The compounds that give vegetables their vibrant colors may also boost the brain power of older adults. Researchers from the University of Georgia found that people with lower levels of carotenoids had to rely on more brainpower to complete memory-oriented tasks.
Researcher Cutter Lindbergh, a doctoral candidate at the university, and L. Stephen Miller, PhD, a professor and director of the Bio-Imaging Research Center Clinical Program, used nifty functional MRI (fMRI) technology to gauge the brain activity of more than 40 adults between 65 and 86 years old while they attempted to recall word pairings they were taught earlier. The researchers then analyzed brain activity while the subjects were in the machine, finding that those individuals with higher levels of carotenoids lutein and zeaxanthin didn't require as much brain activity to complete the task. They measured the levels of lutein and zeaxanthin through blood samples and using noninvasive flicker photometry, which uses lights to determine the level of compounds in eyes.
"There's a natural deterioration process that occurs in the brain as people age, but the brain is great at compensating for that," said Lindbergh in a university release about the research published on medicalxpress.com. "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."
Participants in the study 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 were able to minimize the amount of brain activity necessary to complete the task. In other words, they were more "neurally efficient."
"On the surface, it looked like everyone was doing the same thing and recalling the same words," Lindbergh said, "but when you pop the hood and look at what's actually going on in the brain, there are significant differences related to their carotenoid levels."
Changing diets or adding supplements to increase lutein and zeaxanthin may be a strategy to help buffer the mental decline of older adults, the researchers said.
The research was published in the Journal of the International Neuropsychological Society.