While many supplements can be beneficial for a variety of physical conditions, lutein and zeaxanthin are best known for their role in eye health. Both of these compounds are members of the carotenoid family and are found in vegetables such as spinach, kale, collard greens, mustard greens and corn. Many studies have indicated that lutein and zeaxanthin are capable of reducing the risk of chronic eye diseases, including age-related macular degeneration (AMD) and cataracts — two conditions for which there are minimal options when it comes to effective prevention.
How Lutein and Zeaxanthin Help the Eyes
The highest concentration of lutein and zeaxanthin is found in the macula, located in the back of the eye. It is there, where these carotenoids are believed to help filter out harmful blue light and help prevent oxidative damage and aging to the sensitive structures of the eye. Lutein and zeaxanthin are also found in significant amounts in the lens of the eye, where they perform as antioxidants, further helping defend our eyes from harmful free radicals.
Several recent studies support the fact that carotenoids have not only anti-aging but also anti-cancer compounds. They act as powerful antioxidants in the body, guarding cells from the destruction caused by free radicals.Among the many dietary antioxidants, however, carotenoids seem to have the greatest effect. Lutein and zeaxanthin, in particular, appear to be the most valuable. Lutein and zeaxanthin are the only carotenoids that have been known to come together specifically in the eye tissues. The high concentration of these carotenoids in the eye protects these tissues by reducing free radical damage and by absorbing destructive ultraviolet light.
Age-related macular degeneration occurs when the area of the retina called the macula degenerates slowly over a long period of time. The macula is responsible for central vision and high visual acuity. Damage to the macula caused by oxidative injury can result in a loss of central vision. Free radical damage from ultraviolet radiation is believed to be a contributing factor, if not the primary cause of macular degeneration.
Lutein may help protect the macula by blocking the activity of peroxide free radicals — guarding cell membranes against this damage. A study conducted by Dr. Stuart Richer and published in the April 2004 issue of Optometryfound that lutein alone and lutein combined with other antioxidants may improve vision in patients with age-related macular degeneration.
A cataract is a cloudy area that forms in the lens of the eye. As it grows, it clouds over more of the lens and vision becomes impaired. This condition is also believed to be a result of free radical damage from exposure to ultraviolet light. Lutein and zeaxanthin, acting as antioxidants, may therefore help in the prevention of cataracts by neutralizing the free radicals that cause them.
In fact, research published in the American Journal of Clinical Nutrition confirmed that higher dietary intakes of lutein and zeaxanthin were responsible for a 23% reduced risk of cataract formation in the women in the study. In another study, researchers at Brigham & Women’s Hospital and Harvard Medical School investigated the dietary information presented by 35,551 female health workers who initially joined the Women’s Health Study in 1993. Their nutritional and other health issues were analyzed for a period of ten years. By the end of this period, 2,031 women had gone on to develop cataracts. Investigators concluded that women with the highest intake of lutein and zeaxanthin were 18% less likely to develop cataracts.
Macular degeneration and cataracts aren’t the only eye diseases that these carotenoids help to prevent. In the April, 2010 issue of the Archives of Ophthalmology, a daily supplement containing 12 mg of lutein in combination with vitamin A was shown to slow the vision loss associated with retinitis pigmentosa, an inherited eye disease of the retina that causes vision loss. And in another study appearing in Applied Ergonomics, a supplement containing lutein, zeaxanthin and black currant extract was shown to reverse symptoms of visual fatigue. These findings add to the ever increasing body of knowledge supporting the benefits of lutein and zeaxanthin for eye health.
In addition to performing crucial roles in eye health, lutein and zeaxanthin may well be valuable nutrients in the prevention of cardiovascular disease, stroke, some cancers, and maybe even Alzheimer’s disease.
Cardiovascular Disease and Stroke
Studies have long suggested an association between carotenoid intake and decreased risk of cardiovascular disease and stroke. Research presented in the Annals of Epidemiology showed oxidation of low-density lipoproteins (LDL) to be a main cause in the instigation of atherosclerosis, one of the damaging processes involved in cardiovascular disease. Antioxidants including lutein and zeaxanthin have been explored for their ability to scavenge free radicals and slow down lipid peroxidation in these diseases. And the Los Angeles Atherosclerosis Study supported the hypothesis that increased dietary intake of lutein is protective against the development of early atherosclerosis.
Dietary intake of lutein plus zeaxanthin has been associated with a lower risk of developing ovarian cancer. A study appearing in the Annals of Oncology was conducted among 1,031 patients with confirmed epithelial ovarian cancer and 2,411 controls without the presence of the disease. The study showed that those taking the highest amounts of lutein plus zeaxanthin had a 40% lower risk of developing ovarian cancer than those taking the lowest amounts.
In research conducted in Los Angeles, California, involving 1,204 patients with kidney cancer, a significant association was made between the consumption of lutein supplements and a reduced risk of renal cancer.
In a large study appearing in the American Journal of Clinical Nutrition, Slattery et al. investigated the association between dietary lutein and the risk of colon cancer in 1,993 subjects with cancer of the colon and 2,410 subjects used as controls. An association between dietary lutein intake and the reduced risk of colon cancer was detected. In this study, lutein was the only carotenoid that appeared to lower the risk of this particular type of cancer.
And in a 2002 research paper appearing in the American Journal of Epidemiology, dietary intakes of lutein and zeaxanthin were associated with a 17% decreased risk of lung cancer in a 14-year study of more than 27,000 Finnish male smokers.
There is also some evidence that supplementing the diet with lutein and zeaxanthin can be beneficial for the prevention of Alzheimer’s disease. Researchers at the Department of Medicine, Oregon Health and Science University in Portland, Oregon, measured levels of several antioxidants including lutein and zeaxanthin in the bloodstreams of patients suffering from mild cognitive impairment and Alzheimer’s disease, and found that they were much lower than levels found in the control group.
Mild cognitive impairment can often lead to Alzheimer’s disease, and researchers concluded that increased consumption of these antioxidants could diminish the risk of Alzheimer’s and other forms of dementia in the elderly.
In the same way that these carotenoids protect the eyes from ultraviolet light, they may also prevent cellular damage in skin conditions attributed to extreme ultraviolet light exposure by reducing free radicals. According to a study in the Journal of Investigative Dermatology, lutein, in particular, seems to have greater antioxidant properties when it comes to protecting the skin against damaging effects of UVB radiation.
Adding Lutein and Zeaxanthin to Your Diet
Lutein and zeaxanthin are found in green leafy vegetables, such as kale, spinach, collard greens, turnip greens, and romaine lettuce, as well as egg yolks, broccoli, zucchini, corn, peas and Brussels sprouts. They are also found in orange foods, such as persimmons, tangerines and orange peppers.
Fruits and vegetables contain seven to ten times more lutein than zeaxanthin. Although there is no official recommended daily intake for these specific carotenoids, most recent studies show a health benefit for lutein supplementation at 10-15 mg/day and zeaxanthin supplementation at 2-4 mg/day. Because it is difficult to get a therapeutic amount every day from food alone, Lutein supplementation is recommended by most medical experts, especially for the maintenance of eye health.