If you are taking a vision supplement, it probably contains lutein. This carotenoid is renowned for its protective effects on the eyes. It accumulates in the retina, absorbs up to 90% of harmful wavelengths of light, and slows the progression of age-related macular degeneration and other eye problems.
But that’s not all it does. Although most of the research on lutein, and its partner nutrient zeaxanthin, focuses on the eyes, these carotenoids support tissues throughout your body.
A high blood level of lutein has been linked with better respiratory function, lower markers of inflammation in patients with coronary artery disease, a reduced risk of some types of cancer, and protection against UV-related skin damage.
What I want to highlight, however, are lutein’s benefits for your brain.
Lutein & Brain Health
While our diets are normally high in beta-carotene and other carotenoids, lutein is the dominant carotenoid in the brain—and something we often don’t get enough of.
Its contributions to brain health include:
- Quenching harmful free radicals and protecting against oxidative stress, both of which promote disease and aging.
- Helping to dampen chronic inflammation, an underlying factor in neurodegeneration and other diseases.
- Increasing brain-derived neurotrophic factor (BDNF), a growth factor that promotes the brain’s ability to change and adapt; particularly active in areas associated with learning and memory.
- Enhancing visual processing speed, which is related to alertness and brain “readiness.”
- Reducing eye strain and eye fatigue, which can have an effect on cognitive function, especially during high exposure to blue light from digital screens on smartphones, computers, tablets, etc.
Plus, lutein may improve sleep, particularly if you spend a lot of time on digital screens, which helps blunt the many adverse cognitive effects of poor sleep.
An Essential Nutrient Throughout Life
From gestation on, optimal brain function depends on lutein. Transferred from mother to fetus during pregnancy and abundant in breast milk, it plays a role in prenatal and infant development of the brain and eyes.
A recent study underscores its significance during these critical periods of growth and development. Researchers from Harvard and Tufts University followed participants in the ongoing Project Viva, which is examining the effects of maternal and childhood diets and other factors on health outcomes. They found that a higher intake of lutein and zeaxanthin by mothers during pregnancy was associated with better verbal intelligence and behavior regulation in their offspring during early childhood.
The benefits of lutein for cognition continue throughout life. Population studies have linked a higher intake of lutein-rich foods such as leafy greens with better cognitive health in all age groups—including a reduced risk of developing Alzheimer's disease.
Lutein Levels & Cognitive Function
Autopsies of individuals who died from various causes have revealed parallels between lutein levels in the brain and cognitive function. Those with higher lutein levels had better scores on tests they had previously taken evaluating attention, IQ, and executive function (working memory, flexible thinking, self-control, etc.). They also had fewer signs of neurodegeneration.
A more practical way of evaluating these levels is to measure “macular pigment optical density” (MPOD). Lutein and zeaxanthin accumulate in the macula, an area in the retina that plays a key role in vision. A high MPOD is indicative of an abundance of these carotenoids, which means greater protection for your eyes—and your brain.
MPOD is increasingly used as a biomarker of lutein concentrations in the brain because it tracks well with cognitive function. For example, a study involving 4,453 men and women aged 50 and older found that a lower MPOD was closely associated with poorer performance on several cognitive assessments, including reaction time, memory, and the time taken to complete given tasks. A number of other studies support these results.
Brain Benefits of Supplement Lutein
Research on lutein’s effects in the brain really picked up after lutein supplements came into their own about 10 years ago. Prior to that, there wasn’t much to recommend besides eating more kale and spinach. As you can imagine, that didn’t fly. The average dietary intake for US adults is just 1–2 mg per day.
Fortunately, supplemental lutein and zeaxanthin also effectively boost MPOD and support cognitive function. This has been demonstrated in multiple studies, including a placebo-controlled clinical trial published in Frontiers in Aging Neuroscience. Adults with an average age of 74 were divided into two groups and assigned to take a supplement containing 12 mg of lutein plus zeaxanthin or an identical placebo. When they were reevaluated after 12 months, the group taking lutein/zeaxanthin had significant increases in MPOD, indicative of an increase in lutein levels in the brain as well as improvements in cognitive function.
Lutein supplements also benefit younger adults. In a randomized, double-blind, placebo-controlled study, Irish researchers tested the effects of a lutein-zeaxanthin supplement in healthy people with an average age of 45. Of note, significant improvements were observed in episodic memory, or the ability to learn, store, and retrieve information about specific experiences. Improvements were closely related to increases in lutein concentrations.
The researchers concluded, “The implications of these findings for intellectual performance throughout life, and for risk of cognitive decline in later life, warrant further study.”
Eat Your Greens & Take Supplements
You can get plenty of lutein in your diet. A cup of cooked turnip greens or collards provides 18–19 mg, and cooked spinach and kale have 25–30 mg each. Cooking greens and eating them with a little olive oil or other healthy fat increases absorption. A few other vegetables such as squash, peas, Brussels sprouts, and broccoli are reasonably good sources, with 2–4 mg per cup. Avocados and egg yolks have considerably less, but because their lutein is bound up in fat, it is exceptionally bioavailable.
Supplements are another option, and as noted above, are quite effective at increasing MPOD and concentrations of lutein in the brain. Awareness of the positive effects of lutein and zeaxanthin on the eyes has encouraged many people to take supplemental lutein to protect and preserve their vision.
Now, you can rest assured that you are also protecting and preserving your brain and cognitive function. Suggested daily doses are 20–40 mg of lutein and 4–8 mg of zeaxanthin.