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

Curr Dev Nutr. 2018 Jan 29;2(3):nzy004. doi: 10.1093/cdn/nzy004. eCollection 2018 Mar.


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.

Keywords: Aspergillus oryzae; ferrous sulfate; iron absorption; serum iron; stable iron isotopes.