A new study published in Neurology reinforces an important message: It’s not enough to eat “more plants” — it’s also important what plant foods you eat. The researchers found that a high-quality plant-based diet, based more on whole grains, vegetables, fruits, nuts, legumes, and vegetable oils, was associated with a lower risk of Alzheimer’s disease and other dementias. In contrast, a “lower-quality” plant-based diet, based more on processed grains, fruit juices, potatoes, and added sugars, was associated with a higher risk.

What did they investigate?
The researchers analyzed data from a multiethnic cohort study in the United States, which included 92,849 participants aged 45–75 at baseline. They assessed their diets using detailed dietary questionnaires, calculated three measures: overall plant-based diet, high-quality plant-based diet, and low-quality plant-based diet, and then tracked the onset of Alzheimer's disease and other dementia symptoms using Medicare data. In addition, in a subset of 45,065 participants, they also examined how Changes in diet over 10 years Affect the future risk of dementia.

What did they find?
Compared with those with the lowest intake, those in the highest quintile of overall plant-based diets had a 12% lower risk of dementia, and those in the highest quintile of high-quality plant-based diets had a 7% lower risk. In contrast, those who consumed the most low-quality plant-based foods had a 6% higher risk. Change over time was also important: people who moved to a lower-quality plant-based diet over time had a 25% higher risk of dementia, while people who moved away from a low-quality plant-based diet reduced their risk by 11%.

What are the conclusions?
The main message of the study is that not all plant-based diets are equally good for the brain. It is possible to eat “plant-based” and still choose processed, sugary, or nutritionally poor foods. The researchers conclude that the beneficial association was observed particularly with a plant-based diet. איכותית, and also emphasize that it is probably never too late to improve your diet: even changing in old age has been linked to a lower risk of dementia. However, this is an observational study, so it shows link But does not prove Causality.

What are the recommendations for the public?
The study does not necessarily call for switching to a full vegan or vegetarian diet, but mainly for improving Quality Food: Choose more whole plant foods and fewer processed plant foods. Simply put: more vegetables, fruits, legumes, nuts, and whole grains — and less sugary drinks, white flours, ultra-processed foods, and plant products that are full of sugar and salt. This is an especially important message for those thinking about preventing cognitive decline over time.

The main message from the study:
It’s not enough to eat “more of the plant.” To protect the brain, it’s important to prioritize High-quality plant-based nutrition — and not a processed, low-nutritional plant-based diet.

The full article:

• Link:
  https://www.neurology.org/doi/10.1212/WNL0000000000214916

• Reference:

Park, S.-Y., Setiawan, VW, Crimmins, EM, White, LR, Haiman, CA, Wilkens, LR, Le Marchand, L., & Lim, U. (2026). Plant-based dietary patterns and risk of Alzheimer's disease and related dementias in the Multiethnic Cohort Study. Neurology. doi:10.1212/WNL 0000000000214916