Do Iron Supplements Impact the Gut Microbiome of Women of Reproductive Age?
Condition: Iron-deficiency; Microbial Colonization; Anemia
MeSH terms: Communicable Diseases; Infections; Iron Deficiencies
Study type: Interventional

Summary: 
      In this randomised controlled trial the investigators will determine whether taking iron
      supplements compared to placebo for 21 days alters the bacteria (microbiome) in the large
      intestine of non-pregnant female participants.
    

Detailed description: 
      BACKGROUND: Many women take iron-containing supplements during pregnancy. Indeed, the World
      Health Organization recommends that all pregnant women in low-income countries take an iron
      supplement containing 60 mg/day of elemental iron to reduce iron deficiency and
      iron-deficiency anaemia. However, oral iron has poor bioavailability, less than 10% absorbed
      with the remainder passing into the large intestine unbound, potentially providing a
      competitive advantage to iron-dependent opportunistic pathogens in the large intestine.

      In a large randomized control trial in children, iron supplementation was shown to promote
      the growth of pathogenic species (E. coli, S. aureus, and L. monocytogenes) and inhibited the
      growth of commensal species (Lactobacillus and Bifidobacterium). These pathogens are
      associated with enteric infections, while the commensals act on the host's immune system to
      prevent colonization and invasion by pathogens.

      It is NOT known if iron supplementation during pregnancy impacts the maternal and infant
      microbiome and, by extension, how this affects the neonatal risk of infection and immune
      dysregulation. Vertical transmission of the maternal microbiome to the newborn is a major
      determinant of infant health. If maternal iron supplementation affects the infant's health,
      strategies would be required to mitigate this risk.

      The investigators require preliminary data to show how oral iron supplementation alters the
      intestinal microbiome in women. The Investigators will recruit non-pregnant female
      participants as there is no risk of vertical transmission to an infant in non-pregnant women.
      The investigators will conduct the study in Australia because there is not a natural
      abundance of pathogens that could potentially cause harm to the women. Nevertheless, the
      investigators would expect a shift in the microbiome from non-iron to iron, requiring
      bacterial species to return to baseline after women stop taking the iron.

      HYPOTHESIS: Daily iron supplementation versus placebo for 21 days will alter the stool
      microbiome composition compared to placebo in non-pregnant female participants of
      reproductive age.

      METHODS: 80 female participants (18-45 y) will be randomized to receive capsules containing
      iron (65.7 mg of elemental iron as ferrous fumarate) or placebo to take daily for 21 days.
      Stool samples will be collected at baseline, 21 days, and 42 days (washout).
    

Intervention name(s): Ferrous Fumarate; Placebo
Intervention type(s): Dietary Supplement; Dietary Supplement
Intervention description(s): Gelatin capsule containing 200 mg ferrous fumarate and microcrystalline cellulose; Gelatin capsule containing microcrystalline cellulose
Other intervention name(s): Iron Fumarate; ferro-tab; Control
Intervention MeSH terms: Ferrous fumarate
Allocation: Randomized
Intervention model: Parallel Assignment
Intervention model description: A randomized, controlled, researcher and participant blinded trial with two parallel groups
Masking: Triple (Participant, Investigator, Outcomes Assessor)
Primary purpose: Other
Keywords: iron supplements; microbiome; women