UNL researchers tie healthy brain aging to nutrient profile

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

Questions remain about whether diet and nutrition also could promote brain health. The only options so far for avoiding accelerated brain aging have been guarding against risk factors such as high blood pressure, alcohol and smoking.

Now a novel study led by a University of Nebraska-Lincoln researcher has identified a distinct nutritional biomarker profile in healthy older adults associated with healthy brain aging. And while the researchers didn’t specifically investigate the Mediterranean diet, the nutrient profile they identified shares some nutrients in common with the popular diet.

“We identified that there were particular nutritional biomarker patterns that were associated with healthy brain aging,” said Aron Barbey, director of the UNL’s Center for Brain, Biology and Behavior. “And when we looked at those biomarker patterns, we found there were nutrients that also you’ll commonly find in the Mediterranean diet.”

The study, published recently in Nature Publishing Group Aging, enrolled 100 healthy adults ages 65 to 75. The 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.

In it, the researchers combined brain imaging measures of brain structure, function and metabolism with cognitive assessments that gauged intelligence, executive function and memory. Those measures revealed two types of brain aging among the participants — accelerated and slower-than-expected — as compared to participants’ chronological age. The difference in brain age between the two groups was 5.4 years, a statistically significant margin.

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

Barbey noted that the questionnaires, which are traditionally used to characterize dietary patterns, can be quite valuable when it comes to describing individual diets. But they have limitations because people typically aren’t able to accurately recall the foods — or the amounts of food — they eat each day. Different people also metabolize and absorb nutrients differently, and foods themselves can have varying nutritional density depending on how they were grown, harvested and prepared.

That’s led researchers in recent years to pair questionnaires with blood-based biomarkers that allow researchers to quantify the nutritional content of a participant’s blood.

“That provides a more direct measurement of that individual’s nutritional status,” Barbey said.

In the study, those in the delayed brain aging group had greater concentrations of 13 key nutrients compared to the accelerated brain aging group.

The nutrient profile encompassed several nutrient categories that have been 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 derives from dairy products. Animal-based proteins such as meat, poultry, fish and eggs are significant sources of choline, along with cruciferous vegetables like broccoli and cauliflower and certain beans.

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

But Barbey stressed that the study is an observational one that calls for randomized, controlled trials that would involve determining whether giving specific foods to participants and increasing nutrient biomarkers would have favorable effects on their cognitive performance and brain health. That, in turn, could lead to nutritional interventions designed to promote health brain aging.

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

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

“What we’re all trying to do in the nutritional sciences is that evidence-based research that can lead to effective public policy recommendations about diet and nutrition and how that can promote health,” Barbey said. “But unfortunately, further research is needed to get to that stage.”