Vitamins are small organic compounds that cannot be synthesised by our body but are essential for certain functions. Hence, they must be obtained through diet. The requirements of these compounds are not high, but their deficiency or excess can cause diseases. Each vitamin has a specific function in the living system, mostly as co enzymes. They are not served as energy sources like carbohydrates, lipids, etc.,
The name ‘Vitamin’ is derived from ‘vital amines’, referring to the vitamins earlier identified amino compounds. Vitamins are essential for the normal growth and maintenance of our health.
14.4.1 Classification of vitamins
Vitamins are classified into two groups based on their solubility either in water or in fat.
Fat soluble vitamins: These vitamins absorbed best when taken with fatty food and are stored in fatty tissues and livers. These vitamins do not dissolve in water. Hence they are called fat soluble vitamins. Vitamin A, D, E & K are fat-soluble vitamins.
Water soluble vitamins: Vitamins B (B1, B2, B3, B5, B6, B7, B9 and B12) and C are readily soluble in water. On the contrary to fat soluble vitamins, these can’t be stored. The excess vitamins present will be excreted through urine and are not stored in our body. Hence, these two vitamins should be supplied regularly to our body. The missing numbers in B vitamins are once considered as vitamins but no longer considered as such, and the numbers that were assigned to them now form the gaps.
Table 14.2: Vitamins, their Sources, Functions and their Deficiency disease
| Vitamin | Sources | Functions | Deficiency Disease |
|---|---|---|---|
| Vitamin A (Retinol) | Liver oil, Fish, Carrot, Milk, spinach and fruits such as Papaya and mango | Vision and growth | Night blindness,Xerophthalmia Keratinisation of skin |
| Vitamin B(iamine) 1 | Yeast, Milk, Cereals, Green vegetables, Liver, Pork | Co – enzyme in the form of iamine pyro phosphate (TPP) in glycolysis | B eri – B eri (peripheral ner ve damage) |
| Vitamin B(Riboavin)2 | Soybean, Green vegetable Yeast, Egg white, Milk, Liver kidney | Co enzyme in the form of FMN (Flavin mono nucleotide)and FAD (Flavin adenine dinucleotide) in redox reactions | Cheilosis (lesions of corner of mouth, lips and tongue) |
| Vitamin B(Niacin)3 | Cereals, Green leafy vegetables, Liver, Kidney | Co enzyme in the form of NAD and NADP in redox reactions.+ | Pellagra (photo sensitive dermatitis) |
| Vitamin B(Pantothenic acid)5 | Mushroom, Avocado, Egg yolk, Sunower oil | Part of coenzyme A in carbohydrate protein and Fat metabolism | Inadequate growth |
| Vitamin B(Pyridoxine)6 | Meat, Cereals, Milk, Whole grains, Egg. | Co enzyme in amino acid metabolism, formation of Heme in Hemoglobin | Convulsions |
| Vitamin B(Biotin) 7 | Liver, kidney, Milk, Egg yolk, Vegetables, Grains | Co enzyme in fatty acid Biosynthesis | Depression, Hair loss, muscle pain. |
| Vitamin B(Folic acid) 9 | Egg, Meat, Beet root,Leafy vegetables,Cereals, Yeast | Nucleic acid synthesis, maturation of red blood cells | Megaloblastic anaemia |
| Vitamin | Sources | Functions | Deficiency Disease |
|---|---|---|---|
| Vitamin B12(Cobalamin) | Egg, Meat, Fish | Co-enzyme in amino acid metabolism, Red blood cells maturation | Pernicious Anaemia |
| Vitamin C(Ascorbic acid) | Citrus fruits(Orange, Lemon etc…),Tomato,Amla, Leafy Vegetables | Coenzyme in Antioxidant, building of collagen | Scurvy (bleeding gums) |
| Vitamin D Cholecalciferol(D3),Ergocalciferol (D2) | Fish liver oil, Milk,Egg yolk, (exposure to sunlight) | Absorption and maintenance of calcium | Rickets (children), Osteomalacia (adults) |
| Vitamin E (Tocopherols) | Cotton seed oil, Sun flower oil, wheat germ oil, Vegetable oils | Antioxidant | muscular dystrophy (muscular weakness) and neurological dysfunction |
| Vitamin K (Phylloquinone & Menaquinones) | Green leafy vegetable, soybean oil, tomato | Blood clotting | Increased blood clotting time,Haemorrhagic diseases |