Golden Antioxidants for Eye Health: Lutein and Zeaxanthin
By Nicole Crane, B.S., NTP
Every season, a new superfood takes hold over the minds and plates of foodies everywhere. Over the last several years there has certainly been a craze over kale and spinach. These leafy greens are powerhouses of nutrition, rich in Omega-3 fats, beta carotene, potassium, magnesium, iron, most of the B vitamins, vitamin C and K1. What is unique to vegetables like kale and spinach are two very special carotenoids (antioxidants) called Lutein and Zeaxanthin. Cooking these veggies increases the bioavailability of Lutein and Zeaxanthin by a remarkable five times! There are few nutrients that are more beneficial for the eyes , but the people who need these carotenoids most (older adults) are the same population who consume them the least. Luckily, a simple supplement means you can reap the benefits of Lutein and Zeaxanthin without transforming your diet.
Of the 600 or so carotenoids researchers have discovered so far, only twenty can even make it into the eye, but only two get deposited into a very important area of the eye called the retina. Those two carotenoids that are most essential to eye health are Lutein and Zeaxanthin. There are about 10 million Americans living with macular degenerationiii , another 22 million with cataracts iv and 4 million people who have a visual impairment.v Despite so many people at risk for blindness, lutein and zeaxanthin have yet to get the mainstream attention that they deserve.
Natural Sunglasses for the Eye
Lutein and Zeaxanthin (pronounced “loo-teen” and zee-uh-zan-thin) are both powerful carotenoids whose job is to act as built-in sunglasses for the eye, if you have enough. They filter out harmful high-energy blue wave lengths of light and generally protect the cells of the eye from damage. Cell phones, television and computer screens all emit blue light, so it is more important now than ever to protect the retina. The retina is the innermost of three layers in the eye that covers the back of the eyeball and is highly light sensitive; When light passes into the cornea and lens of the eye and hits the retina, nerve impulses to the brain are triggered. This produces an image in the brain of the local environment, what you see and perceive. Our eyes are simply the most visible part of our brain, and need to be well nourished for optimal function.
As medical technology continues to advance, there are certain biomarkers that can be used to predict the risk of certain diseases and evaluate body system functionality. One of the best ways to assess eye health, predict eye disease, and assess visual acuity is measuring MPOD (macular pigment optical density). MPOD measures the quantity of Lutein and Zeaxanthin in the macular region of the retina. When we have optimal levels of pigments from carotenoids, we have healthy eyes and sight.
Consumption of Lutein and Zeaxanthin
The human body cannot make the Lutein and Zeaxanthin it needs, which is the reason why colorful vegetables are essential to good nutrition , especially for the eyes and brain. If you aren’t getting enough leafy greens and other colorful veggies, it is ideal to supplement with these essential nutrients. The average American is getting just 10% of the amount of Lutein and Zeaxanthin (about 2 mg combined) that is required by the eye to stay healthy for a lifetime.viii An early study showed that just 6 mg of Lutein per day has been shown to reduce the risk of age-related macular degeneration by 43%. ix
Macular degeneration is the leading cause for blindness among the elderly (in the western world) and there are few nutrients more protective than Lutein and Zeaxanthin. A recent review of the research, published in 2009, showed that not only do Lutein and Zeaxanthin successfully increase macular pigment optical density, but these carotenoids reduce the development and can even halt the progression of age-related macular degenration.x Research using natural forms of Lutein and Zeaxanthin that examines the role they play in healthy vision have had very positive outcomes.
Good nutrition is essential for both preventing and addressing the buildup of cataracts . Cataracts are the slow clouding of the lens of the eye, and are the cause of half of the cases of blindness worldwide. A high intake of sugar and a low intake of carotenoids and antioxidants from fruits and vegetables tend to be major and often overlooked causes. It seems that Lutein as an antioxidant, can even aid in improving vision in those with age-related cataracts. In a small, two year long study of 17 participants who received either 15 mg of Lutein, 100 mg of Tocopherol (vitamin E) or a placebo, only the lutein group had a significant improvement in vision, including a reduction in glare and an improved visual acuity, the sharpness of vision, assessed by the lettered eye chart. The tocopherol group maintained their current vision, while the placebo group had a decrease in visual performance.xii
Our eyes are very fragile, but they are also resilient. Given the right nutrients, especially those that can cross into the eye, like Lutein and Zeaxanthin, the eyes can be supported in the way that nature intended.
vii Mozaffarieh, Maneli, Stefan Sacu, and Andreas Wedrich. "The role of the carotenoids, lutein and zeaxanthin, in protecting against age-related macular degeneration: a review based on controversial evidence." Nutr J 2.1 (2003): 20.
viii Abdel-Aal, El-Sayed M., et al. "Dietary sources of lutein and zeaxanthin carotenoids and their role in eye health." Nutrients 5.4 (2013): 1169-1185.
ix Johanna M. Seddon et al, 1994, Journal of American Medical Association 272:1413-20.
x Carpentier, Shannon, Maria Knaus, and Miyoung Suh. "Associations between lutein, zeaxanthin, and age-related macular degeneration: an overview." Critical reviews in food science and nutrition 49.4 (2009): 313-326.
xi Gul, Anjuman, et al. "Advanced glycation end products in senile diabetic and nondiabetic patients with cataract." Journal of diabetes and its complications 23.5 (2009): 343-348.
xii Olmedilla, B., et al. "Lutein, but not á-tocopherol, supplementation improves visual function in patients with age-related cataracts: a 2-y double-blind, placebo-controlled pilot study." Nutrition 19.1 (2003): 21-24.