Improving Iron Levels in Female Endurance, Intermittent, and Power/Strength Athletes Aged 16-35

NCT06942208 | Recruiting

• 1 other identifier: REB25-0095
• Study Type: interventional
• Target: 36
• Locations: 1 country
• Sites: 1

Brief Summary

The goal of this clinical trial is to learn if different types and doses of oral iron supplements can improve iron levels, athletic performance, and gut health in young female athletes with low iron stores. The main questions it aims to answer are:

• Does a low dose of yeast-bound iron improve iron status better than traditional iron supplements?
• Do the different iron supplements cause fewer or more gastrointestinal (stomach) symptoms?
• How do iron supplements affect exercise performance and gut bacteria? Researchers will compare three types of iron supplements:
• A low-dose iron supplement (40 mg)
• A low-dose yeast-bound iron supplement (40 mg)
• A high-dose iron supplement (150 mg) This will help researchers find out which type of supplement is most effective and easiest on the stomach. Participants will:
• Take one of the three assigned iron supplements every other day for 12 weeks
• Complete fitness tests before and after the study, including cycling and jumping tests
• Give blood samples to measure iron levels
• Provide stool and intestinal samples to study gut bacteria
• Swallow a SIMBA capsule before and after the study to collect a sample from the small intestine
• Complete regular online surveys about sleep, stress, menstrual cycles, and gut symptoms

Conditions

Iron Deficiency

Keywords

iron; iron deficiency; athletic performance; female athlete; iron supplements; ferritin; hemoglobin; gastrointestinal; microbiome; Exercise test; Yeast; Saccharomyces cerevisiae; ferrous sulphate; ferrous sulfate; Body composition; exercise

Outcome Measures

Primary Outcomes (6)

• Iron status blood markers

  A forearm venous blood draw

  Baseline

• Iron status blood markers

  A forearm venous blood draw

  4 weeks

• Iron status blood markers

  A forearm venous blood draw

  8 weeks

• Iron status blood markers

  A forearm venous blood draw

  12 weeks

• Gut microbiota

  Effects of the various iron formulations on the gut microbiota using the SIMBA capsule and stool sample analysis. Fecal Collection: Participants will provide two stool samples to assess fecal metabolites and gut microbiota composition. Participants will be provided a stool sample collection kit that will allow them to collect the sample in the privacy of their home. The kit will contain all necessary instructions and materials required to perform the collection. Gut microbiome Assessment: Participants will ingest a SIMBA capsule pre and post intervention. The capsule captures a small fluid sample from the small intestine, which will be retrieved upon excretion to examine the gut microbiome.

  Baseline

• Gut microbiota

  Effects of the various iron formulations on the gut microbiota using the SIMBA capsule and stool sample analysis. Fecal Collection: Participants will provide two stool samples to assess fecal metabolites and gut microbiota composition. Participants will be provided a stool sample collection kit that will allow them to collect the sample in the privacy of their home. The kit will contain all necessary instructions and materials required to perform the collection. Gut microbiome Assessment: Participants will ingest a SIMBA capsule pre and post intervention. The capsule captures a small fluid sample from the small intestine, which will be retrieved upon excretion to examine the gut microbiome.

  12 weeks

Secondary Outcomes (20)

• VO2 Max

  Baseline

• VO2 Max

  12 weeks

• Wingate

  Baseline

• Wingate

  12 weeks

• Countermovement jump test

  Baseline

Study Arms (3)

Low dose iron supplement

ACTIVE COMPARATOR

This supplement consists of encapsulated ferrous sulphate (40 mg elemental iron).

Dietary Supplement: Low-dose iron (ferrous sulfate)

Low dose iron supplement bound to yeast

EXPERIMENTAL

Low dose iron (40 mg elemental iron) in the form of yeast-bound iron, specifically Lalmin® Fe10. This supplement consists of encapsulated ferrous sulphate complexed with inactivated Saccharomyces cerevisiae (nutritional yeast).

Dietary Supplement: Yeast-bound iron (ferrous sulfate)

High dose iron supplement

ACTIVE COMPARATOR

This supplement consists of encapsulated ferrous sulphate (150 mg elemental iron).

Dietary Supplement: High-dose iron (ferrous sulfate)

Interventions

Low-dose iron (ferrous sulfate) DIETARY_SUPPLEMENT

Encapsulated low-dose ferrous sulphate (40mg elemental iron)

Low dose iron supplement

Yeast-bound iron (ferrous sulfate) DIETARY_SUPPLEMENT

Encapsulated yeast-bound low-dose ferrous sulphate (40mg elemental iron)

Low dose iron supplement bound to yeast

High-dose iron (ferrous sulfate) DIETARY_SUPPLEMENT

Encapsulated high-dose ferrous sulphate (150mg elemental iron)

High dose iron supplement

Eligibility Criteria

• Age: 16 Years - 35 Years
• Sex: female
• Healthy Volunteers: Yes
• Age Groups: Child (0-17), Adult (18-64)

You may qualify if:

• Biologically female athlete
• Age 16-35
• At least one year past the age of menarche
• Complete and pass the Get Active Questionnaire (GAQ)
• Suboptimal ferritin levels (≤50 mcg/L)
• Provide informed consent to participate in study
• Activity level based on Participant Classification Framework (McKay et al., 2022)
• Tier 3: Highly Trained / National Level
• Tier 4: Elite / International Level
• Energy availability \>30 kcal/kg LBM
• Have access to a smartphone, tablet, or computer
• Able to swallow a capsule sized 25mm length and 8mm width (i.e. large dose omega 3 pill)

You may not qualify if:

• Non-English speaking
• Anemic (hemoglobin \<120g/L)
• Regular prebiotic (fiber) or probiotic use within 4 weeks of study enrollment
• Current laxative use
• Are a smoker or use tobacco products
• Consume \>21 units of alcohol per week
• Have donated blood in the previous 3 months
• Have a BMI \<16 but \>30kg/m2
• Are dieting for weight loss or are following a low carbohydrate diet
• Have participated in another clinical trial within the 30 days preceding study enrollment.
• Known allergy of hypersensitivity to any ingredient, including non-medicinal ingredients, such as iron, yeast, cellulose, or maltodextrin
• Are taking medications known to affect cardiovascular or metabolic responses to exercise such as beta-blockers, anti-coagulants etc. as assessed by the Principal Investigator
• Known history of thalassemia or thalassemia trait
• Known inherited bleeding disorder
• Major surgery in the past 3 months

Sponsors & Collaborators

• University of Calgary: lead
• Mitacs: collaborator
• Natural Sciences and Engineering Research Council, Canada: collaborator

Study Sites (1)

University of Calgary

Calgary, Alberta, T2N 1N4, Canada

RECRUITING

Related Publications (8)

• Pantopoulos K. Oral iron supplementation: new formulations, old questions. Haematologica. 2024 Sep 1;109(9):2790-2801. doi: 10.3324/haematol.2024.284967.

  PMID: 38618666 BACKGROUND

• McKay AKA, Stellingwerff T, Smith ES, Martin DT, Mujika I, Goosey-Tolfrey VL, Sheppard J, Burke LM. Defining Training and Performance Caliber: A Participant Classification Framework. Int J Sports Physiol Perform. 2022 Feb 1;17(2):317-331. doi: 10.1123/ijspp.2021-0451. Epub 2022 Dec 29.

  PMID: 34965513 BACKGROUND

• McKay AKA, Sim M, Moretti D, Hall R, Stellingwerff T, Burden RJ, Peeling P. Methodological Considerations for Investigating Iron Status and Regulation in Exercise and Sport Science Studies. Int J Sport Nutr Exerc Metab. 2022 Apr 1;32(5):359-370. doi: 10.1123/ijsnem.2021-0343. Print 2022 Sep 1.

  PMID: 35365588 BACKGROUND

• McCormick R, Moretti D, McKay AKA, Laarakkers CM, Vanswelm R, Trinder D, Cox GR, Zimmerman MB, Sim M, Goodman C, Dawson B, Peeling P. The Impact of Morning versus Afternoon Exercise on Iron Absorption in Athletes. Med Sci Sports Exerc. 2019 Oct;51(10):2147-2155. doi: 10.1249/MSS.0000000000002026.

  PMID: 31058762 BACKGROUND

• Low MS, Speedy J, Styles CE, De-Regil LM, Pasricha SR. Daily iron supplementation for improving anaemia, iron status and health in menstruating women. Cochrane Database Syst Rev. 2016 Apr 18;4(4):CD009747. doi: 10.1002/14651858.CD009747.pub2.

  PMID: 27087396 BACKGROUND

• Erdman KA, Fung TS, Doyle-Baker PK, Verhoef MJ, Reimer RA. Dietary supplementation of high-performance Canadian athletes by age and gender. Clin J Sport Med. 2007 Nov;17(6):458-64. doi: 10.1097/JSM.0b013e31815aed33.

  PMID: 17993788 BACKGROUND

• Cordova A, Mielgo-Ayuso J, Fernandez-Lazaro CI, Caballero-Garcia A, Roche E, Fernandez-Lazaro D. Effect of Iron Supplementation on the Modulation of Iron Metabolism, Muscle Damage Biomarkers and Cortisol in Professional Cyclists. Nutrients. 2019 Feb 27;11(3):500. doi: 10.3390/nu11030500.

  PMID: 30818782 BACKGROUND

• Attwell C, McKay A, Sim M, Dugan C, Nicholas J, Hopper L, Peeling P. Timing is everything, but does it really matter? Impact of 8-weeks morning versus evening iron supplementation in ballet and contemporary dancers. Eur J Sport Sci. 2023 Dec;23(12):2275-2282. doi: 10.1080/17461391.2023.2224285. Epub 2023 Jul 10.

  PMID: 37291690 BACKGROUND

MeSH Terms

Conditions

Iron Deficiencies; Motor Activity

Interventions

Iron; ferrous sulfate

Condition Hierarchy (Ancestors)

Iron Metabolism Disorders; Metabolic Diseases; Nutritional and Metabolic Diseases; Behavior

Intervention Hierarchy (Ancestors)

Metals, Heavy; Elements; Inorganic Chemicals; Transition Elements; Metals

Study Officials

• Jane Shearer

  University of Calgary

  PRINCIPAL INVESTIGATOR

Central Study Contacts

Lauren Hundseth

CONTACT

(306) 380-5898; lauren.hundseth@ucalgary.ca

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: QUADRUPLE
• Who Masked: PARTICIPANT, CARE PROVIDER, INVESTIGATOR, OUTCOMES ASSESSOR
• Purpose: TREATMENT
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Professor

Study Record Dates

• First Submitted: April 9, 2025
• First Posted: April 24, 2025
• Study Start: March 26, 2026
• Primary Completion (Estimated): September 1, 2026
• Study Completion (Estimated): September 1, 2026
• Last Updated: April 17, 2026

Record last verified: 2026-04

Data Sharing

• IPD Sharing: Will not share

Locations

CA (1)