Diet can be a major source of many metabolites, some of which have positive or negative effects on how well the brain works.

Dietary decisions and the results of those decisions may affect cognitive function. New research conducted by Brigham and Women’s Hospital, a founding member of the Mass General Brigham healthcare system, and outside collaborators extends on previously published studies (which focused on Puerto Ricans in the United States) by integrating more races and ethnicities.

The research team discovered that specific plasma metabolites—chemicals produced when the body digests food—were related to overall cognitive function scores across a wide range of racial and ethnic groups.

Their findings were published in Alzheimer’s & Dementia: The Alzheimer’s Association Journal.

According to Tamar Sofer, PhD, director of the Biostatistics Core Program in Sleep Medicine Epidemiology and a member of the Brigham’s Division of Sleep and Circadian Disorders, the findings have “huge strengths in expanding the sample size and in adding demographics compared to what previous research has done.” 

It also shows that studies that start by focusing on minorities can lead to ideas that could help other groups of people. 

Today, using methods like metabolomic profiling, which can examine hundreds of compounds in blood samples, researchers can find biomarkers linked to health changes and diseases.

In a first study done in Boston on older people of Puerto Rican descent, a number of metabolites were linked to how well their brains worked.

Building on that research, Brigham researchers examined the relationships between metabolites and cognitive function in 1,365 Europeans and 478 African Americans from the Atherosclerosis Risk In Communities (ARIC) Study as well as 2,222 U.S. Hispanic/Latinx adults from the Hispanic Community Health Study/Study of Latinos (HCHS/SOL).

To confirm causal relationships between the metabolites and cognitive performance as well as between a Mediterranean diet and cognitive function, they next used Mendelian Randomization (MR) analysis.

The group found that, across all of the trials, six metabolites were consistently linked to a decline in global cognitive function. Four of them included sugars or sugar-related compounds. Beta-cryptoxanthin, another metabolite, was linked to improved overall cognitive performance in the HCHS/SOL and had a strong relationship with fruit consumption.

Lead author Einat Granot-Hershkovitz, PhD, a postdoctoral fellow in Sofer’s group at Brigham, explained “It is possible that these metabolites are biomarkers of a more direct relationship between diet and cognitive function.”

Diet can be a major source of many metabolites, some of which have positive or negative effects on how well the brain works. In this study, a higher score for the Mediterranean diet was linked to higher levels of beta-cryptoxanthin, which was linked to better brain function. The Mediterranean diet was also linked to lower levels of other chemicals called metabolites, which were linked to less brain power. Additionally, previous study has demonstrated that the Mediterranean diet is linked to cognitive benefits.

The cross-sectional, observational design of the study, which limited conclusions about the possible influence of altering metabolite levels on cognitive function (causal inference), was one of the study’s limitations. Nevertheless, the researchers made an effort to use MR analyses to account for unmeasured confounding and establish some degree of causal inference. Their findings indicated a tenuous causal relationship between certain metabolites and general cognitive function. Future study should examine metabolite relationships with cognitive performance and determine whether the associations found do, in fact, support the idea that dietary changes, which result in altered metabolite levels, can enhance cognitive health.

“While the causal effect seen in our study may be weak,” adds Sofer, “repeated research has shown that the Mediterranean diet is associated with better health outcomes, including cognitive health.”

“Our study further supports the importance of a healthy diet towards safeguarding cognitive function, consistent across races and ethnicities.”

Source: 10.1002/alz.12786

Image Credit: Getty

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