Bioavaliability of Fe, Ca, P and Mg in Fe-deficient rats treated with different sources of dietary iron

Bioavailability of iron from cereal products enriched with dried shittake mushrooms (Lentinula edodes) as determined by iron regeneration efficacy method in female rats

Lentinula edodes shiitake mushrooms are rich sources of iron, which in addition to their relatively high nutritive value are also characterized by high contents of biologically active components. However, recommendation of products prepared on the basis of dried shiitake mushrooms and introduced to the diet as sources of iron requires a precise determination of bioavailability of this element. The purpose of this study was to assess the bioavailability of iron from cereal products with the addition of dried shiitake mushrooms using the iron regeneration efficacy method in Fe-deficient female rats. Feeding products with 10% and 20% addition of dried shiitake to female rats with a previously evoked Fe deficiency resulted in a gradual repletion of lowered Fe indices, including an increase in blood hemoglobin concentration and serum and liver Fe levels to values comparable to those of the control group. Bioavailability of iron from cereal products enriched with dried shiitake mushrooms is comparable to that of Fe(II) gluconate.

Cooking and Fe Fortification Have Different Effects on Fe Bioavailability of Bread and Tortillas

OBJECTIVE

To identify iron sources for wheat- (WF) and corn-flour (CF) fortification taking into account the effect of cooking.

METHODS

Sixty-six Fe-depleted rats were replete with various Fe sources. Fe bioavailability and utilization in wheat bread (WB) and corn tortillas (CT) fortified with various Fe sources was assessed after the depletion and repletion periods.

RESULTS

Baking decreased the phytates content of WF by 97%. Improvements in Hb and FeHb were greater in rats fed unfortified WB than in those fed unfortified WF. Fe fortification had no benefit. In contrast, phytates content was unchanged by tortilla preparation, but fortification improved iron availability. Iron bioavailability indicators were best in rats fed CT fortified with ferrous sulfate and NaFe(III)EDTA than in those fed unfortified CT or CT plus reduced Fe.

CONCLUSION

We concluded that baking WF bread improved the bioavailability of native Fe with no further effect of fortification. Pan-cooking of lime-treated CF did not improve Fe bioavailability, but addition of Ferrous sulfate or NaFe(III)EDTA did it, despite the high phytate and calcium content of tortillas.

Effects of goats' or cows' milks on nutritive utilization of calcium and phosphorus in rats with intestinal resection

We analysed the effects of goats' milk (GM) on the nutritive utilization of Ca and P in rats with resection of 50 % distal small intestine in comparison with cows' milk (CM) and a standard non-milk diet. The three test diets contained 200 g protein and 100 g fat/kg. The apparent digestibility coefficient (ADC) of Ca and P were considerably higher in the two groups of rats given the GM diet than those given the other two diets. Ca and P retention did not decrease by effect of intestinal resection with GM diet. In both groups of animals, serum Ca and P levels and ionic Ca were higher in the case of the GM diet than the other two diets, whereas the parathyroid hormone levels were lower. Ca content in femur, sternum and longissimus dorsi muscle was higher in rats given the GM diet. P content in femur and sternum was higher among the two groups of rats given a milk-based diet (GM or CM), especially with GM diet. The GM diet has beneficial effects on nutritive utilization of Ca and P in control rats and those with resection of the distal small intestine.

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

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.