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Impact of Probiotics on the Performance of Endurance Athletes: A Systematic Review.
Díaz-Jiménez, J, Sánchez-Sánchez, E, Ordoñez, FJ, Rosety, I, Díaz, AJ, Rosety-Rodriguez, M, Rosety, MÁ, Brenes, F
International journal of environmental research and public health. 2021;18(21)
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The relationship between the gut microbiome and exercise has recently been explored to ascertain potential methods of improving athletic performance. Athletes have begun utilising probiotics to improve performance, support the immune system and reduce gastrointestinal problems, however no systematic review has been done to assess the efficacy behind these notions. The aim of this study is to review the use of probiotics in endurance athletes and assess both the direct and indirect associative factors. This review included nine studies and found improvements in athletic performance, oxidative stress markers, immune support, and incidence of upper respiratory tract infections with probiotic use. While there is little scientific evidence on the causative relationship between probiotics and performance, the authors conclude probiotics can enhance athletic performance by ameliorating the indirect consequences of oxidative stress and infection.
Expert Review
Conflicts of interest:
None
Take Home Message:
- Endurance athletes may take probiotic supplements to support immune or GI health or for other reasons
- Currently there is little evidence that probiotics directly or specifically enhance athletic performance
- Probiotic supplementation potentially impacts on immune health particularly during intensive training and may facilitate muscle recovery or maintain performance
- Whilst probiotics may reduced GI symptom frequency and severity, further research is clearly warranted
Evidence Category:
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A: Meta-analyses, position-stands, randomized-controlled trials (RCTs)
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X
B: Systematic reviews including RCTs of limited number
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C: Non-randomized trials, observational studies, narrative reviews
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D: Case-reports, evidence-based clinical findings
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E: Opinion piece, other
Summary Review:
- There is current interest in the potential therapeutic benefits of probiotic strategies to support training and in-race performance for endurance athletes.
- Probiotic supplements are typically used by endurance athletes to limit or prevent upper respiratory tract infections (URTIs), reduce oxidative stress, support the immune system and modulate gastrointestinal function.
- Based on a limited number of articles sourced in this review (n=26), only 9 met the underlying quality and inclusion criteria. This highlights an important need for further research to be undertaken in this area.
- The review highlighted that different preparations, number of bacterial colony-forming units (CFUs), species type, timecourse and study objectives makes it difficult to determine fundamental conclusions on the efficacy of probiotics.
- That said, papers reviewed indicated the potential for a 55% increase in anti-inflammatory cytokines, reduced prevalence of URTIs, reduced Epstein-Barr and cytomegalovirus citrate antibodies, and improved recovery times.
- Probiotic supplementation likely enhances microbiota diversity and may indirectly support increased training load, and performance maintenance through immune defence. However, there were no indications that endurance performance was specifically enhanced.
Clinical practice applications:
- Most of the papers reviewed used formulae containing either Lactobacillus spp. (e.g. Plantarum, Acidophilus, Casei Shirota) or Bifidobacterium spp. (e.g. animalis subsp., bifidum, lactis, longum subsp.) or combinations. There was little mention of prebiotic or symbiotic strategies.
- Any impact of probiotics on exercise performance is likely to relate to both immune modulation and/or mechanisms leading to reduced muscle damage.
- Surprisingly, there was only partial mention of the use of probiotics for GI support and several notable papers were not included in the review. That said, the authors did note that with increased prevalence of exercise-induced gastrointestinal symptoms with endurance sport due to acute GI hypoperfusion and localised ischemia, acute probiotic strategies have resulted in reduced GI symptom frequency and severity in athletes.
- Importantly no adverse events following probiotic supplementation in endurance athletes were reported.
Considerations for future research:
- Clearly further research is warranted in terms of probiotic strain specific benefits both in training and in-race event effectiveness.
- The authors reported that there were no studies found on the effect of probiotics on hormonal or nervous systems in endurance athletes.
- Further research is needed to consider the impact of acute versus chronic probiotic use on intestinal metabolites, especially considering recent interactions between specific bacterial strains and short-chain fatty acid production being associated with performance (see: https://www.nutrition-evidence.com/article/31235964?term=31235964.
Abstract
BACKGROUND Probiotic supplements contain different strains of living microorganisms that promote the health of the host. These dietary supplements are increasingly being used by athletes to improve different aspects such as athletic performance, upper respiratory tract infections (URTIs), the immune system, oxidative stress, gastrointestinal (GI) problems, etc. This study aimed to identify the current evidence on the management of probiotics in endurance athletes and their relationship with sports performance. METHODS A systematic review of the last five years was carried out in PubMed, Scopus, Web of science, Sportdiscus and Embase databases. RESULTS Nine articles met the quality criteria. Of these, three reported direct benefits on sports performance. The remaining six articles found improvements in the reduction of oxidative stress, increased immune response and decreased incidence of URTIs. There is little scientific evidence on the direct relationship between the administration of probiotics in endurance athletes and sports performance. CONCLUSIONS Benefits were found that probiotics could indirectly influence sports performance by improving other parameters such as the immune system, response to URTIs and decreased oxidative stress, as well as the monitoring of scheduled workouts.
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Danger signals and inflammaging in osteoarthritis.
Millerand, M, Berenbaum, F, Jacques, C
Clinical and experimental rheumatology. 2019;37 Suppl 120(5):48-56
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Osteoarthritis (OA) is the most common and disabling joint disease worldwide and aging is the most important risk factor for its development. It was considered a ‘wear and tear’ disease for a long time, however it is now clear that low-grade inflammation is at the root of OA. This process is called ‘inflammaging’ – the presence of low-grade inflammation and decreased efficiency of the immune system with aging. This highly technical review paper describes the reaction of the immune system to small molecules that begin to circulate after cell stress or damage in the joints (known as damage-associated molecular patterns or DAMPs), causing inflammation. The paper includes a discussion on potential medication targets, including anti-inflammatory compounds such as ginger. Nutrition Practitioners working with OA and wanting to understand the inflammatory process involved will find this paper useful.
Abstract
Osteoarthritis (OA) is the most common age-related chronic and disabling joint disease. Long considered to be a "wear and tear" disease, OA is now seen as a low-grade inflammation disease that affects all tissues of the joint, involving cartilage degradation, bone remodelling, osteophytes, and synovitis. The process, called inflammaging, is characterised by the association of low-grade inflammation, profound changes in intra-cellular mechanisms, and the decreased efficiency of the immune system with ageing. The activation of innate immunity plays a critical role in the development and progression of OA. Innate immunity, including inflammasome activation, is triggered by small endogenous molecules called alarmins or damage-associated molecular patterns (DAMPs). These molecules are released in the extracellular media after cell stress or damage, bind to pathogen-recognition receptors (PRRs), such as Toll-like receptors (TLRs) and the receptor for advanced glycation end products (RAGE), and activate the secretion of pro-inflammatory factors, leading to joint inflammation. Moreover, such sterile inflammation triggers cell senescence, characterised by a senescence-associated secretory phenotype (SASP). Understanding the substantial age-related changes of joint tissues that influence the pathogenesis of OA is critical to improving the quality of life of elderly people in the context of increased life expectancy. This review will focus on age-related sterile inflammation in OA and highlight the various innovative and promising therapies targeting the mechanisms of aging.
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Probiotic Supplements Beneficially Affect Tryptophan-Kynurenine Metabolism and Reduce the Incidence of Upper Respiratory Tract Infections in Trained Athletes: A Randomized, Double-Blinded, Placebo-Controlled Trial.
Strasser, B, Geiger, D, Schauer, M, Gostner, JM, Gatterer, H, Burtscher, M, Fuchs, D
Nutrients. 2016;8(11)
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Moderate physical exercise benefits the immune system. Intensive exercise however, has the opposite effect leading to an increased risk of Upper Respiratory Tract Infections (URTIs). Studies have shown that supplementing probiotics can enhance resistance to URTIs in athletes. During physical exercise, the amino acid tryptophan (Trp) is broken down and may play an important role in the development of infections. Thirty-three athletes took part in this randomized, double-blinded, placebo-controlled trial. One group took a probiotic supplement daily for 12 weeks and the other took a placebo. Serum Trp levels were measured and symptoms of URTIs recorded before and after intensive exercise, at week 1 and week 12. The placebo group had more URTI symptoms during the study and Trp levels decreased. Trp levels remained stable in the probiotics group. Daily supplementation with probiotics was associated with a lower frequency of URTIs in athletes who underwent endurance training. Further investigation is needed to determine the mechanisms involved and to be able to specify how much exercise affects the gut flora.
Abstract
BACKGROUND Prolonged intense exercise has been associated with transient suppression of immune function and an increased risk of infections. In this context, the catabolism of amino acid tryptophan via kynurenine may play an important role. The present study examined the effect of a probiotic supplement on the incidence of upper respiratory tract infections (URTI) and the metabolism of aromatic amino acids after exhaustive aerobic exercise in trained athletes during three months of winter training. METHODS Thirty-three highly trained individuals were randomly assigned to probiotic (PRO, n = 17) or placebo (PLA, n = 16) groups using double blind procedures, receiving either 1 × 1010 colony forming units (CFU) of a multi-species probiotic (Bifidobacterium bifidum W23, Bifidobacterium lactis W51, Enterococcus faecium W54, Lactobacillus acidophilus W22, Lactobacillus brevis W63, and Lactococcus lactis W58) or placebo once per day for 12 weeks. The serum concentrations of tryptophan, phenylalanine and their primary catabolites kynurenine and tyrosine, as well as the concentration of the immune activation marker neopterin were determined at baseline and after 12 weeks, both at rest and immediately after exercise. Participants completed a daily diary to identify any infectious symptoms. RESULTS After 12 weeks of treatment, post-exercise tryptophan levels were lowered by 11% (a significant change) in the PLA group compared to the concentrations measured before the intervention (p = 0.02), but remained unchanged in the PRO group. The ratio of subjects taking the placebo who experienced one or more URTI symptoms was increased 2.2-fold compared to those on probiotics (PLA 0.79, PRO 0.35; p = 0.02). CONCLUSION Data indicate reduced exercise-induced tryptophan degradation rates in the PRO group. Daily supplementation with probiotics limited exercise-induced drops in tryptophan levels and reduced the incidence of URTI, however, did not benefit athletic performance.