The same compounds that give plants and vegetables their vibrant colors might be able to bolster brain functioning in older adults, according to a recent UGA study.
The research from the psychology department is the first to use fMRI technology to investigate how levels of those compounds affect brain activity and showed that study participants with lower levels had to rely on more brain power to complete memory-oriented tasks.
People get these compounds, known as carotenoids, from their diets, and two of them, lutein and zeaxanthin, have been shown in previous research to bolster eye and cognitive health in older adults. What isn’t known is the neural mechanisms underlying the relationship between these compounds and cognition, said Cutter Lindbergh, first author of the study and a doctoral candidate in the psychology department of the Franklin College of Arts and Sciences.
“If you can show that, in fact, there’s a real mechanism behind this, then you could potentially use these nutritional supplements or changes in diet, and you could easily intervene and potentially improve cognition in older adults,” said L. Stephen Miller, a professor of psychology and corresponding author of the study.
With Miller’s help, Lindbergh used fMRI technology, also known as functional MRI, to gauge the brain activity of more than 40 adults between ages 65 and 86 while they attempted to recall word pairings they were taught earlier. The researchers then analyzed brain activity while the participants were in the machine, finding that those individuals with higher levels of lutein and zeaxanthin didn’t require as much brain activity to complete the task.
The researchers determined the level of the compounds in two ways: through serum samples, which are done using a blood sample, and through retinal levels that are measured using noninvasive flicker photometry, which relies on lights to determine levels of the compounds in the eye.
In this study, participants with lower levels of lutein and zeaxanthin had to use more brain power and relied more heavily on different parts of the brain to remember the word pairings they were taught. People with higher levels, on the other hand, were able to minimize the amount of brain activity necessary to complete the task. In other words, they were more “neurally efficient.”
“It’s in the interest of society to look at ways to buffer these decline processes to prolong functional independence in older adults,” Lindbergh said. “Changing diets or adding supplements to increase lutein and zeaxanthin levels might be one strategy to help with that.”
The study showed no relationship between the levels of the compounds and the number of words participants could recall, but this finding, while somewhat unexpected, demonstrated how the brain went into overdrive to compensate for any diminished cognitive functioning.
The next step is to study whether interventions like changing one’s diet to include more vegetables containing the carotenoids or by adding nutritional supplements could boost individuals’ neurocognitive performance.
The study, “Relationship of lutein and zeaxanthin levels to neurocognitive functioning: An fMRI study of older adults,” was published in the Journal of the International Neuropsychological Society. The research was funded in part by Abbott Nutritional Products and UGA’s Bio-Imaging Research Center.