Iron Absorption from Iron-Enriched Aspergillus oryzae Is Similar to Ferrous Sulfate in Healthy Female Subjects

Abstract

Background

Iron deficiency anemia (IDA) remains a global health issue, affecting mainly children and adolescent and pregnant women. Because of problems associated with current iron compounds used in both supplementation and fortification areas, there is an emerging interest in new natural iron sources to combat IDA.

Objective

The objective of this study was to compare the iron absorption of iron-enriched Aspergillus oryzae [Aspiron (ASP)] with FeSO₄ in humans.

Methods

Iron absorption was assessed using stable isotope and serum iron response methods after oral intake of iron by healthy women in 2 separate studies. In the first study, ASP was intrinsically labelled with ⁵⁸Fe into a dry form containing 8% iron. Subjects (n = 16, 18–35 y) were randomly assigned to consume liquid semipurified meals labelled with 2 stable iron isotopes, ⁵⁷FeSO₄ (10 mg) and ASP containing 2 mg ⁵⁸Fe and 8 mg natural abundance iron, in 2 visits. Isotope enrichment was measured 2 wk after the last meal was eaten. In the second study, 17 subjects were randomly assigned to consume a test meal with 3 iron supplements during 3 separate visits: FeSO₄, 10 mg Fe, and ASP in 2 iron doses, 10 mg and 20 mg. Changes in serum iron were measured at regular intervals for 4 h after supplementation.

Results

The first study showed that the difference in iron absorption from FeSO₄ and ASP was not significant (17.18% ± 14.2% compared to 15.14% ± 12.3%; P = 0.07). The results of the second study suggested that the iron from ASP was released slowly compared to FeSO₄ and the area under the curve did not reflect the absorption of ASP iron, but rather the rate of iron release.

Conclusions

Iron-enriched A. oryzae has high relative bioavailability and may cause lower iron surges into the blood compared to FeSO₄.