EVALUATION OF IRON BIOAVAILABILITY IN INFANT WEANING FOODS FORTIFIED WITH HEME CONCENTRATE

Background: Nutritional iron deficiency in infants over 4 months of ag e is one of the most common deficiency disorders. Dietary iron is comp rised of non-haem and haem iron, the latter being absorbed by a separa te pathway and more efficiently than non-haerm iron. Fortification of infant weaning foods is one of the strategies adopted for preventing i ron deficiency and the aim of this project was to examine the potentia l use of haem iron concentrate as a fortificant.Methods: Sixteen non-a naemic 6-month old infants were recruited and allocated to two groups of 8. Each infant consumed 2 meals/day of a commercial weaning food (1 00 g) for 7 consecutive days containing 40 mg ascorbic acid and 2.5 mg haem iron/100 g (Group 1) or the same quantity of iron as ferrous sul phate plus 40 mg ascorbic acid (Group 2). Bioavailability was assessed by chemical balance using carmine to mark the beginning and end of th e faecal collection. The effect of haem iron concentrate (as a candida te for the factor in meat that enhances iron absorption) was examined by measuring its effect on Fe-57-labelled non-haem iron absorption. Re sults: There was no difference in iron balance between the two groups. Mean iron retention was 3.5 (SD 2.1) mg/day in Group 1 (haem iron) an d 3.0 (SD 2.4) mg/day in Group 2 (ferrous sulphate), Haem concentrate did not enhance the absorption of Fe-57-labelled non-haem iron, Group 1, 1710 (SD 11.1)%, Group 2: 28.4 (SD 17.7)%. Conclusions: Haem iron c oncentrate appears to be a highly bioavailable form of iron when added to infant weaning foods. This protein is not, however, responsible fo r the enhancing effect of animal protein on non-haem iron absorption.