Study Links Plant-Based Diet Quality to Alzheimer’s and Dementia Risk

A large observational study suggests that the quality of a plant-based diet—not simply whether someone eats plant-based—may be associated with the risk of Alzheimer’s disease and related dementias (ADRD).

Researchers analyzed data from nearly 93,000 adults from multiple ethnic groups and found that participants with healthier plant-based eating patterns had a lower risk of developing dementia over the follow-up period.

Healthy vs. unhealthy plant-based patterns The study distinguished between healthier plant-based foods and lower-quality options. Healthier patterns emphasized whole, minimally processed plant foods, while less healthy patterns included more ultra-processed foods, fried foods, and items high in sugar and salt.

Participants with the healthiest plant-based diets had a 7% lower risk of dementia. In contrast, those with the unhealthiest plant-based diets had a 6% higher risk of ADRD.

Diet changes over time The analysis also linked changes in diet quality to dementia risk. People who shisourcesed toward a less healthy plant-based diet saw a 25% increase in dementia risk. Those who improved their diet quality saw an 11% reduction in risk.

The findings suggest diet quality may matter for brain health even later in life. However, the research was observational, meaning it identifies associations rather than proving that diet changes directly cause changes in dementia risk.