The antioxidants lutein and zeaxanthin help keep the eyes healthy. A new study has found that these nutrients also improve the circulation of blood to the brain. Seniors experience gradual cognitive decline. A recent study showed that taking enough of these antioxidants halted cognitive decline. Research supports the idea that nutrition has a direct impact on the brains and eyes throughout one’s lifespan from infancy (breast milk contains lutein) to old age.1
What Are the Eyes?
Embryologically, physiologically and neurologically, what are the eyes? They are brain tissue. To work properly, the brain needs blood flow. Blood travels to the brain through arteries. The blood-brain barrier allows select nutrients through. Blood is toxic to the brain itself. However, the nourishment that blood flow provides the brain is vital to its functioning. Without enough oxygen and nutrients, brain cells die. Worst case, the brain shuts down and the person dies. A technical term for brain blood flow is “cerebral blood flow.”
Impaired cerebral blood flow is connected to reduced brain functioning. Neurodegenerative diseases such as Alzheimer’s disease have been linked to impaired cerebral blood flow.2
Exercise has positive effects on the brain. Much of these benefits are attributed to increased oxygen and blood flow. Exercise also helps protect the carotid arteries from plaque build-up. If one of these important arteries becomes clogged (hardening of the arteries), the person may have a stroke.
What are Lutein and Zeaxanthin?
Lutein and Zeaxanthin are carotenoids. Carotenoids are antioxidants that fight free radical damage. Technically, they are xanthophylls, a class of carotenoids. These antioxidants occur in nature and are found in certain foods. They are crucial to vision health.
Foods high in lutein have an orange, green, or yellow color. The yellow pigment is key to lutein’s value. The pigment absorbs blue light. Blue light is very damaging to the eye because it causes oxidization. The eye has tiny structures, and free radicals can cause significant harm. Cataracts and macular degeneration, for example, are associated with or directly attributed to blue light and oxidizing damage. Spinach, kale, broccoli, carrots, Brussel sprouts, egg yolks, and corn are high in lutein. Marigold flowers can be processed into a powerful lutein supplement.
Lutein is found in the macula of the eye. The macula is a yellowish circle in the center of the retina. It gives us our more detailed central vision. A study found that macular degeneration patients had 30% less lutein in the macula than healthy patients.3 4 A lutein-rich diet reduced the chances of developing macular degeneration by 57% in a study.5 6
Zeaxanthin is also an antioxidant for the eye found in the retina. Both lutein and zeaxanthin are in the lenses of the eyes as well. Paprika, corn, marigold flowers and saffron are high in zeaxanthin. This antioxidant helps protect the eye from free radical damage. Also found in the central macula, zeaxanthin is important for preventing macular degeneration.
The protective benefits of lutein and zeaxanthin appear to be related to their special structure.7 Like all xanthophylls, lutein and zeaxanthin can immerse themselves into the membranes of fatty brain cells. They cross between the interior and exterior environments. Therefore, the cell structure is stabilized and protected from oxidative damage. Xanthophylls appear to concentrate automatically in brain regions most susceptible to oxidative damage.
Do We Need Supplements?
The standard American diet may have sweet corn and spinach. However, it often lacks sufficient green and brightly colored fruits and vegetables. The United States Department of Agriculture has not set a Recommended Daily Allowance for these nutrients. Most Americans get only 1-2 mg of lutein in their diets. Studies suggest at least 10 mg of lutein and 2 mg of zeaxanthin for macular degeneration prevention and retinal support. Seniors absorb nutrients less efficiently, and their caloric needs are lower than for their younger counterparts. Thus, they may need supplements for full protection.
Research on Lutein and Zeaxanthin and the Brain
Seniors experience cognitive decline over time. For the first time, a recent study looked at the effects of lutein and zeaxanthin on cerebral blood flow.8 The researchers gave seniors a pill with 10 mg of lutein and 2 mg zeaxanthin. The combination is a xanthophyll supplement. Before and after a year of this treatment, the subjects performed learning and recall tasks in a functional MRI. This imaging technique showed blood flow to brain regions. The more blood flow to a region, the harder the brain is working on the task.
Another group, the controls, took a placebo such as a sugar pill. Their cognitive performance tended to decline after a year.
The subjects who took the xanthophyll supplement had the same cognitive performance during the year. While their counterparts had cognitive decline, the subjects who took the supplement maintained their cognitive powers.
Also, the subjects who took the xanthophyll supplement had increased blood flow to the parts of the brain crucial to memory and cognition. The controls did not.
The researchers concluded that lutein plus zeaxanthin increased blood flow to the brain. This helped seniors maintain their thinking abilities. The supplement had a neuroprotective effect. It insulated the brain from typical declines associated with aging.
The Eyes, Lutein and Zeaxanthin
Just like our brains, our eyes need blood flow too. Blood provides the eyes with oxygen and nutrients. The eyes are the most nutrient-hungry organ for their size. Thus, poor blood flow to the eyes can contribute to eye damage and eye disease. Also, hardening of the arteries can cause a retinal artery and vein occlusions.
The retina is technically brain tissue. Like the brain, the retina benefits significantly from lutein and zeaxanthin. Therefore, getting enough of these xanthophylls has a dual benefit to the eyes and the brain.
Other research discusses the relationship between these carotenoids and more specific visual functions such as contrast sensitivity,9 10 importance of macular pigment quality,11 12 and effect in early AMD/AMD risk.13 14
- Johnson EJ. (2014). Role of lutein and zeaxanthin in visual and cognitive function throughout the lifespan. Nutr Rev. Sep;72(9):605-12. ↩
- Kisler K, Nelson AR, Montagne A, Zlokovic BV. (2017). Cerebral blood flow regulation and neurovascular dysfunction in Alzheimer disease. Nat Rev Neurosci. Jul;18(7):419-434. ↩
- Landrum JT, et al. (1997). The Macular Pigment: A Possible Role in Protection from Age-Related Macular Degeneration. Adv Pharmacol. 38:537-556. ↩
- Eisenhauer B, Natoli S, Liew G, Flood VM. (2017). Lutein and Zeaxanthin-Food Sources, Bioavailability and Dietary Variety in Age-Related Macular Degeneration Protection. Nutrients. Feb 9;9(2):120. ↩
- Seddon, J.M., U.A. Ajani, et al, (1994). Dietary carotenoid, vitamins A, C, E, and advanced age-related macular degeneration. JAMA. ↩
- Khoo HE, Ng HS, Yap WS, Goh HJI, Yim HS. (2019). Nutrients for Prevention of Macular Degeneration and Eye-Related Diseases. Antioxidants (Basel). Apr 2;8(4):85. ↩
- Widomska J, Zareba M, Subczynski WK. Can Xanthophyll-Membrane Interactions Explain Their Selective Presence in the Retina and Brain? Foods. 2016;5(1). ↩
- Lindbergh CA, Renzi-Hammond LM, Hammond BR, et al. Lutein and Zeaxanthin Influence Brain Function in Older Adults: A Randomized Controlled Trial. J Int Neuropsychol Soc. 2018;24(1):77-90. ↩
- Stringham JM, O’Brien KJ, Stringham NT. (2017). Contrast Sensitivity and Lateral Inhibition Are Enhanced With Macular Carotenoid Supplementation. Invest Ophthalmol Vis Sci. Apr 1;58(4):2291-2295. ↩
- Eggersdorfer M, Wyss A. (2018). Carotenoids in human nutrition and health. Arch Biochem Biophys. Aug 15;652:18-26. ↩
- Lima VC, Rosen RB, Farah M. (2016) Macular pigment in retinal health and disease. Int J Ret Vit, Aug 15;2:19. ↩
- Johnson EJ, Hammond BR, Yeum KJ, Qin J, Wang XD, et al. (2000). Relation among serum and tissue concentrations of lutein and zeaxanthin and macular pigment density. Am J Clin Nut. Jun;71(6):1555-62. ↩
- Sabour-Pickett S, Beatty S, Connolly E, Loughman J, Stack J, et al. (2014). Supplementation with three different macular carotenoid formulations in patients with early age-related macular degeneration. Retina. Sep;34(9):1757-66. ↩
- Tan JSL, Wang JJ, Flood V, Rochtchina E, Smith W, et al. (2008). Centre for Vision Research, University of Sidney, Australia. Dietary Antioxidants and the Long-term Incidence of Age-Related Macular Degeneration: The Blue Mountains Eye Study. Ophthalmology. Feb;115(2):334-41. ↩