Psychology professor Aron Barbey and his colleagues found a relationship between blood levels of several key nutrients associated with the Mediterranean diet and healthy brain connectivity and cognition. (Photo: Illinois News Bureau)

CHICAGO, Dec. 19 (Xinhua) -- A study of the University of Illinois (UI) has linked higher levels of several key nutrients in the blood with more efficient brain connectivity and performance on cognitive tests in older adults.

The study looked at 32 key nutrients in the Mediterranean diet, which previous research has shown is associated with better brain function in aging. It included 116 healthy adults 65-75 years of age.

The researchers relied on some of the most rigorous methods available for examining nutrient intake and brain health. They looked for patterns of nutrient "biomarkers" in the blood, and also used functional magnetic resonance imaging to carefully evaluate the efficiency with which various brain networks performed.

Participants also completed several cognitive tests.

The analysis found a robust link between higher levels of several nutrient biomarkers in the blood and enhanced performance on specific cognitive tests. These nutrients, which appeared to work synergistically, included omega-3 and omega-6 fatty acids, carotenoids, lycopene, riboflavin, folate, vitamin B12 and vitamin D.

The analysis revealed that a pattern of omega-3s, omega-6s and carotene was linked to better functional brain network efficiency.

Different nutrient patterns appeared to moderate the efficiency in different brain networks. For example, higher levels of omega-3 fatty acids paralleled the positive relationship between a healthy frontoparietal network and general intelligence. The frontoparietal network supports the ability to focus attention and engage in goal-directed behavior.

"Our study suggests that diet and nutrition moderate the association between network efficiency and cognitive performance," said UI psychology professor Aron Barbey. "This means that the strength of the association between functional brain network efficiency and cognitive performance is associated with the level of the nutrients."

To test the stability of the nutrient-biomarker patterns over time, the researchers invited 40 participants back for a second analysis roughly two years after the first tests. Similar nutrient patterns persisted in this subset of the original group.

Further studies are needed to affirm and extend these results, the researchers hold.

The study has been published in the journal NeuroImage.