Dietary Iron Requirements

Dietary Iron Requirements in US Adults

Dietary Reference Intakes (DRIs) for iron are based on a relatively small number of studies in European populations. This research study will determine iron needs in a representative sample of adults living in the US using the iron isotope dilution technique. Following administration and equilibration of a stable iron isotope, participants will be followed for a 12 week study period. Blood will be collected every 4 weeks and the isotopic composition will be determined. Results will help update dietary iron guidelines making sure they better match the specific needs of the US population.

Study Overview

• Status: Recruiting
• Conditions: Iron Absorption
• Intervention / Treatment: Other: Stable iron isotope

• Study Type: Interventional
• Enrollment (Estimated): 300
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Stephen Hennigar, PhD; Phone Number: 225-763-2612; Email: stephen.hennigar@pbrc.edu

Study Locations

• United States
  • Louisiana
    • Baton Rouge, Louisiana, United States, 70808
      • Recruiting
      • LSU Pennington Biomedical Research Center
      • Contact: Stephen Hennigar, PhD; Phone Number: 225-763-2612; Email: stephen.hennigar@pbrc.edu
  • New York
    • Ithaca, New York, United States, 14853
      • Recruiting
      • Cornell University
      • Contact: Kimberly O'Brien, PhD; Phone Number: 607-255-3743; Email: koo4@cornell.edu

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult
• Accepts Healthy Volunteers: Yes

Study Population

Participants will be enrolled at LSU Pennington Biomedical Research Center in Baton Rouge, Louisiana and Cornell University in Ithaca, New York.

Description

Inclusion Criteria:

• Males and premenopausal females age 18-50 y
• Previously participated in an iron stable isotope study or willing to consume an oral stable iron isotope and undergo a one-year equilibration period
• Willing to refrain from iron-containing supplements for the duration of the study
• Willing to refrain from tobacco smoking for the duration of the study
• Have not donated blood 3 months prior to the start of the study and willing to refrain from donating blood for the duration of the study
• Willing to have blood stored for future use
• Able and willing to comply with study requirements and consent to participate

Exclusion Criteria:

• Females: pregnant or lactating or plans to become pregnant during the study period
• Inability to provide informed consent and engage in informed consent procedures
• Plans to relocate outside the study area

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Other
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: US males and premenopausal females; A representative sample of adult males and premenopausal females living in the US	Other: Stable iron isotope; Stable iron isotopes will be used to determine iron requirements.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Iron isotope composition in blood	Tracer-to-tracee rate in venous blood samples collected at multiple time points	12 weeks

Collaborators and Investigators

• Sponsor: Pennington Biomedical Research Center
• Collaborators: Cornell University

Study record dates

Study Major Dates

• Study Start (Actual): February 6, 2026
• Primary Completion (Estimated): August 1, 2028
• Study Completion (Estimated): May 31, 2029

Study Registration Dates

• First Submitted: August 7, 2025
• First Submitted That Met QC Criteria: August 21, 2025
• First Posted (Actual): August 24, 2025

Study Record Updates

• Last Update Posted (Actual): April 29, 2026
• Last Update Submitted That Met QC Criteria: April 23, 2026
• Last Verified: February 1, 2026

More Information

Terms related to this study

• Keywords: Iron deficiency anemia; Iron deficiency; Iron absorption; Iron isotopes; Iron losses; Iron requirements
• Additional Relevant MeSH Terms: Metabolic Diseases; Hematologic Diseases; Anemia; Iron Metabolism Disorders; Anemia, Hypochromic; Nutritional and Metabolic Diseases; Hemic and Lymphatic Diseases; Iron Deficiencies; Anemia, Iron-Deficiency
• Other Study ID Numbers: 2025-036-PBRC

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No