The Importance of Lutein and Zeaxanthin for Kids
- Exposure to blue light from electronic devices may have long-lasting implications for children’s visual health and cognitive function
- Supplementation with lutein and zeaxanthin can help protect against potential sources of damage and provide vital nutritional support
- Higher concentrations of lutein and zeaxanthin in the brain are associated with greater cognitive functioning and visual health
Despite many parents’ efforts to limit their kid’s “screen time,” children are spending more time engaging with electronic devices (phones, iPads, laptops) than ever before.1 (Don’t worry, this isn’t an article condemning anyone’s parenting choices. We too value sanity during long car rides and restaurant waits).
While the majority of concerns around children’s screen time center around the negative health implications of sedentary behavior and the amount of media influence children are being exposed to, an equally relevant concern is the harmful effects exposure to “blue” light may be having on their visual and cognitive development. (Still not judging).
Although both adults and children should be concerned about their exposure to high-frequency, short wavelength (blue) light from electronic sources, children are particularly susceptible to the harmful effects of blue light. This is because children’s eyes have decreased lens density relative to adults. This means that, in children, more blue light can reach the retina and wreak havoc on the retina and visual function.2,3 Compounding this issue further, many infants and children are not getting enough of the nutrients they need for optimal visual health and development—placing them even more at risk of damage.4,5
But wait! Before you toss out the iPad—keep reading. In this article, we’ll discuss how adequate consumption of the phytonutrients lutein and zeaxanthin can provide protection from blue light, along with the vital nutrients children’s developing eyes and brains need for healthy visual and cognitive function. A real win-win. (Actually, a win-win-win, if you count not having to chuck the iPad. Ha, as if).
Lutein and Zeaxanthin: What, Why, and Where?
For those of you unfamiliar with lutein and zeaxanthin, let’s take a minute to discuss what they are, why they’re important, and where you can find them.
What are Lutein and Zeaxanthin?
Lutein and zeaxanthin belong to a class of phytonutrients known as carotenoids, which are naturally occurring pigments synthesized by plants, algae, and bacteria.6 In addition to giving many plants their colorful red, yellow, and orange hues, carotenoids serve important antioxidant functions, including deactivating free radicals and filtering harmful blue light that can otherwise lead to oxidative stress, inflammation, and damage to the visual system.6
Why are Lutein and Zeaxanthin important?
We know that lutein and zeaxanthin are important in early development for several reasons, including their preferential accumulation in retinal and brain tissue during pregnancy and early infancy.7 This essentially means that, upon ingestion, lutein and zeaxanthin are selectively absorbed by areas of the eye and brain where they play structural and functional roles. (In other words, Mother Nature knows what’s up, and sees to it that the eyes’ and brains’ needs are met). Lutein is particularly prevalent in the infant brain, where it accounts for roughly 60% of total brain carotenoids, despite constituting only 12% of the average infant’s overall carotenoid intake.7,8
We also know that lutein and zeaxanthin are important for eye development in infancy. This is because the developing retina requires oxygen-rich blood vessels to form biological membranes.9 Unfortunately, such a pro-oxidative environment can be detrimental for the eye, which is where lutein and zeaxanthin come into play. The presence of lutein and zeaxanthin in the developing macula is thought to provide an important antioxidant barrier, and thus help avoid oxidative damage in early infancy, when the eye and brain are undergoing rapid development.10
Another reason lutein and zeaxanthin are important is because they combine to create a protective layer in the retina known as macular pigment. Macular pigment provides vital protection from short wavelength light and other sources of oxidative stress, and research suggests our visual health would suffer without it.8,11 For example, a study conducted with rhesus macaques indicated that monkeys brought up on a diet free of lutein and zeaxanthin went on to develop no macular pigment, but instead developed a number of retinal and visual abnormalities.12,13;
Where can you find Lutein and Zeaxanthin?
Humans cannot synthesize lutein and zeaxanthin; therefore, they must be obtained through dietary sources or supplements. Rich sources of lutein and zeaxanthin include dark, leafy green vegetables (e.g., cooked kale, spinach, collards) and brightly colored foods such as corn, mango, and honeydew.9 Although relatively low in lutein, avocado and egg yolk are highly bioavailable sources of lutein, and thus good candidates for meeting children’s carotenoid needs. (Which is great news for the 98% of children who’d sooner have an epic meltdown than eat kale).
How Does Blue Light Affect Your Eyes?
For the sake of brevity, we’ll keep our explanation simple. There are three types of photoreceptors (specialized cells that convert light into neural energy) in the retinal layer at the back of your eye. The first two photoreceptor types are cones and rods, which play well-established roles in absorbing light and converting it into the visual representations we see.14 Scientists recently discovered a third class of photoreceptors, known as photosensitive retinal ganglion cells (pRCGs).15 Unlike cones and rods, pRCGS do not contribute to sight directly, but help differentiate between day and night, synchronize circadian rhythms, and regulate pupil responses. As their name would imply, pRCGs are also very photosensitive, meaning they are sensitive to the photons in visible light.15
In a nutshell, when visible light passes through the media of our eye to the retina, our photoreceptors transform it into an electrochemical signal that we use to process images and regulate our sleep-wake cycle. Unfortunately, many electronic devices emit significant amounts of high-energy, blue light which can be absorbed by the pRCGS, and create localized oxidative stress and damage.16 Laboratory studies conducted with rats and humans show that extended exposure to blue light can actually accelerate rates of retinal cell death, inhibit melatonin, and lead to disturbances in the sleep-wake cycle (which is never a good look on a child).17–19
How Can Lutein and Zeaxanthin Help Protect Your Eyes from Blue Light?
Lutein and zeaxanthin are believed to combat light-induced damage by absorbing incoming wavelengths of damaging light before they can form reactive oxygen species—unstable molecules that contain oxygen and destroy molecules like DNA.20 And when reactive oxygen species do get formed, lutein and zeaxanthin can help protect retinal cells by physically and chemically “quenching” these unstable molecules.20
In addition to dialing up children’s spinach and kale intake, lutein and zeaxanthin in the form of nutritional supplements can also improve children’s carotenoid status. Studies show that lutein and zeaxanthin supplements are safe for children as young as preterm infants, and can effectively increase plasma levels in infants and children.21–23 What’s more, a number of studies show that, in addition to visual benefits, supplementation with lutein and zeaxanthin can enhance cognitive performance during childhood.24–27
Brain Benefits of Lutein and Zeaxanthin
By now, you’re familiar with some of lutein and zeaxanthin’s benefits for visual health (e.g., supporting maturation of the eyes and brain, creating macular pigment, and protecting the macula and retina from oxidative stress); however, emerging research suggests that lutein and zeaxanthin also play functional roles in children’s cognitive functioning.24
For example, in studies conducted with school-aged children (aged 7-10 years), researchers found that children with high macular pigment ocular density (MPOD) made the least errors on a memory task,25 and performed the best on reading, math, written language, and achievement tests.26 Conversely, children in these studies with low MPOD (i.e., low levels of lutein and zeaxanthin in their brain) performed less well.25,26
Also, in a study using cognitive testing in conjunction with a test for brain activity, researchers found that children with higher MPOD showed lower brain activation while performing cognitive tasks than a “matched” peer with low MPOD.27 In other words, children with low MOPD levels had to use more brainpower to do the same tasks (and made significantly more errors) than their high MPOD peer, despite being similar in age, socioeconomic status and a number of other personal variables.
In short, the collective findings from these studies suggest that the greater the amount of lutein and zeaxanthin children consume, the better their brains perform on cognitive tasks. And, fortunately for us parents and grandparents, this isn’t an association exclusive to children. In fact, a well-established and comprehensive body of research indicates that lutein and zeaxanthin supplementation can enhance visual and cognitive health throughout adulthood.28–31
Coupled with inadequate consumption of lutein and zeaxanthin from dietary sources, increasing exposure to high-frequency blue light from electronic devices is putting children’s visual and cognitive health at risk. Fortunately, parents can help protect children’s retinal and brain health by ensuring they receive the foundational nutrients they need from either food or nutritional supplements. We encourage you to speak with your child’s pediatrician about the importance of lutein and zeaxanthin, and whether incorporating supplements into your child’s health regimen is advisable.
Free radical: A molecule that has an unpaired electron and is more reactive and unstable than a paired electron. Because electrons like to be in pairs, free radicals seek out other electrons, which causes damage to cell, proteins, and DNA.
Lutein: A type of phytonutrient that helps protect the eye from oxidative damage; one of the main components in macular pigment.
Macula: An oval-shaped pigmented area near the center of the retina that is responsible for detailed central vision and color vision.
Macular pigment: A yellow-pigmented layer in the retina composed of lutein, zeaxanthin, and meso-zeaxanthin that provides protection from sources of oxidative stress.
Macular pigment ocular density: A biomarker for lutein and zeaxanthin concentrations in the brain that is often used in research studies and for diagnostic purposes.
Photoreceptors: A specialized type of cell found in the retina that converts visible light into signals that can stimulate biological processes.
Photosensitive retinal ganglion cells: A type of photoreceptor in the retina that is particularly sensitive to the photons in light, and helps differentiate between day and night, regulate pupil responses, and synchronize circadian rhythms.
Phytonutrients: Natural chemicals produced by fruits, vegetables, legumes, nuts, and whole grains that can provide a range of health benefits.
Reactive oxygen species: A type of unstable molecule that contains oxygen and that easily reacts with other molecules in a cell.