Kefir, Gut Microbiota, and Athletic Performance in Soccer Players

NCT06753422 | Completed

• 2 other identifiers: 2024-KefirStudyTDK-2023-91
• Study Type: interventional
• Target: 21
• Locations: 1 country
• Sites: 1

Brief Summary

This research work is a clinical trial that will assess the impact of kefir consumption on the gut microbiota profile and athletic performance of female soccer players of age 18-29 years. The participants were divided into two groups namely the kefir intervention group and the control group. The primary end points are the modifications in the alpha diversity of the gut microbiome and the beta diversity of the gut microbiome and also the athletic performance outcomes like VO2 max and finishing speed which will be measured using the 30-15 Intermittent Fitness Test. The other outcomes of the study are the changes in the body composition (measured through BIA and skinfold), the changes in the dietary intake and the variations in certain microbial genera such as Akkermansia muciniphila and Faecalibacterium prausnitzii. The study will be the first to evaluate whether kefir intake can increase the microbial diversity, increase the VO2max and improve the body composition of professional athletes. The anticipated outcomes of this study are enhanced gut microbial diversity, enhanced VO2max and finishing speed, and positive alteration in the body composition parameters.

Conditions

Gut Microbiota Diversity and Composition; Athletic Performance; Functional Food Intervention (Kefir); Body Composition; Dietary Intake Patterns

Keywords

Kefir; Gut microbiota; Athletic performance; Female Athletes; Functional foods; Body composition; Dietary intake

Outcome Measures

Primary Outcomes (2)

• Gut Microbiota Composition Change

  Changes in gut microbiota diversity and abundance at genus and phylum levels, assessed through 16S rRNA gene sequencing of stool samples.

  At baseline and after 4 weeks of intervention (Week 5)

• Athletic Performance Improvement

  Improvement in athletic performance as measured by the 30-15 Intermittent Fitness Test, evaluating VO2max and finishing speed.

  At baseline and after 4 weeks of intervention (Week 5)

Secondary Outcomes (6)

• Dietary Intake Assessment

  At baseline and after 4 weeks of intervention (Week 5)

• Body weight (kg)

  At baseline and after 4 weeks of intervention (Week 5)

• Body Fat Percentage (%)

  At baseline and after 4 weeks of intervention (Week 5)

• Fat mass (kg)

  At baseline and after 4 weeks of intervention (Week 5)

• Fat-free mass (kg)

  At baseline and after 4 weeks of intervention (Week 5)

Study Arms (2)

Kefir Consumption Group

EXPERIMENTAL

Participants in this group will consume 200 ml of kefir daily for 4 weeks. Their diet will remain ad libitum, with no additional dietary restrictions or standardization applied during the intervention period. The primary intervention in our study is the daily consumption of kefir (200 ml/day). No additional drug or medical device was used during the intervention or data collection process. The study focused solely on kefir consumption and its effects on athletic performance and gut microbiota.

Dietary Supplement: Kefir

Control Group

NO INTERVENTION

Participants in this group will not receive any specific intervention. They will continue their usual diet ad libitum, with no dietary restrictions or standardization applied during the study period.

Interventions

Kefir DIETARY_SUPPLEMENT

200 ml/day kefir The primary intervention in our study is the daily consumption of kefir (200 ml/day). No additional drug or medical device was used during the intervention or data collection process. The study focused solely on kefir consumption and its effects on athletic performance and gut microbiota.

Also known as: Altınkılıç Lactose-free Kefir, The kefir product used in this study was purchased independently with no sponsorship or involvement from the manufacturer

Kefir Consumption Group

Eligibility Criteria

• Age: 18 Years+
• Sex: female
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Professional female soccer player
• Aged between 18 and 35 years
• Regular participation in a structured training program
• No allergy or intolerance to kefir or dairy products
• Willingness to voluntarily participate in the study
• Signed informed consent form

You may not qualify if:

• History of allergy or intolerance to kefir or dairy products
• Presence of chronic diseases (e.g., diabetes, heart disease, kidney failure)
• Use of antibiotics or probiotic supplements within the last 3 months
• Pregnancy or breastfeeding
• Inability to comply with the study protocol

Sponsors & Collaborators

• Acibadem University: lead

Study Sites (1)

Fatih Vatan Sports Club

Istanbul, Istanbul, 34091, Turkey (Türkiye)

Location

MeSH Terms

Interventions

Kefir

Intervention Hierarchy (Ancestors)

Fermented Beverages; Beverages; Diet, Food, and Nutrition; Physiological Phenomena; Cultured Milk Products; Milk; Fermented Foods; Dairy Products; Food; Food and Beverages

Study Officials

• Duygu Sağlam, Associate Professor

  Acibadem University

  STUDY CHAIR

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: NONE
• Purpose: BASIC SCIENCE
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: December 20, 2024
• First Posted: December 31, 2024
• Study Start: May 1, 2024
• Primary Completion: June 5, 2024
• Study Completion: December 1, 2024
• Last Updated: December 31, 2024

Record last verified: 2024-12

Data Sharing

• IPD Sharing: Will share
• Shared Documents: STUDY PROTOCOL, SAP
• Time Frame: De-identified IPD and supporting documents (e.g., Study Protocol, SAP) will be available starting 6 months after publication of primary results and will remain available indefinitely
• Access Criteria: Researchers with a methodologically sound research proposal, approved by an independent ethics committee, will be able to access de-identified individual participant data (IPD) and supporting documents (e.g., Study Protocol, SAP). Data will be shared through a secure online repository upon request. Access will be granted after signing a Data Use Agreement, ensuring data confidentiality and ethical use.

Locations

TU (1)