Age-related Macular degeneration (AMD) is one of the leading causes of age-related blindness. It occurs most frequently in adults over the age of 50 and increases with age. It is more common in Caucasians, and those with a family history of the disease. Smoking doubles the risk of development¹. AMD results when there is damage to the macula; a small area in the eye that is responsible for central vision (what you are seeing straight ahead). Over time, this can result in blurry patches in your vision, and can progress to blank areas. While it does not lead to complete blindness (one’s peripheral vision remains intact), it significantly impacts activities of daily living and can decrease the quality of life of affected individuals.
It is predicted that in the U.S., cases of early AMD will increase 96%, from 9.1 million in 2010, to 17.8 million in 2050². In Canada, AMD accounts for 90% of new cases of legal blindness in Canada³. With an aging population; it is likely that Canada will follow similar trends to our U.S. neighbours and we will continue to see a rise in new cases of AMD.
While there are currently no medications that can restore vision that is lost due to AMD, some nutrients and supplements may be able to prevent the onset or slow the progression of AMD.
Lutein and zeaxanthin are carotenoids that are antioxidant -rich nutrients. They are found in high concentrations in leafy green vegetables as well as in orange, yellow, and red coloured fruits and vegetables, such as carrots, yams, peppers, tomatoes, and cantaloupe. Our bodies cannot synthesize these nutrients, so we have to obtain them through dietary means. These nutrients are delivered to the macula where they are found at the highest concentrations anywhere in the human body, suggesting an important functional role for these molecules in the eye⁴.
Previous studies have shown that healthy individuals have higher central macular pigment optical density (MPOD) levels than those afflicted with AMD. MPOD is a measure that correlates to the concentration of lutein and zeaxanthin in the eye² (2).
A meta-analysis, a type of research study that has examined the findings of multiple studies (in this case, 20 randomized control trials, looking at 1764 participants), examined the effects of lutein, zeaxanthin and meso-zeaxanthin (a synthetic form of zeaxanthin) on AMD ⁵. The meta-analysis revealed that lutein, zeaxanthin and meso-zeaxanthin supplementation improved MPOD levels in BOTH patients and healthy subjects. There was a dose-response relationship seen, meaning the greater the quantity of these nutrients provided through dietary or supplementary means, the greater the MPOD⁵ .
Now, we need further research, namely randomized control trials and meta-analysis to determine whether low levels of MPOD CAUSES AMD.
In the meantime, what can we do to support our eye health?
- Quit Smoking
- Ensure your meals consist of a variety of colourful fruits and vegetables. Include 1-2 cups of leafy green vegetables such as spinach, kale, broccoli or bok choy into your diet daily as well as a serving or two of orange, yellow and red vegetables. The more, the better!
- Speak to your ND, MD, or optometrist about whether or not supplementing with lutein and zeaxanthin are right for you!
References
- Facts About Age- Related Macular Degeneration. National Eye Institute. https://nei.nih.gov/health/maculardegen/armd_facts . 2018. Accessed 10 June 2019.
- Bernstein PS, Delori FC, Richer S, van Kuijk FJ, Wenzel AJ. The value of measurement of macular carotenoid pigment optical densities and distributions in age-related macular degeneration and other retinal disorders. Vision Res. 2010;50(7):716–728. doi:10.1016/j.visres.2009.10.014
- Age-Related Macular Degeneration. Canadian Opthamological Society Eye Physicians and Surgeons of Canada. https://www.cos-sco.ca/vision-health-information/conditions-disorders-treatments/retinal-diseases/amd/ . 2019. Accessed 10 June 2019.
- Handelman GJ, Dratz EA, Reay CC, van Kuijk JG. Carotenoids in the human macula and whole retina. Investigative Ophthalmology and Visual Science. 1988;29(6):850–855. [PubMed] [Google Scholar]
- Ma L, Liu R, Du JH, Liu T, Wu SS, Liu XH. Lutein, Zeaxanthin and Meso-zeaxanthin Supplementation Associated with Macular Pigment Optical Density. Nutrients. 2016; 8(7):426
- Photo by Joel Staveley on Unsplash
Photo by Joel Staveley on Unsplash