Carotenoids are some of the most well-known compounds in the world of fruits and vegetables. These pigments are synthesized by a variety of plants, and are also what give many foods their signature color. Warm yellows, bright oranges and bold reds are all attributed to the presence of these potent pigment compounds. Carrots, peppers, tomatoes, and pumpkins are a few of the many carotenoid-containing produce options that come to mind.
These plant pigments are known for their potent antioxidant effects, and their anti-cancer benefits. Some types of carotenoids are converted into vitamin A — which is why they are also known for promoting vision and eye health. There are more than 600 types of carotenoids, so naturally, there is a wide array of benefits to be had from this class of phytonutrients.
Some pigments, such as lutein and zeaxanthin can also be found in dark green veggies, such as kale and spinach. Numerous studies have shown that eating more of these two particular carotenoids can provide a myriad of health benefits — including boosting and maintaining cognitive function as we age.
A research team from the University of Georgia recently investigated just how beneficial these compounds really are for people who are aging. The researchers gathered a group of 43 senior citizens, between the ages of 65 and and 86, and asked them to memorize pairs of unrelated words. The team used functional MRI technology to gauge the amount of brain activity the participants needed to recall the word pairings. The study subjects were hooked up to the machine and the researchers analyzed their brain activity during recall.
The team also examined the levels of the two key carotenoids, lutein and zeaxanthin, through two different means. First, they examined their serum levels of the nutrients via blood samples. Then, they also looked at their retinal levels of the two copounds. The retinal levels were measured with noninvasive flicker photometry — a technique that relies on lights to determine the levels of the compounds in the eye.
What the research team discovered was that the participants with higher levels of lutein and zeaxanthin didn’t require as much brain activity to complete the task. This suggests that their overall cognitive function is better — because their brain doesn’t need to work as hard to get the same result. As we age, our brain will compensate for cognitive deficits by calling upon other regions of the brain to complete tasks.
Cutter Lindbergh, first author of the study and a doctoral candidate in the psychology department in the Franklin College of Arts and Sciences, explained, “There’s a natural deterioration process that occurs in the brain as people age, but the brain is great at compensating for that. 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.”
In this study, the researchers found that the participants with lower lutein and zeaxanthin levels had to use more brain power, and relied more heavily on different regions of the brain, in order to recall the word pairings they had been taught. On the other hand, people who had higher levels of the two carotenoids were more “neurally efficient” and able to minimize the amount of power their brains needed to complete the task.
Lindbergh commented that it would be in society’s best interest to look at ways to buffer the effects of aging and prolong functional independence of the aging population. “Changing diets or adding supplements to increase lutein and zeaxanthin levels might be one strategy to help with that,” he said.
While the sample size for this study was quite small, there was significant variation in brain functioning within the group. Their findings are quite intriguing, and the team hopes to continue to research the possibilities for carotenoids in cognitive health.