Lutein content in spinach and kale may fight cognitive aging

02 Aug 2017 --- Spinach and kale’s benefits may extend to keeping consumers cognitively fit, according to a study from University of Illinois researchers. The study, carried out on 60 adults aged 25-45, found that middle-aged participants with higher levels of lutein – a nutrient found in green leafy vegetables such as spinach and kale, as well as avocados and eggs – had neural responses that were more on par with younger individuals than with their peers. The researchers’ findings were published in the journal Frontiers in Aging Neuroscience.

“Now there's an additional reason to eat nutrient-rich foods such as green leafy vegetables, eggs and avocados,” says Naiman Khan, a professor of kinesiology and community health at Illinois. “We know these foods are related to other health benefits, but these data indicate that there may be cognitive benefits as well.”

The Illinois researchers chose to focus on young to middle-aged adults to see whether there was a notable difference between those with higher and lower lutein levels. Most other studies had focused on older adults, after there had already been a period of cognitive decline.

“As people get older, they experience typical decline. However, research has shown that this process can start earlier than expected. You can even start to see some differences in the 30s,” says Anne Walk, a postdoctoral scholar and first author of the paper. “We want to understand how diet impacts cognition throughout the lifespan. If lutein can protect against decline, we should encourage people to consume lutein-rich foods at a point in their lives when it has maximum benefit.”

Lutein is a nutrient that the body can't make on its own, so it must be acquired through diet. Lutein accumulates in brain tissues, but it also accumulates in the eye, which allows researchers to measure levels without needing to carry out invasive techniques.

The Illinois researchers measured lutein in the study participants' eyes when they looked into a scope and responded to a flickering light. Then, by using electrodes on the scalp, the researchers measured neural activity in the brain while the participants performed a task that tested their attention.

“The neuro-electrical signature of older participants with higher levels of lutein looked much more like their younger counterparts than their peers with less lutein,” Walk says. “Lutein appears to have some protective role, since the data suggest that those with more lutein were able to engage more cognitive resources to complete the task.”

Next, Khan's group is running intervention trials on lutein’s benefits, aiming to understand how increased dietary consumption of lutein may increase lutein in the eye and how closely the levels relate to changes in cognitive performance.

“In this study we focused on attention, but we also would like to understand the effects of lutein on learning and memory,” Khan says. “There's a lot we are very curious about.”

The paper, “The role of retinal carotenoids and age on neuroelectric indices of attentional control among early to middle-aged adults,” is available online.

The potentially important news in the fight against cognitive aging comes as it has also been discovered that a compound in green tea could help to improve memory.