Vitamins are complex organic compounds of high biologic activity. Their quantity in foods is low, the role they play being vital.
In the human body vitamins act as regulators and catalysts. They must be treated as an indispensable food component, even though some vitamins can be built by the body itself provided a person eats a healthy, sensible and well-balanced diet. It is worth mentioning that most vitamins cannot be stored in the body, vitamins A, D and B12 being an exception (they can be stored for a while in the liver but their deposits require constant replenishment.) The message is: the body must get a regular and adequate supply of vitamins. The body wants of them are dependant on the sex, age, physiological state of a person (pregnancy, nursing, menstruation etc.) as well as on the climatic conditions, the level of his/her physical activity, work environment and presence of bad habits. For example, it is a well-known fact that a daily need of vitamin C of a smoker is twice as much as that of a non-smoker.

Vitamins entering the body with fresh natural foods possess the strongest and the most valuable biological action.

The question is: Is it healthy to take in complexes of industrially manufactured vitamins as an addition?

Judging by the opinion of well-experienced dietologists, it is not. But only provided a person eats a healthy, sensible and well-balanced diet, as we have already mentioned. These poly-vitamins are chemical analogues of natural vitamins. So, there is no point in pumping any artificial staff into the body. Besides it is in question whether these chemicals have been properly tested and absolutely safe. Nobody can say for sure what can be the impact of the poly-vitamins over the health in 10 or 20 years. It has been established that overeating of the artificial vitamin C in the childhood raises the risk of cirrhosis of the liver 30 - 40 years after. Who can secure that future researches wont find out that these or those artificial vitamins taken by us now can be responsible for serious and irreversible changes in the body aggravating its medical condition and providing the basis for some bad illness. Besides, the price of these poly-vitamins is undeservedly held up. Trying to reimburse the huge expenses spent on advertising, the producers are more interested in the quickest sale than in the long-lasting (ten years or so) researches dealing with the impact of these vitamin analogues over the body. Buying and taking them in subjects us to risk. Another thing is hypervitaminosis which is often the result of eating too much poly-vitamins. At the same time eating a diet rich in any vitamins of natural origin never causes hypervitaminosis. That is why there is no doubt that the healthiest and the safest vitamins are those contained in food products.

Vitamins are divided into two big groups:

- soluble in water
- soluble in oils

Water soluble vitamins are vitamin C and group B vitamins.

Vitamin C or ascorbic acid is contained in vegetable products. Those of them richest in vitamin C are sweetbrier, black currants, grapefruit, paprika, parsley, sorrel, spinach. smaller quantities of vitamin C are found practically in all vegetables and fruit. Vitamin C provides the main building material for our skin - the protein of collagen which contributes to its elasticity and prevents formation of wrinkles.

Shortage of vitamin C exposes a person to the risk of bleeding, decreases the body resistance to a number of infectious diseases, provokes pains in joints and causes an abundance of other disturbances in the chain of complex biochemical reactions processes going on in the body.

Besides, shortage of vitamin C in the diet interrupts growth of muscles despite anabolic exercising and sufficient and even surplus amount of protein in the diet.
In the average an adult needs 75 mg of vitamin C a day.

Group B vitamins.
Vitamin B1 or thiamine is contained primarily in liver, nuts, rye wholemeal bread, eggs, green peas. This vitamin is essential for good functioning of the nervous system, the liver and the heart. It is involved into the carbohydrate metabolism and helps to cure skin diseases. The daily need of vitamin B1 is 2-2,5 mg.

Vitamin B2 or riboflavin is contained mainly in liver, milk, yeast. Many of us at least once suffered from chaps in the corners of the lips, so called perleches. Shortage of vitamin B2 is responsible for that. Another indirect indicators of shortage of this vitamin in the body are dim and easily coming out hair, scurf. The daily need of vitamin B2 is 2-3 mg.

Vitamin B3 or PP or niacin. Sufficient ingress of this vitamin with food secures good functioning of the digestive system. This vitamin is involved both into protein and carbohydrate metabolism. Thanks to it the skin looks healthy and nice. Sleepiness, the state of depression, dental caries, nasty smell from the mouth indicate shortage of vitamin B3. Besides, tendency to constipation is often conditioned by shortage of high-niacin foods in the diet. The vitamin is contained in the same products as vitamins B1 and B2. But the most valuable sources of vitamin PP are yeast and bran. The daily need of vitamin B3 is 15 mg.

Vitamin B5 or pantothenic acid plays an important role in the fat metabolism. It is also needed for building fatty acids and cholesterine. The sources of vitamin B5 are sea kale, sprouted grain, kidneys, cheese. The daily need of vitamin B5 is about 10 mg.

Vitamin B6 or pyridoxine. It stimulates functioning of the nervous system and contributes to the body resistance to various diseases. The main role of the vitamin is to secure health of the skin, especially of the head skin. The sources of vitamin B6 are chicken meat, nuts, wholemeal bread, bananas. The daily need of the vitamin equals to 2 mg.

Vitamin B8 or inosit. The main function of the vitamin is to prevent the onset of sclerosis. Problems with hair, its premature loss or growing grey, are indications of shortage of vitamin B8 in the body. Inosit sources are mussels, nuts, whole meal. The daily need of vitamin B8 is 1 mg.

Vitamin B12 or cyancobalamine. It is needed by the cells of the nervous tissue and of the bone marrow. Shortage of cyancobalamine is associated with such a serious medical problem as B12 deficiency anemia, when blood cells are affected. This illness requires life-long treatment with injections of vitamin B12. The sources of this vitamin are fat free meat, pluck, fish, mussels. The daily need of vitamin B12 is 0,005 mg.

Pholate. This acid is needed for building of nuclein acids to form protein molecules. Pregnant women need pholate most of all. Shortage of it can aggravate the intrauterine development of the fetus, and affect its nervous system. big volumes of pholate are contained in green leaf vegetables, avocado, oranges, beer yeast, strawberry, cabbage. The daily need of pholate is 1,5 mg.

Oil soluble vitamins are A, D, E, K and N.

Vitamin A. There are two kinds of it - retinol and beta-carotin. Retinol is contained in animal products, such as meat, liver, fish oil, egg yolk, hard cheese. As for carotin, it is contained in many fruit and vegetables of orange and red colour. However, colour cannot serve as a reliable indicator of provitamin A. Biologically active carotine is also found in greenery: dill, parsley, spinach. But the best sources of carotin are carrots, mangoes, apricots, papayas, pumpkins, tomatoes. The main function of beta-carotin is to act as an antioxidant, i.e. to neutralise some harmful oxidation reaction able to start up tumor processes in the body. Shortage of vitamin A affects the skin, making it dry and unhealthy greyish. Hair also suffers from vitamin A deficiency, it loses strength and gets prone to splitting. As for nails, they become fragile and their growth slows down. To make things still worse, the ability to see in the dark reduces considerably, the phenomenon being known as night blindness. Vitamin A is considered to be an agent slackening ageing of the body and helping to keep the skin smooth and fresh. That is why it is well used in the leading centres of medical cosmetology. It is worth mentioning once again that vitamin A is oil soluble, i.e. to activate its valuable properties foods rich in it should be eaten in combination with vegetable oil, butter, sour cream, mayonnaise. The daily need of vitamin A is 1 mg.

Group D vitamins. They are involved in the body calcium and phosphorus metabolism. Therefore, vitamin D is often called an antirachitic factor. Rickets is a disease arising only in the infantile age, the characteristic features of it being irreversible changes of skeleton leading to curvature of the legs, wrong development of the chest and skull bones. Vitamin D prevents the bones of adults from fractures and malacia. The body is able to build vitamin D itself under the influence of ultraviolet rays. However, one should be aware that the possible overdose of vitamin D ( hypervitaminosis) is not safe for the body. The biggest amounts of vitamin D are contained in the codfish oil, butter, cream, egg yolk. The daily need of vitamin D is 0,01 mg.

Vitamin E or tocopherol and tocotrienol. They secure normal intake of oxygen by the body and prevent oxidation processes in it. This vitamin is essential for metabolic processes, especially going on in the muscles, as well as for the energy balance maintenance. That is why vitamin E is of vital need for those who goes in for body building. A number of researches have proven the ability of tocopherol to prevent premature ageing and destruction of the body cells. Judging by the outcomes of epidemiological and clinic tests, vitamin E is also able to reduce the risk of a number of chronic diseases including the ishemic heart disease, the cataract and some kinds of cancer. Vitamin E is of vital importance for normal development of pregnancy and the right course of the birth. In particular, vitamin E prevents misbirth. The best sources of tocopherol and tocotrienol are young shoots of wheat, as well as sprouts of other cereals and leaf vegetables. Besides good sources of vitamin E are olive, maize, sunflower- and lin-seed oils, peanuts. The daily need of vitamin E is 0,0005 mg.

Vitamin K. This vitamin is often called an antihemorrhagic factor, since it facilitates normal blood coagulability. It can be built in the bowel with the help of its bacteria. The best sources of vitamin K are soy-bean oil, liver, nuts, spinach, green salad.

Vitamin N or biotin. It is contained in liver, yeast, milk. Vitamin N stimulates building of fatty acids and facilitates their processing together with carbohydrates. Biotin is an essential diet component, because it prevents dissection of nails and improves their growth. It is also needed to normalise functions of the skin and of mucous coats and to prevent blackheads and comedones. The daily need of vitamin N is 0,1 - 0,3 mg.