Use of stable isotopes to determine bioavailability of minerals in human diets using the method of fecal monitoring.

Use of stable isotopes to determine bioavailability of minerals, by the method of fecal monitoring, in human diets is discussed. Analytical expressions are developed to permit prediction of the accuracy of the method as a function of several variables involved. The effects of extent of absorption, natural abundance of the selected isotope, and the enrichment ratio of administered diet on the accuracy of the estimate of absorption are examined. the method of neutron activation analysis as applied to the isotopic measurement of trace minerals including iron, zinc, copper, chromium, and nickel is briefly discussed. The method of fecal monitoring for zinc and iron is illustrated with data obtained in a healthy adult subject receiving a diet enriched with 70Zn and 58Fe.