what is vitamin
A vitamin (US /ËvaÉªtÉmÉªn/ and UK /ËvÉªtÉmÉªn/) is an organic compound and a vital nutrient that an organism requires in limited amounts.s a result, most of the fat-soluble vitamins (such as the vitamins A, D, E, and K) that contain amounts above the daily allowance are drug products. The daily dosage of a vitamin supplement for example cannot exceed 300% of the recommended daily allowance, and for vitamin A, this limit is even lower (200%).