How often people poop may impact their cognition, researchers say

Saleen Martin, USA TODAY
Updated ·4 min read
8

Researchers say they have linked chronic constipation with cognitive decline, suggesting that people who defecate less may have poorer cognitive function.

Chaoran Ma, an associate professor in the University of Massachusetts Amherst’s School of Public Health and Health Sciences, worked on the study as a research fellow at Brigham and Women’s Hospital and Harvard Medical School.

Dr. Dong Wang, an assistant professor at Harvard Medical School, Brigham and Women’s Hospital and Harvard T.H. Chan School of Public Health, served as senior author.

The study is under review for publication, but Ma presented the team’s findings Wednesday at the Alzheimer’s Association’s International Conference in the Netherlands and online.

Ma said the team’s findings are “first-of-its-kind evidence” that abnormal intestinal function is linked to cognitive decline.

Pooping less linked to poorer cognitive function

“Our study provides first-of-its-kind evidence of abnormal intestinal function being linked to cognitive decline,” she said on the university's website. “Specifically, we found that less frequent bowel movements were associated with poorer cognitive function."

The team she worked with analyzed data from 112,753 women and men from three previous studies.

The team looked at data on their bowel movement frequency collected between 2012 and 2013, as well as self-assessments of cognitive function from 2014 to 2017 and cognitive assessments taken between 2014 and 2018.

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Researchers found 3 years of cognitive aging in participants

The scientists took cognitive data from people who have one bowel movement a day and compared it to cognitive data from people with bowel movements every 3+ days.

Constipated participants who only went once every 3+ days had “significantly worse cognition, equivalent to 3.0 years more of cognitive aging,” Ma said.

But the team also found a “slightly increased” risk of cognitive decline among people who had more than two bowel movements in one day, she said.

Ma said objective cognitive functions the team looked at include learning and working memory scores, as well as psychomotor speed and attention.

At least one participant said they had more trouble than usual doing activities that pertain to four domains of cognitive function, such as:

  • General memory – Remembering recent events and a list of items

  • Executive function – Understanding things, following spoken instructions and following group conversations or plotlines in TV programs

  • Attention – Remembering things from one second to the next

  • Visuospatial skills – Finding one's way around familiar streets

What’s the gut got to do with brain function?

The researchers also looked into the gut to see how its contents impact cognitive function.

According to researchers at Harvard University, the microbiome is made up of microbes that can both help and harm the body. Oftentimes, microbiota on both sides can both exist without issues.

But infectious illnesses, diets or extended use of antibiotics or other bacteria-destroying meds can sometimes leave the body more susceptible to disease, the university wrote on its website.

Microbiota can protect the body from organisms that enter the body such as contaminated drinks or food. Bacteria found in the human gut include Prevotella, Ruminococcus, Bacteroides, and Firmicutes, Harvard University wrote on its website.

Ma’s gut study looked at subjective cognition among 515 women and men and found that bowel movement frequency and subjective cognition were significantly associated with the overall variation of the gut microbiome and specific microbial species.

“Our microbiome study found that individuals with specific microbial profiles in the gut, i.e., more bacteria that can cause inflammation and fewer bacteria responsible for digesting dietary fibers, had less frequent bowel movements and worse cognitive function,” Ma said.

She told USA TODAY in a statement Thursday afternoon that there are some limitations to the study.

The team found that bowel movement frequency was tightly linked to the gut microbiome but the study wasn't designed to test the causal relationship between bowel movements, the gut microbiome and cognitive health, she said.

"We cannot firmly draw conclusions regarding the precise causal sequence underlying this association," she told USA TODAY. "Also, further studies are needed to identify the microbes involved, and their function."

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Talk about gut health with your doctor

The researchers encourage the public to take intestinal issues seriously.

“These results stress the importance of clinicians discussing gut health, especially constipation, with their older patients,” said Wang, from Harvard Medical School.

He also suggested adopting a healthy diet rich in high-fiber and high-polyphenol foods like fruits, vegetables and whole grains, in addition to drinking plenty of water daily and getting regular physical activity.

This article originally appeared on USA TODAY: Poop frequency may impact brain function, researchers say