CATEGORY: FOODS & NUTRIENTS
Adults who regularly ate nuts had a modestly lower risk of developing dementia — the loss of memory and thinking ability that interferes with daily life — than those who ate none, according to a large UK study that followed people for about seven years. Because it tracked people’s existing habits rather than assigning them to eat nuts, it shows an association, not proof that nuts protect the brain.1
How the Study Worked
Researchers drew on the UK Biobank, a long-running health study, and analyzed just over 50,000 adults — average age about 57 — who were free of dementia at the start. Each person recorded everything they ate and drank across a full day using an online diet questionnaire, and the researchers sorted them by how much nut they typically consumed. Over roughly seven years, new dementia diagnoses were identified through hospital, medical and death records. In comparing nut eaters with non-eaters, the team accounted for differences such as age, education, smoking and overall diet quality.
What the Numbers Showed
People who ate any nuts daily had about a 12% lower risk of all-cause dementia than those who ate none. The link was strongest at a moderate amount — up to about one handful, roughly 30 grams, a day — with no added benefit beyond that, and unsalted nuts showed the clearest association. In other words, this was not a “more is always better” pattern; a small daily amount tracked with the greatest difference.1
Why Nuts May Matter
Nuts are rich in unsaturated fats, fiber, vitamin E and plant compounds that help counter inflammation and oxidative stress — a kind of cell damage thought to play a role in brain aging. They may also support healthy blood vessels, which the brain depends on for a steady supply of oxygen and nutrients. Still, this kind of study can’t separate nuts from the company they keep: people who eat nuts often have other brain-healthy habits, and the researchers describe the effect as modest.
What This Does and Doesn’t Mean
Because participants chose their own diets, the study can’t prove that eating nuts prevents dementia. What it adds is real-world evidence linking an everyday food, eaten in ordinary amounts, to a lower chance of dementia in later life. Dementia risk is shaped by many things — including genetics, blood pressure, hearing and physical activity — so no single food tells the whole story.
Key Takeaways
- In a UK study of about 50,000 adults, those who ate nuts daily had roughly a 12% lower risk of dementia than those who ate none.
- The link was strongest at a moderate amount — about a handful (30 grams) a day — with no added benefit from eating more, and unsalted nuts showed the clearest association.
- This was an observational study, so it points to an association, not proof that nuts protect the brain.
- If you’re weighing changes to how you eat for brain health, your healthcare provider or a registered dietitian can help you find an approach that fits you.
References
- Bizzozero-Peroni B, Díaz-Goñi V, Beneit N, Oliveira A, Jiménez-López E, Martínez-Vizcaíno V, Mesas AE. Nut consumption is associated with a lower risk of all-cause dementia in adults: a community-based cohort study from the UK Biobank. GeroScience. 2025;47(2):1721–1733. link