Dietary ascorbic acid raises iron absorption in anaemic rats through enhancing mucosal iron uptake independent of iron solubility in the digesta.

We studied Fe absorption from FeSO4 in rats with Fe deficiency-induced anaemia that were given an Fe-sufficient purified diet without or with ascorbic acid (10.4 g/kg diet). Attention was focused on mucosal Fe uptake as measured in vivo by a double-isotope technique. Haemoglobin repletion and liver Fe levels were not affected when the ascorbic acid-supplemented diet was given, but apparent Fe absorption and retention of orally administered 59Fe were significantly enhanced. The distribution of Fe between liquid and solid phases of contents of both the stomach and the proximal intestine was not affected by the feeding of the ascorbic acid, but ascorbic acid significantly enhanced mucosal Fe uptake. It is concluded that ascorbic acid in the diet raises mucosal Fe uptake through a mechanism independent of the intestinal Fe solubility.