Iron Deficiency (ID)PHIANCT07143890
Iron Absorption From Plant Heme Iron
A study testing Iron chlorophyllin + no-matrix, SoyHb + no-matrix and FeSO4 + no-matrix in people with Iron Deficiency (ID) and Iron Absorption, run by ETH Zurich at 1 site in Switzerland.
Trial 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. Read more about this study
- Who is it for?
- Ages 18 to 45 years, women onlyHealthy volunteers can take part
- Conditions the study is for
- Iron Deficiency (ID), Iron Absorption
- What is being tested?
- Iron chlorophyllin + no-matrix, SoyHb + no-matrix and FeSO4 + no-matrix
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 45 participants
- Where
- 1 siteSwitzerland
- Study dates
- 22 Sep 2025to 26 May 2026
- Phase
- Interventional
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 45 years
- Women only
- Healthy volunteers accepted
- Adult
Who may be able to join
- Serum ferritin < 45 µg/L (iron depleted)
- Body weight < 70 kg
- Body mass index 18,5 - 24,9 kg/m2 (normal weight)
Who cannot join
- 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
Show all 18Show fewer
- 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
Trial locations and contacts
1 site in 1 country.
Switzerland1 site
ETH Zurich, Laboratoy of Clinical Biopharmacy
Zurich, 8092
About this study
Official title: Iron Absorption From Plant-Derived Heme Iron: An Experimental Study in Iron-Deficient Women (PHIA)
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.
- Conditions
- Iron Deficiency (ID), Iron Absorption
- Being tested
- Iron chlorophyllin + no-matrix, SoyHb + no-matrix, FeSO4 + no-matrix, Hb + no-matrix, Iron chlorophyllin + meal-matrix
- Keywords
- Iron sulfate, Iron fortification, plant-derived heme iron, Stable isotopes, Iron bioavailability
- Medical subject headings
- Iron Deficiencies
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Iron chlorophyllin + no-matrixOther
Water with labelled Fe chlorophyllin (54Fe)
SoyHb + no-matrixOther
Water with labelled soy hemoglobin (58Fe)
FeSO4 + no-matrixOther
Water with labelled ferrous sulfate (58Fe)
Hb + no-matrixOther
Water with labelled porcine hemoglobin (57Fe)
Iron chlorophyllin + meal-matrixOther
Maize porridge with labelled Fe chlorophyllin (54Fe)
SoyHb + meal-matrixOther
Maize porridge with labelled soy hemoglobin (58Fe)
FeSO4 + meal-matrixOther
Maize porridge with labelled ferrous sulfate (57Fe)
Hb + meal-matrixOther
Maize porridge with labelled porcine hemoglobin (57Fe)
| Study group | Role | What they receive |
|---|---|---|
| Iron chlorophyllin + Water | Experimental | 3 mg iron as Fe chlorophyllin (54Fe) + water Receives: Other: Iron chlorophyllin + no-matrix |
| Soy hemoglobin + Water | Experimental | 3 mg iron as soy hemoglobin (58Fe) + water Receives: Other: SoyHb + no-matrix |
| Ferrous sulfate + Water (negative control) | Active comparator | 3 mg iron as ferrous sulfate (58Fe) + water Receives: Other: FeSO4 + no-matrix |
| Porcine hemoglobin + Water (positive control) | Active comparator | 3 mg iron as porcine hemoglobin (57Fe) + water Receives: Other: Hb + no-matrix |
| Iron Chlorophyllin + Inhibitory Meal | Experimental | 3 mg iron as Fe chlorophyllin (54Fe) + maize porridge Receives: Other: Iron chlorophyllin + meal-matrix |
| Soy Hemoglobin + Inhibitory Meal | Experimental | 3 mg iron as soy hemoglobin (58Fe) + maize porridge Receives: Other: SoyHb + meal-matrix |
| Ferrous sulfate + Inhibitory Meal (negative control) | Active comparator | 3 mg iron as ferrous sulfate (57Fe) + maize porridge Receives: Other: FeSO4 + meal-matrix |
| Porcine hemoglobin + Inhibitory Meal (positive control) | Active comparator | 3 mg of iron as porcine hemoglobin (57Fe) + maize porridge Receives: Other: Hb + meal-matrix |
What is being measured
The primary outcome is the main question the study is designed to answer.
Fractional Iron Absorption (percent)
Fractional iron absorption will be calculated based on the shift of the iron isotope ratios in the collected blood samples after the administration of the intervention products. Fractional iron absorption will be measured as erythrocyte incorporation of the naturally occurring iron forms with different masses used to label the iron supplements.
Measured: Day 22
Fractional Iron Absorption (percent)
Fractional iron absorption will be calculated based on the shift of the iron isotope ratios in the collected blood samples after the administration of the intervention products. Fractional iron absorption will be measured as erythrocyte incorporation of the naturally occurring iron forms with different masses used to label the iron supplements.
Measured: Day 43
Fractional Iron Absorption (percent)
Fractional iron absorption will be calculated based on the shift of the iron isotope ratios in the collected blood samples after the administration of the intervention products. Fractional iron absorption will be measured as erythrocyte incorporation of the naturally occurring iron forms with different masses used to label the iron supplements.
Measured: Day 64
Secondary outcomes (19)
Hemoglobin (g/dL)
Iron status marker
Measured: Day 1
Hemoglobin (g/dL)
Iron status marker
Measured: Day 22
Hemoglobin (g/dL)
Iron status marker
Measured: Day 43
Hemoglobin (g/dL)
Iron status marker
Measured: Day 64
Serum Ferritin (µg/L)
Iron status marker
Measured: Day 1
Serum Ferritin (µg/L)
Iron status marker
Measured: Day 22
Serum Ferritin (µg/L)
Iron status marker
Measured: Day 43
soluble Transferrin Receptor (mg/L)
Iron status marker
Measured: Day 1
soluble Transferrin Receptor (mg/L)
Iron status marker
Measured: Day 22
soluble Transferrin Receptor (mg/L)
Iron status marker
Measured: Day 43
C-reactive protein (mg/L)
Chronic inflammation marker
Measured: Day 1
C-reactive protein (mg/L)
Chronic inflammation marker
Measured: Day 22
C-reactive protein (mg/L)
Chronic inflammation marker
Measured: Day 43
Alpha-1-acid Glycoprotein (g/L)
Acute inflammation marker
Measured: Day 1
Alpha-1-acid Glycoprotein (g/L)
Acute inflammation marker
Measured: Day 22
Alpha-1-acid Glycoprotein (g/L)
Acute inflammation marker
Measured: Day 43
Hepcidin (ng/mL)
A major regulator of iron absorption
Measured: Day 1
Hepcidin (ng/mL)
A major regulator of iron absorption
Measured: Day 22
Hepcidin (ng/mL)
A major regulator of iron absorption
Measured: Day 43
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted27 Aug 2025
- Study start22 Sep 2025
- Primary completion26 May 2026
- Study completion26 May 2026
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Iron Deficiency (ID)Studies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Prevention
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- Single blind
- Who is masked
- Participant
- Enrolment
- 45 participants (actual)
Sponsor and investigators
- Lead sponsor
- ETH Zurich
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Nicole Stoffel, ETH Zurich
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07143890
- Sponsor's protocol ID
- PHIA
- Acronym
- PHIA
- Status last verified
- Aug 2025
- First submitted
- 20 Aug 2025
- Last updated
- 2 Jun 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 2 Jun 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Iron Absorption From Plant-Derived Heme Iron: An Experimental Study in Iron-Deficient Women (PHIA)
- ClinicalTrials.gov ID
- NCT07143890
- Acronym / sponsor ID
- PHIA / PHIA
- Conditions
- Iron Deficiency (ID), Iron Absorption
- Keywords
- Iron sulfate, Iron fortification, plant-derived heme iron, Stable isotopes, Iron bioavailability
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 45 participants (actual)
- Lead sponsor
- ETH ZurichUniversity, hospital or other
- Study start
- 22 Sep 2025 (actual)
- Primary completion
- 26 May 2026 (actual)
- Study completion
- 26 May 2026 (actual)
- First posted
- 27 Aug 2025 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
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.
Study design
- Primary purpose
- Prevention
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- Single blind (participant)
- Number of arms
- 8
| Arm | Type | Receives |
|---|---|---|
| Iron chlorophyllin + Water | Experimental | Other: Iron chlorophyllin + no-matrix3 mg iron as Fe chlorophyllin (54Fe) + water |
| Soy hemoglobin + Water | Experimental | Other: SoyHb + no-matrix3 mg iron as soy hemoglobin (58Fe) + water |
| Ferrous sulfate + Water (negative control) | Active comparator | Other: FeSO4 + no-matrix3 mg iron as ferrous sulfate (58Fe) + water |
| Porcine hemoglobin + Water (positive control) | Active comparator | Other: Hb + no-matrix3 mg iron as porcine hemoglobin (57Fe) + water |
| Iron Chlorophyllin + Inhibitory Meal | Experimental | Other: Iron chlorophyllin + meal-matrix3 mg iron as Fe chlorophyllin (54Fe) + maize porridge |
| Soy Hemoglobin + Inhibitory Meal | Experimental | Other: SoyHb + meal-matrix3 mg iron as soy hemoglobin (58Fe) + maize porridge |
| Ferrous sulfate + Inhibitory Meal (negative control) | Active comparator | Other: FeSO4 + meal-matrix3 mg iron as ferrous sulfate (57Fe) + maize porridge |
| Porcine hemoglobin + Inhibitory Meal (positive control) | Active comparator | Other: Hb + meal-matrix3 mg of iron as porcine hemoglobin (57Fe) + maize porridge |
Who may qualify
- Ages
- 18 to 45 years
- Sex
- Female only
- Healthy volunteers
- Accepted
- Age groups
- Adult
Key inclusion criteria (3 listed)
- Serum ferritin < 45 µg/L (iron depleted)
- Body weight < 70 kg
- Body mass index 18,5 - 24,9 kg/m2 (normal weight)
Key exclusion criteria (18 listed)
- 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
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Iron chlorophyllin + no-matrixWater with labelled Fe chlorophyllin (54Fe) | Other | Iron chlorophyllin + Water |
| SoyHb + no-matrixWater with labelled soy hemoglobin (58Fe) | Other | Soy hemoglobin + Water |
| FeSO4 + no-matrixWater with labelled ferrous sulfate (58Fe) | Other | Ferrous sulfate + Water (negative control) |
| Hb + no-matrixWater with labelled porcine hemoglobin (57Fe) | Other | Porcine hemoglobin + Water (positive control) |
| Iron chlorophyllin + meal-matrixMaize porridge with labelled Fe chlorophyllin (54Fe) | Other | Iron Chlorophyllin + Inhibitory Meal |
| SoyHb + meal-matrixMaize porridge with labelled soy hemoglobin (58Fe) | Other | Soy Hemoglobin + Inhibitory Meal |
| FeSO4 + meal-matrixMaize porridge with labelled ferrous sulfate (57Fe) | Other | Ferrous sulfate + Inhibitory Meal (negative control) |
| Hb + meal-matrixMaize porridge with labelled porcine hemoglobin (57Fe) | Other | Porcine hemoglobin + Inhibitory Meal (positive control) |
Primary outcome
Fractional Iron Absorption (percent)
Time frame: Day 22
Fractional iron absorption will be calculated based on the shift of the iron isotope ratios in the collected blood samples after the administration of the intervention products. Fractional iron absorption will be measured as erythrocyte incorporation of the naturally occurring iron forms with different masses used to label the iron supplements.
Fractional Iron Absorption (percent)
Time frame: Day 43
Fractional iron absorption will be calculated based on the shift of the iron isotope ratios in the collected blood samples after the administration of the intervention products. Fractional iron absorption will be measured as erythrocyte incorporation of the naturally occurring iron forms with different masses used to label the iron supplements.
Fractional Iron Absorption (percent)
Time frame: Day 64
Fractional iron absorption will be calculated based on the shift of the iron isotope ratios in the collected blood samples after the administration of the intervention products. Fractional iron absorption will be measured as erythrocyte incorporation of the naturally occurring iron forms with different masses used to label the iron supplements.
19 secondary outcomes
Hemoglobin (g/dL)
Time frame: Day 1
Hemoglobin (g/dL)
Time frame: Day 22
Hemoglobin (g/dL)
Time frame: Day 43
Hemoglobin (g/dL)
Time frame: Day 64
Serum Ferritin (µg/L)
Time frame: Day 1
Serum Ferritin (µg/L)
Time frame: Day 22
Serum Ferritin (µg/L)
Time frame: Day 43
soluble Transferrin Receptor (mg/L)
Time frame: Day 1
soluble Transferrin Receptor (mg/L)
Time frame: Day 22
soluble Transferrin Receptor (mg/L)
Time frame: Day 43
C-reactive protein (mg/L)
Time frame: Day 1
C-reactive protein (mg/L)
Time frame: Day 22
C-reactive protein (mg/L)
Time frame: Day 43
Alpha-1-acid Glycoprotein (g/L)
Time frame: Day 1
Alpha-1-acid Glycoprotein (g/L)
Time frame: Day 22
Alpha-1-acid Glycoprotein (g/L)
Time frame: Day 43
Hepcidin (ng/mL)
Time frame: Day 1
Hepcidin (ng/mL)
Time frame: Day 22
Hepcidin (ng/mL)
Time frame: Day 43
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 2 Jun 2026.
- Individual participant dataSharing planned: No
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
The record lists no contact. Use the official record to reach the sponsor.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Iron chlorophyllin + no-matrix, SoyHb + no-matrix and FeSO4 + no-matrix in people with Iron Deficiency (ID) and Iron Absorption, run by ETH Zurich at 1 site in Switzerland.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 3 inclusion and 18 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 2 Jun 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Switzerland. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Fractional Iron Absorption (percent) (time frame: Day 22). The study lists 3 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 2 Jun 2026; AzTrials last refreshed its copy on 26 Oct 2026.