Overview
Young women living with obesity (OB) have a greater risk of developing iron deficiency. Plus, the risk of anemia and/or ID in young women living with overweight (OW) and obesity (OB) is further increased by inadequate dietary intake and/or poor bioavailability of iron, as well as gastrointestinal and menstrual iron losses. It is not certain whether women living with OW/OB can meet their iron requirements from their day-to-day diet.
The aim of this study is to compare iron absorption and losses over a long period between women living with and without OW and OB. Secondary outcomes include iron and inflammation status, as well as dietary iron intake.
Description
Adiposity-related inflammation stimulates an increase in secretion of hepcidin hormone thus limiting the absorption of iron and increasing the risk for iron deficiency (ID). In addition, the risk of anemia and/or ID in young women living with overweight (OW) or obesity (OB) is further increased by inadequate dietary intake and/or poor bioavailability of iron, as well as gastrointestinal and menstrual iron losses. Although one study quantified iron losses and absorption in young African women using the stable isotope dilution method the focus was on normal-weight women. Thus, whether women living with OW/OB can meet their iron requirements from their habitual diet remains uncertain.
This is a longitudinal study including an iron absorption study (Phase 1) and a follow-up period (Phase 2) in women living with and without OW and OB.
In phase 1, 70 healthy, mildly- and non-anemic young women living with and without OW or OB will receive a test drink labelled with 15 mg of labelled ferrous sulfate (57Fe) (Visit 1). Fractional iron absorption from the test drink will be determined by measuring the incorporation of the isotopic label into red blood cells 14 days after administration (Visit 2), and will be compared between the two groups. Participants will then undergo a one-year equilibration period. During this time, they will be contacted monthly to ask about their health status, medication and supplements use, blood donation or transfusion, and whether they have fallen pregnant. About 1 year after isotope administration, participants will be contacted again and screened (Visit 3) for phase 2 of the study. Phase 2 of the study will involve 4 visits (Visits 4 to 7), where they will be followed up for 6 months. During this time, blood samples will be drawn every 8 weeks for the determination of isotopic composition. In addition, iron and inflammation status, as well as dietary intake of iron, including its absorption enhancers and inhibitors, will be assessed.
Eligibility
Inclusion Criteria:
- Of African descent
- BMI of 18.5 to 24.9 kg/m2 for participants living without OW/OB and BMI ≥ 28 kg/m2 for participants living with OW/OB
- Having low to moderate inflammation-adjusted iron stores (ferritin ≤50 µg/L)
- Absence of low-grade inflammation (CRP<2 mg/l) for participants living without OW/OB and presence of low-grade inflammation CRP 2-20 mg/l) for participants living with OW/OB
- Planning to reside in the study area for at least 2 years
Exclusion Criteria:
- Hemoglobin < 11 g/dl
- Treated or self-reported chronic or malabsorptive disorder
- Current use of chronic anti-inflammatory medication, like corticosteroids or non-steroidal anti-inflammatory medication
- Pregnancy or planning to become pregnant in the next 2 years
- Lactation
- Fear of needles or experiencing vaso-vagal episodes when exposed to blood
- Difficulty drawing blood due to poor quality veins
- Blood donation in the past 4 months or plans to donate blood during the study
- On a weight-loss diet or program or planning to start the same during the study
- Smoking
- Unwillingness to stop taking iron and /or vitamin C-containing supplements during phase 1 of the study
Additional inclusion criteria applicable to phase 2 of the study
- Labelled with stable iron isotope (tracer) for a minimum of one year
- Willingness not to start or stop contraceptive use during the 6 months
- BMI ≥ 18.5 to 24.9 kg/m2 for participants living without OW/OB and BMI ≥ 28 kg/m2 for participants living with OW/OB
Additional exclusion criteria applicable to phase 2 of the study
- Blood transfusion, intravenous iron infusion, blood donation or significant blood loss during the equilibration period