Vitamin Vitamin is any of various fat-soluble or water soluble organic substances essential in minute amounts for normal growth and activity of the body and obtained naturally from plant and animal foods Vitamins act as catalysts; very often either the vitamins themselves are coenzymes or they form integral parts of coenzymesVitamin • Vitamin is Any of various fat-soluble or water￾soluble organic substances essential in minute amounts for normal growth and activity of the body and obtained naturally from plant and animal foods. • Vitamins act as catalysts; very often either the vitamins themselves are coenzymes, or they form integral parts of coenzymes