Iron supplementation is a common approach to address iron deficiency with recommendations for women of childbearing age, particularly those at risk of iron deficiency. Because of its considerably higher absorption, ferrous sulphate is the common iron compound used in iron supplements. However, concerns about iron supplements arise from the knowledge that a large portion of the supplement consumed is not absorbed. This unabsorbed iron travels to the colon and, in preclinical studies, has been shown to promote the growth of enteric pathogens at the expense of beneficial commensal bacteria and increase infection risk, including the clinical incidence of diarrhea. The objective of this study is to compare the effects of iron as ferrous sulfate (FeSO4) or FeSO4-enriched Aspergillus oryzae (Ao iron) on the growth and virulence of common enteric pathogens using an in vitro fecal fermentation model. Stool samples will be collected from women of reproductive age following ingestion of an iron supplement as either FeSO4 or Ao iron. Stool samples will be spiked with common enteric pathogens, and outcome measures will be determined following in vitro fecal fermentation.

Inclusion Criteria:

• Women 18-44 y
• Are able to swallow the iron pills provided for the study
• BMI 18.5 to 29.9 kg/m2
• Willing to provide blood samples
• Willing to collect stool samples

Exclusion Criteria:

• Currently taking any antibiotics
• Iron overload condition/hemochromatosis
• History of chronic gastrointestinal disorders/diseases
• Currently smoke cigarettes (including vaping)
• Have donated blood recently (in the last two weeks)
• Currently taking a vitamin and mineral supplement containing iron
• Pregnant and lactating/breastfeeding women
• Allergic to any of the ingredients (wheat, egg, butter, milk, and baking powder, blue dye) in the muffins

Self-representation of gender identity at birth

This is a double-blind study