Constipation Could Influence Cognitive Decline? New Study Suggests

New research links chronic constipation to higher risk of cognitive decline, raising concerns about the ageing brain.

In a first-of-its-kind study, scientists have made a significant discovery, revealing concerning links between chronic constipation and cognitive decline among older adults. 

The groundbreaking research, presented at the Alzheimer’s Association International Conference 2023 in Amsterdam, Netherlands, highlights a potential connection between infrequent bowel movements and cognitive ageing. These findings add to the growing body of evidence emphasizing the vital link between gut health and brain function.

The Gut-Brain Axis: A Key Connection

Emerging research continues to highlight the interdependence of various body systems, and the gut-brain axis is no exception. Scientists have long speculated about the impact of the gut microbiome on essential bodily functions, and new investigations are drawing increasing attention to this relationship.

“Our body systems are all interconnected,” said Heather M. Snyder, Ph.D., Alzheimer’s Association vice president of medical and scientific relations.” “When one system is malfunctioning, it impacts other systems. When that dysfunction isn’t addressed, it can create a waterfall of consequences for the rest of the body.” Snyder said. 

To delve further into this intriguing relationship, the Alzheimer’s Association U.S. Study to Protect Brain Health Through Lifestyle Intervention to Reduce Risk (U.S Pointer) is currently investigating the effects of behavioural interventions on the gut-brain axis. This study aims to shed light on how healthy habits impact gut microorganisms and how changes in gut bacteria might influence brain health.

The Link between Constipation and Cognitive Decline

Constipation, affecting approximately 16% of the world’s population, is particularly prevalent among older adults due to factors like fibre-deficient diets, sedentary lifestyles, and certain medications. 

Chaoran Ma, M.D., Ph.D., former research fellow at Brigham and Women’s Hospital and Harvard Medical School and current Assistant Professor at University of Massachusetts Amherst, and his team examined data from three prospective cohort studies involving over 110,000 participants to assess the relationship between bowel movement frequency and cognitive function.

Additionally, the findings of the study revealed that participants with chronic constipation had significantly worse cognition, equivalent to three additional years of cognitive ageing, in comparison to those with daily bowel movements.

Furthermore, the study highlighted that infrequent bowel movements were associated with a 73% higher risk of subjective cognitive decline.

Unravelling Alzheimer’s Biomarkers and Gut Bacteria

Yannick Wadop, Ph.D., a postdoctoral fellow at the Glenn Biggs Institute for Alzheimer’s and Neurodegenerative Diseases at UT Health San Antonio, and his colleagues, have discovered a connection between gut bacteria and brain health in a study.

The research, which involved 140 individuals with normal memory and cognitive abilities, focused on investigating the influence of brain substances known as amyloid and tau on the gut. Amyloid and tau are proteins that have been linked to Alzheimer’s and other neurodegenerative diseases.

What they discovered was nothing short of remarkable. Interestingly, the team found that participants with elevated levels of amyloid and tau in their brains exhibited distinct differences in their gut bacteria when compared to those with lower levels of these substances.

They found two specific gut bacteria, Butyricicoccus and Ruminococcus, notably reduced in individuals with higher brain amyloid and tau levels. Researchers have noted a significant observation regarding these particular bacteria’s potential neuroprotective effects, making their scarcity noteworthy.

While the gut-brain relationship is not fully understood, this study hints at a connection. It may help tackle Alzheimer’s and other neurodegenerative diseases.

Implications and Future Directions

The connection between bowel movement frequency and cognitive decline opens up a fascinating avenue for future research. Understanding the gut-brain axis could lead to innovative strategies for reducing the risk of dementia and improving overall brain health. 


  1. Constipation Associated with Cognitive Aging & Decline | (n.d.). AAIC. https:////
  2. Forootan, M., Bagheri, N., & Darvishi, M. (2018, May 18). Chronic constipation: A review of literature. PubMed Central (PMC).
  3. U.S. POINTER Study | Alzheimer’s Association. (n.d.). U.S. POINTER.
  4. POINTER-Microbiome Study. (n.d.). U.S. POINTER.

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