UNL researchers link healthy brain aging to nutrient profile

Scientists often study these patterns by tracking participants’ diets through questionnaires. Such studies have linked a Mediterranean diet, which focuses on plant-based foods and healthy fats (vegetables, fruits, whole grains, and extra virgin olive oil), to improved physical health outcomes, including reduced cardiovascular risk.

Questions remain about whether diet and nutrition also support brain health. Until now, the only options for avoiding accelerated brain aging have been to guard against risk factors such as high blood pressure, alcohol and smoking.

Now, a new study led by a University of Nebraska-Lincoln researcher has identified a distinct dietary biomarker profile associated with healthy brain aging in healthy older adults. And although the researchers did not specifically study the Mediterranean diet, the nutrient profile they identified shares some nutrients with the popular diet.

“We found that there were certain dietary biomarker patterns that were associated with healthy brain aging,” said Aron Barbey, director of UNL’s Center for Brain, Biology and Behavior. “And when we looked at those biomarker patterns, we found that there were foods that you would often find in the Mediterranean diet as well.”

The study, recently published in the Nature Publishing Group Aging, involved 100 healthy adults ages 65 to 75. Other members of the research team were Jisheng Wu, a doctoral student at UNL, and Christopher Zwilling, a research scientist at the University of Illinois at Urbana-Champaign.

The researchers combined brain imaging measures of brain structure, function, and metabolism with cognitive assessments measuring intelligence, executive function, and memory. These measures revealed two types of brain aging among the participants: accelerated compared to the participants’ chronological age and slower than expected. The difference in brain age between the two groups was 5.4 years, a statistically significant difference.

But instead of using methods known as food frequency questionnaires to characterize participants’ dietary patterns, the researchers assessed the nutritional status of participants in the delayed brain aging group using biomarkers in their blood.

Barbey noted that questionnaires traditionally used to characterize dietary patterns can be quite valuable when it comes to describing individual diets. However, they have limitations in that people often cannot accurately recall the foods or amounts they eat each day. Different people also metabolize and absorb nutrients differently, and foods themselves can have varying nutrient density depending on how they are grown, harvested, and prepared.

This has led researchers in recent years to pair surveys with blood-based biomarkers that allow researchers to measure the nutrient content of a participant’s blood.

“This provides a more direct measure of the nutritional status of that individual,” Barbey said.

The study found that people in the delayed brain aging group had higher concentrations of 13 essential nutrients compared to those in the accelerated brain aging group.

The nutrient profile covered several categories of nutrients associated with healthy brain aging: seven fatty acids, three antioxidants and carotenoids, two forms of vitamin E, and choline.

Dietary sources of these nutrients include fish and shellfish, as well as many seeds, nuts and seed oils, and a variety of colorful fruits and vegetables. At least one type of fatty acid on the list comes from dairy products. Animal proteins, such as meat, poultry, fish and eggs, are important sources of choline, along with cruciferous vegetables such as broccoli and cauliflower and some beans.

“This is very promising evidence to further support the recommendations that have been made,” Barbey said. “The Mediterranean diet is a broad dietary pattern that includes some of these nutrients that we observed in our study.”

But Barbey stressed that the study was an observational one, requiring randomized, controlled trials to determine whether giving participants specific foods and increasing their nutrient biomarkers would have positive effects on their cognitive performance and brain health, which could lead to nutritional interventions designed to support healthy brain aging.

Meanwhile, he said, there is also great scientific and medical interest in understanding the impact of nutrition on brain health.

The National Institutes of Health recently launched a 10-year strategic plan to dramatically accelerate nutrition research. And Barbey is co-editing a special collection for the Journal of Nutrition, “Nutrition and the Brain—Exploring Pathways to Optimal Brain Health through Nutrition.” The articles will begin appearing next year.

“What we are all trying to do in nutritional sciences is to have evidence-based research that can lead to effective public policy recommendations about diet and nutrition and how it can support health,” Barbey said. “But unfortunately, more research is needed to get to that stage.”