Understanding the biological processes of getting older could help us lead longer lives, and stay healthier later in life – and a new study links the speed at which our brain ages with the nutrients in our diets.

Researchers from the University of Illinois and the University of Nebraska-Lincoln mapped brain scans against nutritional intake for 100 volunteers aged between 65 and 75, looking for connections between certain diets and slower brain aging.

They identified two distinct types of brain aging – and the slower paced aging was associated with nutrient intake similar to what you would get from the Mediterranean diet, shown in previous studies to be one of the best for our bodies.

"We investigated specific nutrient biomarkers, such as fatty acid profiles, known in nutritional science to potentially offer health benefits," says neuroscientist Aron Barbey, from the University of Illinois.

"This aligns with the extensive body of research in the field demonstrating the positive health effects of the Mediterranean diet, which emphasizes foods rich in these beneficial nutrients."

Importantly, the researchers didn't rely on the study participants to report on their diets. Instead, they analyzed blood samples to look for nutrient biomarkers: solid scientific evidence for what these elderly individuals were eating and drinking.

Fatty acids, like those in fish and olive oil, and antioxidants such as vitamin E, present in spinach and almonds, were among the beneficial biomarkers identified, as well as carotenoids, plant pigments found in carrots and pumpkin that have previously been found to lower inflammation in the body and protect cells from damage. Another beneficial biomarker associated with slower aging in this research was choline, which is contained in high concentrations in egg yolks, organ meats and raw soybean.

The researchers assessed brain aging through both MRI brain scans and cognitive assessments. This pair of approaches gave a picture of practical mental agility along with the more subtle details of neuron configuration.

"This allows us to build a more robust understanding of the relationship between these factors," says Barbey.

"We simultaneously examine brain structure, function and metabolism, demonstrating a direct link between these brain properties and cognitive abilities."

The evidence is now mounting that nutrition plays a significant role in how the brain ages, and each new study helps in providing more insight about how our brains are closely connected to every other part and function of the body.

This research only captured a snapshot in time, and isn't comprehensive enough to prove cause and effect. However, similar conclusions were reached by a 2023 study, which followed participants for 12 years and also found a connection between the Mediterranean diet and lower cognitive decline.

Next, the team wants to look at clinical trials across a significant amount of time to see how diet and nutrition might affect brain aging. It's possible that simple tweaks to what we eat could help cut down the risk of neurodegenerative diseases such as Alzheimer's.

"The present study identifies particular nutrient biomarker patterns that are promising and have favorable associations with measures of cognitive performance and brain health," says Barbey.

The research has been published in npj Aging.