Table 1.

Existing Facts of Animal and Human Experiments: The Effects of Intestinal Microbiota on Muscle Function and Quantity

References	Objects	Methods	Results	Mechanisms
Fielding et al20	Germ-free mice	Transferred fecal samples from two older adults (high-functioning groups and low-functioning groups) into germ-free mice	HF-colonized mice has stronger grip strength compared with LF-colonized mice	Strengthened the intestinal barrier
Chen et al31	Older people aged 65 and over	Supplementation of probiotics: L.plantarum TWK10 (LP10)	Improvement of muscle strength and endurance	Reduced cytokine production; enhanced glucose utilization
Lee et al23	Mice	Supplementation of Lactobacillus salivarius	Improvement of muscle strength and endurance	Related to the increased BCAA pathway, BCAA can increase themicroorganismMethanobrevibactersmithii, which can use H2 in the colon to convert into SCFA and ATP,thereby providing energy for synthesis of muscle protein.
Lee et al24	Mice	Supplementation of Bifidobacterium longum	Increase of muscle strength, and endurance	Increased intestinal SCFA content
Kazmierczak-Siedlecka et al28	Healthy people and cancer patients	Supplementation of lactobacillus (extracted from pickle)	Improvement of exercise performance, reduction of the muscle loss in cancer patients	Increased iron absorption, reduced the side effects of antibiotics on colonic fermentation
Munukka et al22	Mice	Supplement of Faecalibacterium prausnitzi	Increase of muscle mass	Enhanced mitochondrial respiration; reduced inflammation; improved insulin sensitivity

Abbreviations: BCAA, branched chain amino acid; SCFA, short-chain fatty acids; ATP, adenosine triphosphate.