Plant-Based Diet May Slow Cognitive Decline in Black Adults as They Age

Eating a predominantly plant-based diet may substantially slow the rate of cognitive decline in older Black adults in the U.S., according to preliminary research.

However, this dietary pattern had less effect on cognitive decline in older white adults, according to the findings presented Friday at the American Heart Association’s Epidemiology and Prevention, Lifestyle and Cardiometabolic Health conference in Chicago.

“It’s not that the diet doesn’t work on white people,” said lead researcher Xiaoran Liu, an assistant professor at Rush University Medical Center’s Institute for Healthy Aging in Chicago. “It just had a greater impact on African Americans.”

Previous studies have found healthy dietary changes can slow cognitive decline, but little research looked at the impact on Black adults, who face roughly twice the risk for dementia as white adults. Other studies have linked a predominantly plant-based diet to a lower risk for stroke, heart disease and Type 2 diabetes.

The importance of a plant-based diet

“Science is really coming out to support the importance of a healthy plant-based diet,” says Maya Vadiveloo, an assistant professor of nutrition and food sciences at the University of Rhode Island. “It doesn’t mean we can’t have any animal-sourced foods or low-fat dairy, but people should focus on eating more legumes and whole grains. These plant-based foods are really important for our overall health.”

In the new study, researchers analyzed diet and cognitive performance over a decade for 4,753 Black and white adults who were 74 years old on average at the start of the study. Based on their scores from self-reported dietary patterns, participants were divided into three groups:

those with healthy plant-based diets high in fruits, vegetables, nuts, whole grains, legumes, vegetable oils, tea and coffee
those who ate a less-healthy plant-based diet that included fruit juices, refined grains, potatoes, and sugar-sweetened beverages sweets
those who ate a diet with animal fats, dairy, eggs, meats, fish or seafood

Overall, Black adults in the study ate more eggs, fish or seafood, sugary drinks and whole grains than their white peers.

Researchers then used tests to measure overall cognition, perceptual speed and episodic memory – the ability to recall personal experiences associated with a particular time and place. The findings showed the healthiest plant-based diet slowed the decline more in all three areas for Black adults than it did for white adults.