Whole-Grain Rich Diet May Slow Cognitive Decline in Older Black Adults

A diet high in whole grains is associated with slower cognitive decline among Black adults compared to White adults and those who consumed whole grains less frequently, according to study findings published in Neurology.

Researchers at the Rush Institute for Healthy Aging and the Rush University Medical Center collaborated to conduct an offshoot study from the longitudinal, community-based, investigation called the Chicago Health and Aging Project (CHAP), which enrolled participants aged 65 and older beginning in October 1993 through April 1997.

The researchers enrolled 3326 participants (mean age at baseline, 75; 63.7% women; 60.1% Black) from the original CHAP cohort who responded to a 144-item Food Frequency Questionnaire (FFQ) for dietary assessment and underwent both the APOE ε4 genotype assessment and 2 or more cognitive assessments. Cognitive function for each participant was assessed using the Mini Mental State Examination (MMSE), the East Boston Story test, and the Symbol Digit Modalities Test. Follow-up duration lasted an average of 6.1 years.

The researchers evaluated the association of whole grain consumption and longitudinal change in global cognition, perceptual speed, and episodic memory among participants of different ethnicities/races. Whole grain foods consisted of dark breads, breakfast cereal, cornbread, kasha, bulgar, quinoa, tortilla, couscous, and popcorn among other grains. Refined grains included white bread, pita bread, PopTarts, pretzels, and other more heavily processed foods.

Compared with participants who consumed the least whole grains (lowest quintile), those who consumed the most whole grains (highest quintile) demonstrated significantly slower rates of decline in global cognition (β = 0.024; 95% CI, 0.008–0.039; P =.004), perceptual speed (β = 0.023, 95% CI, 0.007–0.040; P =.005), and episodic memory (β = 0.028, 95% CI, 0.005–0.050; P =.01). In particular, Black participants consuming more than 3 servings of whole grains per day had the slowest rates of decline in global cognition compared to those who consumed less than 1 serving per day (β = 0.021; 95% CI, 0.005–0.036; P =.0093).

In contrast, this association was not observed among White participants; however, the researchers did note a suggested association between consumption of more than 3 servings of whole grains per day and slower cognitive decline among White participants (β = 0.025; 95% CI, −0.003 to 0.053; P =.08). The researchers speculated that “because AA [African American] adults have a higher prevalence of developing CVD [cardiovascular disease], the race-specific association between diet and cognitive function could be mediated by the effects of diet on CVD [cardiovascular disease].”

“The results presented in this study could be informative in facilitating tailored dietary recommendations for diverse populations,” the researchers concluded.

Study limitations included the use of self-reported data introducing the potential for recall error and misclassification of dietary intake, the inability to generalize results to populations outside of the south side of Chicago of a different socioeconomic status, the inability to assess the causal association of dietary changes over time with changes in cognitive function since the researchers only used data from the baseline FFQ, and restriction of sample size according to those with the APOE genotype.

Disclosures: Several study authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see original source for full list of disclosures.