PECTIN WITH LOW-MOLECULAR-WEIGHT AND HIGH-DEGREE OF ESTERIFICATION INCREASES ABSORPTION OF FE-58 IN GROWING RATS

Effects of pectins with different degrees of esterification (DE) and m olecular weights (MW) on iron bioavailability were investigated in hea lthy growing rats by following erythrocyte incorporation of a dose of Fe-58. Rats were fed a control diet for 8 d and then deprived of food for 16 h. Two hours after the start of feeding iron-deficient diets, w ith or without pectin (80 g/kg diet), a dose of FeSO4 rich in Fe-58 (6 0.28%) was intubated into the stomach; rats were then allowed to feed for an additional 4 h before withdrawal of food for 10 h. Rats were th en fed iron-adequate diets for 9 d. The pectins differed in DE and MW, respectively, as follows: P-A (73%, 860,000), P-B (75%, 89,000), P-C (22%, 1,260,000) and P-D (24%, 114,000). Rats fed pectin-free diet wit h free access to food or restricted to the same quantity consumed by a respective pectin group served as controls. Iron absorption was 48% i n the control group and 57% in rats fed PB. Rats fed P-B had higher (P less than or equal to 0.05) serum iron, transferrin saturation, hemat ocrit and liver and spleen iron than the control group or the group fe d P-C. These indices, except for transferrin saturation, were also hig her in rats fed P-A and P-D compared with those fed P-C and controls, but to a lesser extent than in rats fed P-B. The data indicate that bi oavailability of dietary non-heme iron was enhanced when pectin of low MW and high DE was added to the diet. This improvement was not eviden t with pectins having high MW and/or low DE.