High-fiber diet linked to lower risk of dementia

Scientists from Japan are sharing another important reason to increase your fiber intake. A new study finds that having a diet high in soluble fibers (think oats and legumes) is connected to a lower risk of developing dementia.

Fiber is important in lowering cholesterol levels and helps the digestive system process nutrients. Despite its many health benefits, many Americans still eat less than the recommended fiber intake.

Experts hope the new findings will give people more motivation to follow a fiber-rich diet. That’s especially the case amid predictions that dementia cases will triple worldwide by 2050.

“Dementia is a devastating disease that usually requires long-term care,” says lead author of the study Professor Kazumasa Yamagishi in a statement. “We were interested in some recent research which suggested that dietary fiber may play a preventative role. We investigated this using data that were collected from thousands of adults in Japan for a large study that started in the 1980s.”

The team recruited 3,739 adults to complete a survey on their diet between 1985 and 1999. Most people were considered healthy and between the ages of 40 and 64. Participants were split into four groups depending on the amount of fiber they regularly consumed with their diet.

Scientists followed-up with participants from 1999 until 2020 and took note if a person was later diagnosed with dementia. Their results showed people who ate high amounts of fiber had a lower chance of dementia.

The team also investigated the health benefits of eating soluble versus insoluble fibers. Soluble fibers are found in foods such as oats and legumes and provide nutrients for gut bacteria. Insoluble fibers are mainly  found in whole grains, vegetables and other foods and are associated with good bowel health. Between the two, the risk of dementia was lowest in people who ate the most soluble fiber foods.

While the researchers established a connection between dietary fiber and dementia risk, it remains poorly understood what drives this association.

“The mechanisms are currently unknown but might involve the interactions that take place between the gut and the brain,” explains Professor Yamagishi. “One possibility is that soluble fiber regulates the composition of gut bacteria. This composition may affect neuroinflammation, which plays a role in the onset of dementia. It’s also possible that dietary fiber may reduce other risk factors for dementia, such as body weight, blood pressure, lipids, and glucose levels. The work is still at an early stage, and it’s important to confirm the association in other populations.”

The study is published in the journal Nutritional Neuroscience.


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About the Author

Jocelyn Solis-Moreira

Jocelyn is a New York-based science journalist whose work has appeared in Discover Magazine, Health, and Live Science, among other publications. She holds a Master’s of Science in Psychology with a concentration in behavioral neuroscience and a Bachelor’s of Science in integrative neuroscience from Binghamton University. Jocelyn has reported on several medical and science topics ranging from coronavirus news to the latest findings in women’s health.

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