Power state

Insufficiency and redundancy of nutrition are important risk factors for premature aging, so their correction is important in terms of increasing longevity.

As energy consumption ages, energy consumption decreases. In Fig. It is shown that the energy expenditure in people aged 40-74 is almost one third less( 2100-2300 kcal / day) than in people aged 24-34 years( 2700 kcal / day) [McGandy RB et al., 1966].In many older people, energy consumption is even lower. Approximately 16-18% of elderly people consume less than 1,000 calories per day [Abraham S. et al., 1977].

The physiological needs of people over the age of 50 in food are significantly different. These differences are as follows.

■ The energy needs of the body are reduced.

■ The need for proteins is increasing: every day it is necessary to obtain 1.2-1.5 g / kg of high-quality proteins containing essential amino acids.

■ The proportion of carbohydrates in food should not be more than 40%;should avoid the use of mono- and disaccharides.

■ The need for vitamins and minerals( especially in calcium) is increasing.

The nutritional status affects the duration and quality of life. The restriction of calories( except for the state of their deficiency) generally leads to an increase in life expectancy.

Physiological bases explaining the increased need for a number of substances in the elderly are associated with a number of metabolic features and changes in the functional state of organs and systems.

Starting with the age of 45, gastric secretion and release of free hydrochloric acid decrease. According to a number of researchers, 30% of people aged 60-70 years and 40% of those 70-80 years old do not have gastric secretion [Russell R. M., Suter P. M., 1993], which leads to a deficiency of the internal factor of Castle.

Internal factor - a protein produced by parietal cells of the stomach. Its main role is to ensure the absorption of cyanocobalamin( vitamin B12).Deficiency of vitamin B12 usually manifests itself not earlier than in 1-3 years after the violation of its intake( which is associated

with the presence of its reserves in the liver).The emergence of deficiency leads to the development of macrocytic anemia and degeneration of nerve fibers. Vitamin B12 is part of food only of animal origin and is completely absent from plant foods. In the stomach, released from food under the influence of hydrochloric acid, vitamin B12 combines with the R-protein of saliva. After cleavage in the duodenum of the R protein with pancreatic proteases, vitamin B12 binds to the internal factor. Alkaline environment in the duodenum strengthens the connection of the internal factor with vitamin B12, as a result of which vitamin B12 becomes resistant to the action of proteolytic enzymes. In the future, the molecule of the internal factor and vitamin B12 is absorbed in the ileum.

In addition to reducing gastric 1 2 secretion, elderly people have a high prevalence of infection with Helicobacter pylori and atrophic gastritis. The frequency of Helicobacter pylori detection increases with age and in people over 60 years is more than 80% [Shamburek R. D., Farrar J. T., 1990].More than 30% of people over 60 years of age have serological markers of atrophic gastritis. The immediate reason for the rather rapid development of atrophy of the gastric mucosa lies in the development of autoantibodies to cover cells and the internal factor. Autoantibodies bind to the lining cells of the gastric mucosa, damage the glands and lead to progressive atrophy.

Fig. Consumption of proteins, fats and calories as a function of age

Fig. Consumption of proteins, fats and calories depending on the age of the

AT to the internal factor blocks the connection of vitamin B12 with the internal factor and thereby prevents its absorption.12

For the reasons given, the level of vitamin B12 in the body decreases with age. In 12% of elderly people, vitamin B12 deficiency can be detected in the study of blood serum [Lindebaum J. et al., 1994], in the vast majority of the remaining elderly people, metabolic deficiency of vitamin B12 can be detected by increasing concentrations of methylmalonic acid and homocysteine. These metabolites are sensitive markers of vitamin B12 deficiency in tissues. It should be borne in mind that with prolonged weak deficit of vitamin B12, the development of neuropsychiatric disorders without megaloblastic anemia is possible.

In elderly and senile age the length of the intestine slightly increases, its walls undergo atrophic changes, the number of functioning glands and villi per unit surface of the mucous membrane decreases. In the duodenum and jejunum, a decrease in the thickness of the mucous membrane, atrophy of the muscular layer, which leads to functional disorders( "old constipation"), is noticeable. As the aging decreases the absorption capacity of the small intestine. As a result, the absorption of amino acids, vitamins, macro- and microelements is sharply reduced. These disorders are particularly pronounced in relation to calcium. All dietary calcium salts are better soluble in an acidic environment. Violation of the secretion of hydrochloric acid by the gastric mucosa is one of the reasons for the decrease in calcium absorption in the intestine. Another reason is the age-related decline in the formation of active forms of vitamin D.

Vitamin D3( cholecalciferol) is formed in the skin of 7-dehydrocholesterol under the influence of sunlight or enters the body with food. The synthesized and received vitamin D3 is transported by blood to the liver, where it is converted into 25 hydrochlorolecalciferol [25( OH) D3] in the mitochondria. This intermediate is converted to either 25( OH) 2D3 or 24.25( OH) 2D3.Calcitriol - 1.25( OH) 2D3 is formed in mitochondria of kidney cells under the action of 1-hydroxylase, this is the most active form of vitamin D3.After synthesis in the kidneys, it is transported by blood to the intestine, where in the cells of the mucosa stimulates the synthesis of calcium-binding protein, which is able to bind calcium coming from food( this is the main function of vitamin D).As a result of these processes, the concentration of calcium in the blood rises.

Reducing the content of 7-dehydrocholesterol in the skin, as well as reducing the cortical substance of the kidneys( decreasing the activity of 1-hydroxylase) during aging reduces the ability of the body to maintain calcium homeostasis and lead to a decrease in bone mass( osteoporosis).The determination of the concentration of calcitriol in the blood serum makes it possible to identify elderly people at risk of calcium deficiency.

The pancreas is involved in the process of age-related changes from 40-45 years. By the age of 80 her weight is reduced by 60%, there are noticeable changes in blood supply. The activity of pancreatic enzymes decreases, especially after 60 years. Functional pancreatic insufficiency is usually manifested in stressful situations( diet excesses, alcohol intake).A good marker for assessing functional pancreatic insufficiency is the study of pancreatic elastase-1 in feces.