Eating whole grains is known to improve cholesterol, blood pressure and other health parameters. A new study finds that it is associated with slower cognitive decline in Black people.

People who consumed more food containing whole grains had a slower rate of memory decline, equivalent to being 8.5 years younger, compared to those who ate less whole grains, according to the study published in the journal Neurology.

The findings do not indicate that whole grains slow down memory decline, but there is an association between the two. The researchers observed the link only in Black participants.

"With Alzheimer's disease and dementia affecting millions of Americans, finding ways to prevent the disease is a high public health priority. It's exciting to see that people could potentially lower their risk of dementia by increasing their diet of whole grains by a couple of servings a day," said Xiaoran Liu, a lead author of the study.

The research team examined 3,326 people, of which 60% were Black. The participants had an average age of 75 with no signs of dementia. They were followed up for an average of six years.

Every three years, the participants responded to questionnaires that assessed their whole grain intake. They also completed cognitive and memory tests that included tasks to recall lists of words, remember numbers and put them in the correct order.

Based on the amount of whole grains they had in their diet, they were grouped into five. The lowest group consisted of participants who took less than half a serving per day, and the highest group had 2.7 servings per day.

One serving of whole grain was equivalent to eating one slice of bread, a half cup of cooked pasta or rice, an ounce of crackers or a cup of dry cereal.

The team noticed that 67% of Black participants had more than one serving per day of whole grains, while only 38% of white people consumed the same amount.

After summarizing the scores of four cognitive tests, the team came up with an overall global cognition score, which was then used to measure cognitive decline.

"Among African American participants, individuals with higher consumption of whole grains and more frequent consumption of whole grain had a slower decline in global cognition, perceptual speed, and episodic memory. We did not see a similar trend in White adults," the researchers wrote.

A limitation of the study is that the food frequency was measured using self-reported data that could have errors.

"These results could help medical professionals make tailored diet recommendations. More large studies are needed to validate our findings and to further investigate the effect of whole grains on cognition in different racial groups," Liu said.

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