NCIt definition : A group of organic food substances found in animals and plants in small quantities.
They must be supplied in diet or dietary supplement and are essential for normal metabolism.;
Alternative definition : NCI-GLOSS: A nutrient that the body needs in small amounts to function and stay healthy.
Sources of vitamins are plant and animal food products and dietary supplements. Some
vitamins are made in the human body from food products. Vitamins are either fat-soluble
(can dissolve in fats and oils) or water-soluble (can dissolve in water). Excess fat-soluble
vitamins are stored in the body's fatty tissue, but excess water-soluble vitamins
are removed in the urine. Examples are vitamin A, vitamin C, and vitamin E.; CRCH: A class of micronutrients that regulate and support chemical reactions in the
body.;