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NCT Number: NCT06146608

Heme and Non-heme Iron Intakes, Gut Microbiota, and Influence on Host Iron Absorption

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.

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Key information

Conditions

Anemia, Iron Deficiency Anemia Anemia, Hypochromic Anemia, Iron-Deficiency Hematologic Diseases Hemic and Lymphatic Diseases Iron Deficiencies Iron Metabolism Disorders Iron Overload Metabolic Diseases Nutritional and Metabolic Diseases

Age range

18 year–40 year

Sex eligibility

All sexes

Study type

Observational

Primary location

Cornell University

Ithaca, New York, 14853, United States

Location status: Recruiting

Location contact

Kimberly O O'Brien, PhD

CONTACT

[email protected]

607-255-3743

Kimberly O O'Brien, PhD

PRINCIPAL_INVESTIGATOR

About this study

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.

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • 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.

Exclusion criteria

  • 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

Treatment and study plan

Primary outcomes

  1. 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

  2. The concentrations of hemoglobin

    Time frame: baseline

    The concentrations of hemoglobin (d/dL)

  3. The concentrations of ferritin

    Time frame: baseline

    The concentrations of ferritin (ug/L)

  4. Serum transferrin receptor

    Time frame: baseline

    Serum transferrin receptor in mg/L

  5. The hematocrit

    Time frame: baseline

    Blood hematocrit in %

  6. Habitual dietary information

    Time frame: baseline

    Habitual dietary information will be obtained from Diet History Questionnaire III.

  7. 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.

  8. 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.

Study contacts

Contact information is provided by the study sponsor or research team.

Kimberly O O'Brien, PhD

CONTACT

[email protected]

607-255-3743

Sponsors and collaborators

Lead sponsor

Cornell University

Other

Registry information

Acronym: FeMicrobiome

Important dates

Study start
2023
Primary completion
2026
Study completion
2026
First posted
Nov 24, 2023
Registry last updated
Feb 24, 2025

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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