In a recent study published in the journal *Cell Reports Medicine*, researchers have uncovered significant insights into the long-term health implications associated with the frequency of bowel movements. The study, which involved over 1,400 healthy adults, revealed that individuals who defecated less frequently exhibited signs of decreased kidney function, while those who defecated more frequently showed signs of impaired liver function.

Sean Gibbons, an associate professor at the Institute for Systems Biology in Seattle and a co-author of the study, highlighted the long-standing recognition that issues such as constipation are linked to chronic diseases. However, the causal relationship between constipation and chronic disease remains unclear. The critical question that persists is whether early-life constipation leads to chronic diseases or if it is a symptom of pre-existing chronic conditions.

To investigate this question, Gibbons and his research team utilized data from Arivale, a now-defunct wellness company. The study participants, who were predominantly healthy white adults from the Pacific Northwest, provided blood and stool samples and completed questionnaires regarding their diet, exercise habits, and mental health. The researchers analyzed these samples to detect blood chemicals indicative of low organ function, such as impaired kidneys and livers. Additionally, they genetically sequenced the participants' gut microbiomes to understand the composition of beneficial and potentially harmful microbes residing in the gut.

Participants were categorized based on their bowel movement frequency into four groups: one or two bowel movements per week, three to six per week, one to three per day, and diarrhea, defined as four or more times per day. The study found that the optimal number of bowel movements for overall health was one or two per day. Notably, younger individuals, women, and those with lower body mass indices (BMIs) tended to have less frequent bowel movements. Chronic constipation, defined as two or fewer bowel movements per week, was associated with decreased kidney function. Conversely, diarrhea, characterized by four or more bowel movements per day, was linked to decreased liver function.

The human gut hosts various microbes that feed on and ferment nutrients in stool, primarily fiber. In cases of chronic constipation, these microbes deplete their fiber supply and turn to proteins, typically sourced from the protein-rich mucus layer lining the gut. Gibbons explained that if microbes are not adequately fed, they begin to consume the body's own resources. This creates a three-fold problem: microbes produce toxic metabolites when they feed on proteins, leading to kidney and liver dysfunction; the more these bacteria rely on protein, the fewer fiber-eating bacteria remain; and over time, this can cause the gut's mucus membrane to degrade, resulting in a "leaky" gut. This condition allows harmful bacteria and metabolites to enter the bloodstream, potentially leading to inflammation and diseases affecting the heart, liver, and kidneys.

Dr. Phillipp Hartmann, an assistant professor of pediatric gastroenterology at the University of California, San Diego, who studies the interaction between the gut microbiome and other organs, noted that increased gut permeability contributes to disease. While it might not be the sole factor, it often exacerbates existing conditions.

A similar chain of microbial events can occur in cases of diarrhea, where inflammation degrades the mucosal membrane lining the gut, allowing toxins to enter the bloodstream. Joseph Petrosino, chair of molecular virology and microbiology at the Baylor College of Medicine, emphasized that both constipation and diarrhea lead to the accumulation of microbes that produce disease-influencing toxins.

The study found that individuals with either regular constipation or diarrhea had more protein-feasting gut bacteria, while those who had one or two bowel movements daily had more fiber-fermenting bacteria. Gibbons suggested that the association between constipation and kidney dysfunction, and diarrhea and liver dysfunction, might be related to how diarrhea affects bile acid absorption, which in turn impacts the liver. Meanwhile, kidneys are more affected by the metabolites produced by protein-consuming gut microbes.

Though the study was not a randomized clinical trial and therefore cannot definitively conclude that bowel movement frequency directly causes chronic disease, Gibbons mentioned that their hypothesis was supported by the findings. They observed higher levels of protein-derived toxins in the blood of individuals with lower bowel movement frequencies, suggesting potential damage to the liver and kidneys.

Petrosino advised that maintaining a healthy lifestyle could help manage both constipation and diarrhea. Key recommendations include eating a balanced diet rich in fruits and vegetables, staying hydrated, and exercising regularly. While probiotics can be beneficial for those experiencing chronic digestive issues, Petrosino cautioned against using them unnecessarily if one is already healthy.

This study underscores the intricate relationship between gut health and overall well-being, highlighting the importance of monitoring bowel movement frequency as a potential indicator of underlying health issues.