Older adults who take laxatives on a regular basis could face a 51% higher risk of developing dementia compared to those who do not use them, a new study published in the journal Neurology suggests.
However, there are caveats to the study.
Titled "Association Between Regular Laxative Use and Incident Dementia in UK Biobank Participants," the study was conducted at the UK Biobank.
It's a "large-scale biomedical database and research resource containing in-depth genetic and health information from half a million U.K. participants," according to the study.
Researchers from the University of Cambridge, Harvard Medical School and other universities looked at 502,229 participants between the ages of 40 and 69 (with an average age of 56.5) who had no history of dementia.
Among those who said they took laxatives "most days of the week" over the last four weeks, 1.3% had developed all-cause dementia or vascular dementia after a span of 9.8 years.
Only 0.4% of those who did not use laxatives had the same outcome.
Vascular dementia is a condition that causes "problems with reasoning, planning, judgment, memory and other thought processes caused by brain damage from impaired blood flow to your brain," as defined by the Mayo Clinic.
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The study found no association between laxative use and the development of Alzheimer’s disease, which makes up 60%-70% of all dementia cases, per the World Health Organization.
Two of the most common types of over-the-counter laxatives are osmotics and stimulants. Osmotic laxatives work by attracting water to hydrate and soften the stool, while stimulant laxatives trigger the bowel muscles to contract.
The study found that osmotic laxatives had the strongest association with dementia risk, with a 64% increase.
"Constipation and laxative use is common among middle-aged and older adults," said study author Feng Sha, PhD, of the Shenzhen Institute of Advanced Technology at the Chinese Academy of Sciences, in a press release from the American Academy of Neurology.
"However, regular laxative use may change the microbiome of the gut, possibly affecting nerve signaling from the gut to the brain or increasing the production of intestinal toxins that may affect the brain."
She went on, "Our research found regular use of over-the-counter laxatives was associated with a higher risk of dementia, particularly in people who used multiple laxative types or osmotic laxatives."
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Those who took multiple types of laxatives were found to have an even higher risk of dementia, with a 90% increase.
Researchers adjusted the results to account for lifestyle factors, pre-existing medical conditions, medications, family history and other socio-demographic attributes.
Dr. Laura Purdy, M.D., a board-certified family medicine physician in Nashville, Tennessee, said the study is very high-level and looks only broadly at the association between dementia and laxative use. She was not involved in the study.
"It shows that there is an increased risk of all-cause dementia, which means that any type of dementia seems to be increased in this patient population," she told Fox News Digital in an email.
"Much more information is needed, such as which laxatives may contribute, how much use is risky, and what, if any, clinical recommendations should or shouldn’t be made regarding laxative use."
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The researchers based their hypothesis on the "microbiome-gut-brain axis," which links the body’s intestinal functions with the brain’s cognitive centers.
Dr. Marc Siegel, professor of medicine at NYU Langone Medical Center in New York City and a Fox News medical contributor, believes the association between laxatives and all-cause dementia makes sense.
"There are electrolyte disturbances with chronic laxative use," he told Fox News Digital in an email.
"Also, laxatives can and do draw chemicals out of the gut (microbiome), which also work as neurotransmitters in the brain. There is a strong gut/brain connection that you don’t want to disrupt."
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Approximately four million people suffer from constipation in the U.S., the Johns Hopkins Medicine website says. The condition leads to 2.5 million doctor visits each year.
About one-third of older adults experience at least occasional constipation, the National Institute on Aging states on its website.
"More research is needed to further investigate the link our research found between laxatives and dementia," said Dr. Sha, per the press release.
"If our findings are confirmed, medical professionals could encourage people to treat constipation by making lifestyle changes such as drinking more water, increasing dietary fiber and adding more activity into their daily lives."
