Determination of iron absorption from intrinsically labeled microencapsulated ferrous fumarate (sprinkles) in infants with different iron and hematologic status by using a dual-stable-isotope method

Background: The use of microencapsulated ferrous fumarate sprinkles is a new approach for home fortification. Iron and hematologic status may affect the absorption of iron from sprinkles. Objective: The objective was to measure the absorption (corrected erythrocyte incorporation of Fe-57) of 2 different doses of iron from sprinkles added to a maize-based complementary food provided to infants with different iron and hematologic status. Design: Infants aged 6-18 mo were randomly assigned to receive either 30 (n = 45) or 45 (n = 45) mg elemental Fe as Fe-57-labeled sprinkles added to a maize-based porridge on 3 consecutive days. A Fe-58 tracer (0.2 mg as ferrous citrate) was also infused intravenously (n = 46). Blood was drawn at baseline and 14 d later to determine erythrocyte incorporation of Fe-57 and Fe-58 by using inductively coupled plasma mass spectrometry. On the basis of hemoglobin and soluble transferrin receptor concentrations, subjects were classified as having iron deficiency anemia (IDA), iron deficiency (ID), or sufficient iron status. Results: There was no significant effect of dose on iron absorption (P > 0.05). Geometric mean iron absorption was 8.25% (range: 2.9-17.8%) in infants with IDA (n = 32),4.48% (range: 1.1-10.6%) in infants with ID (n = 20), and 4.65% (range: 1.5-12.3%) in iron-sufficient infants (n = 20). Geometric mean iron absorption was significantly higher in infants with IDA than in infants with ID or iron-sufficient infants (P = 0.0004); however, there were no significant differences between infants with ID and iron-sufficient infants. Conclusion: During infancy, iron absorption from sprinkles in a maize-based porridge meets and surpasses requirements for absorbed iron and is up-regulated in infants with IDA.