Irregular bowel schedules, particularly constipation and diarrhea, are so common that people often see them as mere annoyances. However, a new study suggests they may increase the risk of chronic diseases.
The researchers used a comprehensive set of biological, health, diet, and lifestyle data from 1,425 healthy participants from the defunct scientific wellness company Arivale to study the associations between bowel movement frequency and factors such as gut microbiome composition and blood proteins in healthy individuals.
Constipation and Diarrhea Affect Gut Health
Constipation affects the gut ecosystem and is linked to chronic diseases.
“The gut ecosystem largely focuses on fermenting dietary fiber. That’s sort of the main function of the microbiome; it takes fibers and ferments them into organic [fatty] acids,” Mr. Gibbons said.
“When we looked at people with diarrhea, we saw that markers of liver dysfunction and inflammation were higher,” Mr. Gibbons said.
A healthy gut microbiome prevents inflammation and colonization from pathogens, but diarrhea disrupts the microbiome, driving up inflammation. Mr. Gibbons postulates that diarrhea may also harm the liver, as the rapid movement of stool prevents the reabsorption of bile acids, which the liver produces to digest dietary fats.
This loss burdens the liver to produce more bile acids, contributing to liver dysfunction.
Bacteria Abundance Linked to Bowel Movements
The researchers explored how bowel movement frequency (BMF) variations affect different molecules in the body, organ function, and disease. Participants’ BMF was categorized into four groups: constipation (passing stool once or twice a week), low-normal (three to six times a week), high-normal (one to three times a day), and diarrhea (four times a day).
The researchers found that specific gut bacteria are more or less abundant depending on how often people have bowel movements. For instance, beneficial bacteria associated with dietary fiber fermentation were more abundant in those with one to two bowel movements a day. In contrast, people who regularly suffered from constipation and diarrhea had more potentially pathological bacteria in their upper gastrointestinal tract.
Bowel Movements Linked to Diet, Lifestyle, and Mental State
The researchers also looked at potential associations between BMF and demographic factors such as age, sex, body mass index (BMI), and mental state. Results showed the following:
- Higher snack intake was linked to low-normal BMF.
- Higher intake of fruits and vegetables, easier bowel movements, and more frequent diarrhea were linked to high-normal BMF.
- Individuals with lower low-density lipoprotein (better cholesterol) reported eating more fruit.
- Those with lower C-reactive protein (less inflammation) reported eating more vegetables.
The study also found that people with siblings or family members with a history of depression or anxiety experienced abnormal bowel frequency. Similarly, individuals with a personal history of depression or anxiety disorders were associated with low-normal BMF.
These findings align with recent research showing that constipation is linked to an increased risk of depression and anxiety.
Lifestyle Changes to Improve Gut Health
The study emphasized that “common-sense dietary and lifestyle changes, like increasing intake of fruits and vegetables, may help normalize BMF and perhaps reduce BMF-associated risk.”
Mr. Gibbons illustrated that the microbes in the gut act like an engine, transforming what we consume into the body’s biomass. However, this engine doesn’t burn clean and produces toxic byproducts. “Our body is designed to deal with the toxicity, but if it overwhelms our mechanisms for dealing with it, then it causes damage.”
Fortunately, people may be able to improve their bowel movement frequency through diet.
Mr. Gibbons said that feeding the microbes with a lot of fiber can help correct the physiological processes associated with increased disease risk.” Taking prebiotics and probiotics, including fermented foods like yogurt, sauerkraut, and kimchi, are also good sources of probiotics.
He also recommended a whole-food diet rich in various plants, fruits, and vegetables while avoiding a high-protein diet. “It’s pretty well accepted in the nutrition field that really-high-protein diets are actually very damaging to the body,” he said. For those on a high-protein diet, he suggested supplementing with complex carbs and fibers.
Currently, people—and perhaps even clinicians—do not view bowel movement abnormalities as a cause for concern. “I think our work is showing that it actually perhaps is an important component of what needs to be managed in our health care,” Mr. Gibbons said.