A predominantly whole‑food, plant‑based diet may lower the long‑term risk of dementia for adults who have a history of cardiovascular disease, type 2 diabetes or stroke, new research published in JACC: Advances reports.
An observational study of more than 71,000 adults over 55 found lower dementia incidence among those who scored highest for healthy plant‑based eating, but the authors say further research is needed to confirm causality.
The key findings
- Researchers analysed UK Biobank data from 71,000+ participants aged 55+ and assigned each person a plant‑based diet index (PDI) reflecting the quality of their whole‑food, plant‑based diet.
- About 13.5% of participants had a prior diagnosis of cardiovascular disease, type 2 diabetes or stroke. After a median follow‑up of 12.5 years, 1.2% of this high‑risk group developed dementia.
- Individuals with a very healthy PDI had a reduced risk of developing dementia compared with those eating a very unhealthy PDI.
- Combining a somewhat healthy PDI with other healthy behaviours — for example, regular moderate to vigorous physical activity — was also linked to lower dementia risk.
What the researchers say
“There is increasing evidence that a whole food, plant‑based diet, which minimises both animal‑based and processed foods, may lead to considerable cardiometabolic and cognitive benefits,” wrote first author Michelle M. Dunk, PhD, and colleagues from the Ageing Research Centre at Sweden’s Karolinska Institute.
They note randomised trials have shown superior improvements in cardiometabolic risk factors from predominantly whole‑food, plant‑based diets compared with Mediterranean or healthy omnivorous diets, and that such diets can halt or reverse atherosclerosis and help remit type 2 diabetes.
The team describes their study as among the first to examine how plant‑based diet quality relates to dementia risk, specifically in people with existing cardiometabolic disease, a group already at elevated dementia risk.
The authors emphasised that the study is observational and cannot prove causation. They called for further research to determine whether high‑quality plant‑based diets directly reduce dementia risk, and to clarify how much of any protective effect is mediated through improvements in cardiometabolic risk factors.
Long-term risk
People with cardiovascular disease, stroke or diabetes have a higher long‑term risk of cognitive decline and dementia. Identifying modifiable lifestyle factors that could lower that risk is a public health priority, especially as populations age.
If confirmed by trials and mechanistic studies, improving diet quality toward whole plant foods and away from processed and animal‑based products could become part of dementia prevention strategies, particularly for those with cardiometabolic disease.
For clinicians and people managing cardiometabolic conditions, the findings add to evidence supporting diets rich in whole plant foods — vegetables, fruit, whole grains, legumes, nuts and seeds — and low in processed and animal‑derived foods.
Combining dietary improvements with regular physical activity may offer added benefit for long‑term brain health. Researchers stress that clinical trials and mechanistic work are needed before firm dietary recommendations for dementia prevention can be made.
