Article 4 adult 4 controlled study 4 female 4 male microbial diversity nonhuman 4 community structure 3 human 3 microbial community 3 RNA 16S 2 Ruminococcus 2 amino acid metabolism 2 bacterial metabolism 2 bacterium 2 carbohydrate metabolism 2 cohort analysis 2 disease association 2 fatty acid synthesis 2 fermentation 2 intestine flora 2 major clinical study 2 metagenomics 2 operational taxonomic unit 2 population abundance 2 probiotic agent 2 species diversity 2 1,3 propanediol 1 Acinetobacter 1 Actinomyces 1