Iron and calcium bioavailability of fortified foods and dietary supplements.

Bioavailability is a key consideration when developing strategies for preventing mineral deficiencies through improved dietary supply. Factors that affect the bioavailability of iron and calcium, forms used for fortification and supplementation, and methods used to assess bioavailability are described. Illustrations of the impact of introducing iron-fortified foods in developing and industrialized countries are given, and the alternative approach of supplementation with iron and calcium is discussed.