The Effect of Oral Iron Supplements on Insulin and Glucose Metabolism in Overweight and Obese Women

The study will be a randomized, double-blind, 17-day metabolic intervention trial including 14 days of high-dose or low-dose iron supplementation. A total of 70 overweight or obese (OW/OB) women will be enrolled. Participants will be individually randomized into either the high-iron or low-iron group.

Women in the low-iron group will receive 15 mg of iron as ferrous fumarate daily for 14 days, while women in the high-iron group will receive 195 mg of iron as ferrous sulfate daily for 14 days.

The study consists of three visits in total. On Day 0, a fasting blood sample will be collected and an OGTT will be performed, with additional blood samples collected at 1 hour and 2 hours post-OGTT. The OGTT will be repeated on Day 14, after 14 days of oral iron supplementation, and again on Day 17, four days after oral iron supplementation has been stopped

Study Overview

• Status: Recruiting
• Conditions: Overweight and Obese Women
• Intervention / Treatment: Dietary supplement: 195 mg iron daily; Dietary supplement: 15 mg iron daily

• Study Type: Interventional
• Enrollment (Estimated): 70
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Omar Obeid; Phone Number: +961 1 350 000; Email: oo01@aub.edu.lb

Study Locations

• Lebanon
  • Beirut, Lebanon
    • Recruiting
    • American University of Beirut
    • Contact: Omar Obeid, PhD; Phone Number: +961 1 350 000; Email: oo01@aub.edu.lb

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• BMI ≥ 27.5 kg/m2
• serum ferritin <30 μg/L
• hemoglobin ≥ 11 g/dl
• fasting blood glucose < 5.6 mmol/L

Exclusion Criteria:

• intravenous or high dose oral iron in the preceding 2 months
• medical disorders are known to affect iron absorption or metabolism, or T2DM
• cigarette smoking
• recent blood transfusion or major blood loss

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Other
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Double

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: high-dose iron supplementation; 195 mg iron as ferrous sulfate daily for 14 days	Dietary supplement: 195 mg iron daily; 3 x 65 mg iron as ferrous sulfate
Active Comparator: low-dose iron supplementation; 15 mg iron as ferrous fumarate daily for 14 days	Dietary supplement: 15 mg iron daily; 3 x 5 mg iron as ferrous sulfate

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Blood glucose increase during OGTT Day 0	Blood glucose increase during OGTT before the intake of oral iron for 14 days	Day 0
Blood glucose increase during OGTT Day 14	Blood glucose increase during OGTT after the intake of oral iron for 14 days	Day 14

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Insulin increase during OGTT Day 0	Insulin increase during OGTT before the intake of oral iron for 14 days	Day 0
Insulin increase during OGTT Day 14	Insulin increase during OGTT after the intake of oral iron for 14 days	Day 14
Serum Hepcidin Day 0	Serum Hepcidin measured before the intake of oral iron	Day 0
Serum Hepcidin D14	Serum Hepcidin measured after the intake of oral iron	Day 14
Serum Ferritin Day 0	Serum Ferritin measured before the intake of oral iron	Day 0
Serum Ferritin Day 14	Serum Ferritin measured after the intake of oral iron	Day 14
Soluble Transferrin Receptor (sTfR) Day 0	sTfR measured before the intake of oral iron	Day 0
Soluble Transferrin Receptor (sTfR) Day 14	sTfR measured after the intake of oral iron	Day 14
Hemoglobin Day 0	Hemoglobin measured before the intake of oral iron	Day 0
Hemoglobin Day 14	Hemoglobin measured after the intake of oral iron	Day 14
C-reactive protein (CRP) Day 0	CRP measured before the intake of oral iron	Day 0
C-reactive protein (CRP) Day 14	CRP measured after the intake of oral iron	Day 14
Alpha-1-acid glycoprotein (AGP) Day 0	AGP measured before the intake of oral iron	Day 0
Alpha-1-acid glycoprotein (AGP) Day 14	AGP measured after the intake of oral iron	Day 14
Serum Iron Day 0	Serum Iron measured before the intake of oral iron	Day 0
Serum Iron Day 14	Serum Iron measured after the intake of oral iron	Day 14
Total Iron Binding Capacity (TIBC) Day 0	TIBC measured before the intake of oral iron	Day 0
Total Iron Binding Capacity (TIBC) Day 14	TIBC measured after the intake of oral iron	Day 14
Transferrin Saturation (TSAT) Day 0	TSAT measured before the intake of oral iron	Day 0
Transferrin Saturation (TSAT) Day 14	TSAT measured after the intake of oral iron	Day 14
Transferrin Saturation (TSAT) Day 17	TSAT measured at endpoint	Day 17
Total Iron Binding Capacity (TIBC) Day 17	TIBC measured at endpoint	Day 17
Serum Iron Day 17	Serum Iron measured at endpoint	Day 17
Serum Hepcidin Day 17	Serum Hepcidin measured at endpoint	Day 17
Insulin increase during OGTT Day 17	Insulin increase during OGTT at Endpoint	Day 17
Blood glucose increase during OGTT Day 17	Blood glucose increase during OGTT at Endpoint	Day 17
Fasting blood glucose Day 0	Fasting blood glucose before iron intake	Day 0
Fasting blood glucose Day 14	Fasting blood glucose after iron intake	Day 14
Fasting blood glucose Day 17	Fasting blood glucose at Endpoint	Day 17
Fasting insulin Day 0	Fasting insulin before iron intake	Day 0
Fasting insulin Day 14	Fasting insulin after iron intake	Day 14
Fasting insulin Day 17	Fasting insulin at Endpoint	Day 17
Blood glucose profile measured over the 14 days	blood glucose profile measured by wearable FreeStyle Libre Sensor	Day 0 - Day 14

Collaborators and Investigators

• Sponsor: Nicole Stoffel
• Collaborators: American University of Beirut Medical Center

Study record dates

Study Major Dates

• Study Start (Estimated): December 23, 2025
• Primary Completion (Estimated): June 30, 2026
• Study Completion (Estimated): June 30, 2026

Study Registration Dates

• First Submitted: December 18, 2025
• First Submitted That Met QC Criteria: December 18, 2025
• First Posted (Estimated): January 2, 2026

Study Record Updates

• Last Update Posted (Estimated): January 2, 2026
• Last Update Submitted That Met QC Criteria: December 18, 2025
• Last Verified: December 1, 2025

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Nutrition Disorders; Overnutrition; Body Weight; Pathological Conditions, Signs and Symptoms; Nutritional and Metabolic Diseases; Signs and Symptoms; Overweight
• Other Study ID Numbers: FIND

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