If you have a bowel movement every day like clockwork, that might be a sign that you have a healthy brain.

People who are constipated — meaning they go three or more days between bowel movements — are 73 percent more likely to score lower on cognitive tests than people who tend to have one bowel movement every day, according to preliminary results of a new study presented at the 2023 Alzheimer’s Association International Conference.

At the same time, people who poop two or more times a day are 37 percent more likely to score lower on cognitive assessments, the study also found.

“Our body systems are all interconnected,” said Heather Snyder, PhD, the vice president of medical and scientific relations for the Alzheimer’s Association, in a statement. “When one system is malfunctioning, it impacts other systems.

“Still, there are a lot of unanswered questions about the connection between the health of our digestive system and our long-term cognitive function,” Dr. Snyder said. “Answering these questions may uncover novel therapeutic and risk-reduction approaches for Alzheimer’s and other dementias.”

Who Is Affected by Constipation?

Constipation is common at all ages, and affects about one-third of adults age 60 and older, according to the National Institutes of Health (NIH). It’s also more common among women and people of color, as well as individuals who take medications that cause constipation.

People are considered constipated when they have fewer than three bowel movements a week and have stools that are dry, lumpy, hard, or painful to pass, according to the NIH.

It’s not a disease, but it can sometimes indicate other medical issues. Lack of exercise, dehydration, a low-fiber diet, and conditions like celiac disease, diabetes, thyroid disorders, and gastrointestinal problems can all contribute to constipation, the NIH notes.

Irregular Pooping Could Age Your Brain by 3 Years

For the new study, researchers examined data on more than 110,000 U.S. adults who participated in the Nurses’ Health Study, the Nurses’ Health Study II, and the Health Professionals Follow-up Study. Scientists looked at data on bowel movement frequency in 2012 to 2013, data on how participants described their own cognitive abilities from 2014 to 2017, and data from cognitive tests completed by a subset of about 12,000 people between 2014 and 2018.

Compared with participants who had regular daily bowel movements, participants who were constipated had significantly worse cognition. The difference between these groups was roughly the equivalent of three years of aging.

Scientists also looked at data on the gut microbiome — trillions of fungi, bacteria, parasites, and other organisms that live in the digestive tract — for a subset of about 500 study participants. They found that people who had fewer bacteria in their guts that help digest dietary fibers had both less frequent bowel movements and worse cognitive function.

The study wasn’t designed to prove whether or how the timing of bowel movements or composition of the gut microbiome might directly impact brain function. It’s entirely possible that factors not measured in the study, such as eating or exercise habits, might independently influence both bowel movements and cognitive function.

In addition, the findings presented at the medical meeting haven’t been published in a medical journal, a process that typically involves the analysis being vetted by independent experts.

Talk to Your Doctor About Constipation

Even so, the findings suggest that it’s important for clinicians to discuss gut health and constipation with patients — especially when people are older, said the senior study author, Dong Wang, MD, ScD, an assistant professor at Harvard Medical School, Brigham and Women’s Hospital, and the Harvard T.H. Chan School of Public Health, in the statement.

“Interventions for preventing constipation and improving gut health include adopting healthy diets enriched with high-fiber and high-polyphenol foods such as fruits, vegetables and whole grains; taking fiber supplementation; drinking plenty of water every day; and having regular physical activity,” Dr. Wang said.