Biodisponibilidade de ferro em feijão (Phaseolus vulgaris L.) usando o 59Fe marcado intrínsecamente

Abstract

The common bean (Phaseolus vulgaris) is widely consumed in Brazil, especially in the Northeast, in which it is a component of the basic regional diet (RBD). Beans furnish important quantities of proteins and iron, therefore, is indicated in the prevention/treatment of anemia, since the prevalence of iron deficiency is a national and world-wide problem and it results in increased mortality and morbidity rates, decreased labor productivity, and impaired mental development, which reduces the capacity of people to have healthy and productive life. Several attempts are made to supply the necessary quota of iron through diet. One of them is the use of the alternative feeding. In Brazil, alternative feeding aims at, among other things, the recovery of nutritional state of iron in children, and as co-adjuvant in the treatment of malnutrition, supplying multi-mixture (MM). Several studies emphasize the importance of the composition of the diet for the recovery and/or maintenance of the nutritional state toward iron. The determination of the total iron content and iron bioavailability in food usually consumed by the population is, therefore, necessary. For this reason, the objective of this research project was to evaluate the bioavailability of iron of the bean Phaseolus vulgaris, “carioca” variety, in iron depleted and non depleted Wistar rats. To produce iron depletion in the animals, they were fed with pre-tested diets for depletion devoid of iron, and a control pre-tested diet based on the AIN-93 diet, for eight weeks. This phase was followed by the test diets: control, AIN-93 extrinsically labeled with 59FeCl3; diet containing carioca beans FF, as exclusive source of iron in accordance with diet AIN-93, and labeled intrinsically with 59Fe; FFMM FF plus multi-mixture; RBD, containing carioca beans as exclusive source of iron intrinsically labeled with 59Fe; and, RBDMM, RBD supplemented with MM, supplied in a single meal. Hemoglobin concentration, weight gain, dietary intake and effectiveness alimentary coefficient were determined in the pretest phase. The iron bioavailability was determined using the whole body animal counting for seven days, using a solid scintillation detector. For the analysis of the centesimal composition of beans, the methodology indicated by the AOAC was used. The iron content from the beans and diets was determined by the technique of X-rays fluorescence. The results were applied to the ANOVA, test t, Tukey at the level of p ≤ 0,05. The hemoglobin concentration, weight gain and dietary intake were bigger in the non-depleted animals than in the iron depleted ones, however, there was no significant difference for the effectiveness alimentary coefficient. Iron bioavailability of the diets did not significantly differ. The supplementation with MM did not exert any influence on the bioavailability of dietary iron in the diets FF and DBR in iron-depleted or non-depleted rats. The magnitude of the bioavailability of dietary iron in all the herein investigated diets was determined by the iron nutritional status of the animals. Thus, it can be concluded that the iron bioavailability of beans (Phaseolus vulgaris), “carioca” variety, was similar to that one presented by the standard source of iron for Wistar rats; being beans, thus, a good source of iron for feeding, due to its high bioavailability.