Vitamins differ from macronutrients- in structure, function and amounts.Vitamins are similar to macronutrients- all are vital to life, organic and available from all food groupBoth defecienies and excesses of a vitamin can affect health
Vitamin is derived from the fact that substances are needed for life(vita) and because thiamine happened to be an amine.Not all vitamins are amines or nitrogen containing compounds
A. History.It was first recognized as an essential nutritional factor by Elmer McCollum in1915 and then isolated from fish-liver oil by Holmes in 1917. On account of its established rolein the visual process, it is often called as antixerophthalmic factor or the “bright eyes” vitamin.It was first synthesized in 1946 by Milas.
Vitamin A originates in marine algae, and then passes up the food chain to reach the largecarnivorous animals. Toxic levels of vitamin A may accumulate in the livers of a wide range ofcreatures such as Polar bears, seals, porpoises, dolphins, sharks, whales, Arctic foxes and huskies.Even a small meal of southern Australian seal liver, say 80g, may produce illness in man. Mostof the foods recommended as source of vitamin A contain well below the toxic levels of vitaminA, but one– Halibut liver oil– contains dangerously high amounts of vitamin A.As regards the vitamin A contents of polar animals, one can see that, in reality, very littlequantities of livers of these animals are required to kill a human being : 30–90 g of polar bear liveror halibut liver, 80–240 g of bearded seal liver and 100-300 g of Antarctic husky liver is enoughto kill a human being.
Fat soluble vitamins Vitamin A ppt BIOCHEMISTRY firstname.lastname@example.org
Dr. Vijay Marakala, MBBS, MD.
SIMS & RC