Studies on iron availability in man, using stable isotope techniques

Abstract

1. Iron absorption from 10 mg Fe (as ferrous sulphate), labelled with 1.3 mg⁵⁸Fe, was measured in fasting, non-anaemic adult subjects by the faecal-balance technique. The measurement was performed twice, each subject being given, in random order, either 50 mg Fe or a placebo 18 h before the⁵⁸Fe-labelled FeSO₄.2. The 50 mg Fe load significantly reduced Fe absorption the following day (P< 0.01), from a mean of 35.4 (SEM 4.6)% to 29.0 (SEM 5.1)%. This points to the importance of strict dietary control during Fe-absorption studies to eliminate bias in results.3. In a separate study, the feasibility of using S6Fe-enrichment of erythrocytes, measured by neutron activation analysis (NAA), 10 d after a meal labelled with 0.69 mg⁵⁸Fe as an index of Fe absorption was examined. The levels of⁵⁸Fe in the blood were detectable by NAA. Regression analysis showed a significant relation between⁵⁸Fe-enrichment of blood and⁵⁸Fe absorption, calculated as the difference between intake and faecal excretion (R0.59,P< 0.05).