Study of 92,849 People Links Plant-Based Eating to 12% Lower Dementia Risk

Researchers at the University of Hawaii tracked the diets of 92,849 people for an average of 11 years and found those who ate the most plant foods had a 12% lower risk of Alzheimer's disease and related dementias. The study is published today in Neurology, the medical journal of the American Academy of Neurology.

The participants came from the Multiethnic Cohort Study and included African American, Japanese American, Latino, Native Hawaiian and white adults, with an average age of 59 at the start. Over the study period, 21,478 of them developed Alzheimer's or another dementia.

The researchers scored everyone on three versions of plant-based eating. On the overall plant-based score, which simply rewards eating more plants than animal products, the top group had a 12% lower risk of dementia than the bottom group. On the healthful score, which rewards whole grains, fruit, vegetables, nuts, legumes, vegetable oils, tea and coffee, the top group had a 7% lower risk. Those eating the most refined grains, fruit juice, potatoes and added sugars had a 6% higher risk.

Here is the really encouraging part. In 45,065 people who reported their diet again ten years later, those whose diets moved the furthest away from junk plant foods had an 11% lower risk. Those who drifted toward them had a 25% higher risk. It is never too late to change.

Lead author Song-Yi Park, PhD, of the University of Hawaii at Manoa's Cancer Center, said:

"Plant-based diets have been shown to be beneficial in reducing the risk of diseases like diabetes and high blood pressure, but less is known about the risk of Alzheimer's disease and other dementias. Our study found that the quality of a plant-based diet mattered, with a higher quality diet associated with a reduced risk, and a lower quality diet associated with an increased risk."

"We found that adopting a plant-based diet, even starting at an older age, and refraining from low-quality plant-based diets were associated with a lower risk of Alzheimer's and other dementias."

As with any diet study of this kind it shows an association rather than proof, and it relies on food questionnaires. The researchers did not look at vegan or vegetarian diets specifically. But the message is simple: eat more whole plants, and go easy on the white bread and sugary stuff. (Vegan cookies count as plants only in the loosest sense.) The work was funded by the National Institute on Aging and the National Cancer Institute.

It adds to a mountain of evidence. The largest study of its kind linked meat to nine major diseases, the American College of Cardiology recommends plant protein for heart health, plant-based diets have been shown to help reverse type 2 diabetes, and the Stanford twin study found the vegan twin had a healthier heart in just eight weeks. And with 30 million people trying vegan this January, more people than ever are putting it to the test.

Food for thought, literally.