Problems of mineral supply in industrialized countries.

The main nutritional problems, related to mineral supply, can be seen in two respects: (1) Minerals with sufficiently known parameters, so that RDA have been generally established. Basic knowledge is advanced, open questions are connected with insufficient (Fe, I, Zn, Cu), or excessive (Na) intake, or with imbalances. (2) Metals, occurring in food and needed in metabolism in trace amounts. exact RDA have not been established due to lack in basic knowledge. Open questions are conncected with analytics, bioavailability, requirements, mode of action, effects of deficiency and excess in relation to homeostasis and disease, and in some cases with essentiality. Nutritional problems exist in (a) differences in trace element contents between mother's milk and infant milk formula; (b) the reduction of trace element contents in modern diet due to changing food habits and food processing and refining; (c) increasing information about protective or harmful influences of trace elements upon chronic degenerative diseases: (d) toxicology, including cancerogenicity of trace metals, and (e) relations to pharmaceuticals like contraceptives or to fiber.