Lutein and the Eyes

Lutein has long been recognized (along with its carotenoid partner zeaxanthin) as a critical component for eye health. These two carotenoids are the only two found in the eyes, where they make up the macular pigment, which protects the thousands of photoreceptor cells that reside on the macula, a small spot on the retina that allows us to see color and fine detail and is important for central vision, or what is directly in front of us. The macular pigment absorbs harmful blue light, reducing photochemical damage and protecting this delicate part of the eye. Lutein also appears to reduce inflammation in the eyes.¹ The components of macular pigment—lutein and zeaxanthin—are not made by the body and must be acquired exclusively from the diet or supplementation.²

This sort of protection is becoming even more crucial as we become increasingly dependent on our smartphones, TVs, tablets and computers, which emit high amounts of blue light that can be seriously damaging to our eyes. Even energy-efficient compact fluorescent bulbs and LED lights emit significant amounts of blue light.³ Blue light penetrates deep into the eye and cumulative exposure can damage the retina; it is also implicated in the development and worsening of age-related macular degeneration (AMD).^{4 5 6} There is evidence that people with thicker macular pigment have a significantly lower risk of developing AMD (82% lower risk) compared to people with thin macular pigment, and that supplementation (10mg lutein + 2 mg zeaxanthin) can reduce the risk and slow the progression of AMD.⁷ 

Recent research also confirms that lutein may protect from some of the more immediate deleterious effects of screen time on eye health. After six months of supplementation with lutein (24 mg total of lutein + zeaxanthin) adults who were exposed to six or more hours of screen time a day experienced significant improvements in headache frequency, eye strain, and eye fatigue.⁸

Lutein and the Skin

In much the same way that lutein absorbs blue light to protect the eyes, it also helps to protect the skin from ultra-violet (UV) radiation and blue light. UV exposure produces free-radicals in the skin, which leads to sunburn, but also breaks down DNA, proteins and fats in the skin cells, leading to photodamage. Excessive UV exposure ages skin prematurely by causing dryness and flaking and degrading the collagen that keeps the skin supple and toned. Besides sunburn, the outward appearance of photodamage is wrinkles, fine lines, and age spots. By depositing in the skin, lutein (and again its partner zeaxanthin) helps to protect the skin from photo-damage and reduce the skin’s inflammatory response.⁹ In one study, supplementing with just 10 milligrams of lutein and 0.6 mg of zeaxanthin a day for 12 weeks, significantly increased skin hydration, elasticity and skin lipid content.¹⁰ Supplementation (10 mg lutein + 2 mg zeaxanthin) was also found to decrease the intensity of sunburn after skin was exposed to UV light, due to its photoprotective and antioxidant activity.^{11 12}  

Lutein and the Brain

Lutein and zeaxanthin are the most dominant carotenoids in the brain and the thickness of the macular pigment is directly related to the amount of lutein found in the brain. In fact, researchers use macular pigment as a biomarker of lutein content in the brain, and a significant correlation has been observed between macular pigment density and how well our brains age—thicker macular pigment is an indicator of a healthy and better performing brain as we grow older.¹³ A population study published in late 2017 including 4,076 adults aged 50 and older found that higher levels of lutein and zeaxanthin were associated with better scores in several measures of cognitive function, including memory, executive function (which includes reasoning and judgement, planning, focus, and regulating emotions), and better processing speed.¹⁴  Other recent studies have shown that supplementation with lutein (12 mg/day) significantly improves cognitive function in older adults.^{15 16}

But lutein’s brain benefits aren’t just for older adults—lutein is also the most dominant carotenoid in the infant brain¹⁷ and research has shown that a higher maternal intake of lutein (and zeaxanthin) during pregnancy is associated with greater verbal intelligence, as well as behavioral and emotional control in children.¹⁸ A denser macular pigment (a measure of lutein in the brain) is not only associated with better performance on cognitive tests, but also better brain efficiency in children, that is, their brains don’t have to work as hard.¹⁹ Research has also found that thicker macular pigment in children is positively related to academic achievement²⁰ and that supplementation with lutein and zeaxanthin (10 mg lutein + 2 mg zeaxanthin) improved cognitive function (specifically reasoning, memory, and attention) even in healthy college students “at the peak of their cognitive life.”²¹

One of lutein and zeaxanthin’s most important jobs in the brain is to protect polyunsaturated fatty acids (PUFAs) from oxidative damage. Brain cells are rich in PUFAs, like docosahexaenoic acid (DHA), and are especially susceptible to free radical damage. Lutein and zeaxanthin concentrate in the lipid layers of the cells, where, because of their unique structure, they help stabilize cell membranes and protect these important PUFAs from oxidative damage.²² In addition to being powerful antioxidants, lutein and zeaxanthin exert anti-inflammatory properties, enhance blood flow to the brain, and improve communication between neurons.^{23 24 25} They have also been found to increase brain-derived neurotropic factor (BDNF), which plays an important role in neuronal growth and also promotes brain plasticity, essential for learning and memory.²⁶

Get Your Lutein

Getting enough lutein to provide adequate protection to the eyes, skin and brain is essential to good health. Lutein cannot be made by the body and instead must be obtained through the diet or supplements. Six to 20 milligrams of lutein a day is the amount believed to be necessary to reduce the risk of macular degeneration,²⁷ but considering the importance of lutein to the skin and brain, 20 milligrams a day may offer better overall protection. Unfortunately the average American adult consumes only 0.67-0.89 milligrams a day, a far cry from the suggested minimum of 6 milligrams a day, making supplementation important for most adults who want to protect their eyes, skin and brain.²⁸ Lutein supplements come in two forms, free and esterified, and both have comparable bioavailability when taken with a meal containing fat. No matter which form you choose to get your lutein, it should be consumed with some healthy fat for optimal absorption.

References

1. Kijlstra A, Tian Y, et. al. Lutein: more than just a filter for blue light. Prog Retin Eye Res. 2012 Jul;31(4):303-15
2. Kijlstra A, Tian Y, Kelly E, Berendschot T. “Lutein: More than just a filter for blue light.” Progress in Retinal and Eye Research. July 2012;31(4):303-315. 
3. Melton R. Ultraviolet and Blue Light. Review of Optometry. February 2014. Available at: http://www.reviewofoptometry.com/continuing_education/tabviewtest/lesso…;
4. https://www.macular.org/ultra-violet-and-blue-light 
5. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4734149/ 
6. https://academic.oup.com/ajhp/article/65/13/1232/5127866 
7. https://iovs.arvojournals.org/article.aspx?articleid=2645720  
8. Stringham, J.M., Stringham, N.T., O’Brien, K.J. ( 2017). Macular carotenoid supplementation improves visual performance, sleep quality, and adverse physical symptoms in those with high screen time exposure. Foods, 6(7), 47. doi: 10.3390/foods6070047  
9. Lee EH, Faulhaber D, Hanson KM. Dietary lutein reduces ultraviolet radiation-induced inflammation and immunosupression. Journal of Investigative Dermatology. 2004;122:510-517. 
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11. https://www.sciencedirect.com/science/article/pii/S2405580815000692#bib…;
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19. https://europepmc.org/articles/PMC5551452;jsessionid=8EE6DEB5F4A4FF260D…;
20. https://www.tandfonline.com/doi/full/10.1080/1028415X.2017.1329976 
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23. https://www.ncbi.nlm.nih.gov/pubmed/29161349 
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27. n.a. Lutein and Zeaxanthin Monograph. Alternative Medicine Review. 2005; 10(2):128-135. 
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