person holding a bowl of fruit
Photo: lucigerma/iStock/Getty Images Plus
person holding a bowl of fruit
Photo: lucigerma/iStock/Getty Images Plus

There’s some good news for regular consumers of beans, whole grains, brown rice, berries, bran cereal and other foods that are high in fiber. Such choices may help their brains function better in old age.

In a new study appearing in the journal Nutritional Neuroscience, researchers in Japan showed that a high-fiber diet can help reduce the risk of developing dementia.

“Dementia is a devastating disease that usually requires long-term care,” said the lead author of the study, Kazumasa Yamagishi, M.D., Ph.D., from the University of Tsukuba.

For the investigation, participants completed surveys that assessed their dietary intake between 1985 and 1999. They generally were healthy and aged between 40 and 64 years. They were then followed up from 1999 until 2020, and it was noted whether they developed dementia that required care. 

Investigators found that the groups who ate lower levels of fiber had a higher dementia risk. Researchers also discovered that the link between fiber intake and dementia was more pronounced for soluble fibers. 

The team had some ideas as to what might underlie the link between dietary fiber and the risk of dementia.

“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,” Yamagishi said. “It’s also possible that dietary fiber may reduce other risk factors for dementia, such as body weight, blood pressure, lipids, and glucose levels.”

More work needs to be done before definitive conclusions can be made, according to the researchers.

“The work is still at an early stage, and it’s important to confirm the association in other populations,” Yamagishi  added. The findings may be particularly relevant for the United States, however. Here, many people consume less-than-recommended levels of high-fiber food.

Additional benefits of a high-fiber diet may include normalized bowel movements, reduced cholesterol levels and living longer.