Vitamins are essential organic compounds needed daily in a very small quantity to perform specific functions in the body. Since most vitamins are not synthesized in the body in adequate amounts, it is necessary to obtain them from the diet. A properly formulated diet can supply all vitamins in adequate quantities from natural foods. However, synthetic vitamins too are nutritionally equivalent to natural vitamins.

Functions of Vitamins
In the digestive process, vitamins interact with other nutrients to enhance absorption. They can work as co–enzymes to speed up body chemical reactions. Vitamins help release energy from biological reaction during metabolism. They themselves do not provide energy.

Classification of Vitamins
Water soluble Vitamins
Water soluble vitamins cannot be stored in the body, the excess gets excreted in urine. Daily supply of these vitamins is therefore, important to avoid ill effects of inadequacy. Carefully selected foods in daily diet can supply adequate amount of vitamins. Supplements in synthetic forms are not advisable in normal conditions, as they do not provide any additional benefits.

Vitamin	Sources	Effects of Inadequacy
C–Ascorbic Acid	Amla, Guava, Citrus Fruits Orange, Sweet lime Lemon, StrawberriesDrumstick, Papaya, Watermelon, Tomato, Cabbage	Acute–Scurvy. Delayed wound healing, Low resistance to infection,Iron deficiency, Anemia,Fragile capillaries, Decayed teeth.
B1–Thiamin	Nuts & Oil seeds, Sesame, peanuts, Whole grain cereals, Wheat Germ, Soyabean	Acute–Beriberi, Leg Cramp, Mental Depression, Edema, Loss of appetite, Weight Loss
B2–Riboflavin	Milk & Milk Products, Wheat germs Yeast,Green leafy vegetables	Lesions around mouth and nose.Glossitis, Hair loss Scaly skin,Light sensitivity
B3–Niacin	Yeast, Peanuts & Peanut ButterSesame seeds, Soybean Whole grain cereals, Nuts, Meat, Fish, Poultry, organ meat	Acute–Pellagra, Anorexia, Sore mouth, Weakness, Irritability Mental depression, Damage to central nervous system, skin