Gut microbes and muscle function: can probiotics make our muscles stronger?

Abstract

Evidence suggests that gut microbiota composition and diversity can be a determinant of skeletal muscle metabolism and functionality. This is true in catabolic (sarcopenia and cachexia) or anabolic (exercise or in athletes) situations. As gut microbiota is known to be causal in the development and worsening of metabolic dysregulation phenotypes such as obesity or insulin resistance, it can regulate, at least partially, skeletal muscle mass and function. Skeletal muscles are physiologically far from the gut. Signals generated by the gut due to its interaction with the gut microbiome (microbial metabolites, gut peptides, lipopolysaccharides, and interleukins) constitute links between gut microbiota activity and skeletal muscle and regulate muscle functionality via modulation of systemic/tissue inflammation as well as insulin sensitivity. The probiotics able to limit sarcopenia and cachexia or promote health performances in rodents are mainly lactic acid bacteria and bifidobacteria. In humans, the same bacteria have been tested, but the scarcity of the studies, the variability of the populations, and the difficulty to measure accurately and with high reproducibility muscle mass and function have not allowed to highlight specific strains able to optimize muscle mass and function. Further studies are required on more defined population, in order to design personalized nutrition. For elderly, testing the efficiency of probiotics according to the degree of frailty, nutritional state, or degree of sarcopenia before supplementation is essential. For exercise, selection of probiotics capable to be efficient in recreational and/or elite athletes, resistance, and/or endurance exercise would also require further attention. Ultimately, a combination of strategies capable to optimize muscle functionality, including bacteria (new microbes, bacterial ecosystems, or mix, more prone to colonize a specific gut ecosystem) associated with prebiotics and other 'traditional' supplements known to stimulate muscle anabolism (e.g. proteins), could be the best way to preserve muscle functionality in healthy individuals at all ages or patients.

Lacticaseibacillus casei CNCM I-5663 supplementation maintained muscle mass in a model of frail rodents

“…In contrast, we saw no tangible benefits arising from strain 62. Over recent years, several studies have tested the health effects of probiotic bacteria in elderly animals [see Giron et al ( 29 ) for a recent review]. To our knowledge, none of this research has applied conditions of food restriction, even though lower food intake contributes to sarcopenia and frailty in elderly people ( 1 , 65 – 69 ).…”

“…Recent studies have found that the gut microbiota and skeletal muscle engage in cross-talk ( 5 , 16 – 20 ), which leads us to hypothesize that strategies targeting gut community composition and function could help frail elderly individuals improve their skeletal muscle health. Indeed, some probiotics have been demonstrated to modulate inflammation, metabolic issues (e.g., age-related declines in insulin sensitivity), and muscle function in juvenile rodents ( 21 – 24 ), adult rodents ( 25 ), and humans of various ages ( 26 – 28 ) [for a review, see Giron et al ( 29 )]. The benefits of probiotics have also been investigated using rodent models of aging [SAMP-8 ( 30 – 32 ) and D-galactose ( 33 )] and animal models of cachexia ( 34 ).…”

Live and Heat-Killed Probiotic Lactobacillus paracasei PS23 Accelerated the Improvement and Recovery of Strength and Damage Biomarkers after Exercise-Induced Muscle Damage

“…Currently, there are no complete studies investigating the mechanism by which probiotic supplementation improves CK and myoglobin. However, in a retrospective study, probiotics were found to help increase short-chain fatty acids (SCFA) in the gut, which in turn increased glycogen concentration and protein digestibility, and promoted muscle repair and recovery [ 60 ]. A past animal study also showed that L. plantarum Tana supplementation for four weeks significantly improved exercise performance and reduced post-exercise blood lactate and blood ammonia levels, as well as CK activity [ 61 ].…”

Underlying mechanisms of acupuncture therapy on polycystic ovary syndrome: Evidences from animal and clinical studies

“…The protein expression of GLUT4 was found to be increased in skeletal muscle, which may be involved in the mechanism of EA on insulin sensitivity. In addition, the gut microbiota is known to be causal in the development of obesity/insulin resistance ( 111 ). A recent study showed that EA intervention decreased body weight, probably through regulating gut microbiota in PCOS rats ( 112 ).…”