood plasma proteins in the liver, the formation of digestive tract enzymes and hormones.

3) synthesis of regeneration (recovery) - synthesis of proteins in regenerating tissues after injury or malnutrition.

4) synthesis of self-renewal associated with stabilization of the body - constant replenishment of components of the internal environment that are destroyed during dissimilation.

All these forms weaken, although unevenly, throughout individual development. In this case, especially significant changes are observed in growth synthesis. The intrauterine period has the highest growth rates. For example, the weight of a human embryo increases by 1 billion compared to the weight of a zygote. 20 million times, and over 20 years of progressive human growth it increases no more than 20 times.

Protein metabolism in a developing organism

Growth processes, the quantitative indicators of which are an increase in body weight and the level of positive nitrogen balance, are one side of development. Its second side is the differentiation of cells and tissues, the biochemical basis of which is the synthesis of enzymatic, structural and functional proteins.

Proteins are synthesized from amino acids that come from the digestive system. Moreover, these amino acids are divided into essential and non-essential. If essential amino acids (leucine, methionine and tryptophan, etc.) are not supplied with food, then protein synthesis in the body is disrupted. The supply of essential amino acids is especially important for a growing organism, for example, the lack of lysine in food leads to growth retardation, depletion of the muscular system, and a lack of valine leads to balance disorders in a child.

In the absence of essential amino acids in food, they can be synthesized from essential ones (tyrosine can be synthesized from phenylalanine).

And finally, proteins that contain the entire necessary set of amino acids that ensure normal synthesis processes are classified as biologically complete proteins. The biological value of the same protein varies for different people depending on the state of the body, diet, and age.

The daily protein requirement per 1 kg of weight in a child: at 1 year - 4.8 g, 1-3 years - 4-4.5 g; 6-10 years - 2.5-3 g, 12 and more - 2.5 g, adults - 1.5-1.8 g. Therefore, depending on age, children under 4 years old should receive 50 g of protein, up to 7 years - 70 g, from 7 years - 80 g per day.

The amount of proteins entering the body and destroyed in it is judged by the value of the nitrogen balance, that is, the ratio of the amounts of nitrogen that enters the body with food and is excreted from the body with urine, sweat and other secretions.

Studies have shown that the progressive phase of development is characterized by intense protein metabolism and a positive nitrogen balance. The younger the body, the higher the positive balance and the greater the ability to retain food nitrogen. With a decrease in growth rates, the ability to retain protein metabolism also decreases.

As can be seen, the ability to retain nitrogen and sulfur in children is subject to significant individual fluctuations and persists throughout the entire period of progressive growth. With the cessation of growth, there is a sharp decrease in retention of nitrogen and sulfur from food, which is observed in adults and elderly people.

As a rule, adults do not have the ability to retain dietary nitrogen; their metabolism is in a state of nitrogen equilibrium. This indicates that the potential for protein synthesis remains for a long time - thus, under the influence of physical activity, muscle mass increases (positive nitrogen balance).

During periods of stable and regressive development, upon reaching maximum weight and cessation of growth, the main role begins to be played by the processes of self-renewal, which occur throughout life and which fade into old age much more slowly than other types of synthesis. The intensity of self-renewal can be judged by the wear coefficient (Rubner), which characterizes those minimal expenses that are associated with basic life processes in the absence of proteins in food. This indicator is calculated by the minimum amount of nitrogen excreted in the urine, with a sufficient calorie but protein-free diet, that is, by the level of “endogenous” urine nitrogen.

The amount of urine nitrogen under these conditions decreases with age, and in men it is slightly higher than in women, but with old age the gender differences are smoothed out. Data show that the magnitude of self-renewal synthesis decreases with age.

Age-related changes affect not only protein, but also fat and carbohydrate metabolism.

The main biological feature of a growing organism is its high metabolic rate. At the biological level, this is manifested in high rates of metabolic reactions.

As you know, metabolism is a set of chemical reactions occurring in the internal environment of the body. Metabolism, in turn, is divided into catabolism and anabolism. Catabolism refers to chemical processes in which macromolecules are broken down into smaller molecules. The end products of catabolism are carbon dioxide (CO 2), water (H 2 O) and ammonia (NH 3).

The following patterns are characteristic of catabolism:

• · in the process of catabolism, oxidation reactions predominate;
• · the process occurs with the consumption of oxygen;
• · the process is accompanied by the release of energy, most of which is accumulated in the form of ATP (adenosine triphosphate). Some of the energy is released as heat.

Anabolism includes various synthesis reactions and is characterized by the following features:

• · reactions are restorative in nature;
• · the process occurs with the consumption of hydrogen (in the form of NADPH 2);
• · Anabolism occurs with the consumption of energy, the source of which is ATP.

In an adult, both of these processes occur at approximately the same speed, which ensures the renewal of the chemical composition of the body.

In children, adolescents and young men, catabolism and anabolism occur at higher rates than in adults, and at the same time, anabolism in its speed significantly exceeds catabolism, which leads to the accumulation of chemicals in the body and, first of all, proteins. The accumulation of proteins in the body is a prerequisite for its growth and development.

Protein metabolism

Protein metabolism of a growing organism has a certain direction and its own characteristics. It must be taken into account that protein is the main building material for the cells and tissues of a growing organism. During the growth of muscle tissue, the protein content in its cells increases (sarcoplasm, enzymes, contractile enzymes, etc., which make up 80% of the dry residue). The percentage of the ratio of muscle tissue weight to body weight increases. At 16 years old it makes up about 44.2% of total body weight, while at 8 years old it makes up only about 27.2%.

Proteins also perform other important functions in the body (catalytic, contractile, regulatory, energy, protective, etc.).

Protein metabolism of a growing organism, like metabolism in general, is characterized by high intensity and the predominance of anabolic reactions over catabolic reactions, as evidenced by a positive nitrogen balance.

Nitrogen balance is one of the most important indicators of protein metabolism.

With a positive balance, the amount of input nitrogen entering the body with dietary proteins is greater than the total amount of excreted nitrogen, excreted mainly in the urine (in the form of urea, ammonia, creatinine and other nitrogen-containing compounds). The percentage of use and retention of nitrogen entering the body in an infant is twice as high as in adults.

An indicator of the intensity of protein synthesis in a growing organism is also the high content of DNA and RNA in cells.

To maintain the positive nitrogen balance necessary for normal growth and development, a sufficient amount of protein must be supplied to the growing body from food.

The average daily protein requirement in our country for adults is about 100 g; for children the absolute value is lower, but per kg of weight higher: for a 2-5 year old child it is recommended 3.5 - 4 g/kg body weight, for a 12-13 year old child - 2.5 g/kg body weight, for a 17-18 year old child - 1.5 g/kg.

The biological value of food proteins, physical activity and the nature of physical activity have a significant impact on the protein norm.

Violation of the growth and development of a child can be caused by both insufficient and excessive intake of dietary proteins.

An early manifestation of protein deficiency is a decrease in the amount of albumin in the blood and a decrease in the albumin-globulin ratio (A/G). A decrease in urea and total nitrogen in the daily urine of a growing organism is also a signal of insufficient protein intake from food.

Protein deficiency can lead to growth retardation, puberty, weight loss, and weakening of the body's protective properties.

The intensity of metabolism in an athlete’s body increases the need for proteins, especially during speed-strength exercises, during which the breakdown of proteins, mainly muscle proteins, increases.

If there is an excess intake of proteins into the body, digestive enzymes are not able to completely hydrolyze them. The activity of proteolytic enzymes that catalyze the digestion of proteins into amino acids (pepsin, trypsin, chymotrypsin, etc.) is low in children under 11-12 years of age. With age, the secretory function of gastric juice increases, its acidity increases, reaching adult levels by the age of 13.

At an early age, the secretory function of the pancreas is also poorly developed. Due to the increased permeability of the intestinal wall in children, along with amino acids, partially broken down proteins - peptides that have toxic properties - can be absorbed into the blood.

Impaired digestion of proteins can lead to disruption of the metabolic processes of a growing organism.

Carbohydrate metabolism

Carbohydrate metabolism also has a number of age-related characteristics. Carbohydrates are the main source of energy. Carbohydrates provide more than half of the daily energy value of the diet. Carbohydrates also perform a number of specialized functions in the body (structural, protective, and others).

The special role of carbohydrates as energy sources is due to the fact that they can be oxidized in the body both aerobically and anaerobically, while the oxidation of proteins and fats occurs only aerobically. The need for carbohydrates for children of different ages is very individual, but carbohydrates should provide more than 50% of the daily calorie intake. As the child grows and his energy expenditure increases, the absolute need for carbohydrates should increase.

With a reduced intake of carbohydrates from food, the body accelerates the use of fats and proteins as energy sources. Increased breakdown of proteins can lead to a decrease in their content in cells and the appearance of signs of “protein starvation”.

Due to the imperfection of neuroendocrine regulation of metabolism, children are more likely than adults to have a tendency to hypoglycemia, especially during physical activity associated with endurance.

Unlike the body of an adult, the body of a child does not have the ability to quickly mobilize carbohydrate reserves and maintain a high intensity of carbohydrate metabolism.

Long-term increased consumption of carbohydrates can lead to metabolic disorders in children, since the digestion and assimilation of carbohydrates have their own specific characteristics. During growth, the carbohydrate composition of food changes. Thus, in children under 1 year of age, the main dietary carbohydrate is lactose, which is part of breast milk. Then this carbohydrate gives up the leading role in nutrition to sucrose and polysaccharides (starch, glycogen). In addition, in children, the salivary enzyme amylase, which catalyzes the breakdown of polysaccharides in the oral cavity, has low activity and reaches its maximum activity only by the age of 7 years. The amylolytic activity of pancreatic juice also slowly increases, which also makes it difficult to digest carbohydrates into monosaccharides (glucose and others).

The most important criterion for assessing the state of carbohydrate metabolism in children is the fasting blood glucose level. In young children it is 2.6 - 4.0 mmol/l and only by the age of 14-16 it reaches the value of an adult: 3.9 - 6.1 mmol/l.

Fat metabolism

The fat metabolism of a growing body also has specific characteristics. Fats (lipids) play an important role biologically. They are energy material that can be deposited in fat depots and further used as fuel. In terms of energy value, fats are superior to carbohydrates and proteins. When 1 g of fat is oxidized, about 9 kcal of energy is released, and 1 g of carbohydrates or proteins releases about 4 kcal. Lipids play a significant role in thermoregulation processes, have protective and mechanical significance, perform structural functions, etc.

The need for fat is determined by age, external environment, the nature of physical activity, etc. For example, the need for fat per kg of body weight for a child 7 - 10 years old is 2.6 g per day, and for children 14 - 17 years old - 1.6-1.8 g per day. The absolute need for fats increases with age: for a 7-10 year old child it should be about 80 g per day, and for 14-17 year olds it should be about 90-95 g. The fat requirement for an adult is about 100 g.

Fat-like substances - lipoids - play an important role in the body's metabolic processes. Among them, phospholipids and steroids are of particular importance. Phospholipids and cholesterol (a representative of steroids) are essential components of cell membranes that take part in barrier, transport, receptor and other functions. Steroids (cholesterol and its derivatives) perform a hormonal function (sex hormones and corticosteroids) and are involved in the formation of bile acids.

With age, the formation of bile acids increases, which allows for increased fat consumption and their further inclusion in metabolic processes.

The intensity of lipid metabolism at different stages of ontogenesis is not the same. The breakdown of fats in infants occurs under the action of gastric juice lipase. As the child grows and the nature of nutrition changes, the main role in the digestion of fats is given to the enzyme - pancreatic juice lipase and bile acids.

Metabolic disorders in children can be caused by both a sharp restriction of fat consumption and their excessive intake from food. During physical activity, especially long-term aerobic exercise, in children and adolescents, fats are used for energy supply to a greater extent compared to the utilization of carbohydrates, as evidenced by an increase in the concentration of free fatty acids (FFA) and glycerol already at the beginning of work.

The value of the respiratory coefficient in children and adolescents after prolonged exercise is less than 1, which indicates increased utilization of fats. As is known, the respiratory coefficient is the ratio between the volumes of carbon dioxide removed from the body and oxygen consumed (CO 2 /O 2) during the exercise. With loads provided by the anaerobic breakdown of carbohydrates to lactate, this coefficient is greater than 1. With loads performed through aerobic oxidation of carbohydrates, it is equal to 1. With prolonged exercise, when the main source of energy is fat, the respiratory coefficient becomes less than 1.

Water-mineral metabolism

Water-mineral metabolism for a growing organism is essential and has its own characteristics.

Water is the living medium of the body and is especially necessary during the period of growth, when it constitutes the main part of all organs and tissues. As the child's age increases, its content gradually decreases, and the amount of minerals increases. The younger the organism, the relatively more extracellular water it has, which mainly participates in water metabolism. Most of the water in the adult human body comes from intracellular water. The need for water per kilogram of body weight in a child of the first year of life is three times higher than in adults. During the growth process, this value remains quite high, decreasing only by the age of 14 to 50-70 ml/kg.

A child's water metabolism is characterized by high intensity, greater mobility and is easily disrupted under the influence of various reasons. This is explained by greater loss of water through the skin and lungs, immaturity of the kidneys and imperfect hormonal regulation. The absolute need for water increases with age.

Water metabolism is closely related to the metabolism of carbohydrates, fats, proteins, but especially mineral salts. Minerals play an important role in many physical and chemical processes of a growing organism (bone formation, synthesis of enzymes, hormones). They create the basis of the internal environment of the body, maintain osmotic pressure and acidity of the environment. The chemical elements most necessary for life include: sodium, potassium, chlorine, calcium, magnesium, phosphorus, iron, copper, iodine, fluorine, manganese, zinc, etc.

For the formation of the skeleton, growth and development of bone tissue, a growing body requires sufficient intake of calcium and phosphorus.

Calcium is also necessary for muscle contraction, nervous system tone, activation of certain enzymes, blood clotting, etc. The daily requirement for calcium in infants is 0.15-0.18 g and should gradually increase to 1 gram at school age. At the same time, the relative need for calcium (per kg of body weight) is especially high in the first years of a child’s life.

The biological role of phosphorus is multifaceted. As mentioned above, it forms the basis of bone tissue, is part of nucleic acids, phospholipids, and plays an important role in energy metabolism, which is due to its ability to form high-energy bonds, i.e. energy-rich bonds (ATP, ADP, CP).

Vitamin D plays an important role in the exchange of calcium and phosphorus. Parathyroid hormone, together with vitamin D, stimulates the absorption of calcium and phosphorus from the intestine, and calcitonin with vitamin D is involved in the inclusion of calcium and phosphorus in bone tissue.

Physical education and sports significantly increase the need for minerals. Moderate-intensity physical activity has a positive effect on the metabolism of calcium and phosphorus, while intense physical activity, especially under anaerobic conditions, can lead to impaired posture, osteosynthesis and the development of osteoporosis.

In addition to iron, copper, cobalt and nickel are involved in hematopoietic processes. Lack of iodine leads to dysfunction of the thyroid gland, delayed growth and development, lack of fluoride leads to caries. Zinc deficiency is reflected in slow growth and underdevelopment of the genital organs in young men.

Iron is an essential trace element used for the synthesis of hemoglobin, myoglobin, cytochromes - enzymes of tissue respiration, etc.

Iron deficiency is often observed in adolescents, especially during puberty, which can lead to the development of nutritional anemia. Iron deficiency anemia occurs in approximately 20% of women, and among athletes this figure is even higher.

Consequently, minerals, like water, are necessary for the normal functioning of all metabolic processes, especially in a growing organism. However, the growth and development of a child determine a certain pattern of mineral metabolism in children, which consists in the fact that their entry into the body and removal from the body are not balanced with each other, as is the case in adults. Due to imperfect thermoregulation processes in the growing body, children experience large losses of minerals through sweat.

In the regulation of metabolic processes of a growing organism, great biological importance is assigned to vitamins - biologically active substances that enter the body mainly with food.

The role of vitamins is multifaceted. Many of them provide a number of catalytic reactions, as they participate in the construction of coenzymes (low-molecular compounds that participate together with the enzyme in catalysis). These vitamins include B1, B2, B6, PP, etc. Vitamins B1, C, PP, etc. stimulate oxidative processes, and vitamins A, E, C are the strongest antioxidants. Thus, vitamins can be considered as the most important factors in growth, development and increasing the levels of energy supply and performance of a child.

Depending on the age of children and adolescents, the daily intake of vitamins varies.

As a child, we could eat kilos of baked goods and overeat with chocolate at night without any consequences for our figure. Now we are afraid of fast carbohydrates like fire, we try to eat a balanced diet, but we still periodically suffer from excess weight. Why?! Let's discuss each of the possible reasons- after all, it will be easier to resist the insidious nature.

Metabolism at 20+

Peak metabolic activity

“For most women, their metabolic rate peaks between 17 and 25 years old,” says Ph.D. Christopher Ochner, weight loss specialist at Mount Sinai Hospital in New York. Some women experience it earlier, others later. This mainly depends on genetics, but lifestyle can also affect it. For example, the earlier you decided to go to fitness, the more muscle mass you built, which helps burn calories even at rest. In addition, until about age 25, your body continues to build bone mass, and this process also requires a lot of energy.

Metabolism begins to slow down

According to the American Committee on Physical Education, metabolic rate declines by approximately 1.5% every 10 years. “By the age of 30, most women notice that they can no longer eat high-calorie foods without negative consequences for their figure, and the extra pounds begin to fall off much more slowly,” says Ochner. “Since this decline in metabolic activity occurs precisely during the period when most of us find (mostly sedentary) permanent jobs and cease to maintain the same level of physical activity, we can say that career also plays an unpleasant role in slowing metabolism.”

Metabolism at 30+

Vicious circle of weight gain

In a sedentary job, you lose muscle mass, which means that your ability to burn calories at rest also deteriorates. “And with a decrease in muscle mass and an increase in fat, visceral fat can grow inside the muscles and further reduce activity and provoke digestive disorders,” says MD. Caroline Cederquist, creator of the Bistro MD Diet and author of The MD Factor. “Well, this bleak picture is complemented by the fact that after thirty, the body stops producing the same volumes of growth hormone, which also leads to a slowdown in metabolism.”

Help build muscle mass and Strength training can force the body to produce more growth hormone. Then it will be possible to speed up metabolism to the same (or even higher) level.

Impact of pregnancy

If you decide to conceive, keep in mind that pregnancy can speed up your metabolism. But this does not mean that you will be able to eat everything again or even double your portions. “During pregnancy, you really eat for both yourself and the baby, but it’s more about the quality of food, rather than its quantity. Pregnancy is no excuse for eating larger meals or eating more calories, especially in the early stages when the baby inside you is tiny,” says registered dietitian Wesley Delbridge, liaison for the Academy of Nutraceuticals and Dietetics.

“During pregnancy, the body spends approximately 200 kcal per day more than usual. Women whose weight before pregnancy was normal should not gain more than 10-15 kg during these nine months.” Unfortunately, a 2015 study published in the journal Obstetrics and Gynecology reports that about 50% of all pregnant women gain more weight than expected, and this leads to muscle breakdown, the growth of visceral fat and even the development of insulin resistance (pre-diabetes).

The benefits of breastfeeding

During breastfeeding, calorie expenditure increases significantly. “Women who breastfeed without formula lose up to 500-1,000 extra calories per day,” says Delbridge. Unfortunately, as soon as any of us begins to introduce complementary foods, the metabolic rate becomes exactly the same as it was before pregnancy - and that is provided that you have not lost a lot of muscle mass over these months.

Metabolism at 40+

Hormones are rebelling

When a woman is about forty, the body is preparing for the end of the childbearing period. “Progesterone, estrogen, and growth hormone levels drop (again!),” says Dr. Cederquist. Next Metabolism also slows down. “This means cutting back on the number of calories you eat. to maintain your current weight,” advises Delbridge. If you exercise regularly, it will be enough to reduce your diet by 150 kcal. Do you lead a mostly sedentary lifestyle? You'll have to sacrifice more.

Need to build muscle mass

Of course, this is required at any age, but after forty, muscle mass begins to rapidly melt: this process even has a medical name - sarcopenia. At this age, to maintain muscle mass and help the body fight aging, it is simply necessary to include strength training in your training program. According to a study conducted by the Harvard School of Public Health, people who prefer weight training to cardio exercises suffer less from extra pounds around the waist. "Of course, any type of exercise helps burn calories," Ochner says. “But strength training allows you to speed up your metabolism and maintain it at a higher level even after you finish training.”

A diet with a sufficient amount of protein (100-120 g per day) will also allow you to maintain strength and develop endurance. “A woman who was sedentary in her 20s and 30s has a good chance of surpassing her friends' metabolic rate in the 40s if she exercises regularly and makes appropriate changes to her diet,” Cederqvist says encouragingly.

Proper metabolism and energy provide the vital functions of the human body. But people are susceptible to various diseases. Why this happens, and how metabolism relates to diseases, you will learn from this article.

What you need to know about metabolism

What is metabolism? This is the activity of the body, as a result of which tissues, organs and organ systems receive the necessary nutrients (fats, carbohydrates and proteins) and remove waste products of the body (salts, unnecessary chemical compounds). If these processes work well in the body, a person does not have health problems, and, on the contrary, with metabolic disorders, various diseases develop.

Why does the body need nutrients? In the human body, continuous, intense synthesis occurs, that is, complex chemical compounds are formed from simpler ones in organs, tissues and at the cellular level. At the same time, the second process is continuous - the process of decay and oxidation of organic compounds that are no longer needed by the body and are removed from it. This complex metabolic process ensures the vital activity, formation and growth of new cells, and nutrients are the building material of all organs and systems as a whole.

Nutrients are not only needed for the construction of tissues and organs, but also for the intensive, smooth functioning of all systems - the cardiovascular, respiratory, endocrine, genitourinary systems and gastrointestinal tract. This is the energy that enters the human body during the oxidation and breakdown of organic compounds in the metabolic process. Therefore, nutrients are a significant source of energy necessary for the smooth functioning of the whole organism.

If we talk about types nutrients, then proteins, namely their enzymes, are the main material for the structure and growth of organs. Fats and carbohydrates are designed to produce and cover energy costs. All types of nutrients, including minerals and vitamins, must be supplied to the body in certain daily amounts. A lack of vitamins or a norm that exceeds the permissible limit leads to disorders in the functioning of the whole organism and provokes various diseases. Therefore, the role of metabolism is certainly significant for the body in every sense of the word.

When metabolism is disturbed and slow, a problem often appears excess weight. Many people ask: “Is it possible to speed up the metabolic process?” Of course, but you need to put in a lot of effort to achieve the desired result. So, dreaming of having an ideal weight and, many women resort to grueling training and sports exercises. Of course, physical activity can build muscle mass while destroying fat deposits, but this requires a comprehensive approach to losing weight, including a balanced diet. Regular consumption of green tea helps speed up metabolism, which has been proven by famous nutritionists.

Many people want to change their weight in extraordinary ways. Some even start smoking because they believe that smoking helps burn fat. Indeed, the body uses up fat reserves to restore the body from tobacco poisons. In this case, you need to think about whether it is worth sacrificing the health of the entire body for the sake of losing a few kilograms.

Often hereditary diseases provoke excess weight gain and a slowdown in the metabolic process. Thus, obesity is observed in patients with diabetes mellitus due to dysfunction of the thyroid gland. In most cases, these diseases are passed on through genes to children. Therefore, the most optimal dietary option is prescribed by an endocrinologist.

Age-related features of metabolism

The nutritional needs of a child's body are much higher than those of an adult. Therefore, there is an intense metabolism, where the processes of anabolism (synthesis) and catabolism (decomposition) occur much faster than in the body of an adult. Since intensive cell growth and development of a young organism occurs, protein as a building material is needed two or even more times than an adult. So, if child under 4 years old A daily requirement of 30...50g is required, then a 7-year-old needs up to 80g of protein per day. Protein enzymes do not accumulate in the human body like fats. If you increase the daily dose of proteins, this can lead to digestive disorders.

Together with fats, hormones and vitamins necessary for life enter the body. They are divided into 2 main groups: those that are broken down using fats and those that only need water. The younger the child is, the higher the percentage of fat required for his development. So, a baby receives approximately 90% through mother’s milk, and the older child’s body absorbs 80%. The digestibility of fats directly depends on the amount of carbohydrates, the deficiency of which leads to various unwanted changes in digestion and increased acidity in the body. It is a sufficient daily intake of fat that helps strengthen the immune system.

Carbohydrates are needed by the child's body in large quantities. With age, the growing body's need for them also increases. Exceeding the norm of carbohydrates raises the child’s blood sugar only for a few hours after taking carbohydrates, then the level is normalized. Therefore, the danger of developing diabetes is practically eliminated, but in adults the opposite is true.

Metabolism in older people changes significantly, as this is associated with hormonal changes in the body. 2 main stages of metabolism slow down: the processes of synthesis and breakdown of compounds. So, people over 60 need to limit their protein intake. Therefore, meat consumption should be limited, but not completely. Since older people are prone to frequent constipation and intestinal problems, it is useful for them to take fermented milk products, raw vegetables and fruits. It is better to consume fats to a minimum, preferably vegetable ones. You should also not get carried away with carbohydrates (this means sweets, but sweet fruits are ok).

Poor nutrition, age-related changes, aging of organs, tissues and cells complicate and inhibit metabolism in the body. Therefore, older people should eat moderately and lead an active lifestyle.

Age anatomy and physiology Antonova Olga Aleksandrovna

Topic 10. AGE FEATURES OF METABOLISM AND ENERGY