Iron availability and absorption in rats fed sodium phytate.

Effects of dietary sodium phytate on iron availability and absorption in rats were assessed in two experiments. In the first experiment, iron-deficient rats were switched to diets containing variable levels of added sodium phytate and variable levels of iron as ferrous sulfate. Iron availability was evaluated by measuring hemoglobin regeneration after 2 weeks of feeding these diets. In the second experiment, both iron-adequate and iron-deficient rats were force-fed a slurry containing an iron-deficient diet, 59Fe and sodium phytate. Iron absorption was assessed by measuring the percentage of the 59Fe dose retained by the rats after 9 days. The results of the first experiment indicated that levels of dietary phytate up to 4% of the diet do not impair hemoglobin regeneration by anemic rats. The results of the second experiment indicated that sodium phytate does not affect iron absorption differently in iron-adequate rats compared to iron-deficient rats. It is suggested that conflicting results in the literature on effects of phytate on iron absorption may be explained by differences in experimental conditions or by the presence in the diet of some inhibitory component besides phytate, possibly dietary fiber.