Black Americans are roughly 1.5 to 2 times more likely than their white counterparts to develop Alzheimer’s and related dementias. A new study, however, shows that eating more foods with whole grains in them — including some breads and cereals, quinoa, and popcorn — may offer some protection against this mental decline.
In research published online this November in the journal Neurology, researchers found that Black adult participants who consumed just a few extra servings per day of these foods had a slower rate of decline in memory and cognition.
Those who ate the most whole grains had lower levels of memory decline — equivalent to being 8.5 years younger than those who ate fewer daily servings of whole grains.
“It’s exciting to see that people could potentially lower their risk of dementia by increasing whole grains in their diet by a couple of servings a day,” says the lead author, Xiaoran Liu, PhD, a researcher and an assistant professor in the department of internal medicine at the Rush Institute for Healthy Aging in Chicago. “Overall dietary pattern is very important. A healthy diet may benefit overall health, including brain health.”
Dr. Liu and her collaborators stressed that the results indicated an association but did not prove that eating more whole grains will slow memory decline.
A Benefit Noted for Black Adults but Not White Adults
Over about six years, researchers followed more than 3,000 adults who were 75 years old on average and none of whom had dementia at the study’s start. Roughly 60 percent of the adults in the study were Black.
Every three years, participants filled out a questionnaire detailing how often they ate whole grains, and they completed cognitive and memory tests. These included recalling lists of words and remembering numbers and putting them in the correct order.
Liu and her collaborators divided the study subjects into five groups according to the amount of whole grains they were eating. The lowest-consumption group ate less than a half serving per day, while the highest group ate about 2.5 servings per day.
That highest amount was still less than what’s recommended by the Dietary Guidelines for Americans released in January 2020, which states that all adults should get at least three to five servings of whole grains every day.
The analysis revealed that Black individuals with the highest whole-grain intake demonstrated a slower cognitive decline rate — measured as 0.2 standard deviation units per decade — compared with those with the lowest consumption.
The protective effects of whole grains, however, were observed only in Black adults. The study highlighted that a higher proportion of Black participants (67 percent) consumed more than one serving per day of whole grains compared with white participants (38 percent). Black participants tended to consume more whole-grain foods — such as dark bread, corn bread, and oats, according Liu. Other whole-grain products mentioned in the study include kasha, couscous, bulgur, and quinoa.
This higher consumption among Black adults may partly explain the protective association in this population, but more research is needed, wrote the authors.
Avoiding Refined-Grain Products to Stay Healthier
For Ronald Petersen, MD, PhD, a professor of neurology who focuses on cognition in normal aging and dementia at the Mayo Clinic in Rochester, Minnesota, this new study contributes to previous evidence demonstrating that what we eat may influence our ability to think and reason.
“Other research also suggests that diets like the Mediterranean diet may impact cognitive outcomes,” says Dr. Petersen, who is a fellow of the American Academy of Neurology. “Diet may influence our own cognitive aging trajectory.”
Petersen, who was not involved in the study, further advises that adults may gain additional benefit by avoiding processed foods and refined grains. Examples include white bread, English muffins, bagels, muffins, white rice, and pasta.
Liu and her team speculate that whole-grain foods may provide a protective effect when it comes to cognition and memory because they contain fiber and compounds called polyphenols, as well as vitamins B and E, that provide antioxidants that may reduce the inflammation and oxidation previously associated with mental decline.