Relative bioavailability in adults of iron from a soybean product intended for complementary feeding of infants

Abstract

The relative bioavailability of iron sulphate added to a soybean product intended for use as a fortified product for complementary feeding of infants was determined. Ten adults received 100mg elemental iron in an aqueous Fe(II)-sulphate solution and 1 week later 100 mg elemental iron mixed into 30 g soybean milk powder. Plasma iron concentrations were measured before, and 1, 2, 4, 6, 8 and 10 h after consumption. The area under the concentration/time curve (AUC+), the peak plasma level (t_max) and the relative bioavailability were determined. The peak of the plasma iron level after receiving 100 mg of iron solution was 176.71 ± 39.05 μg/dl at t_max = 2.8 ± 1.03h while it was 139.82 ± 34.47 μg/dl at t_max = 2.4 ± 1.3 h after consuming 30 g of soybean milk product mixed with 100mg iron solution. The relative bioavailability of iron in the soybean product was 45.8% compared to iron solution. Based on these results it is suggested that the soybean product should be fortified with 10 mg/100 g product of iron sulphate to provide 30% of the iron RDA for infants.