biostudies-literatureJung SHOtoki Ham Taiho Foundation3937https://www.ebi.ac.uk/biostudies/studies/S-EPMC12813636biostudies-literatureUnknown17(24)<h4>Background</h4>Postbiotics produced by kefir lactic acid bacteria through bioconversion of polyphenol-rich extract and whey protein are emerging as promising modulators of gut microbiota and muscle health. This study investigated whether <i>Lentilactobacillus kefiri</i> DH5-derived postbiotics, prepared with <i>Cucumis melo</i> L. and whey protein (KP, Kefir lactic acid bacteria-derived postbiotics), improve muscle strength and gut microbiota composition in healthy adults.<h4>Methods</h4>In this 12-week, randomized, double-blind, placebo-controlled trial, participants consumed either KP (6 g/day) or placebo. Handgrip strength, circulating biomarkers, and fecal microbiota profiling (using 16S rRNA sequencing) were analyzed. Correlations between microbial taxa and muscle-related biomarkers were assessed.<h4>Results</h4>KP supplementation significantly increased dominant-hand grip strength and plasma irisin and reduced IL-1β concentrations after 12 weeks, whereas IGF-1, lean mass, and non-dominant grip strength showed no significant changes. Gut microbiota profiling revealed enrichment of <i>Bifidobacterium adolescentis</i>, <i>Latilactobacillus sakei</i>, <i>Lentihominibacter hominis</i>, <i>Mediterraneibacter gnavus</i>, <i>Streptococcus anginosus</i> and <i>Phocaeicola plebeius</i>, with concomitant reductions in <i>Lachnospira eligens</i>, <i>Roseburia inulinivorans</i>, <i>Ruthenibacterium lactatiformans</i> and <i>Vescimonas fastidiosa</i>. Notably, relative abundance of <i>Faecalibacterium prausnitzii</i> was positively correlated with plasma irisin concentration.<h4>Conclusions</h4>KP supplementation produced a modest within-group improvement in grip strength, potentially through gut-muscle axis modulation involving irisin and anti-inflammation pathways. These preliminary findings suggest that kefir-derived postbiotics may have potential relevance for muscle health.NutrientsBioconversion-Based Postbiotics Enhance Muscle Strength and Modulate Gut Microbiota in Healthy Individuals: A Randomized, Double-Blind, Placebo-Controlled Trial.PMC12813636Otoki Ham Taiho FoundationJung SHPark YSeo KHHwang SKim HKim MJfalseBioconversion-Based Postbiotics Enhance Muscle Strength and Modulate Gut Microbiota in Healthy Individuals: A Randomized, Double-Blind, Placebo-Controlled Trial.<h4>Background</h4>Postbiotics produced by kefir lactic acid bacteria through bioconversion of polyphenol-rich extract and whey protein are emerging as promising modulators of gut microbiota and muscle health. This study investigated whether <i>Lentilactobacillus kefiri</i> DH5-derived postbiotics, prepared with <i>Cucumis melo</i> L. and whey protein (KP, Kefir lactic acid bacteria-derived postbiotics), improve muscle strength and gut microbiota composition in healthy adults.<h4>Methods</h4>In this 12-week, randomized, double-blind, placebo-controlled trial, participants consumed either KP (6 g/day) or placebo. Handgrip strength, circulating biomarkers, and fecal microbiota profiling (using 16S rRNA sequencing) were analyzed. Correlations between microbial taxa and muscle-related biomarkers were assessed.<h4>Results</h4>KP supplementation significantly increased dominant-hand grip strength and plasma irisin and reduced IL-1β concentrations after 12 weeks, whereas IGF-1, lean mass, and non-dominant grip strength showed no significant changes. Gut microbiota profiling revealed enrichment of <i>Bifidobacterium adolescentis</i>, <i>Latilactobacillus sakei</i>, <i>Lentihominibacter hominis</i>, <i>Mediterraneibacter gnavus</i>, <i>Streptococcus anginosus</i> and <i>Phocaeicola plebeius</i>, with concomitant reductions in <i>Lachnospira eligens</i>, <i>Roseburia inulinivorans</i>, <i>Ruthenibacterium lactatiformans</i> and <i>Vescimonas fastidiosa</i>. Notably, relative abundance of <i>Faecalibacterium prausnitzii</i> was positively correlated with plasma irisin concentration.<h4>Conclusions</h4>KP supplementation produced a modest within-group improvement in grip strength, potentially through gut-muscle axis modulation involving irisin and anti-inflammation pathways. These preliminary findings suggest that kefir-derived postbiotics may have potential relevance for muscle health.2025-01-01T00:00:00Z2025 Dec2026-06-03T03:16:45.432Z2026-06-03T03:10:50.88ZS-EPMC128136364147088510.3390/nu17243937