Fat soluble vitamins a d e k
FAT-SOLUBLE VITAMINS:
The fat-soluble vitamins are those soluble in fats and in fat solvents. Included in this classification are vitamins A, D, E, and K. The role of vitamins as food accessories usually is considered in relation to nutritional deficiencies. It should be pointed out that does of the fat-soluble vitamins, when given far in excess of normal requirements, also can have toxic effects. Vitamin poisoning occurred in a number of arctic explorers, who became seriously ill after eating polar bear liver. There also have been numerous cases of vitamin poisoning in infants. Young mother, eager to fulfill all vitamin requirements of their first offspring, sometimes give overdoses of fat-soluble vitamins. Poisoning by water-soluble vitamins is not possible because any amounts not required are voided from the body in urine.
Each of the fat-insoluble vitamins is discussed briefly in the following sections.
VITAMIN A:
May be obtained from the colouring matter of many green and yellow vegatables. Vitamin A as such, is not found in plants, only b-carotene, its precursor or provitamin. The b-carotene molecule when cleaved in the center of the linear chain and converted at each and to an alcohol function, yields two molecules of vitamin A. Other sources of vitamin A are fish-liver oil, the livers of other animals, eggs, butter, and cheese.