Vitamins: Vitamins are required by the body for its various metabolic processes and the normal working of the body. They are required by the body in very small amount. Vitamins do not yield energy but enable the body to use other nutrients. For a healthy person these requirements are met by a normal, well balanced diet. However, if our diet is lacking in any vitamin, we suffer from deficiency diseases.
Vitamins are divided into two groups:
(a) Fat-soluble vitamins (vit. A,D,E and K)
(b) Water-soluble vitamins (vit. of B,C group)
Each Vitamin has specific functions to perform.
(a) Fat-soluble vitamins:
Vitamin A: Vitamin A is essential for the construction of many different body tissues. It covers both retinol and beta carotene.
(i) It is indispensable for normal vision. It contributes to the production of retinal pigments which are needed for vision in dim light.
(ii) It is necessary for normal functioning of glandular and epithelial tissue.
(iii) It supports growth especially skeletal growth.
(iv) It is anti-infective.
(v) For keeping eyes and skin healthy.
Food rich in retinol are liver, eggs, butter, cheese, whole milk, fish and meat. Vegetable sources are green leafty vegetable (spinach), yellow fruits, carrot and tomatoes (Red Pigment).
Deficiency of vitamin A is associated with skin damage and impaired resistance to infection, night blindness, Bitot's spots.
Vitamin D: The nutritionally important form of vitamin D in men is calciferol. This conversion takes place partly in the liver and kidneys and partly in the skin under the influence of sunlight. Its function is to promote intestinal absorption of calcium. It is important for strong teeth.
Sources: It is found in cheese, butter, milk, green vegetables, fish, liver oil and sunlight. Infants and small children have relatively high vitamin D requirement. Deficiency of Vitamin D in children causes rickets/abnormal growth and development of bones and overdosage of it may cause kidney or even brain damage.
Vitamin E: It is found in vegetable oils, butter, milk, whole grain, corn. nuts, seeds and spinach. It is important to protect the cell membranes and also important in formation of Red Blood Cells (RBC).
Vitamin K: It is found in cabbage, cauliflower, cereals, soyabean. spinach and other green leafy vegetables. vitamin K helps in clotting of blood. Deficiency of vitamin K causes excessive bleeding from wounds.
Water-soluble Vitamins: These include vitamin B1 B2, B3, B12. and vitamin C. which are not stored by the body.
Vitamin B: It is found in peanuts, fish, eggs, milk, cheese, peas. cereals and meat. Some of the complex vitamins are B1 B2 B3. B6 and B12. These are all water-soluble and necessary for growth and development. Deficiency of vitamin B results in a disease called Beri-Beri, Pellagra, malformation of Red Blood Cells (RBC).
Vitamin C: It is needed for the maintenance of the ligaments, tendons. and other supportive tissues and strong blood vessels. Vitamin C is found in amla, citrus fruits, tomatoes, green leafy vegetables and potatoes.