The time of day when a person has a bowel movement is often considered an ordinary detail with little significance. However, a study published in *Cell Reports Medicine* suggests that this habit may reveal deeper aspects of health, even in individuals who consider themselves completely “healthy.”

The research found that bowel movement patterns are closely linked to changes in the gut microbiome, blood metabolites, and clinical markers associated with liver, kidney, and cardiovascular function.

According to the study, both constipation and unusually frequent bowel movements may represent more than just personal habits. They could serve as early indicators of biological risks that develop silently long before chronic diseases appear.

Bowel Movement Patterns and Overall Health

The study analyzed more than 1,000 individuals who were generally considered healthy. Participants were categorized based on their bowel movement frequency, ranging from constipation to diarrhea. Researchers found that deviations from the “normal” range were associated with measurable changes in the composition of the gut microbiome.

People with fewer weekly bowel movements showed higher levels of bacteria associated with protein fermentation. This metabolic shift promotes the production of microbial toxins that can be harmful to various organs. These bacteria tend to replace those that produce short-chain fatty acids, beneficial compounds that help the intestines function efficiently.

In contrast, individuals with very frequent bowel movements displayed blood markers linked to inflammation, reduced microbial diversity, and greater susceptibility to digestive disturbances. Although for different reasons, both extremes appeared to reflect a gut environment under stress.

Microbial Toxins and Risks to Vital Organs

One of the study’s most consistent findings was the elevated presence of microbiome-derived compounds in the bloodstream, including p-cresol sulfate, phenylacetylglutamine, and indoxyl sulfate, particularly among people with infrequent bowel movements. These substances have previously been associated with kidney damage, systemic inflammation, and cognitive decline.

Indoxyl sulfate stood out because of its strong association with reduced kidney function. Even among individuals considered healthy, higher levels of this metabolite were linked to lower glomerular filtration rates, an early indicator of kidney performance.

Statistical analysis also suggested that part of the impact of slow intestinal transit on kidney function may be mediated by indoxyl sulfate itself. In other words, infrequent bowel movements could contribute to the buildup of toxins that place increasing stress on the kidneys over time.

 Lifestyle Habits and Dietary Patterns

In addition to biological measurements, the study evaluated questionnaires covering diet, emotional well-being, lifestyle factors, and digestive health. Participants with lower bowel movement frequency generally consumed fewer fruits and vegetables, which provide fiber that helps support healthy bowel function. They also reported eating more ultra-processed snack foods.