Anemia, Iron DeficiencyFeMicrobiomeNCT06146608
Heme and Non-heme Iron Intakes, Gut Microbiota, and Influence on Host Iron Absorption
An observational study of Anemia, Iron Deficiency and Iron Overload, run by Cornell University at 1 site in United States.
Trial summary
The FeMicrobiome study will evaluate gut microbiome features and their relationships with dietary iron absorption in healthy adults. The investigators hypothesize that (1) the gut microbiota can be shaped by the heme and non-heme Fe content of the diet and that (2) this will influence individual variation in dietary… Read more about this study
- Who is it for?
- Ages 18 to 40 yearsHealthy volunteers can take part
- Conditions the study is for
- Anemia, Iron Deficiency, Iron Overload
- How many people
- 120 participants
- Where
- 1 siteUnited States
- Study dates
- 15 Jan 2023to 14 Jan 2027
- Phase
- Observational
- Are there results?
- Not yet: the study is under way
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 40 years
- All sexes
- Healthy volunteers accepted
- Adult
Study population: 120 healthy adults who habitually consume plant-based diets or habitually consume diets containing animal protein
Who may be able to join
- Healthy adults
- Age between 18- 40y
- Non-smoking
- Not currently taking vitamin, mineral, prebiotic, and probiotic supplements.
- Females: premenopausal and not pregnant or lactating
- No preexisting medical complications (such as eating disorders, hemoglobinopathies, malabsorption diseases, steroid use, substance abuse history, or taking medications known to influence iron homeostasis)
- Body mass index (BMI) between 18 - 27 kg/m2.
Who cannot join
- BMI <18 or > 27 kg/m2,
- Age <18 y or > 40y,
- Smoking
- Pregnancy, lactating
- Have gastrointestinal disorders/malabsorption diseases/hemoglobinopathies/dietary restrictions/steroid use/ medication use of medications known to impact iron status, iron utilization or inflammatory status
- Currently take vitamin, mineral, prebiotic, and probiotic supplements.
- Recently received antibiotic treatment
Trial locations and contacts
1 site in 1 country.
About this study
The FeMicrobiome study will evaluate gut microbiome features and their relationships with dietary iron absorption in healthy adults. The investigators hypothesize that (1) the gut microbiota can be shaped by the heme and non-heme Fe content of the diet and that (2) this will influence individual variation in dietary Fe absorption.
Read the detailed description
Iron is an essential micronutrient ingested as either heme iron (from animal products) or non-heme iron (from both plant and animal sources). Humans have no regulatable means of eliminating absorbed iron, necessitating tight control of dietary iron absorption. Likewise, native microbes have evolved efficient iron sensing and utilization pathways to scavenge iron from the gastrointestinal environment, resulting in a competition for iron between the host and their microbiota. As growing numbers of Americans adopt plant-based diets, heme iron intakes are markedly reduced. This may shift the gut microbiome as some gut microbiota cannot independently synthesize heme and require host dietary heme sources to support their heme-dependent functions. Animal data have recently discovered that other gut microbiota respond to a low iron. To date, significant knowledge gaps exist on the interplay between dietary iron sources, native gut microbes, and iron utilization in humans. In the FeMicrobiome study, study investigators will recruit 120 adults who habitually ingest plant-based diets or habitually ingest diets containing animal protein (e.g., beef, pork, chicken, fish, and seafood). Iron absorption will be measured by using an in vivo, functional approach based on stable iron isotopes (i.e., 57Fe). Study participants will consume 57Fe (as ferrous sulfate) in the fasted state followed by two standardized meals. Two weeks after iron dosing, a blood sample will be collected from each participant and the amount of 57Fe incorporated into red blood cells will be measured using magnetic sector thermal ionization mass spectrometry. A stool sample will be collected near the time of 57Fe consumption. DNA will be extracted from this stool sample and sequenced using a high-depth shotgun metagenomic approach.
- Conditions
- Anemia, Iron Deficiency, Iron Overload
- Medical subject headings
- Anemia, Iron-Deficiency, Iron Overload
What is being measured
The primary outcome is the main question the study is designed to answer.
The percent of non-heme iron absorption
Percent non-heme iron absorption will be determined by red blood cell iron incorporation of stable 57Fe
Measured: 2-week
The concentrations of hemoglobin
The concentrations of hemoglobin (d/dL)
Measured: baseline
The concentrations of ferritin
The concentrations of ferritin (ug/L)
Measured: baseline
Serum transferrin receptor
Serum transferrin receptor in mg/L
Measured: baseline
The hematocrit
Blood hematocrit in %
Measured: baseline
Habitual dietary information
Habitual dietary information will be obtained from Diet History Questionnaire III.
Measured: baseline
Dietary information on the day prior to iron dosing
Detailed dietary information about all foods and beverages consumed on the day prior to iron dosing will be obtained from the Automated Self-Administered 24-Hour Dietary Assessment Tool. Total iron intake will be presented as a proportion of the daily iron requirement. Total heme and non-heme iron intakes will be quantified.
Measured: baseline
Gut microbiome composition
Shotgun metagenomic sequencing will be performed to assess the gut microbiome compositions and gene functional features in a stool sample collected within one day before or after iron dosing.
Measured: baseline
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted24 Nov 2023
- Study start15 Jan 2023
- Primary completion14 Jan 2027 (estimated)
- Study completion14 Jan 2027 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Anemia, Iron DeficiencyStudies 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
- Observational
- Observational model
- Case only
- Time perspective
- Cross-sectional
- Enrolment
- 120 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Cornell University
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor
- Investigators
- KIMBERLY ORA OBRIEN, PhD, Principal investigator, Cornell University
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06146608
- Sponsor's protocol ID
- IRB0147198
- Other IDs
- 2023-67017-39059, 2023
- Acronym
- FeMicrobiome
- Status last verified
- Oct 2026
- First submitted
- 11 Jul 2023
- Last updated
- 23 Oct 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Undecided
Study at a glance
From the registry record, last updated by the sponsor on 23 Oct 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Heme and Non-heme Iron Intakes, Gut Microbiota, and Influence on Host Iron Absorption
- ClinicalTrials.gov ID
- NCT06146608
- Acronym / sponsor ID
- FeMicrobiome / IRB0147198
- Conditions
- Anemia, Iron Deficiency, Iron Overload
- Study type
- Observational
- Recruitment status
- Active, not recruiting
- Enrolment
- 120 participants (estimated)
- Lead sponsor
- Cornell UniversityUniversity, hospital or other
- Study start
- 15 Jan 2023 (actual)
- Primary completion
- 14 Jan 2027 (estimated)
- Study completion
- 14 Jan 2027 (estimated)
- First posted
- 24 Nov 2023 (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.
The FeMicrobiome study will evaluate gut microbiome features and their relationships with dietary iron absorption in healthy adults. The investigators hypothesize that (1) the gut microbiota can be shaped by the heme and non-heme Fe content of the diet and that (2) this will influence individual variation in dietary Fe absorption.
Detailed description
Iron is an essential micronutrient ingested as either heme iron (from animal products) or non-heme iron (from both plant and animal sources). Humans have no regulatable means of eliminating absorbed iron, necessitating tight control of dietary iron absorption. Likewise, native microbes have evolved efficient iron sensing and utilization pathways to scavenge iron from the gastrointestinal environment, resulting in a competition for iron between the host and their microbiota. As growing numbers of Americans adopt plant-based diets, heme iron intakes are markedly reduced. This may shift the gut microbiome as some gut microbiota cannot independently synthesize heme and require host dietary heme sources to support their heme-dependent functions. Animal data have recently discovered that other gut microbiota respond to a low iron. To date, significant knowledge gaps exist on the interplay between dietary iron sources, native gut microbes, and iron utilization in humans. In the FeMicrobiome study, study investigators will recruit 120 adults who habitually ingest plant-based diets or habitually ingest diets containing animal protein (e.g., beef, pork, chicken, fish, and seafood). Iron absorption will be measured by using an in vivo, functional approach based on stable iron isotopes (i.e., 57Fe). Study participants will consume 57Fe (as ferrous sulfate) in the fasted state followed by two standardized meals. Two weeks after iron dosing, a blood sample will be collected from each participant and the amount of 57Fe incorporated into red blood cells will be measured using magnetic sector thermal ionization mass spectrometry. A stool sample will be collected near the time of 57Fe consumption. DNA will be extracted from this stool sample and sequenced using a high-depth shotgun metagenomic approach.
Study design
- Observational model
- Case only
- Time perspective
- Cross-sectional
Who may qualify
- Ages
- 18 to 40 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult
- Study population
- 120 healthy adults who habitually consume plant-based diets or habitually consume diets containing animal protein
Key inclusion criteria (7 listed)
- Healthy adults
- Age between 18- 40y
- Non-smoking
- Not currently taking vitamin, mineral, prebiotic, and probiotic supplements.
- Females: premenopausal and not pregnant or lactating
Key exclusion criteria (7 listed)
- BMI <18 or > 27 kg/m2,
- Age <18 y or > 40y,
- Smoking
- Pregnancy, lactating
- Have gastrointestinal disorders/malabsorption diseases/hemoglobinopathies/dietary restrictions/steroid use/ medication use of medications known to impact iron status, iron utilization or inflammatory status
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Primary outcome
The percent of non-heme iron absorption
Time frame: 2-week
Percent non-heme iron absorption will be determined by red blood cell iron incorporation of stable 57Fe
The concentrations of hemoglobin
Time frame: baseline
The concentrations of hemoglobin (d/dL)
The concentrations of ferritin
Time frame: baseline
The concentrations of ferritin (ug/L)
Serum transferrin receptor
Time frame: baseline
Serum transferrin receptor in mg/L
The hematocrit
Time frame: baseline
Blood hematocrit in %
Habitual dietary information
Time frame: baseline
Habitual dietary information will be obtained from Diet History Questionnaire III.
Dietary information on the day prior to iron dosing
Time frame: baseline
Detailed dietary information about all foods and beverages consumed on the day prior to iron dosing will be obtained from the Automated Self-Administered 24-Hour Dietary Assessment Tool. Total iron intake will be presented as a proportion of the daily iron requirement. Total heme and non-heme iron intakes will be quantified.
Gut microbiome composition
Time frame: baseline
Shotgun metagenomic sequencing will be performed to assess the gut microbiome compositions and gene functional features in a stool sample collected within one day before or after iron dosing.
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 23 Oct 2026.
- Individual participant dataSharing planned: Undecided
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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.
KIMBERLY ORA OBRIEN, PhD principal investigator
Cornell University
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
An observational study of Anemia, Iron Deficiency and Iron Overload, run by Cornell University at 1 site in United States.
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 7 inclusion and 7 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: under way, not looking for participants, as of the sponsor's last update on 23 Oct 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 United States. 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?
This study is still under way. Results are not available in the source record yet.
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?
The percent of non-heme iron absorption (time frame: 2-week). The study lists 8 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 23 Oct 2026.