Our bodies require at least thirteen vitamins and sixteen minerals from food for efficient daily operation. Vitamins are classed as fat-soluble (A, D, E, and K) or water-soluble (the various B vitamins and C). Fat-soluble vitamins must be eaten along with fat in order to be absorbed. They can be stored by the body and, if overconsumed, can build up to harmful levels. Water-soluble vitamins dissolve readily in water and so are easily excreted; they must be supplied frequently to the diet, and excessive intake rarely causes problems. Diets that contain a sufficient quantity and variety of foods easily meet our daily requirements for most of the essential minerals. Sodium is a notable exception, in that we often consume much more than the small quantity we need, in the form of salt, much of it added to processed foods. Many studies link high blood pressure at least in part to excessive use of salt and recommend moderating its use.
