Why Fiber Is Good for Your Brain (and How to Get More of It)
Published on June 12, 2026
ON THIS PAGE
ON THIS PAGE
Fiber is a type of carbohydrate that can help with constipation, weight control, and lowering the risk of type 2 diabetes, heart disease, and a few types of cancer. It’s found in fruits, vegetables, whole grains, legumes, nuts, and seeds. Growing research suggests the nutrient may yield benefits for the brain, too.
Fiber’s potentially positive effect on the brain is likely caused by the gut-brain connection, which is how the brain and digestive systems communicate with and influence one another via neurotransmitters. The gut microbiome contains bacteria and other microorganisms that are affected by the foods you eat.
“Eating a high fiber diet improves the gut microbiome and changes the brain as well,” says Nicolas Bazan, MD, PhD, a professor of neurology and the director of the Louisiana State University Neuroscience Center of Excellence in New Orleans, whose work has focused on early signals of disease in the brain. One study found an association between higher fiber intake and a lower risk of dementia, though more studies are needed before we can conclusively link eating more fiber with a lower risk of dementia.
How Fiber Helps Protect Your Brain
As microbes in the gut break down fiber, they produce short-chain fatty acids. One of these acids, butyrate, has an anti-inflammatory effect that research suggests may benefit cognition, as many brain-related conditions are the result of inflammatory environments. At the onset of Parkinson's disease and Alzheimer's disease, for example, the brain experiences heightened levels of damaging inflammation, Dr. Bazan says.
Higher butyrate intake has been connected to better cognitive function in adults age 60 and older, according to a study involving about 2,000 individuals that evaluated brain function using tests to evaluate processing speed and executive function.
Eating fibrous foods may also improve high blood pressure levels because of the short-chain fatty acids, according to a review. People with high blood pressure have higher risks of cognitive decline and dementia.
Additionally, fiber may have the potential to improve insulin sensitivity, which helps blood sugar levels, according to a study utilizing survey results from nearly 2,700 individuals age 60 or older. “High-fiber diets are very well known to slow down sugar absorption from the intestine,” Bazan says.
Improving insulin sensitivity can lower the risk of diabetes, which ultimately benefits the brain. People with diabetes have about a 59 percent greater risk of developing dementia than those without diabetes, as issues with insulin resistance, blood sugar fluctuations, and chronic inflammation negatively impact brain health, according to one meta-analysis that included data from more than 10 million people, 8.8 million of whom had diabetes.
What Research Says About Fiber Intake and Dementia Risk
Research has suggested that fiber may boost brain function as measured by various cognitive tests.
One study involving Americans age 60 and older found that a diet high in fiber was associated with better cognitive function as measured by tests that evaluated learning ability, categorical verbal fluency, sustained attention, working memory, and how quickly the brain interprets information. “The implication is that the gut is an active participant in brain health,” Bazan says.
Another study out of Italy of about 850 people age 65 and older looked at people with and without the APOE-e4 gene, which is a genetic risk factor for developing Alzheimer’s disease. Researchers tracked eating habits and tested memory and cognition over 15 years. The results suggest that a fiber-rich diet didn’t significantly improve everyone’s brain function, but it did lower the risk of cognitive decline in those with the APOE-e4 gene.
Short-chain fatty acids are particularly relevant, as they regulate inflammation, immune signaling, and brain cell growth, which help determine brain resilience over one’s lifetime, Bazan says.
And a study of over 3,700 Japanese adults found that those who consumed more fiber had a lower risk of dementia that requires daily care (disabling dementia). The researchers tracked self-reported diets and health of participants for about 20 years and found that those who ate 18 to 65.3 grams (g) of fiber per day had a 26 percent lower risk of dementia than those who consumed 10.7 g or less per day. “This long-term population study provides important evidence showing that higher dietary fiber intake, especially soluble fiber, is associated with a reduced risk of disabling dementia,” Bazan says.
Chronic, low-grade inflammation and vascular dysfunction are major drivers of cognitive decline, and fiber appears to attenuate both.
The fatty acids produced after eating fiber may also support vascular health and may positively affect blood sugar, blood pressure, and cholesterol levels. This is important, as a dysfunctional connection between the blood vessels and brain may lead to cognitive issues associated with neurodegenerative diseases (like Alzheimer’s) and neurovascular issues (like stroke).
“Chronic, low-grade inflammation and vascular dysfunction are major drivers of cognitive decline, and fiber appears to attenuate both,” Bazan says.
Soluble vs. Insoluble Fiber: Which Is Better for Your Brain?
The recommended daily fiber intake is:
- 25 g for women 50 or younger
- 21 g for women older than 50
- 38 g for men 50 or younger
- 30 g for men over age 50
Both types of fiber — soluble and insoluble — have possible beneficial effects on the brain.
Soluble fiber dissolves in fluids and becomes gel-like during digestion. Examples of foods containing soluble fiber include oats, barley, nuts, seeds, beans, lentils, fruits, and vegetables. Many prebiotics, which are foods that benefit the gut’s microbiome, are a type of soluble fiber.
According to the study of Japanese adults, soluble fiber offers more brain protection than insoluble fiber for those at risk of disabling dementia.
That said, insoluble fiber, which doesn’t dissolve in liquid, supports healthy bowel movements, has also been found to lower the risk of dementia. Examples of foods high in insoluble fiber include almonds, lentils, black beans, and pears.
4 Simple Ways to Add More Fiber to Your Diet
Here are some ways to add more fiber to your diet — but do it gradually. “Add fiber to your diet slowly to avoid any bloating or stomach discomfort, typically by increasing fiber intake by about 5 g per day every three to five days,” says Marisa Landetta, RD, who provides nutrition counseling for Cecelia Health and is based in Lehi, Utah.
Make sure you’re drinking plenty of water to keep your bowels soft.
- Dress up your salads with fiber. Top a salad with sources of fiber (both soluble and insoluble), such as diced apples, beans, or chickpeas, Landetta says.
- Prioritize snacks with fiber. Do this by adding ½ to 1 cup of fruit to your usual snack, Landetta suggests. Other high-fiber snack choices include raw vegetables, low-fat popcorn, whole-grain crackers, nuts, and dried fruit.
- Incorporate fiber boosters. Add flaxseed, chia seeds, or nuts to smoothies, yogurt, oatmeal, and salads, Landetta says.
- Consider supplementing. Landetta says the best way to increase your fiber intake is through your diet, but if you’re falling short one day, consider adding a fiber supplement, such as a serving of psyllium husk in a smoothie or water. It’s best to consult your healthcare professional on which type of supplement is right for you.
The Takeaway
- Research suggests that fiber-rich diets may have the potential to support cognitive performance and reduce the risk of dementia.
- Fiber may have this effect on the brain by reducing inflammation while potentially offering vascular benefits.
- Some research indicates that soluble fiber (found in foods such as nuts, seeds, beans, fruits, and vegetables) and insoluble fiber (such as whole grains) may both support brain health.
- Ways to increase your fiber intake include adding another fiber-rich veggie to your salads, stirring fiber boosters into smoothies or yogurt, and adding a fiber supplement if needed when recommended by your physician. Drink plenty of water when increasing your fiber intake to avoid stomach discomfort.
EDITORIAL SOURCES
Everyday Health follows strict sourcing guidelines to ensure the accuracy of its content, outlined in our editorial policy. We use only trustworthy sources, including peer-reviewed studies, board-certified medical experts, patients with lived experience, and information from top institutions.
Resources
- Dietary Fiber: Essential for a Healthy Diet. Mayo Clinic. December 23, 2025.
- The Gut-Brain Connection. Cleveland Clinic. September 20, 2023.
- Yamagishi K et al. Dietary Fiber Intake and Risk of Incident Disabling Dementia: The Circulatory Risk in Communities Study. Nutritional Neuroscience. February 6, 2022.
- Tu J et al. Higher Dietary Butyrate Intake Is Associated With Better Cognitive Function in Older Adults: Evidence From a Cross-Sectional Study. Frontiers in Aging Neuroscience. March 28, 2025.
- Jama HA et al. Recommendations for the Use of Dietary Fiber to Improve Blood Pressure Control. Hypertension. April 8, 2024.
- About High Blood Pressure. Centers for Disease Control and Prevention. January 28, 2026.
- Sun W et al. Dietary Fiber Intake Is Positively Related With Cognitive Function in US Older Adults. Journal of Functional Foods. March 2022.
- Cao F et al. The Relationship Between Diabetes and the Dementia Risk: A Meta-Analysis. Diabetology & Metabolic Syndrome. May 14, 2024.
- Unión-Caballero A et al. Apolipoprotein E Gene Variants Shape the Association Between Dietary Fibre Intake and Cognitive Decline Risk in Community-Dwelling Older Adults. Age and Ageing. January 27, 2023.
- Corliss J. How a Fiber-Rich Diet Promotes Heart Health. Harvard Health Publishing. August 1, 2022.
- Iadecola C et al. The Neurovasculome: Key Roles in Brain Health and Cognitive Impairment: A Scientific Statement From the American Heart Association/American Stroke Association. Stroke. April 3, 2023.
- Soluble and Insoluble Fiber. MedlinePlus. August 12, 2024.
- Understanding Prebiotics and Fiber. International Scientific Association for Probiotics and Prebiotics. 2018.
- Nye J. High Dietary Fiber Intake Linked to Reduced Incident Dementia Risk. Neurology Advisor. April 20, 2026.
- Soluble & Insoluble Fiber Foods List. North Ottawa Wellness Foundation.
- Eat More Soluble Fibre. Alberta Health Services. February 2025.
- How Do I Choose the Best Fiber Supplement? Cleveland Clinic. June 29, 2023.
Meet Our Experts
Lynn Grieger, RDN, CDCES
Medical Reviewer
Lynn Grieger is a registered dietitian-nutritionist, certified diabetes care and education specialist, certified personal trainer, and certified health and wellness coach. She comp...
Moira Lawler
Author
Moira Lawler is a journalist who has spent more than a decade covering a range of health and lifestyle topics, including women's health, nutrition, fitness, mental health, and trav...