Exercise and Galactooligosaccharide Supplementation on Inflammation and Iron Absorption (FexerGOS) (FexerGOS)

Effects of Exercise and Acute and Chronic Galactooligosaccharide Supplementation on Inflammation and Iron Absorption in Female Athletes

Iron depletion is common in female athletes depending on the sports discipline. Endurance and resistance exercise can induce inflammation thereby reducing dietary iron absorption. Galacto-oligosaccharides (GOS) improved iron absorption in young healthy women and infants, and improved gut inflammation in iron-supplemented infants. A stable isotope study will be performed to investigate the effect exercise and acute and chronic GOS supplementation on inflammation and iron absorption in female athletes.

Study Overview

• Status: Completed
• Conditions: Resistance Exercise
• Intervention / Treatment: Dietary supplement: Galactooligosaccharides (GOS)

Detailed Description

Iron depletion is common in athletes, particularly in females, reaching prevalence rates up to 70% depending on the sports discipline. As iron is essential for energy production and oxygen transport, a deficiency can impair performance, especially in endurance athletes. Iron deficiency in athletes may be caused by inadequate intake, but reduced iron absorption and increased losses also seem to play a role. Both endurance and resistance exercise at a high intensity, can induce inflammation resulting in a hepcidin response via interleukin-6 (IL-6) regulation. Hepcidin is the master regulator of systemic iron homeostasis, and a recent study in adult males showed that vigorous exercise decreases dietary iron absorption associated with increases in IL-6 and hepcidin. Iron losses induced by exercise have been attributed to several factors, including gastrointestinal bleeding associated with endothelial damage, haematuria, haemolysis, and increased sweating. Galacto-oligosaccharides (GOS) have been shown to acutely enhance iron absorption in young, healthy women. In Kenyan infants with a high infectious disease burden, chronic GOS administration improved iron absorption and mitigated the negative effects of iron supplementation on gut inflammation, likely mediated by its bifidogenic effect. Whether GOS has the potential of improving iron absorption has not been studied in athletes.

The study aims are to determine 1) the effects of a bout of resistance exercise at 70% 1 repetition maximum (RM) on inflammation, hepcidin and iron absorption in female team athletes; and 2) the effect of acute and chronic GOS supplementation on iron absorption in response to the exercise bout.

The trial will entail two series of three iron absorption conditions separated by six weeks of GOS supplementation (10 g/day). The study participants will be 22 female athletes recruited from the North-West University and Potchefstroom area, South Africa. At baseline, the first series of three iron absorption studies will be conducted, all measuring iron absorption from a supplement administered with labelled ferrous fumarate in the following conditions: 1) after a period of rest; 2) three hours after an acute resistance exercise bout; and 3) three hours after an acute resistance exercise bout, co-administered with GOS. Following this, participants will consume GOS daily for 6 weeks, followed by an identical series of iron absorption studies. Markers of systemic and gut inflammation, hepcidin, microflora composition and iron status indicators before and after the GOS intervention will be determined. In addition, erythrocyte iron incorporation will be determined after both series of isotope studies. Furthermore, the kinetics of isotope appearance, inflammatory markers, and hepcidin for 24 hours during each of the six iron absorption studies will be investigated.

The primary hypotheses are that fractional iron absorption from a supplemental dose of ferrous fumarate will be: 1) lower three hours post exercise than post resting period; 2) higher with co-administration of GOS than without, both before and after six-week GOS intervention; and 3) higher after six-week intervention with GOS compared to baseline.

The secondary hypotheses are: 1) acute exercise bout will result in increased inflammatory and hepcidin response before and after intervention with GOS but the intervention may mediate these two responses; 2) chronic GOS intervention will increase relative abundance of Bifidobacterium spp, reduce gut inflammation and improve gut integrity and gut health; 3) chronic GOS intervention will improve iron status.

• Study Type: Interventional
• Enrollment (Actual): 22
• Phase: Not Applicable

Contacts and Locations

Study Locations

• South Africa
  • North West
    • Potchefstroom, North West, South Africa, 2531
      • Esté Vorster Research Facility

Participation Criteria

Eligibility Criteria

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

Description

Inclusion Criteria:

1. Female athlete.
2. Train at least 6 hours per week at moderate to high intensity.
3. Having low to moderate iron stores.
4. Willingness to consume the study supplement GOS during the intervention period.
5. Willingness not to consume daily nutritional supplements containing >20 mg iron and/or pre- or probiotics (excluding food and beverages containing live cultures such as yoghurt, raw milk and cheese) during the study.
6. Willingness to not take any iron-containing supplements two days before and during the iron absorption study days or vitamin C on the iron absorption study days.

Exclusion Criteria:

1. Haemoglobin <11 g/dl.
2. Treated or self-reported chronic disease, malabsorptive or gastrointestinal disorders (e.g. irritable bowel syndrome, functional bloating).
3. Pregnancy or lactation.
4. Subjects who cannot be expected to comply with the study protocol.
5. Difficulty drawing blood due to poor quality veins.
6. Individuals that have a fear of needles or suffer from vaso-vagal episodes when exposed to blood.
7. Participants who plan to start or stop the use of contraceptives before or during study period.
8. Participants who are lactose intolerant.
9. Participants who donated blood in the past 4 months or plan to donate during the study period.
10. Participants who use chronic anti-inflammatory medication such as corticosteroids or non-steroidal anti-inflammatory medication (NSAIDS).

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Prevention
• 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: Experimental; Participants will receive 10 g of GOS daily for 6 weeks. Fractional iron absorption will be determined pre- and post the 6-week intervention from 3 conditions: 1) after a period of rest; 2) three hours after an acute resistance exercise bout without GOS and 3) three hours after an acute resistance exercise bout, co-administered with 10 g GOS.

Dietary supplement: Galactooligosaccharides (GOS); 10 g of GOS provided as 14 g of powder will be consumed after mixing it in water or yoghurt. The absorption study test drinks administered during the 3 test conditions will be comprised as follows: Post rest period - 50 mg of iron as ferrous fumarate (Fefum) supplement, 6 mg 54Fe as Fefum and 300 ml of water with sucrose and lactose. Post exercise bout - 50 mg of iron as Fefum, 6 mg 58Fe as Fefum and 300 ml of water with sucrose and lactose. Post exercise bout co-administered with GOS - 50 mg of iron as Fefum, 6 mg 57Fe as Fefum and 300 ml of water with 10 g GOS.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
a. Fractional iron absorption (%)	Fractional iron absorption will be measured at rest and after an exercise bout.	Visit 8 (day 29) and 15 (day 92).
b. Fractional iron absorption (%)	Fractional iron absorption will be measured after an exercise bout with and without co-administration of GOS.	Visit 8 (day 29) and 15 (day 92).
c. Fractional iron absorption (%)	Fractional iron absorption will be measured at rest and after an exercise bout before and after a 6-week intervention with GOS.	Visit 8 (day 29) and 15 (day 92).

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Method comparison in the measurement of RBP4 (µmol/L)	Two methods will be compared in the measurement of RBP4 (µmol/L).	Screening
Method comparison in the measurement of Ferritin (µg/L)	Two methods will be compared in the measurement of Ferritin (µg/L).	Screening
Method comparison in the measurement of sTfR (mg/L)	Two methods will be compared in the measurement of sTfR (mg/L).	Screening
Method comparison in the measurement of CRP (mg/L)	Two methods will be compared in the measurement of CRP (mg/L).	Screening
Method comparison in the measurement of AGP (g/L)	Two methods will be compared in the measurement of AGP (g/L).	Screening
Method comparison in the measurement of I-FABP (pg/mL)	Two methods will be compared in the measurement of I-FABP (pg/mL).	Screening
Method comparison in the measurement of Thyroglobulin (µg/L)	Two methods will be compared in the measurement of Thyroglobulin (µg/L).	Screening
Interleukin 6 (pg/mL)	Interleukin 6 (IL-6) will be measured over 24 hours after rest and after exercise as a marker of exercise-induced inflammation.	Visits 2 (day 1), 3 (day 2), 4 (day 8), 5 (day 9), 6 (day 15), 7 (day 16), 9 (day 64), 10 (day 65), 11 (day 71), 12 (day 72), 13 (day 78) and 14 (day 79)
C-reactive protein (mg/L)	C-reactive protein (CRP) will be measured in plasma to detect the presence of acute inflammation.	Visits 2 (day 1), 4 (day 8), 6 (day 15), 9 (day 64), 11 (day 71) and 13 (day 78).
Alpha-1-acid glycoprotein (g/L)	Alpha-1-acid glycoprotein (AGP) will be measured in plasma to determine the presence of chronic inflammation.	Visits 2 (day 1), 4 (day 8), 6 (day 15), 9 (day 64), 11 (day 71) and 13 (day 78).
Hepcidin (ng/mL)	Hepcidin, a major regulator of iron absorption and influenced by exercise-induced inflammation, will be measured in plasma over 24 hours.	Visits 2 (day 1), 3 (day 2), 4 (day 8), 5 (day 9), 6 (day 15), 7 (day 16), 9 (day 64), 10 (day 65), 11 (day 71), 12 (day 72), 13 (day 78) and 14 (day 79)
Lipid mediators (pg/µL )	The following lipid mediators will be measured over 24 hours in plasma in response to exercise-induced inflammation:17-hydroxydocosahexaenoicacid (17-HDHA); 5-, 8-, 9-, 11-, 12-, 15 and 18- hydroxyeicosapentaenoicacid (HEPE); 5-, 8-, 11-, 12- and 15-hydroxyeicosatetraenoicacid (HETE); prostaglandin (PG) E2 and D2, and resolvin (Rv) D1 and E1).	Visits 2 (day 1), 3 (day 2), 4 (day 8), 5 (day 9), 6 (day 15), 7 (day 16), 9 (day 64), 10 (day 65), 11 (day 71), 12 (day 72), 13 (day 78) and 14 (day 79)
Erythropoietin (mIU/mL)	Plasma erythropoietin, a marker of erythropoiesis, will be measured before and after period of rest and exercise.	Visits 2 (day 1), 4 (day 8), 6 (day 15), 9 (day 64), 11 (day 71) and 13 (day 78).
Serum iron isotope (%)	Kinetics of serum iron isotope appearance during a period of rest and post-exercise, before and after intervention with GOS, and with and without co-administration of GOS.	Visits 2 (day 1), 3 (day 2), 4 (day 8), 5 (day 9), 6 (day 15), 7 (day 16), 9 (day 64), 10 (day 65), 11 (day 71), 12 (day 72), 13 (day 78) and 14 (day 79).
Gut microbial composition	Gut microbiota profile will be assessed at baseline and endpoint.	Visit 8 (day 29) and 15 (day 92).
Faecal short chain fatty acids (µmol/g)	Concentration of short chain fatty acids - acetate, propionate, isobutyrate, butyrate, formate, isovalerate will be measured in faecal samples before and after the 6-week intervention with GOS.	Visit 8 (day 29) and 15 (day 92).
Faecal pH	Faecal pH will be measured at baseline and endpoint to determine a response to the GOS intervention.	Visit 8 (day 29) and 15 (day 92).
Faecal calprotectin (µg/g)	Faecal calprotectin will be measured at baseline and endpoint as a marker of gut inflammation.	Visit 8 (day 29) and 15 (day 92).
Faecal zonulin (ng/mL)	Faecal zonulin will be measured at baseline and endpoint as a marker of the integrity of the intestinal mucosal barrier.	Visit 8 (day 29) and 15 (day 92).
Intestinal fatty acid-binding protein (pg/mL)	Intestinal fatty acid-binding protein (I-FABP), a marker of intestinal damage, will be measured in plasma at baseline and endpoint.	Screening, Visits 4 (day 8), 8 (day 29), 9 (day 64), 11 (day 71) and 15 (day 92).
Haemoglobin (g/dL)	Haemoglobin will be measured in whole blood to determine presence of anaemia and for calculation of fractional iron absorption.	Screening,Visit 8 (day 29), 9 (day 64) and 15 (day 92).
Ferritin (µg/L)	Ferritin will be measured in plasma to determine the presence of iron deficiency.	Screening, Visits 2 (day 1) and 9 (day 64).
Soluble transferrin receptor (mg/L)	Soluble transferrin receptor (sTfR) will be measured in plasma to determine the presence of iron deficiency.	Screening, Visits 2 (day 1) and 9 (day 64).
Retinol-binding protein 4 (µmol/L)	Retinol-binding protein 4 (RBP4) will be measured in plasma as a marker of vitamin A status.	Screening, Visits 2 (day 1) and 9 (day 64).
Thyroglobulin (µg/L)	Thyroglobulin will be measured in plasma as a marker of iodine status.	Screening, Visits 2 (day 1) and 9 (day 64).
Fibroblast growth factor 21 (pg/mL)	Fibroblast growth factor 21 (FGF-21) will be measured in plasma as a marker of environmental enteric dysfunction (EED).	Screening,Visits 2 (day 1) and 9 (day 64).
Insulin-like growth factor 1	Insulin-like growth factor 1 (IGF-1) will be measured in plasma as on of the markers of environmental enteric dysfunction.	Screening, Visits 2 (day 1) and 9 (day 64).
Dietary intake	Dietary intake will be captured using a quantified food frequency questionnaire.	Screening, Visit 8 (day 29) and 15 (day 92).

Collaborators and Investigators

• Sponsor: North-West University, South Africa
• Collaborators: King's College London; Swiss Federal Institute of Technology
• Investigators: Principal Investigator: Isabelle Herter-Aeberli, ETH Zurich; Principal Investigator: Jesslee du Plessis, North-West University

Study record dates

Study Major Dates

• Study Start (Actual): March 1, 2024
• Primary Completion (Actual): November 19, 2024
• Study Completion (Actual): November 25, 2024

Study Registration Dates

• First Submitted: August 31, 2023
• First Submitted That Met QC Criteria: September 8, 2023
• First Posted (Actual): September 15, 2023

Study Record Updates

• Last Update Posted (Actual): March 25, 2025
• Last Update Submitted That Met QC Criteria: March 10, 2025
• Last Verified: March 1, 2025

More Information

Terms related to this study

• Keywords: inflammation; iron absorption; Galacto-oligosaccharides; female athletes
• Additional Relevant MeSH Terms: Pathologic Processes; Inflammation
• Other Study ID Numbers: F_ExerGOS

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
• product manufactured in and exported from the U.S.: No