The brain is a complex organ, one that requires proper nourishment to work at optimal levels. And, as we age, one very important brain function—our cognitive abilities—are at risk for decline. Therefore, it’s crucial to explore ways to support the brain, from an early start (as early as in the womb) throughout our lives.
One of the ways to do this is through a brain-supporting diet that includes fruits and vegetables, fatty fish (a rich source of omega-3 EPA and DHA—abbreviations for eicosapentaenoic acid and docosahexaenoic acid, respectively), coffee (or tea), nuts and a whole host of other foods that promote brain development, improve cognitive function, alertness, and memory and help reduce the risk of brain conditions like dementia.
By now you’ve probably heard about lutein, but maybe not in the context we’ll be discussing in today’s blog. As it happens, lutein, may be one of those nutrients that is vital to brain health.
What is Lutein?
Lutein is a carotenoid, those colorful—yellow, orange, red—pigments that are produced and synthesized by plants and algae. But lutein is also a powerhouse antioxidant with anti-inflammatory properties. In your body, lutein resides in the retina (specifically in the macula) and, as it turns out, in your brain.
To ensure your body has enough lutein—most of us need to consciously work on that, and even still, so many of us (some estimates are as high as 70%) are falling short. To increase your body’s store of lutein, you need to eat enough leafy green or yellow or green vegetables (e.g., kale, spinach, romaine lettuce, parsley, corn, green peppers, etc.) and fruits (e.g., blueberries, oranges, kiwi, purple grapes and others). Pistachios and eggs can also help.
And there are plenty of options of lutein in dietary supplements, with some of the most popular containing both lutein and zeaxanthin.
Now let’s talk about why lutein is important for your health.
When it comes to bodily benefits, lutein is best known for its work in supporting eye health, more specifically for reducing the risk of age-related macular degeneration (AMD), itself a progressive eye condition that can lead to serious central vision loss and even blindness.
Lutein, with its partner in fighting eye-crime, zeaxanthin, another carotenoid, is best known as an eye hero, thanks to the second major clinical trial published in in the Age-Related Eye Disease Studies (AREDS) in 2013. Known as AREDS2, one of the most important findings in this trial was the beneficial impact that arose from testing the original AREDS formula—500 mgs vitamin C, 400 IU vitamin E, 80 mgs zinc and 2 mgs copper, and 15 mgs beta-carotene—with one important distinction.
In AREDS2, researchers replaced the beta carotene (due to potential safety concerns) from the original formula with 10 mg of lutein and 2 mg of zeaxanthin.
Using the AREDS2 formula, participants in that specific cohort were found to have an 18% lower risk of progressing to advanced AMD compared with those who took the original AREDS formula. What’s more, the impact was even greater for those with the lowest dietary intake of lutein and zeaxanthin at trial enrollment, with the AREDS2 formula resulting in a 26% lower risk of progressing to advanced AMD, compared to the participants with the original AREDS formula, suggesting that the lutein and zeaxanthin made the difference.
As importantly, the powerful duo of lutein and zeaxanthin were not associated with the increased cancer risk discovered in smokers from beta-carotene in AREDS, demonstrating overall safety for lutein and zeaxanthin and justifying the replacement. We blogged about this before, if you’d like to read more.
AREDS2 is not the only research to lead to lutein being nicknamed “the eye vitamin.” In part, that moniker is due to the fact that lutein (and also zeaxanthin) are the main dietary carotenoids found in our retinas, more specifically in the macular region, which likely explains the strong connection between eye health and lutein.
Benefits of Lutein for Brain Health
Now, here’s where we’re going today. Did you know that lutein is also the dominant carotenoid found in the brain? This intrigues researchers, who also wonder about the positive similarities between DHA and lutein. DHA, too, is found in high concentrations in the brain and research that has demonstrated the necessity of DHA on brain growth and development (starting in vitro) and proper brain function throughout life. Don’t forget: DHA is also a key player in a baby’s eye functional development, starting with the need for the pregnant mom to get sufficient DHA in her own diet, in large part, for the benefit of the fetus.
What is the connection between the health of the eyes and the health of the brain? We know that the brain powers the eyes; could the same thing be said in reverse? And could lutein also play a role, beyond eye health, in overall brain function, especially enhanced cognitive abilities?
This article suggests that macular pigment optical density (MPOD) might serve as a “biomarker of brain lutein concentrations.” (First, some quick definitions: macular pigment (MP) describes the yellow pigment composed principally of carotenoids, including lutein; MPOD is a measure of the density of MP in the retina’s center—the denser, the more protective). The authors suggest plausibility for the possibility that, “given that for lutein to be taken up in the retina it must cross the blood-brain barrier.” (DHA also passes the blood-brain barrier.) And the authors offer up that “MPOD measures might be a useful tool for cognitive studies testing the efficacy of lutein interventions.”
Although we may not yet know the reason why, there is emerging science to support the need for lutein for optimal brain health. We’re bringing you in a little early, offering a peek at a hypothesis that researchers are beginning to explore. And that hypothesis and the research show promise.
Clinical Evidence of the Link Between Lutein and Brain Health
When it comes to the potential brain health benefits for lutein, there is a growing body of emerging science, some of it supporting or building on previous research.
For example, findings in this 2018 study supported the theory that “there is a biologically plausible rationale” for lutein (L), zeaxanthin (Z), and meso-zeaxanthin (MZ) to maintain cognitive function through their antioxidant and anti-inflammatory properties. (These three carotenoids are collectively referred to as macular pigment, or MP, in the central retina, which is where the macula is located.)
This double-blind, placebo-controlled, randomized clinical trial was conducted in a population of 91 low MP subjects, both males and females. Over a 12-month period, 45 subjects consumed a daily formulation of 10 mg L, 10 mg MZ and 2 mg Z, while the remaining 46 were given a placebo. The authors reported that the individuals in the active group exhibited statistically significant improvements in episodic memory compared to the placebo group. (The Memory and Aging Center defines “episodic memory” as what most people think of as memory and includes information about recent or past events and experiences, such as where you parked your car this morning or the dinner you had with a friend last month.) Episodic memory is subject to age-related decline, which accelerates after age 60.
The authors concluded that this trial “demonstrates a memory-enhancing effect of daily supplementation with L, Z, and MZ in healthy subjects with low MP at baseline. The implications of these findings for intellectual performance throughout life, and for risk of cognitive decline in later life, warrant further study.”
In addition, they stated that “these findings are consistent with the literature, where positive associations between MP levels and cognitive function have been demonstrated.”
The authors also said that “given that MP levels correlate with L and Z concentrations in brain tissue, and that concentrations of these carotenoids relate positively to cognitive function, it is reasonable to hypothesize that these compounds assist in optimizing the neurocognitive environment. The implications of these findings for cognition in health and disease warrants further exploration.”
This 2021 prospective cohort study assessed maternal intake of lutein + zeaxanthin during pregnancy using food frequency questionnaires and cognition tests for the offspring in early childhood in 1580 mother-child pairings. The moms-to-be consumed a daily mean of 2.6 (2.0) mg of lutein + zeaxanthin in the first and second trimesters of pregnancy.
The results demonstrated that higher maternal intake of lutein + zeaxanthin during pregnancy was associated with better offspring verbal intelligence and behavior regulation ability in mid-childhood, with the authors “suggesting a potential benefit [for lutein + zeaxanthin] during prenatal development.” They also advised that the results did not find a benefit from higher maternal intake of the two nutrients on other child cognitive or behavioral outcomes.
Another 2021 study examined a population of 80 overweight and obese middle-aged adults, seeking to determine whether there was a connection between certain nutrients and cognitive function. Indeed, in this observational study, there was.
Specifically, the authors concluded that among this sample, greater intake of choline and lutein + zeaxanthin was associated with faster performance of a cognitive flexibility task. According to the authors, “future work examining methods of increasing consumption of both of these dietary components as a possible means of improving or maintaining cognitive flexibility among adults with overweight and obesity is therefore warranted.”
And yet another 2021 study, one that the researchers called a “novel systematic review” investigated the effects of lutein on the brain. The review covered results from nine studies, in older adults, measuring brain activities or structures either through magnetic resonance imaging (MRI) or electroencephalography (EEG). The study authors gave greater focus to the seven MRI studies, which looked at brain activities during rest, cognitive tasks and brain structure.
The authors reported that the three RCTs using MRI identified that 10 mg lutein intake over 12-months had a positive impact on healthy older adult brains during learning, resting-state connectivity and gray matter volumes, while the four cross-sectional studies using MRI suggested a positive association between lutein and brain structure and neural efficiency during cognitive tasks. In other words, lutein had a positive impact on brain health in healthy older adults, according to the researchers.
This scientific article notes that “the vast majority of Americans do not consume quantities of lutein and zeaxanthin sufficient to produce increases in MPOD.” The good news there is that dietary changes, whether through food or supplementing with lutein and zeaxanthin can lead to relatively quick and meaningful changes in visual health and performance.
The bottom line: There is demonstrative benefit from lutein (and zeaxanthin) when it comes to eye health. At the same time there is emerging and positive research that is building for the benefits of lutein (and zeaxanthin) as it relates to brain health, particularly for babies-to-be, infants and an older population. Lutein for brain health looks promising and is one area to keep an eye on.