Probiotic supplementation improves body composition, lipid profiles, and fatty acid metabolism in combat sports athletes during the weight reduction phase.
Yang S, Cheng Z, et al. • Journal of the International Society of Sports Nutrition • 2026
Probiotic supplementation improved body composition, enhanced short-chain fatty acid levels, and decreased circulating free fatty acids in combat sports athletes during a 4-week weight reduction phase, suggesting probiotics may have a beneficial impact on pre-competition weight management.
Key Findings
Results
All athletes experienced decreases in body weight, BMI, body fat percentage, and muscle mass following the 4-week weight loss intervention.
Both the probiotic group (Group E) and placebo group (Group C) underwent a 4-week weight reduction period.
The study included 32 combat sports athletes assigned to either probiotic or placebo conditions.
Reductions in body weight, BMI, body fat percentage, and muscle mass were observed across both groups.
These changes indicate that the weight reduction protocol itself was effective regardless of supplementation.
Results
Probiotic supplementation produced a significantly greater reduction in body fat percentage compared to placebo.
A more significant reduction in body fat percentage was observed in Group E compared to Group C (p < 0.05).
Both groups lost body fat, but the magnitude of reduction was greater in the probiotic group.
The study duration was 4 weeks.
The sample consisted of 32 combat sports athletes split between the two groups.
Results
Probiotic supplementation was associated with lower levels of triglycerides (TG) and low-density lipoprotein cholesterol (LDL-C).
Lower TG and LDL-C levels were observed specifically in Group E (probiotic group).
These lipid profile improvements were noted after the 4-week weight reduction phase.
The specific p-values for TG and LDL-C differences between groups were not individually reported in the abstract beyond being characterized as notably lower in Group E.
This suggests probiotic supplementation may favorably modify lipid metabolism during caloric restriction and weight cutting.
Results
Weight loss intervention increased levels of short-chain fatty acids (SCFAs), including acetic acid, propionic acid, and butyric acid, with significantly higher mean SCFA values in the probiotic group.
SCFAs specifically identified included acetic acid, propionic acid, and butyric acid.
Group E exhibited higher mean values for SCFAs compared to Group C (p < 0.05).
Both groups showed increased SCFA levels following the intervention, but the probiotic group showed a greater increase.
SCFAs are produced through gut microbial fermentation and are associated with metabolic regulation.
Results
Serum levels of γ-linolenic acid and 8,11,14-eicosatrienoic acid were significantly reduced in the probiotic group.
Significant reductions in γ-linolenic acid and 8,11,14-eicosatrienoic acid were observed specifically in Group E (p < 0.05).
These are polyunsaturated fatty acids, and their selective reduction in the probiotic group suggests a specific effect on fatty acid metabolism.
The reduction was not similarly observed or was less pronounced in the placebo group.
This finding suggests probiotics may influence specific pathways of unsaturated fatty acid metabolism.
Results
The majority of free fatty acids (FFAs) increased during the weight loss intervention, with significantly greater increases observed in the placebo group compared to the probiotic group.
Most circulating FFAs showed significant increases during the 4-week weight reduction period across both groups.
Greater magnitudes of FFA change were observed in Group C (placebo) compared to Group E (probiotic) (p < 0.05).
This suggests that probiotic supplementation attenuated the rise in circulating FFAs during weight cutting.
The authors concluded that probiotics can 'decrease circulating FFAs' in combat sports athletes undergoing weight reduction.
What This Means
This research suggests that taking probiotic supplements during the weight-cutting phase before competition may offer measurable metabolic benefits for combat sports athletes beyond weight loss alone. In a 4-week study of 32 combat sports athletes, those who took probiotics lost more body fat and showed better blood lipid profiles—specifically lower triglycerides and LDL (often called 'bad') cholesterol—compared to athletes who took a placebo. Both groups lost weight, but the probiotic group appeared to do so in a way that was more favorable for body composition.
The study also found differences in how fatty acids were handled in the body. Athletes in the probiotic group had higher levels of short-chain fatty acids (SCFAs) like acetic acid, propionic acid, and butyric acid, which are compounds produced by gut bacteria and linked to metabolic health. Additionally, the probiotic group showed smaller increases in circulating free fatty acids during weight loss—a potentially important finding since large spikes in free fatty acids during rapid weight cutting may have metabolic consequences.
This research suggests that probiotic supplementation could be a useful tool for combat sports athletes who need to reduce body weight before competition, potentially helping them lose proportionally more fat while better managing blood lipids and fatty acid metabolism. However, the study was small (32 athletes) and limited to 4 weeks, so further research with larger groups and longer timeframes would be needed to confirm and extend these findings.
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Yang S, Cheng Z, Shen W, Wang J, Lai M, Yu X, et al.. (2026). Probiotic supplementation improves body composition, lipid profiles, and fatty acid metabolism in combat sports athletes during the weight reduction phase.. Journal of the International Society of Sports Nutrition. https://doi.org/10.1080/15502783.2026.2726522