Vitamin - Introduction by Dr.M.Jothimuniyandi

Vitamin - Introduction
- Dr.M.Jothimuniyandi - types - sources - biological importance

1. V I TA M I N S - INTRODUCTION Dr.M.Jothimuniyandi Assistant Professor

2. Vitamins are defined as • • • "small organic molecules present in diet which are required in small amounts. " Most of the vitamins are not synthesized in the body and hence they must be supplied in the diet. However few vitamins are synthesized in the body. Though most of them are present in diet as such some are present as precursors . The precursor forms of vitamins are called as provitamins . In the body these provitamins are converted to vitamins.

3. Classification of Vitamins Vitamins are divided into two groups. fat soluble vitamins water soluble vitamins. Fat Soluble Vitamins They are vitamins A, D, E and K. They have some common properties. They are: Fat soluble. Require bile salts for absorption. Stored in liver. Stable to normal cooking conditions. Excreted in feces.

4. Water Soluble Vitamins: They are members of vitamin B complex and Vitamin C. Their common properties are Water solubility. Except Vitamin B 12 others are not stored. Unstable to normal cooking conditions. Excreted in urine.

5. Source of vitamins Vitamin A : Carrots, sweet potatoes, spinach, kale, liver, fish oil, and fortified dairy products . Vitamin B Complex : B1 (Thiamine) : Whole grains, pork, legumes. B2 (Riboflavin) : Eggs, milk, green vegetables, fortified cereals. B3 (Niacin) : Poultry, fish, peanuts, whole grains. B5 (Pantothenic acid) : Chicken, beef, potatoes, oats. B6 (Pyridoxine) : Chickpeas, tuna, salmon, bananas. B7 (Biotin) : Eggs, nuts, seeds, sweet potatoes. B9 ( Folate ) : Leafy greens, oranges, legumes, fortified cereals. B12 ( Cobalamin ) : Meat, fish, eggs, dairy, fortified foods.

6. Vitamin C : Citrus fruits (oranges, lemons), strawberries, bell peppers, broccoli, tomatoes . Vitamin D : Sunlight exposure, fatty fish (salmon, mackerel), fortified milk and cereals, egg yolks . Vitamin E : Nuts, seeds, spinach, sunflower oil, almonds, avocado . Vitamin K : Leafy green vegetables (kale, spinach), broccoli, Brussels sprouts, and fermented foods. Source of vitamins

7. BIOLOGICAL IMPORTANCE 1. Vitamins are essential f or growth, m a i n ten a n c e a n d reproduction. However, the y are not used f or e n e rg y production. Fat soluble vitamins are required for normal colour vision, blood clotting, bone formation and maintenance of membrane structure . B vitamins help with energy production, red blood cell formation, and brain function. Most of the water soluble vitamins function as coenzymes or prosthetic groups of several enzymes involved in carbohydrate, lipid and amino acid metabolism etc. Vitamins A and D act as steroid hormones.

8. BIOLOGICAL IMPORTANCE (Cont..) 6. Deficiency of fat soluble vitamins produce night blindness, skeletal deformation, haemorrhages and hemolysis . 7. Deficiency of water soluble vitamins produce beriberi, glossitis , pellagra, microcytic anaemia, megaloblastic anaemia and scurvy. 8. Some vitamin analogs are used as drugs. For example folic acid analogs are used as anticancer agents and antibiotics . 9. Consumption of vitamin C in significant amounts reduces severity of cold. They slow down ageing process also. However , excessive consumption of fat soluble vitamins leads to toxicity.

9. BIOLOGICAL IMPORTANCE (Cont..) 10. Vit B 12 , Folic acid and Vit B 6 are beneficial to coronary artery disease patients. They lower plasma homocysteine levels. 11. Essential for immune health, wound healing, and collagen production. 12. Moderate consumption of some vitamins is found to decrease occurrence or severity of some disease. For example carotenes, Vitamin E and Vitamin D consumption at moderate level reduces incidence of cancer and cardiovascular diseases.

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