Differences in gut microbiota associated with age, sex, and stool consistency in healthy Japanese subjectsOriginal paper
Karen Pendergrass is a microbiome researcher specializing in microbiome-targeted interventions (MBTIs). She systematically analyzes scientific literature to identify microbial patterns, develop hypotheses, and validate interventions. As the founder of the Microbiome Signatures Database, she bridges microbiome research with clinical practice. In 2012, based on her own investigative research, she became the first documented case of FMT for Celiac Disease, four years before the first published case study.
Read MoreWhat was studied?
This study examined how the composition of the human gut microbiota relates to age, sex, and stool consistency in healthy adults. Researchers analyzed fecal samples to characterize the gut microbiome and compared microbial community structure and diversity across demographic groups. They also assessed stool consistency using the Bristol stool scale (BSS) and tested its association with microbial composition. The investigation aimed to fill a gap, since sex-related and stool-consistency-related differences in gut microbiota had not been fully characterized previously.
Who was studied?
The study enrolled 277 healthy Japanese subjects ranging in age from 20 to 89 years. Fecal samples were collected from this cohort to profile the gut microbiome. Both sexes were represented, allowing comparisons of microbial structure between males and females and across different age groups.
What were the most important findings?
Overall microbial diversity (alpha-diversity) did not differ significantly by sex or by age group, but the underlying microbial community structure did differ significantly between males and females. Prevotella, Megamonas, Fusobacterium, and Megasphaera were significantly increased in males, while Bifidobacterium, Ruminococcus, and Akkermansia were significantly increased in females. Stool consistency also varied by sex: hard stools (BSS types 1 and 2) were more common in females, loose stools (BSS type 6) were more common in males, and no younger male had hard stool types 1 or 2. Fusobacterium levels in males were significantly higher among those with loose stool consistency.
What are the greatest implications of this study?
These findings suggest that sex and stool consistency, rather than age or overall microbial diversity, are meaningfully linked to variation in gut microbial composition in healthy adults. The association between specific genera, such as Fusobacterium, and stool consistency indicates that bowel habit should be considered as a variable in microbiome research. This has implications for study design, since failing to account for sex and stool consistency could confound comparisons of gut microbiota across populations or in disease-association studies.