Biochemical Basis of Human Vital Activity - Volkov N.I., Nesen E.N. 2000

Biochemical Basis of Human Vital Activity
Vitamins
General Overview of Vitamins

The Development of The Study of Vitamins is associated with the Russian physician N.I. Lunin. In 1880, he was the first to conclude that, along with Proteins, fats, CARBOHYDRATES, salts, and Water, the body requires some other, yet unknown substances, which was confirmed by subsequent research. Thus, in 1912, the Polish chemist C. Funk isolated an amine-containing substance from rice bran extracts that prevented the development of beriberi. Funk proposed calling this substance a vitamin (from the Latin vita — life), i.e., an "amine of life." Currently, about 50 vitamins and Vitamin-like substances are known. Many of them have been synthesized. Although some vitamins do not contain amino groups or even nitrogen, the term "vitamins" continues to be used to describe BIOLOGICALLY ACTIVE SUBSTANCES that must be supplied to The Human Body through food.

Vitamins are a group of low-molecular-weight Organic compounds of diverse chemical structures that participate in The regulation of many biochemical reactions and physiological Functions. They influence reproduction, growth, hematopoiesis, Vision, energy production, Protein Synthesis, The Immune System, and other processes that ensure the normal Development of the body, its health status, and adaptation to various environmental factors. Generally, vitamins are not synthesized in the human body and must be obtained from food. Consequently, Vitamins are essential dietary factors.

The primary sources of vitamins are plant-based foods, as they are synthesized by plants. Animal products are also rich in vitamins, because many Tissues, especially The Liver and Muscles, accumulate them. Some Vitamins can be synthesized by the intestinal microflora or even by specific tissues; however, their amounts are insufficient to fully meet the needs of the human body.

The daily human requirement for vitamins is only a few milligrams or micrograms and depends on age, sex, and physical activity level. Only vitamins C and P are required by the body in larger amounts—up to 100 mg of Vitamin C and 30 mg of Vitamin P. For athletes, the daily recommended intake of vitamins is increased by 2 to 4 times, which is due to the intensification of METABOLISM during training.

The Effect of many vitamins on metabolism is closely linked to Enzymes. Vitamins are used by the body to construct the non-protein part of enzymes—Cofactors and prosthetic groups. Therefore, high enzyme activity and its influence on metabolic rate depend on the body's vitamin supply. Depending on the adequacy of the vitamin supply, it is customary to distinguish such conditions as avitaminosis, hypovitaminosis, and hypervitaminosis.

Avitaminosis is a specific metabolic disorder caused by a prolonged absence (deficiency) of a particular vitamin in the body, which leads to a specific disease or death.

Hypovitaminosis is a condition characterized by an insufficient (reduced) level of vitamins in the body. It manifests as rapid fatigue, decreased physical and mental performance, impaired night vision, Skin peeling, and reduced Resistance to Infectious diseases.

Hypervitaminosis is a disruption of biochemical processes and physiological functions resulting from an excessive (prolonged) intake of vitamins. Hypervitaminosis is typical for Fat-soluble vitamins, especially A and D, which can accumulate in the body's fat stores.

The causes of hypovitaminosis and avitaminosis in humans can include dietary imbalances, impaired intestinal Absorption of Vitamins, or failure to replenish them during periods of increased demand, such as during strenuous Physical Exercise. Hypovitaminosis is most frequently observed in late winter and spring, when vitamin levels in food products decline.