September 23, 2025
6 min read
Key takeaways:
- Women account for nearly two-thirds of Alzheimer’s disease.
- Soluble fiber improves inflammation and gut-brain axis regulation.
- The study will compare fiber consumption and dementia development in men and women.
CHICAGO — Researchers at Rush University Medical Center will study whether fiber intake affects risks for dementia and if it can impact women as they age in particular, according to a poster presented at the Women in Medicine Summit.
“Alzheimer’s is one of the leading causes of death right now in the U.S., and there aren’t many treatment options, so that makes preventive strategies especially important,” Nicole Glick, BS, second-year student at Rush Medical College, told Healio.
Noting that women account for nearly two-thirds of patients with Alzheimer’s disease and exhibit faster cognitive decline than men, Glick and principal investigator Puja Agarwal, PhD, MS, said that preventive strategies based on sex are limited.
“There are definitely disparities,” Agarwal, scientist and nutritional epidemiologist, Rush Alzheimer’s Disease Center, told Healio.
Puja Agarwal
“Prior studies that have been done at Rush and elsewhere have shown that foods like leafy greens, whole grains and berries are really rich in fiber, but are also linked to slower cognitive decline,” Glick said.
Fiber in diets rich in plant-based foods improves glycemic control, gastrointestinal function, gut-brain signaling modulation and systemic inflammation, the researchers said, which may promote cognitive health.
“There are two different types of fiber,” Glick said. “There’s insoluble fiber, which adds bulk to stool and helps with bowel movements, and there’s also soluble fiber, which is fermented by gut bacteria into short chain fatty acids.”
Specifically, the researchers said, the soluble fiber in oats, lentils, fruits and similar foods may offer additional protection for neurons because of its role in inflammation reduction and gut-brain axis regulation.
Variations in hormonal regulation, gut microbiota composition, dietary patterns and overall metabolic profiles also may lead to differences between men and women fiber intake and related metabolism, they said.
Yet the specific role of fiber in dementia prevention has not been studied much, according to Glick.
“This gap motivated us to look at fiber in a large community-based study,” she said.
“We do have ongoing studies on different nutritional aspects in aging, and one of the primary ones is looking at different components of food and overall dietary patterns for its role in reducing dementia risk,” Agarwal said.
The researchers will investigate the association of fiber with dementia risk and whether this association differs in men and women via data from 1,724 participants (mean age, approximately 80 years) in the Rush Memory and Aging Project (MAP).
“This is an ongoing longitudinal cohort study at our center, and it’s been running since 1998,” Agarwal said.
Participants do not have any known dementia at enrollment and are followed annually with clinical assessments including lifestyle factors until their death. In 2004, MAP introduced dietary studies.
A modified version of the validated >142-item Food Frequency Questionnaire provides data on calories, nutrients and total daily fiber intake, quantified by grams per day.
At baseline, the cohort’s median total fiber intake was 19.6 g per day, ranging from 11 g per day in the lowest quintile to 30 g per day in the highest quintile of fiber intake.
Guidelines recommend that adults consume 25 g of fiber per day, the researchers noted, although many older adults typically do not reach this goal, particularly women.
Participants with higher fiber intake consumed more fruits, vegetables, whole grains and beans. They also had higher total energy intake and higher Mediterranean-DASH Intervention for Neurodegenerative Delay (MIND) diet scores (r = 0.42).
Additionally, the participants with greater fiber consumption were slightly more educated (r = 0.17) and engaged in more physical and cognitive activities than those with less consumption, the researchers said.
Correlation coefficients with total fiber included 0.91 for soluble fiber and 0.98 for insoluble fiber. The strongest correlations for foods included other vegetables (r = 0.72), fruits (r = 0.6) and leafy greens (r = 0.47).
“This is preliminary, but it’s good to see those correlations, so we know that that we’re testing the right things,” Glick said.
Dementia evaluations include a 21-test cognitive battery and multi-step adjudication using criteria from the National Institute of Neurological and Communicative Disorders and Stroke and the Alzheimer’s Disease and Related Disorders Association.
The researchers also will adjust results based on age, sex, education, apolipoprotein e4 (ApoE4) status, total calories and other lifestyle factors, with sex interaction terms used to test differences in associations between men and women. The researchers will conduct stratified analysis if the interaction is significant.
“We need to look at how it varies between men and women, if we can, using this data set,” Agarwal said.
Glick and Agarwal have completed quality control for their data and have begun modeling using Cox proportional hazard models.
“By the end of this year, we should have more analysis on the actual association,” Agarwal said, “which will inform us if some small changes, such as modifying your diet by including more fiber, might impact your overall dementia risk.”
If later findings indicate an association between fiber intake and reduced risks for dementia with differences based on sex, the researchers said, more personalized nutrition recommendations may mitigate the impact of Alzheimer’s disease on women.
“It’s really exciting to see that fiber might have a reduction in risk of dementia,” Glick said. “Implementing that one day would be really special.”
“Whenever it comes to anything relating to any preventable measure or modifiable risk factor, it can have a huge public health impact,” Agarwal said. “Definitely, we need more studies in this space.”
For more information:
Nicole Glick, BS, can be reached at nkglick@gmail.com. Puja Agarwal, PhD, MS, can be reached at Puja_Agarwal@rush.edu.
Perspective
Certainly, there is plausible support for the hypothesis that varying levels of consumption of soluble fiber may impact onset and risk of dementia in men vs women. That said, sex-specific differences limit the likelihood of generalizability of such data to the population at large.
The concept that soluble fiber consumption can influence differences in risk of developing various types of dementia among men and women does have some validity. However, direct evidence of this relationship is quite limited, and mechanisms to support this remain unclear.
Epidemiological studies demonstrate that higher soluble fiber intake is associated with a lower risk of developing severe dementia, with the risk most evident for non-vascular dementia subtypes. The caveat is that these studies did not stratify results by gender.
Recent studies demonstrate that women are disproportionately affected by Alzheimer’s disease and that gender differences in dietary habits, neuroinflammatory responses and hormonal differences may help to explain this disparity.
While soluble fiber modulates the composition of the gut microbiome and reduces neuroinflammation — mechanisms important to dementia progression — there is a lack of direct evidence to confirm that these effects vary by sex.
A review by Warren discusses the interplay between diet, hormones, and neuroinflammation in the context of gender differences in Alzheimer’s disease, suggesting that dietary interventions, including fiber, may have sex-specific effects, but does not provide conclusive data on soluble fiber specifically.
While there is a biological rationale and some indirect evidence to support sex-specific effects of soluble fiber on risk of developing dementia, current clinical research does not clearly establish that soluble fiber consumption explains differences in dementia risk between men and women. More research is necessary to better elucidate such potential interactions and mechanisms.
In my clinical practice, dietary choices have broad implications for maintenance of cognitive health as well as immune resilience and responsiveness via tighter glycemic control (by reducing insulin resistance), but also by direct prevention of associated chronic diseases including diabetes and metabolic dysfunction-associated steatohepatitis.
The MIND, DASH and Mediterranean diets are known to reduce inflammation and maintain ideal immune function based on measurement of inflammatory markers, helping to preserve and maintain cognitive health.
At first glance, the methodology employed in this proposed study seems sound. However, its methods of data collection and monitoring are problematic when questionnaires and patient recall are the benchmark for data collection.
As a result, observational data makes it difficult to establish causal relationships as opposed to linkages or associations. We know this from many studies looking at the effects of diet on variables such as inflammatory markers, mood, and even physiological markers related to exercise and performance.
A more accurate and real-world approach would be to conduct a randomized controlled trial that can better assess the effects of variable amounts of soluble fiber on cognitive performance among different individuals, with secondary outcomes and analyses based not only on gender, but quality of life, biomarkers and changes in body composition.
Robert Glatter, MD
Assistant professor at the Zucker School of Medicine at Hofstra/Northwell
Disclosures: Glatter reports holding membership on the board of directors of CaringKind.
Sources/Disclosures
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Glick N and Agarwal P. Fiber intake and dementia risk: A modifiable dietary factor to support women’s brain health. Presented at Women in Allergy Summit; Sept. 18-20, 2025; Chicago.
The authors report no relevant financial disclosures.
