Study: Mediterranean Diet Positively Associated with Cognitive Function

Researchers have observed that specific plasma metabolites could be associated with global cognitive function scores independent of race or ethnicity, according to a recent study. The results are published in Alzheimer's & Dementia: The Journal of the Alzheimer's Association.

“Our study has huge strengths in expanding the sample size and in adding demographics compared to what previous research has done,” said Tamar Sofer, PhD, director of the Biostatistics Core Program in Sleep Medicine Epidemiology, and a member of the Division of Sleep and Circadian Disorders at the Brigham, in a press release.

Plasma metabolites are created when the body breaks down food. Through processes like metabolomic profiling, which surveys metabolites in blood samples, plasm metabolites can act as biomarkers associated with diseases or health changes. Many metabolites come from diet, which can be either positively or negatively associated with cognitive function.

A previous study looked at metabolites in older adults of Puerto Rican descent. In this former study, certain metabolites were associated with a higher level of cognitive function. Sofer’s team used Mendelian Randomization (MR) analyses to expand on the original Boston study. Sofer and colleagues set out to find a causal association between metabolites and cognitive function, in addition to analyzing the Mediterranean diet’s impacts on cognitive function.

The team used MR to compare the diet and cognitive function among 2,222 US Hispanic/Latinx adults from the Hispanic Community Health Study/Study of Latinos (HCHS/SOL), 1,365 European adults, and 478 African Americans who were a part of the Atherosclerosis Risk In Communities (ARIC) Study.

According to Sofer and colleagues, all the studies showed that 6 metabolites were associated with lower global cognitive function, and 4 of the 6 were derived from sugar. Comparatively, the beta-cryptoxanthin metabolite was associated with higher global cognitive function in the NHHS/SOL community. Fruit was found to provide beta-cryptoxanthin.

“It is possible that these metabolites are biomarkers of a more direct relationship between diet and cognitive function,” said lead author Einat Granot‐Hershkovitz, PhD, who worked as a postdoctoral fellow in Sofer’s lab.

The Mediterranean diet was associated with higher levels of cognitive-boosting beta-cryptoxanthin. It was also negatively associated with the metabolites that decrease cognitive function.

This was a cross-sectional and observational study, which limits the ability to conclude a relationship between metabolite levels and cognitive function. The research team recommends that future studies assess metabolite associations with cognitive function to see if a change in diet can improve cognitive health.

“While the causal effect seen in our study may be weak, repeated research has shown that the Mediterranean diet is associated with better health outcomes, including cognitive health,” Sofer said in the press release. “Our study further supports the importance of a healthy diet towards safeguarding cognitive function, consistent across races and ethnicities. It also illustrates that studies that begin by focusing on minorities can give rise to insights that may be beneficial to other populations. We hope our findings will help people in making specific nutritional choices and in improving their cognitive health.”

Reference

Diet could play a role in cognitive function across diverse races and ethnicities. EurekAlert! September 16, 2022. Accessed on September 16, 2022. https://www.eurekalert.org/news-releases/964717