Probiotic supplementation can influence sports performance by enhancing nutrient absorption, immune function, and endurance while reducing anxiety and gastrointestinal symptoms.

This review, published in Nutrients, summarises the key evidence related to the efficacy of probiotics in gut modulation and performance in different sports areas. 

Endurance sports

Several clinical trials showed a significant improvement in aerobic capacity and endurance in athletes after probiotic consumption compared to placebo. For example:

  • 4 weeks of probiotics improved running performance in triathletes 
  • Lactobacillus and Bifidobacterium strains for 5 weeks helped the distance covered by marathon runners. Improvements also in their vascular functions
  • An increase in the duration of exercise to failure and oxygen availability was shown after 8 weeks/4 months depending on the sport with a parallel reduction of respiratory infections
  • the only study based on team sports showed a 16% decrease in anxiety and 20% in stress after a 6-week probiotics intervention 

Power sports

Muscular strength is fundamental in power sports. Plenty of evidence shows how probiotics maintain or improve muscle strength and mass in the general population. However, few studies have shown probiotics’ role in athletes’ power performance. Among these: 

  • the cycling performance was improved after an 8-week intervention in triathletes with better power output and fatigue index
  • probiotics and protein supplementation for 60 days led to a significant increase in the one-rep max (17%) and vertical jump power (8%) vs proteins alone
  • the addition of probiotics to proteins also showed better muscle recovery and power performance

Probiotic mechanisms in sporting performance

The benefits of probiotic intake are clear. But how does this work? Here is an overview of the mechanisms known in the sports field. 

Exercise recovery

A fast recovery is essential in intense conditioning and competition training. Thermic shock exposure, mobility, sleep, and medications are common interventions for professional athletes to achieve their best physical performance. Gut microbiome modulation may support recovery from intense exercise as well. For example, 6 weeks of Lactobacillus paracasei intake significantly reduced blood biomarkers or muscle injury and inflammation after intense exercise. Also, a different regime in rugby players improved muscle soreness and sleep quality. 

Nutrient absorption

The gut microbiota plays a fundamental role in the metabolism and use of vital substances, including nutrients that support muscle growth and recovery. Among them, branched-chain amino acids (BCAAs) showed a significant increase after probiotic supplementation with a parallel improvement in exercise execution. Moreover, combining probiotics with whey protein and other macronutrients can improve protein absorption, metabolism, and physical power, prevent fatigue and enhance physiological adaptations to training. 

Gastrointestinal symptoms

Gastrointestinal symptoms (nausea, vomiting, flatulence, etc.) are common, especially in endurance athletes. Probiotics have been demonstrated to benefit patients with gastrointestinal issues. Similarly, recent studies suggest their efficacy in athletes during intense cycling and running. 

Immune function

Due to prolonged and intense exercise outside or in water, professional athletes are at higher risk of upper respiratory infections. This results in a loss of training and competition. Intake of probiotics reduced illness frequency and duration in the general population by 30-55%. However, limited studies investigating their benefits on athletes are available. 

Performance anxiety

Competitions and high-intensity exercise for a long time can lead to anxiety and stress, negatively impacting the athlete’s results. Certain probiotics reduce stress in the general population. Not only. Badminton players showed less anxiety and stress but, on the contrary, better attention and relaxation after probiotics consumption (Lactobacillus Casei Shirota). However, further studies on team and solo sports are needed.  

Conclusions

This review summarises the effect of gut microbiome modulation through multiple probiotic supplementations on different types of sports and their potential mechanisms of action. “In conclusion, the current evidence indicates that probiotic supplementation may benefit athletes’ sporting performance, particularly in respect to the endurance domains.”, the authors say.