Cutter Lindbergh, left, a doctoral candidate in the psychology department, and Stephen Miller, director of the Bio-Imaging Research Center, used fMRI technology to see how different levels of carotenoids, chemical compounds derived from fruits and vegetables, affected brain functioning in older adults. Credit: UGA
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 study from University of Georgia. The research 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 carotenoids, from their diets, and 2 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.
“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 Prof. L. Stephen Miller.
With Miller’s help, Lindbergh used fMRI to gauge the brain activity of >40 adults 65 – 86 years old while they attempted to recall word pairings taught earlier. The researchers analyzed brain activity while the participants were in the machine, finding that individuals with higher levels of lutein and zeaxanthin didn’t require as much brain activity to complete the task.
They determined the level of the compounds in two ways: through serum samples ie 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. “There’s a natural deterioration process that occurs in the brain as people age, but the brain is great at compensating for that,” Lindbergh said. “One way it compensates is by calling on more brain power to get a job done so it can maintain the same level of cognitive performance.”
Those with lower levels of lutein and zeaxanthin had to use more brain power and relied more heavily on different parts of the brain in order 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.”
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 participants weren’t randomly selected and the total sample size is small, but the amount of variation in brain functioning within the group was significant. 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.
http://news.uga.edu/releases/article/plant-compounds-brain-function-older-adults/
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