Optimization of a phytase-containing micronutrient powder with low amounts of highly bioavailable iron for in-home fortification of complementary foods

Background: In-home fortification of complementary foods with micronutrient powders containing low amounts of iron may be potentially safer than powders containing high amounts of iron. However, low iron doses have little nutritional effect, unless iron absorption is high. Objective: The objective was to maximize iron absorption from a low-iron micronutrient powder for in-home fortification by testing combinations of iron as NaFeEDTA, ascorbic acid, and a microbial phytase active at gut pH. In addition, a recently proposed enhancer of iron absorption, L--glycerophosphocholine (GPC), was tested. Design: In 6 separate iron-absorption studies using a crossover design, women (n = 101) consumed whole-maize porridge fortified with 3 mg stable isotope–labeled FeSO4 or NaFeEDTA with different combinations of enhancers added to the meals at the time of consumption. Incorporation of iron isotopes into erythrocytes 14 d later was measured. Results: The addition of phytase when iron was present as either NaFeEDTA or FeSO4, with or without ascorbic acid, significantly increased iron absorption. The combined addition of phytase, ascorbic acid, and NaFeEDTA resulted in an absorption of 7.4%, compared with an absorption of 1.5% from FeSO4 without enhancers in the same meal (P