FATTY-ACID COMPOSITION OF ERYTHROCYTE-MEMBRANES AFFECTS IRON-ABSORPTION IN RATS

We studied the influence of the fatty acid composition of three differ ent diets on iron absorption in relation to the lipid peroxidation of the erythrocyte membranes. After weaning, three groups of rats were fe d isoenergetic semipurified diets for 16 wk: control diet (containing canola oil and peanut oil), tripalmitin diet (a saturated fatty acid d iet) and a sardine oil diet rich in polyunsaturated fatty acids. Eight rats from each group were administered (FeSO4)-Fe-59 by gastric intub ation for ferrokinetic studies, and six rats from each group were used for several analyses in blood, liver, spleen and erythrocytes. Result s obtained from Fe-59 eliminated in feces and Fe-59 present in plasma, both calculated by the area under the curve and from maximum concentr ation in plasma, indicated that the sardine oil diet induced higher ir on absorption than the control diet. The lipid peroxidation of erythro cyte membranes in rats fed sardine oil was higher than that in control rats due to high membrane's (n-3) polyunsaturated fatty acid content and low alpha-tocopherol level. The Fe-59 in liver and spleen of rats fed the sardine oil diet was higher than in rats fed the control diet, and Fe-59 was diverted to erythrocytes to a greater extent than in ra ts fed the control diet due to their reduced life-span. The sardine oi l diet, by lessening alpha-tocopherol and raising the degree of lipid peroxidation in erythrocytes, augments iron absorption, whereas the tr ipalmitin diet, by protecting erythrocyte membranes from lipid peroxid ation, leads to a lower rate of iron absorption.