INTRODUCTION Vitamins may be regarded as organic compounds required in the diet in small amounts to perform specific biologic functions for normal maintenance of optimum growth and health of the organisms Generally, vitamins are not synthesized by the body, and need to be supplied through the diet History and Nomenclature HOPKINS - Coined term ACCESSORY FACTORS to unknown and essential nutrients present in the natural foods FUNK - 1) Isolated an active principle from rice polishing's and in yeast cured Beri - Beri in pigeons 2) Coined the term VITAMINE from the words vital + amines 3) Later it was called “ VITAMIN ” Mc COLLUM and DAVIS - Introduced the usage of A, B, and C to vitamins CLASSIFICATION There are about 13 vitamins, essential for humans classified as follows Vitamers: Chemically similar substances that possess qualitatively similar vitamin activity VITAMIN A Fat soluble vitamin Present only in foods of animal origin Carotenes - Plants Dietary Sources: Animal sources Liver Kidney Egg yolk Milk Cheese Fish liver oils Plant sources Carrots Papaya, Mangoes Avocado, Melon Pumpkins RDA (Recommended Dietary Allowance): Men - 1000 RE (3500 IU) Women - 800 RE (2500 IU) Children - below 6 years - 350 - 400 µg Retinol - 6-17 years – 600 µg Retinol Pregnancy – 800 µg Retinol Lactation – 950 µg Retinol 1 RE – 1 µg of Retinol 1 IU – 0.3 mg of Retinol Biochemical Functions: Vision - the role of vit A in the process of vision was first elucidated by GEORGE WALD(1968) The events occur in a cyclic process known as Rhodopsin Cycle (or) Wald’s Cycle RODS and CONES: Retina of eye possesses rods and cones Human eye - 10 million rods 5 million cones Rods –Periphery – Dim light vision Cones – Centre – Bright light and color vision Deficiency of Vitamin A: 1) Night Blindness 2) Conjuctival X VITAMIN D ANGUS – Isolated and named it as CALCIFEROL Resembles sterols in structure Functions like hormone Dietary Sources: Fatty acids Fish liver oils Egg yolk Cheese Butter RDA: 400 IU or 10 mg of cholecalciferol Countries with good sunlight – 200 IU or 5 mg Deficiency: 1) RICKETS - In young children aged 6 months to 2 years Due to reduced calcification of young bones Characterized by Growth failure Bone deformity Muscular hypotonia Tetany and convulsions Elevated conc. Of alkaline phosphatase in serum Bony deformities - Bow legs, Deformed pelvis, Pigeon chest, Harrison’s sulcus walking and teething are delayed. OSTEOMALACIA In adults, women, during pregnancy and lactation Prevention: Educating parents to expose their children regularly to sunshine.