Adherence to Mediterranean diet linked to improved cognition in Hispanic, Latino adults

Adherence to a Mediterranean diet was associated with better cognitive performance and decreased learning and memory decline after 7 years among middle-aged and older Hispanic or Latino adults, per a study published in JAMA Network Open.

“Hispanic/Latino adults have a substantial burden of Alzheimer’s disease and other dementias. In addition, they constitute one of the fastest growing demographic groups in the U.S.,” study author Fernando D. Testai, MD, PhD, of the department of neurology and rehabilitation at the University of Illinois at Chicago College of Medicine, told Healio. “Yet, Hispanic or Latino people have been underrepresented in dementia research.”

Testai and colleagues sought to investigate the association of a Mediterranean diet with cognitive performance among community-dwelling Hispanic or Latino adults by analyzing data from the Hispanic Community Health Study/Study of Latinos (HCHS/SOL) and the Study of Latinos–Investigation of Neurocognitive Aging (SOL–INCA).

They identified 6,321 study participants (mean age, 56.1 years; 57.8% women) from San Diego, Chicago, New York City and Miami. Cognition tests were administered in the HCHS/SOL from March 2008 to June 2011 (visit 1) and in the SOL–INCA from October 2015 to March 2018 (visit 2). Participants included in the present study had completed a diet assessment at visit 1 and neurocognitive evaluations at visits 1 and 2.

Researchers measured diet adherence with the Mediterranean diet score (MDS), categorized as either low (0-4 points), moderate (5-6 points) or high (7-9 points). The mean of two 24-hour dietary recalls was used to calculate the MDS. Researchers also calculated cognitive change between visits 1 and 2 by subtracting the cognitive score at visit 2 from the cognitive score at visit 1 and adjusting by the time elapsed between visits and cognitive score at visit 1.

Brief Spanish-English Verbal Learning Test (B-SEVLT) Sum, B-SEVLT Recall, word fluency and Digit Symbol Substitution Test (DSST) were administered, and the results of each were z score-transformed. The means for each test were averaged to create a global cognition score. Researchers used complex sample linear regression analysis to assess associations between MDS and neurocognitive performance at each visit and neurocognitive change.

Results showed diet adherence weighted frequencies were 35.8% (n=2,112 of 6,321) for the low adherence group, 45.4% (n=2,795) for the moderate adherence group and 18.8% (n=1,414) for the high adherence group.

In the fully adjusted model, z score-transformed cognitive scores at visit 1 in the high adherence group were higher for B-SEVLT Sum (=0.11; 95% CI, 0.02-0.2), B-SEVLT Recall (=0.16; 95% CI, 0.07-0.25) and global cognition (=0.10; 95% CI, 0.04-0.16) tests compared with the low adherence group.

In addition, over the mean follow-up of 7 years, cognitive change in the high adherence group was less pronounced for B-SEVLT Sum (=0.12; 95% CI, 0.05-0.2) and B-SEVLT Recall (=0.14; 95% CI, 0.05-0.23) compared with low adherence group, but not for word fluency, DSST score or global cognition score.

“Our study demonstrated that a higher adherence to a [Mediterranean diet] was associated with better cognitive performance and decreased age-dependent learning and memory decline,” Testai said. “This suggests that this particular diet may reduce the risk of cognitive impairment in Hispanic/Latino adults.”

In a related editorial, Farzaneh A. Sorond, MD, PhD, of the Davee Department of Neurology at Northwestern University Feinberg School of Medicine, agreed with the findings.

“The association found between Mediterranean diet adherence and better performance with regard to episodic learning is particularly noteworthy and in line with data that suggested an association between Mediterranean diet adherence and cognitive domains most often affected in Alzheimer’s disease,” Sorond wrote.

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