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You may be used to hearing or reading the word “lutein” together with zeaxanthin. This duo is two of the most popular carotenoids — the pigments responsible for the red, yellow and orange color of various fruits and vegetables — on the planet, and are also well-known antioxidants. Researchers sometimes refer to lutein and zeaxanthin as the “macular pigments” because they’re the only carotenoids (apart from meso-zeaxanthin) in the macula of the human eye. Located in the center of your retina, the macula is responsible for your central vision and color vision.
But there’s more to these carotenoids than meets the eye. One-half of this duo, in particular, offers other benefits, besides protecting your eyes from age-related macular disease — the leading cause of blindness among the elderly. According to a 2017 study by American researchers, including more lutein-rich foods in your diet could also help protect you from cognitive aging.
Brain aging starts early, according to research
The decline in cognitive abilities is a normal part of aging. Research shows that as you age, noticeable changes occur in your brain that affect your attention, working memory, context processing, executive functioning and processing speed. For instance, brain imaging studies show that older adults require more brain activity to complete certain cognitive tasks than younger individuals.
There is also evidence suggesting that as your brain ages, it gets less coordinated. Normally, various regions of your brain work together to help you accomplish tasks. But a study led by Harvard University researchers found that the brains of older adults no longer show the same coordination seen in younger brains because of disruptive changes caused by aging. Of these changes, the degradation of white matter — the brain tissue composed of nerve fibers — appears to be the root cause of this lack of coordination.
But while most of these changes happen in advanced age, there is reason to believe that some alterations occur much earlier than previously thought. According to Psychology Professor Timothy Salthouse, head of the Cognitive Aging Laboratory at the University of Virginia, some aspects of age-related cognitive decline begin in healthy adults when they are in their 20s and 30s. In fact, some studies have reported seeing a decrease in cognitive performance among early and middle-aged adults when cognitive load is increased. Cognitive load refers to the amount of information that your working memory can hold at a given time.
Brain imaging studies have also found neural patterns in healthy early and middle-aged adults that are reminiscent of those seen in the elderly. These patterns not only reveal loss of brain neurons, but also a decrease in grey matter volume, white matter volume and even in whole brain volume.
Lutein can help prevent or delay cognitive decline
In their study, researchers at the University of Illinois and the University of Georgia hypothesized that if cognitive impairment begins early in adulthood, then it can be countered by certain strategies, such as switching to a well-balanced diet and making healthy lifestyle changes. This assumption is based on several reports about the cognitive benefits of certain foods and regular physical activity for older adults.
For instance, a 2019 study reported that aerobic exercise, and even a low-intensity workout like stretching and toning, can improve brain function in patients with amnestic mild cognitive impairment. Researchers also found that aerobic exercise can help reduce the loss of neurons caused by neurofibrillary tangle formation. Neurofibrillary tangles are a common feature of Alzheimer’s disease.
When it comes to dietary interventions for preventing dementia, the carotenoids lutein and zeaxanthin are two of the most widely studied nutrients. Research has found that the accumulation of these antioxidant pigments, especially lutein, in the macula is not only linked to improved eye function, but also to improved brain health. According to studies, this can be attributed to lutein’s ability to cross the blood-retina barrier and the blood-brain barrier and its distribution in the brain cortices of both infants and older adults.
Like zeaxanthin, lutein has anti-inflammatory and antioxidant properties that can help protect neurons from damaging free radicals and inflammation. Research has found that older adults with mild cognitive impairment enjoy certain brain benefits from having high levels of lutein.
To find out if lutein can also help protect the brain from the disruptive effects of aging, the researchers recruited 60 individuals aged 25 to 45 years. The measured each participant’s macular pigment optical density (MPOD), which correlates with the amount of lutein in their brain. The researchers then measured each participant’s cognitive control based on their neural activities while performing various cognitive control tasks.
The researchers found that MPOD is related to both age and attentional control. They also noted that the neural activities of older adults with high lutein levels were similar to those of younger adults. In addition, high lutein levels seemed to negate the influence of age on attentional control, suggesting that lutein does offer protection against brain aging decades prior to the onset of old age.
“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,” said Anne Walk, the study’s lead author. “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.”
“Now there’s an additional reason to eat nutrient-rich foods such as green leafy vegetables, eggs and avocados,” added Professor Naiman Khan, the study’s senior author.
Lutein is a carotenoid found in many plant-based foods, such as peas, summer squash, pumpkin, Brussels sprouts, asparagus, lettuce, carrots and pistachios. Add these foods to your diet to get your daily dose of lutein and keep your brain sharp at any age.
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