Trace Elements in Human Nutrition

Trace elements (trace metals) are minerals present in living tissues in small amounts (trace amounts). Some of them are essential in daily nutrition and play an important function in the human body, for example, as catalysts in enzyme systems; participating in oxidation-reduction reactions in energy metabolism, or involvement with oxygen transport. All trace elements are toxic if they are consumed at sufficiently high levels for long enough periods. The human body requires different amounts of each mineral according to: age, sex, physiological state, and sometimes state of health. The bioavailability of trace elements from foods may be influenced by a variety of factors and depend upon the chemical form of the mineral, other substances present in the diet and, the individual person's needs. Of the elements mentioned in this chapter, the consumption of foods providing adequate amounts of particular trace elements has an important influence on body functioning.