Iron Bioavailability and Utilization in Rats Are Lower from Lime-Treated Corn Flour than from Wheat Flour When They Are Fortified with Different Sources of Iron

Abstract

Although iron bioavailability from wheat flour fortified with iron has been widely studied, the bioavailability of lime-treated corn flour has not been evaluated sufficiently. We compared iron bioavailability and utilization of lime-treated corn flour and wheat flour supplemented with various iron sources. Bioavailability and utilization were determined in Sprague-Dawley rats using the iron balance and hemoglobin depletion-repletion methods. Rats were iron depleted by feeding them a low iron, casein diet for 10 d. During the repletion period, the rats were fed diets based on lime-treated corn flour or wheat flour, both supplemented with ferrous fumarate, ferrous sulfate, ferric citrate and reduced iron for 14 d. Hemoglobin was determined at the end of depletion and repletion periods. The phytate concentration was lower in wheat flour (114 mg/100g) than in lime-treated corn flour (501 mg/100g). Iron bioavailability and utilization by rats were higher from fortified and unfortified wheat flour than from the lime-treated corn flour counterparts. Iron utilization was greater in rats fed wheat flour supplemented with ferrous sulfate, followed by fumarate and citrate than in rats fed reduced iron. In lime-treated corn flour, iron utilization by rats fed unfortified flour and flour fortified with reduced iron did not differ, but utilization was higher in rats fed corn flour fortified with iron sulfate, fumarate and citrate than with reduced iron. We conclude that fortification of lime-treated corn flour with reduced iron has no effect on iron bioavailability or utilization, probably due to the high phytate content. Other iron compounds must be selected to fortify lime-treated corn flour when intended for public nutrition programs.

Effect of Calcium and Phosphorus on Nonhaeme Iron Absorption and Haematogenic Characteristics in Rats

“…This finding was in agreement with [30] who reported that there no differences in food intake and body weight gain among groups fed flours supplemented with reduced and increased iron. From the above results, it could be concluded that supplementation the diets with calcium carbonate (as a source of Ca) and calcium phosphate (as a source of Ca + P) reduced the iron absorption in rats fed these diets, which must be continuous to have a long -term influence on serum ferritin, total iron binding capacity, transferrin saturation, hemoglobin, haematocrit, red blood cell and mean corpuscular volume.…”

Chemical composition and effects of micronized corn bran on iron bioavailability in rats

“…Strube et al (2002) reported lower weight gain (p <0.01) in Sprague-Dawley rats fed an irondeficient diet. Similar behavior was found by Hernández et al (2003) in Sprague-Dawley rats fed a wheat flour diet with low iron levels.…”

“…On the other hand, Hernández et al (2003) reported that Sprague-Dawley rats fed a alkali-cooked corn flour diet showed lower iron absorption and hemoglobin level than those treated with wheat flour. These authors add that this fact must have occurred because the corn flour contained almost four times more DF and phytate, and the alkaline environment may have contributed to reduce Fe absorption since in this environment, the ferric form predominates and is less absorbed than the ferrous form.…”

Iron-Induced Virulence of Salmonella enterica Serovar Typhimurium at the Intestinal Epithelial Interface Can Be Suppressed by Carvacrol

“…Although carvacrol clearly restricted iron uptake of both ferrous sulfate and ferric citrate, it did not block iron uptake completely like tannic acid, a well-known iron binder, did (17). In general, the bioavailability of ferrous iron is better than that of ferric iron (18)(19)(20), but with ferric citrate larger amounts of ferritin were measured than with ferrous sulfate, indicating that in this system the bioavailability of ferric citrate is better. The higher solubility and stability of ferric citrate than those of ferrous sulfate are probably the reasons for this observation.…”