Heat-treated Lactiplantibacillus plantarum MYO Improves Muscle Strength and Modulates Gut Microbiota in Older Adults with Reduced Muscle Strength

Age-related sarcopenia is a condition characterized by a decline in muscle strength and physical function with aging, and its improvement is important given its close association with falls, fractures, and mortality. Recently, as the link between age-related gut microbiota dysbiosis and sarcopenia has been elucidated, modulation of the gut microbiota has gained attention as a therapeutic strategy for sarcopenia. In particular, with growing interest in paraprobiotics, various health-promoting effects-including gut microbiota modulation and improvement of muscle strength-have been reported. However, clinical evidence supporting the association between the gut microbiota and muscle strength remains limited. Accordingly, this clinical study was conducted to investigate the effects of heat-treated Lactiplantibacillus plantarum MYO (LPMYO) intake on quadriceps muscle strength, hand grip strength, muscle quality index (MQI) and gut microbiota composition in older adults with reduced muscle strength, and to examine the correlation between muscle strength and gut microbiota. After 12 weeks of heat-treated LPMYO supplementation, quadriceps muscle strength, hand grip strength and MQI were significantly improved compared with the placebo group. In addition, the abundance of beneficial bacteria, including Faecalibacterium, Lachnospira, Turicibacter, Megasphaera, and the [Eubacterium]_ventriosum group, was significantly increased. Notably, Turicibacter and Megasphaera showed positive correlations with muscle parameters. In addition, enrichment of predicted microbial functions, such as amino acid metabolism, nicotinate and nicotinamide metabolism, and oxidative phosphorylation (OXPHOS), was observed following supplementation with heat-treated LPMYO. Taken together, heat-treated LPMYO significantly improved muscle strength and muscle quality, and these muscle strength-enhancing effects may be associated with alterations in the gut microbiota.