Higher dietary fiber intake, particularly insoluble fiber, was associated with lower rates of incident dementia, according to study results presented at the American Academy of Neurology (AAN) Annual Meeting, held in Chicago, IL, from April 18 to 22, 2026.

Researchers evaluated the association between dietary fiber intake and incident dementia among participants in the Rush Memory and Aging Project. The analysis included 1526 adults without dementia at baseline, of whom the mean (SD) age was 81 (7), and 75% were women.

The participants reported their typical diet at annual visits using a validated food frequency questionnaire. Dementia diagnoses were determined using National Institute of Neurological and Communicative Disorders and Stroke and Alzheimer’s Disease and Related Disorders Association criteria.

 

Overall, I hope this work contributes to the ongoing efforts on prevention and how everyday lifestyle choices, like diet, can play a meaningful role in supporting long-term health and quality of life.

Over a mean 6.9-year follow-up, 28.2% of participants were diagnosed with incident dementia.

Higher total fiber intake was associated with lower rates of incident dementia, with individuals in the highest vs lowest quintile demonstrating a reduced risk (hazard ratio [HR], 0.66; 95% CI, 0.45-0.96; P =.04). This association remained significant after adjustment for vitamin E, folate, omega-3 fatty acids, and lutein. Models were adjusted for age, sex, education, body mass index, physical activity, caloric intake, and apolipoprotein E ε4 status.

In a subsample analysis (n=606), the association appeared to be driven by insoluble fiber intake. Participants in the highest vs lowest quintile of insoluble fiber intake had a 54% lower incidence of dementia (HR, 0.46; 95% CI, 0.25-0.86; P =.01), whereas no significant trend was observed for soluble fiber.

We spoke with Nicole Glick, third-year medical student at Rush Medical College, and study presenter, who said, “I hope this research helps facilitate more conversations about the role of diet, especially fiber intake, in cognitive health. I also think it’s important to acknowledge that the typical Western diet often falls short in fiber, which may have broader implications for long-term health.”

She concluded, “Overall, I hope this work contributes to the ongoing efforts on prevention and how everyday lifestyle choices, like diet, can play a meaningful role in supporting long-term health and quality of life.”