Lipids are a large class of compounds, which include fats, oils, waxes and a variety of other compounds such as cholesterol, phospholipids and lipoproteins. Their common properties are insolubility in water, solubility in organic solvents and usability by living organisms. Fats can be defined in three different ways.
Vitamins are nutrients that are essential for maintenance of normal metabolic function. Vitamins cannot be synthesized by mammalian cells and function as cofactors for enzymatic reactions. The water-soluble vitamins play vital roles in the conversion of carbohydrate, protein, and fat into tissue and energy.