Editorial note: We only cite studies published in peer-reviewed journals. We summarize findings without overstating conclusions.
Published in Current Developments in Nutrition in June 2019, this review by researchers from the Visual Performance Laboratory at Duke Eye Center, the Friedman School of Nutrition at Tufts University, and the Department of Psychology at the University of Georgia synthesizes the growing body of evidence on lutein’s role not only in the aging eye — its most studied territory — but across every stage of human life, from fetal development through childhood, adulthood, and into extreme old age. The paper’s central argument is that lutein’s biological importance to humans is not simply a matter of protecting against age-related eye disease; it extends to brain development and cognitive performance in ways that science is only beginning to fully characterize. The full study is available at: https://pmc.ncbi.nlm.nih.gov/articles/PMC6629295/
Note on funding: This review was supported by the Hass Avocado Board and the Egg Nutrition Center. One author served as a scientific advisor for the Hass Avocado Board. These relationships are disclosed; the findings discussed reflect the body of published literature rather than any proprietary research conducted by the funders.
A Wider Lens on Lutein
Other articles in this series have examined how lutein and zeaxanthin protect the macula from age-related macular degeneration, reduce cataract risk, and shield retinal cells from blue light and oxidative stress. Those findings are established and clinically recognized. What this review adds is a fundamentally different framing: lutein’s role in the human body is not primarily geriatric. Its accumulation in the retina begins before birth. It is the dominant carotenoid in the infant brain. And it may be influencing cognitive performance in children, adults, and centenarians through mechanisms that have nothing to do with preventing degenerative disease — mechanisms that are still being discovered.
The review makes the point explicitly: AMD occurs near the end of life, after the reproductive cycle ends, so evolutionary pressure would not have selected for lutein accumulation in the retina to prevent AMD. There must be earlier, more fundamental reasons the body prioritizes this specific carotenoid in both the retina and brain — reasons related to development, performance, and neural function throughout life.
Before Birth: Lutein in Fetal Development
The accumulation of lutein in the human eye begins remarkably early. Starting at approximately 14 weeks of gestation, lutein and zeaxanthin begin concentrating in the vitreous humor — the large fluid-filled interior of the developing eye. This accumulation peaks between 20 and 22 weeks of gestation, at which point the lutein is diverted out of the vitreous and into the developing retinal tissue itself.
The timing is significant. This precise window coincides with the development of key retinal layers: Bruch’s membrane, the plexiform layer, the ganglion cell layer, the nuclear layer, and the photoreceptor layer. The parallel suggests that lutein is not merely accumulating passively — it appears to be playing an active role in retinal development at the cellular level, present when and where the structural architecture of vision is being constructed.
Direct evidence for this role comes from a study of premature infants born before 33 weeks of gestation — infants whose access to maternal lutein has been cut short. In this study, formula supplemented with lutein (along with beta-carotene and lycopene) was compared with a control formula containing no added carotenoids. After approximately four months of feeding with the respective formulas, electroretinography — a test that measures the electrical response of the retina to light — was used to assess retinal development. Plasma lutein concentrations correlated significantly with the amplitude of the full-field electroretinogram response. The supplemented group showed greater rod photoreceptor sensitivity and faster neural response latency (meaning faster signal transmission from retina to brain) than the unsupplemented group. These findings suggest a meaningful, rapid contribution of lutein to retinal development in the critical months following premature birth.
Macular pigment — the visible yellow layer of lutein and zeaxanthin in the central retina — can be detected and imaged with optical instruments as early as four months of age in healthy full-term infants, consistent with the prenatal accumulation pattern.
Macular Pigment and Visual Performance in Adults
The macular pigment optical density (MPOD) — a measure of how much lutein and zeaxanthin have concentrated in the macula — varies enormously between individuals, ranging from near zero to as high as 1.60. This is not a trivial range. An MPOD of 1.60 means that only about 2.5% of incident short-wavelength (blue-violet) light penetrates through to the photoreceptors beneath. An MPOD of zero means that 100% of that light reaches the photoreceptors unfiltered.
The review documents a consistent finding across multiple studies: visual performance improves as a function of MPOD across several distinct dimensions.
Speed of Visual Processing
The speed at which the visual system processes information correlates linearly with MPOD — people with higher macular pigment concentrations process visual information more quickly. This speed advantage also translates into accuracy: positional judgments of fast-moving objects are more precise in individuals with higher MPOD. The mechanism here appears to go beyond simple light filtration; the review points to more efficient neural communication within the visual system as a likely contributor.
Glare Resistance and Photostress Recovery
One of the most practically relevant visual benefits documented is glare performance. Visual discomfort from bright light is significantly inversely correlated with MPOD — people with higher macular pigment tolerate more light before experiencing discomfort or averting their gaze. Glare disability (the “washed out” vision caused by light scattered within the eye) is significantly reduced as a function of both naturally higher MPOD and supplementation-induced increases in MPOD. Photostress recovery — the time required to regain vision after exposure to a bright flash — is significantly shorter in individuals with higher MPOD, and can be meaningfully shortened within individuals who supplement with lutein and zeaxanthin.
These findings have direct practical implications for activities involving high glare exposure: driving, outdoor sports, operating in bright hospital environments, and working with screens in varying light conditions.
Contrast Sensitivity
Contrast sensitivity — the ability to distinguish objects from their backgrounds based on differences in luminance or color — also benefits from higher MPOD and from supplementation-induced MPOD increases, in studies of both healthy individuals and early-stage AMD patients. The review notes that the mechanism here is likely related to the optimization of lateral inhibition — a fundamental neurophysiological process in the visual system by which signals from adjacent neurons are suppressed to sharpen the boundaries of visual objects. MPOD was found to correlate significantly with lateral inhibition, suggesting that lutein and zeaxanthin in the retina support not just tissue health but the underlying neural architecture of visual perception.
Low-Light Vision
Visual function in dim lighting also benefits from higher MPOD, at least in younger adults. Dark-adapted visual sensitivity — the ability to detect very dim targets in darkness — correlated significantly with MPOD in older individuals aged 60–84. In younger healthy adults, individuals with high MPOD recovered their ability to see a very dim target after bright-light exposure nearly two minutes faster than those with low MPOD. The review notes one important qualification: this speed-of-dark-adaptation advantage appears to hold primarily for younger individuals; in adults over 60, dark adaptation speed may become independent of MPOD, likely because other age-related changes in the photoreceptors and RPE become dominant.
The Consumption Gap
The vast majority of Americans do not consume sufficient lutein and zeaxanthin to produce meaningful increases in MPOD. Averaged MPOD values from 11 studies conducted over 15 years converge around a mean of approximately 0.35 — a level that leaves substantial room for improvement through dietary modification and supplementation. The review frames this not as a counsel of despair but as an opportunity: dietary change and supplementation can produce relatively quick — within less than a year — and meaningful changes in both macular pigment density and the visual performance benefits it confers.
Lutein in the Brain: A Dominant Carotenoid Across All Ages
The review’s most scientifically striking section concerns lutein’s preferential accumulation in human brain tissue — a finding that has emerged relatively recently and shifts the understanding of this nutrient fundamentally.
Although lutein is not the most abundant carotenoid in the American diet for any age group, it is the carotenoid present in the highest concentration in human brain tissue. This preferential accumulation is thought to be mediated by a specific lutein-binding protein present in brain tissue (StARD3), paralleling the specific binding proteins that capture lutein in the retina.
The degree of this preferential accumulation is striking across the full lifespan. In full-term newborn infants, lutein accounts for approximately 60% of all carotenoids in the brain — despite making up only about 12% of the carotenoids consumed in the diet during the first year of life. The brain is selectively and aggressively concentrating this specific carotenoid at the most formative period of neural development. Preterm infants, cut off from the fetal lutein supply earlier, have significantly lower brain lutein concentrations, along with undetectable macular pigment and very low plasma carotenoids — a finding that connects retinal and neural carotenoid status and raises questions about the downstream developmental consequences of lutein deficiency in premature infants.
At the opposite end of life, in centenarians (people aged 100 or older), lutein still accounts for approximately 35% of all carotenoids in the brain, despite making up only about 20% of the carotenoids in matched serum — indicating that the brain continues preferentially concentrating lutein throughout the entire human lifespan, not just in development.
The Retina as a Window to the Brain
A methodologically important finding documented in the review is that macular pigment optical density — the non-invasive measurement of lutein and zeaxanthin in the retina — can serve as a biomarker for lutein concentrations in the brain. Studies comparing lutein concentrations in matched retinal and brain tissue sections from both non-human primates and humans found significant correlations between retinal lutein and brain lutein in the cerebellum, pons, occipital cortex, and frontal cortex. In humans specifically, lutein in the retina was significantly related to lutein in the occipital cortex.
This finding matters enormously for research: it means that researchers can measure lutein’s presence in brain tissue non-invasively, simply by measuring macular pigment in the eye. This has allowed a growing body of studies on lutein and cognitive function that would not otherwise be possible without brain biopsy or autopsy.
Lutein and Cognitive Function in Older Adults
The review surveys a substantial body of observational evidence linking MPOD — and by extension brain lutein — to cognitive performance in older adults. Several large studies are described:
In the Health, Aging, and Body Composition Study, 118 healthy older adults aged 76–85 were assessed for MPOD and a battery of cognitive measures. MPOD was significantly related to processing speed, accuracy, and task completion ability — associations that remained significant after adjusting for age, sex, and ethnicity.
In the Irish Longitudinal Study on Ageing — a much larger study involving 4,453 participants aged 50 and older — lower MPOD was significantly associated with poorer performance on the mini-mental state examination and the Montreal cognitive assessment (two standard screening tools for cognitive impairment), poorer prospective memory, longer time to complete a trail-making task, and slower and more variable reaction times on a choice reaction time task.
A study of 29 healthy older adults (aged 65–95) and 24 older adults with mild cognitive impairment found that MPOD was associated with cognitive performance in all subjects, but the correlations were broader and more extensive in the mild cognitive impairment group — spanning language, attention, visual-spatial ability, and constructional ability.
A study of 226 subjects — 105 without retinal disease but low in MPOD, and 121 with AMD — found that higher MPOD was significantly related to better performance in phonemic fluency, attention switching, visual and verbal memory, and learning, even after adjusting for age, sex, diet, and education level.
Perhaps most strikingly, a study of 4,076 subjects over the age of 50 found a positive relationship between lutein status, global cognition, memory, and executive function. And postmortem analyses of centenarians found that among all carotenoids measured in brain tissue, lutein concentration was the most consistently related to cognitive test scores taken before death — including global cognition, delayed recall, delayed recognition, retention, IQ, and executive function.
Can Supplementation Improve Cognition? Evidence From Intervention Trials
Moving from observational association to causal demonstration requires intervention studies — trials in which supplementation is administered and cognitive outcomes are measured before and after. The review describes several:
A four-month double-blind randomized trial assigned 49 healthy women aged 60–80 to lutein (12 mg/day), DHA (800 mg/day, an omega-3 fatty acid), a combination of both, or placebo. After supplementation, verbal fluency scores improved significantly in all three treatment groups compared to placebo. Memory scores and rate of learning improved significantly in the combined lutein plus DHA group, which also showed a trend toward more efficient learning. The authors note this is consistent with postmortem centenarian data showing that brain concentrations of lutein and DHA together predict cognitive performance better than either alone — suggesting an additive or synergistic relationship between these two nutrients.
A dietary intervention study in older adults (mean age 63) using avocado — a food naturally rich in lutein with high bioavailability due to its fat content — found that avocado consumption increased MPOD, which correlated with improved cognitive function.
A double-blind placebo-controlled study in younger adults aged 18–32 found that four months of supplementation with lutein, zeaxanthin, and DHA increased macular pigment and improved neural processing speed — demonstrating that the cognitive benefits of these nutrients are not confined to older populations.
Lutein and Cognitive Function in Children
The most novel section of the review concerns preadolescent children — a population in which the study of lutein and brain function is very recent. The review describes four cross-sectional studies using MPOD as a non-invasive biomarker of brain lutein in children aged 7–13, and the findings are consistent and notable.
In the first study, 40 children aged 7–10 had their MPOD, aerobic fitness, and adiposity measured and compared with performance on a relational memory task known to depend on hippocampal function (the hippocampus being a brain structure known to preferentially accumulate lutein in infancy). MPOD was negatively correlated with relational memory errors — children with higher macular pigment made fewer memory mistakes — even after controlling for IQ and physical health variables including aerobic fitness.
A second study of 56 children aged 8–9 assessed academic achievement using the Kaufman Test of Educational Achievement. MPOD correlated with overall achievement (r = 0.40, p < 0.01), reading (r = 0.28, p < 0.05), math (r = 0.35, p < 0.01), and written language (r = 0.41, p < 0.01). These are meaningful effect sizes for a nutritional variable in school performance.
A third study of 51 children aged 7–13 using the Woodcock-Johnson III cognitive battery found that MPOD was significantly related to executive processes (r = 0.29, p < 0.05) and brief intellectual ability (r = 0.27, p < 0.05).
A fourth study, using both cognitive testing and electroencephalography (EEG brain wave measurement) in a case-control design matched for socioeconomic status, age, and developmental timing, found that children with higher MPOD showed lower brain activation when performing the same cognitive tasks as children with lower MPOD. In other words, children with lower macular pigment had to recruit more brain activity to accomplish the same tasks, and they made significantly more errors. The EEG finding is particularly important because it suggests a genuine neural efficiency difference — not simply a health or socioeconomic confound.
The review makes an important interpretive point about these child findings: the relationship between lutein and cognition in children is unlikely to be explained by a disease-prevention mechanism (children do not have AMD or significant neurodegeneration). Instead, it appears to reflect lutein’s role in neural efficiency and possibly in the organization of neurotransmitter systems. Research cited in the review shows that lutein concentrations in brain tissue relate to major amino acid neurotransmitters — particularly glutamate and GABA — that are central to cognitive processing.
How Lutein May Protect Brain Function: Proposed Mechanisms
The review acknowledges that the precise mechanisms by which lutein influences cognitive function across the lifespan remain incompletely understood. Several candidate mechanisms are discussed:
The brain, like the retina, is a tissue of extraordinarily high metabolic activity and rich polyunsaturated fatty acid (PUFA) content — particularly DHA (docosahexaenoic acid), which makes up a large proportion of neuronal membrane lipids. These conditions make the brain uniquely vulnerable to oxidative damage. Elevated DHA oxidation has been observed in patients with dementia and cognitive impairment, suggesting that protecting DHA from oxidation in neuronal membranes is important for cognitive health.
Lutein’s molecular structure is well-suited for this protective role. Unlike non-polar carotenoids such as beta-carotene and lycopene, lutein has polar groups at each end of its molecule, which is believed to cause it to span the membrane perpendicular or semi-perpendicular to the membrane surface — a physical orientation that positions it along the membrane’s full thickness rather than lying parallel to it. Research shows that lutein specifically localizes to membrane domains rich in PUFAs including DHA, placing it precisely where oxidative damage to these vulnerable lipids is most likely to occur. By protecting DHA from oxidation, lutein not only preserves membrane structure and fluidity but also keeps DHA available for its conversion into anti-inflammatory signaling molecules.
Beyond direct antioxidant protection of membrane lipids, lutein may also influence membrane stability and the efficiency of communication between neurons — effects that could directly explain the performance differences seen in the visual and cognitive studies.
Dietary Sources, Typical Intakes, and the Gap
The review provides a practical food composition table. Among common dietary sources, cooked frozen spinach leads with approximately 29.8 mg of lutein plus zeaxanthin per cup, followed closely by cooked frozen kale at 25.6 mg. Summer squash provides about 4.0 mg per cup; green peas, pumpkin, Brussels sprouts, and broccoli each provide 2.0–3.8 mg per cup. Sweet yellow corn provides about 1.5 mg per cup. Avocado provides approximately 0.4 mg per medium fruit, and a single egg yolk provides about 0.2 mg.
While eggs and avocados rank low in absolute lutein content, both are considered highly bioavailable sources because their fat content — egg yolk fat and avocado monounsaturated fat — substantially improves the absorption of the lutein they contain. Studies using avocados specifically as a lutein intervention have produced meaningful MPOD increases and associated cognitive improvements in older adults, demonstrating that bioavailability matters as much as absolute content.
Average lutein and zeaxanthin intake in American adults is estimated at approximately 1–2 mg per day. For early adolescents, the picture is even more concerning: intake in this age group averages only about 300–500 micrograms per day — less than one-third to one-half of the already-low adult level. The review estimates that intakes of approximately 6 mg per day have been associated with reduced AMD risk, and that intervention studies improving cognition in older adults have used 12 mg per day. The gap between typical consumption and these levels is substantial at every age, and appears to be most severe during the adolescent years when, the review argues, the brain is particularly sensitive to nutritional input.
Implications for Breastfeeding and Infant Formula
The review addresses the early-life lutein supply chain directly. Breast milk is the primary lutein source for infants, but breast milk lutein content is directly dependent on maternal intake. Given that maternal lutein intakes are typically low, lutein levels in breast milk may not be optimal for supporting the brain development evidence suggests lutein facilitates. Studies show that supplementing lactating mothers with lutein increases lutein concentrations in both breast milk and the plasma of their nursing infants. Lutein-supplemented infant formulas have been shown to enrich lutein in the retina and brain of infants compared to standard formulas — a finding with developmental implications.
The review stops short of making specific intake recommendations for infants or children, noting that the intervention evidence in these populations is not yet sufficient to support formal guidelines. But it identifies breastfed infants and early adolescents as groups of particular concern given the evidence for developmental importance and low typical intakes.
Summary of Key Takeaways
- Lutein begins accumulating in the human eye as early as 14 weeks of gestation, peaking in the vitreous humor at 20–22 weeks and then concentrating in the developing retinal layers — suggesting a role in retinal development before birth. In premature infants, carotenoid supplementation improved rod photoreceptor sensitivity and neural response speed, providing direct evidence for lutein’s developmental role.
- Among all carotenoids, lutein is preferentially concentrated in the human brain across every life stage tested — from newborn infants (where it accounts for ~60% of brain carotenoids despite making up only ~12% of dietary carotenoids) to centenarians (where it accounts for ~35% of brain carotenoids). This preferential accumulation is mediated by a specific lutein-binding protein in brain tissue.
- Macular pigment optical density (MPOD) — the measurable concentration of lutein and zeaxanthin in the retina — correlates significantly with brain lutein concentrations, making it a non-invasive biomarker that allows research on lutein’s neural effects without brain biopsy.
- Higher MPOD in adults is consistently associated with better visual performance across multiple dimensions: faster visual processing, greater glare resistance, faster photostress recovery, improved contrast sensitivity, and enhanced low-light vision. These effects are measurable in both healthy individuals and AMD patients, and can be produced within months through supplementation.
- In older adults, multiple large observational studies across thousands of participants consistently link higher MPOD to better performance on tests of processing speed, memory, executive function, and global cognition. In centenarians, brain lutein concentration was the most consistently predictive carotenoid for a range of premortem cognitive test scores.
- Randomized controlled intervention trials demonstrate that lutein supplementation (12 mg/day) improves verbal fluency and, in combination with DHA, improves memory and learning rate in healthy older women. Avocado-based lutein dietary interventions also produced cognitive benefits. Supplementation improved neural processing speed even in adults aged 18–32.
- Four cross-sectional studies of children aged 7–13 found consistent correlations between MPOD and academic achievement, relational memory, intellectual ability, and executive function. EEG evidence showed that children with lower MPOD require greater neural effort to accomplish the same cognitive tasks and make more errors — suggesting a difference in fundamental neural efficiency, not merely a health or socioeconomic confound.
- Average American adult lutein intake (~1–2 mg/day) is estimated to be 3–6 times below the levels associated with AMD risk reduction and cognitive benefits in intervention trials. Early adolescents consume even less — approximately 300–500 mcg/day — at the developmental stage when the brain may be most sensitive to nutritional input.
- Leading dietary sources include cooked spinach (~29.8 mg/cup), cooked kale (~25.6 mg/cup), and other dark leafy greens and yellow-orange vegetables. Eggs and avocados, while lower in absolute lutein content, provide highly bioavailable forms and have been used successfully in cognitive intervention studies in older adults.
Source: Stringham JM, Johnson EJ, Hammond BR. Lutein across the Lifespan: From Childhood Cognitive Performance to the Aging Eye and Brain. Curr Dev Nutr. 2019 Jun 4;3(7):nzz066. doi: 10.1093/cdn/nzz066. Full text available at: https://pmc.ncbi.nlm.nih.gov/articles/PMC6629295/
