Iron Absorption From Plant Heme Iron
Iron Absorption From Plant-Derived Heme Iron: An Experimental Study in Iron-Deficient Women (PHIA)
ETH Zurich
45 participants
Sep 22, 2025
INTERVENTIONAL
Conditions
Summary
Heme, an iron protoporphyin IX complex, consists of a ferrous ion captured in a porphyrin ring acting as a tetradentate ligand. The unique features of heme iron -its unusually high absorption in foods and its resistance to luminal inhibitors of iron absorption- make it a potentially interesting iron fortificant. This study aims to compare fractional iron absorption from two plant-derived heme iron compounds-iron chlorophyllin and soy hemoglobin-with ferrous sulfate (negative control) and porcine hemoglobin (positive control) in iron-deficient women. All four compounds will be intrinsically labeled with stable iron isotopes. Fractional absorption will be assessed 14 days after test meal administration via erythrocyte iron incorporation. Absorption will be tested in two matrices: water and maize porridge (an inhibitory matrix). Each participant will consume all test conditions in a randomized order, allowing for within-subject comparisons.
Eligibility
Inclusion Criteria3
- Serum ferritin \< 45 µg/L (iron depleted)
- Body weight \< 70 kg
- Body mass index 18,5 - 24,9 kg/m2 (normal weight)
Exclusion Criteria18
- Hb \< 120 g/L (anemia)
- CRP \> 5 µg/L (inflammation)
- Strict vegan and vegetarians
- Any metabolic, gastrointestinal kidney or chronic disease
- Consumption of mineral and vitamin supplements since screening and over the study period until last blood sample collection
- Blood transfusion over the past 6 months
- blood donation over the past 6 months
- Significant blood loss (accident, surgery) over the past 6 months
- Women who are pregnant or breast feeding
- Smoker (\> 1 cigarette per week)
- Continuous/long-term use of medication (except for contraceptives)
- Therapeutic iron infusion over the past 6 months,
- Known hypersensitivity or allergy to iron supplements,
- Intention to become pregnant during the course of the studies,
- Known or suspected non-compliance, drug or alcohol abuse,
- Inability to follow the procedures of the studies, e.g. due to language problems, psychological disorders, dementia, etc. of the participant,
- Participation in another study with investigational drug within the 30 days preceding and during the present studies,
- Enrolment of the investigator, his/her family members, employees and other dependent persons
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Interventions
Water with labelled Fe chlorophyllin (54Fe)
Water with labelled soy hemoglobin (58Fe)
Water with labelled ferrous sulfate (58Fe)
Water with labelled porcine hemoglobin (57Fe)
Maize porridge with labelled Fe chlorophyllin (54Fe)
Maize porridge with labelled soy hemoglobin (58Fe)
Maize porridge with labelled ferrous sulfate (57Fe)
Maize porridge with labelled porcine hemoglobin (57Fe)
Locations(1)
View Full Details on ClinicalTrials.gov
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NCT07143890