Healthier plant-based diet tied to lower risk of dementia
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- Reviewed by Robert H. Shmerling, MD, Senior Faculty Editor, Harvard Health Publishing; Editorial Advisory Board Member, Harvard Health Publishing
Plant-based diets have already been linked to lower risk of diseases like diabetes and high blood pressure. Increasing evidence suggests a benefit for preventing dementia as well - especially when the diet prioritizes whole grains, fruits, vegetables, vegetable oils, nuts, and legumes - according to a study published May 12, 2026, in Neurology.
The study involved 92,849 people (average age 59, 55% women) who completed detailed food questionnaires in the 1990s. About half of them reported similar diet information 10 years later. Researchers classified them according to three diet categories: an overall plant-based diet, which includes more plant foods than animal products like meat and eggs; a healthful plant-based diet; and a less healthful plant-based diet because it also included more refined grains, fruit juices, potatoes, and added sugars.
After noting how many participants developed Alzheimer's disease or other forms of dementia over the following decade, the researchers found that people who ate healthier plant-based diets had a 32% lower risk of cognitive impairment and a 15% lower risk of dementia compared to those who ate a plant-based diet that also included more unhealthy foods and beverages.
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About the Author
Maureen Salamon, Executive Editor, Harvard Women's Health Watch
About the Reviewer
Robert H. Shmerling, MD, Senior Faculty Editor, Harvard Health Publishing; Editorial Advisory Board Member, Harvard Health Publishing
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