Mediterranean-style diet linked to better brain health in older Hispanic and Latino adults

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Adhering to a Mediterranean-style eating pattern may help Hispanic and Latino adults strengthen the tissue connections in their brains, supporting overall brain health and potentially contributing to better cognitive outcomes, new research suggests.

The largest brain health benefit came from eating whole grains and fish, according to the findings, which will be presented Thursday at the American Stroke Association's International Stroke Conference in Los Angeles. The research is considered preliminary until full results are published in a peer-reviewed journal.

"Other studies have shown adherence to the Mediterranean diet is associated with preserved brain health, but these studies have mainly looked at white people," said Dr. Gabriela Trifan, the new study's lead researcher and an assistant professor of neurology at the University of Illinois Chicago. "Our study is the first to address Hispanic and Latino people living in the U.S., a growing population that is at increased risk for cardiovascular disease and dementia."

According to the Centers for Disease Control and Prevention, 1 in 10 adults in the U.S. age 45 and older experience cognitive decline and worsening memory. The rate is even higher – 11.4% – among Hispanic adults. Along with Black adults in the U.S., this group is expected to see the largest increase in Alzheimer's disease, the most common form of dementia, over the next several decades.

Prior research by Trifan and her team showed consuming a culturally tailored Mediterranean diet could lower the risk for Alzheimer's disease and cognitive decline in middle-aged Hispanic and Latino adults. In the new study, the researchers looked deeper into the mechanisms involved, exploring the link between diet and the integrity of the tissue that includes connections between brain cells, known as white matter, as well as how large a role cardiovascular health may play.

Researchers asked 2,774 participants in the Study of Latinos-Investigation of Neurocognitive Aging-MRI Ancillary Study to recall what they had eaten in the past 24 hours, then calculated a score from 0 to 9 for how closely the meals adhered to the Mediterranean diet. This style of eating emphasizes fruits, vegetables, whole grains, beans, nuts, seeds and moderate amounts of dairy products, fish and poultry, with very little red meat or processed foods. Olive oil, used for cooking, is the primary fat source.

After about 10 years of follow-up, brain scans were used to measure participants' white matter integrity and volume, considered indicators of the strength of connections in the brain that allow it to communicate and function effectively. Cardiovascular health also was assessed based on adherence to a set of behaviors and health factors that included exercising regularly, eating a healthy diet, not smoking, maintaining a healthy weight and keeping blood pressure, blood glucose and cholesterol within a healthy range. Participants, who were an average 64 years old, received a score between 0 and 14 for how well they adhered to these heart health measures.

Participants received an average score of 5 on Mediterranean diet adherence and 7.1 for cardiovascular health. The higher diet scores were associated with better preservation of white matter integrity and volume and less evidence of structural damage to the brain.

Higher cardiovascular health scores accounted for some, but not all, of the improved white matter protections, suggesting the benefits of eating a Mediterranean diet extended beyond its ability to improve heart health.

"This tells us that eating a Mediterranean diet might not just improve cognition by improving heart health, it might actually be making important changes to the brain," said Dr. Andreana Benitez, an associate professor of neurology at the Medical University of South Carolina in Charleston. She was not involved in the research.

Benitez said studying a population at higher risk for cognitive decline was one of the study's strengths and an important step toward better prevention. "It identifies a way that we can mitigate these risks in the years to come," she said.

Culturally tailoring the Mediterranean diet to better appeal to Hispanic and Latino adults could prove beneficial by lowering cognitive decline, said Dr. Sandra Billinger, a professor in the neurology department of the University of Kansas Medical Center in Kansas City.

She suggested that future research could look more closely at the strength of individual dietary components but said focusing on this segment of the U.S. population was a much-needed step.

"Historically, this group of adults is underrepresented in studies," said Billinger, who was not involved in the study. "It's really important for us to get an understanding of how diet impacts brain health in this population. It's going to drive the field forward."