Iron bioavailability of cocoa powder as determined by the Hb regeneration efficiency method

Fe deficiency is a public-health problem worldwide, and effective measures for preventing Fe deficiency are needed. The aim of the present study was to determine the bioavailability of Fe in cocoa using the Hb regeneration efficiency (HRE) method. Thirty-five F344/N male weanling rats were fed a low-Fe diet for 4 weeks to deplete body Fe stores. Then, four groups of seven animals each were repleted for 20 d using a modified AIN-93G diet fortified with ferrous sulphate, ferric citrate or two brands of cocoa powder to provide a total dietary Fe concentration of 20 mg/kg. As a negative control, seven rats were maintained on the low-Fe diet. The HRE were 0.733, 0.350, 0.357 and 0.336 for ferrous sulphate, ferric citrate and the two brands of cocoa powder, respectively. The relative biological values (RBV), defined as the ratio of the sample HRE to that of ferrous sulphate, were 0.478, 0.488 and 0.459 for ferric citrate and the two brands of cocoa powder, respectively. The Fe bioavailability of cocoa was significantly less than that of ferrous sulphate and was similar to that of ferric citrate. The difference in Fe bioavailability between the two brands of cocoa powder was negligible. When the negative control was used to correct the data, estimates of the RBV derived from Hb gain were similar to those derived from the HRE. These results suggest that cocoa is a significant source of moderately bioavailable Fe.