Iron Dialyzability in a Multiple Nutrient Formulation and Effect of the Addition of Separate Nutrients

Introduction: Different nutrients added to nutritional formulations can facilitate, reduce or block the iron absorption. Objective: The aims of this study was to assess the modulation of iron bioavailabily by other minerals and vitamins in an multiple nutrient formulation and in an aqueous iron solution. Material and Methods: We analyzed the iron dialyzability in the multiple nutrients formulation developed to simulate an enteral diet. Furthermore, the iron dialyzability was determined in aqueous solutions containing 25 mg of iron, which were added separately usual amounts of soluble fiber, salt mixture, vitamin mixture, calcium and vitamin C. The dialysed iron was measured by atomic absorption spectrometry. Results: In the multiple nutrients formulation, we documented low bioavailability of iron (0.80 ± 0.01%). Compared with the aqueous iron solution (70.0 ± 6.0%), the addition of 135 mg of vitamin C increased the iron dialyzability (90.0 ± 3.0%). There was reduction of iron dialysis after addition of soluble fiber (1.00 ± 0.01%), the vitamin mixture (25.00 ± 0.12%), salt mixture (2.00 ± 0.06%) and calcium (0.80 ± 0.02%). Conclusion: The low iron bioavailability in the multiple nutrients formulation can be attributed to the protein source and supply of fiber and calcium, thereby affecting the absorption of iron.