- People are living longer, but concerns about cognitive decline remain.
- Researchers are still seeking to understand factors that protect against cognitive decline and what factors put people more at risk for cognitive decline.
- Data from a recent study found that consuming higher levels of whole grains was associated with slowed cognitive decline among Black participants.
- However, further research is required to understand the differences between Black and white participants observed in this study.
Eating whole grains offers several unique health benefits. Still, one area of interest is the relationship between eating whole grains and the benefits for the mind.
In an analysis of over 3,000 participants, researchers found that eating more than three servings of whole grains daily was linked to slower rates of cognitive decline, mainly for Black individuals.
Whole grains are often part of a healthy diet. Karen Z. Berg, registered dietitian nutritionist who was not involved in the study, explained to Medical News Today, “Some benefits of whole grains include weight control, better digestion, improved blood glucose control, lowering risk of CVD, lowering risk of colorectal cancers, and the list goes on.”
Researchers of the current study wanted to look at the relationship between whole grain consumption and cognitive decline among older adults.
To do this, they looked at data from the Chicago Health and Aging Project participants. Overall, they included 3,326 individuals. The average age of participants was 75 years. According to the paper, about 60% of the participants were African American. Researchers followed participants for an average of about six years to complete their data collection.
Participants filled out information on food consumption and participated in specific tests for researchers to analyze cognitive function. For example, researchers measured episodic memory, perceptual speed, and global cognition. They then ultimately created a score, where a higher score indicated better cognitive function. Researchers further collected data on several covariates to create a more complete health picture.
The study found that Black participants typically consumed more whole grains than white participants.
Overall, researchers found that higher levels of whole grain consumption were associated with slower cognitive decline.
But things changed when they did a breakdown, specifically looking at Black and white individuals. They found among Black individuals that those who consumed the highest amounts of whole grains had slower rates of cognitive decline than those who consumed the lowest quantity of whole grains. Among white participants, the observed benefits were not as distinct.
Study author Dr. Xiaoran Liu, assistant professor in the Department of Internal Medicine at Rush University Medical Center and Rush Institute for Healthy Aging, explained some of the critical findings of the research to MNT:
“We were not entirely surprised by the results. Our previous study showed that Black people had different dietary patterns than white people in the Chicago Healthy and Aging Project. This race-specific association may be partially explained by the differences in background diet among minority groups.”
“Our study found that a higher proportion of Black participants had more than one serving per day of whole grains than white participants, with 67% and 38%, respectively. Among Black people, those who ate the most whole grains had lower levels of memory decline—equivalent to being 8.5 years younger than those who ate small amounts of whole grains.”
— Dr. Xiaoran Liu
The study’s researchers discussed some speculations about the observed differences between Black and white individuals. They note that whole grain consumption may reflect overall healthier dietary choices among Black participants.
Still, they were able to account for several dietary factors in their models. The positive effects may further be related to decreasing risk for cardiometabolic diseases. They also note that the results may reflect differences in diet from earlier in life and that more Black participants met recommendations for more than three servings of whole grain a day.
Dr. Liu said the difference could be because of the following underlying reasons:
“One of the reasons is that African American participants have different dietary patterns than white participants. They eat more whole grains, less refined grains, less animal foods, etc. Also, African Americans have a higher risk of having heart diseases and related risk factors, i.e., hypertension, diabetes, and stroke.”
“Previous evidence supports that higher intake of whole grains was associated with lower heart disease risk, which could be another potential mechanism of action contributing to the benefits on cognition,” he added.
Regardless of the differences seen in this study, whole grains still offer other health benefits that individuals should consider.
“It is surprising that this study shows more benefits for African Americans who consume whole grains. I think more research is needed to determine why. Whole grains are an important part of everyone’s diet, regardless of ethnicity, race, or age. Americans, in general, do not consume enough fiber or whole grain foods, so I always recommend that people make sure at least half of the grains on their plate are whole grains.”
— Karen Z. Berg, registered dietitian nutritionist
This research does have certain limitations. First, much of the data relies on participants reporting on the food they have eaten and other factors, which is not always an accurate data collection method. The research also doesn’t establish a causal relationship between eating whole grains and cognitive function.
The study included participants from a specific area in the United States, meaning that the results might not be as applicable to other regions, groups, or groups with different socioeconomic statuses.
Researchers were also limited by their choice to use the first available food frequency questionnaire, and their choice on the final model could have reduced their sample size.
Even though researchers did adjust for several cardiovascular disease comorbidities, there’s still the possibility for residual confounding. Future research could also include more participants and different racial groups and look into the causal influences of consuming whole grains on cognitive function.
Dr. Liu noted the following areas of clinical research:
“We are further looking into specific nutrients from whole grains and their relation to brain health. Also, given that whole grains have high fiber content, emerging research on the microbiota-gut-brain axis suggests that fiber contributes to the effects of nutrition on the brain through its influence on gut microbiota and the immune system. Further understanding the mechanisms would help tailor dietary recommendations for diverse populations.”