Age-related macular degeneration (AMD) and cataracts, are both regarded to be two of the leading causes of vision impairment, and potentially acquired blindness across the United States. To date, these two conditions have been responsible for affecting the eyesight of literally millions of aging Americans. While there are a number of preventative steps that a person can take when it comes to caring for their eyesight and reducing the risk of suffering from various degenerative conditions, one of the most promising way to prevent the progression of AMD and cataracts, or at least delay further symptoms, is diet. Two carotenoids, lutein and zeaxanthin are the most commonly cited substances that matter when it comes to eye health. These antioxidants can be found within the eye itself, and they help to promote better health within the ocular and visual system. Many studies have shown that a healthy dose of zeaxanthin and lutein in our regular diets can help to reduce our chances of various chronic eye diseases – including cataracts and AMD.
What Is Zeaxanthin and Where Does It Come From?
In their natural state, zeaxanthin and lutein can be found as substances that are able to easily store and absorb excess light, therefore protecting plants from too much damage as a result of exposure to excessive blue light and UV rays. Besides simply being found in the skin and inner flesh of various colorful fruits and leafy green plants, zeaxanthin and lutein can be found in particularly high levels within the macula segment of the human eye. In fact, it is the presence of these two substances that gives the human macula it’s yellowish hue. What’s more, the macula is regularly known as the macula lutea, which comes from a Latin term which literally means yellow spot.
Interestingly, some recent research studies have discovered the presence of a third carotenoid in the macula. This substance is known as meso-zeaxanthin, and it is not found in food sources, but can be created within the actual retina by processing ingested lutein. Both zeaxanthin and lutein have earned a reputation over the years, as a scientific study has found that they appear to have important functions for antioxidant purposes within the body. Alongside a range of other antioxidants such as natural vitamin C, vitamin E, and beta carotene, these pigments are responsible for guarding the body from the damaging impact of free radicals, which are generally forms of unstable molecules that might destroy cells and play a role in various diseases.
Zeaxanthin, like lutein, is a vitamin for the eye that migrates naturally towards the eye when it is absorbed into the body. When it reaches the eye, zeaxanthin is drawn into the lens, fovea, and macula. Within the macula and fovea, zeaxanthin helps to build up the yellow pigment that works as a shield for protecting the eye from dangerous frequencies of light that might cause long-lasting damage to our vision. What’s more, a regular intake of zeaxanthin can also provide a powerful antioxidant effect that works to neutralize some of the free radicals that are responsible for damaging eye cells over time.
Zeaxanthin and Its Benefits to Eye Health
Although some people still appear to be unsure about the benefits of substances like zeaxanthin and lutein when it comes to eye health, the National Eye Institute (NEI) has been quoted as stating that if supplementation were more common among individuals who possess a higher risk of developing AMD conditions, then vision loss could potentially be prevented in more than 300,000 people over the age of fifty-five, during a period of five years. Zeaxanthin is actually one of the supplements that the NEI is referring to in this instance. In fact, the NEI has noted that zeaxanthin has been proven to improve vision ability in patients who suffer from macular disease. Researchers have even linked zeaxanthin to a reduced risk of AMD overall.
Of the 600 carotenoids found in nature, it is only lutein and zeaxanthin that are deposited in such high quantities throughout the macula and retina of the eye. From their location, these substances can filter high-energy blue wavelengths that might be harmful to the eyes and to vision. Doctors and health experts can measure the amount of zeaxanthin and lutein in the retina through macular pigment optical density (MPOD) tests. In recent years, MPOD tests have been used as a useful biomarker for predicting visual function and disease. Unfortunately, it’s worth noting that the human body is unable to produce the zeaxanthin and lutein that it needs naturally. This is why many doctors recommend eating plenty of green vegetables and taking supplements when necessary. Obtaining a regular amount of zeaxanthin in your nutritional diet should help in maintaining proper eye health.
Many of the studies that have looked into the value of zeaxanthin for eye health and visual problems have combined zeaxanthin and lutein with other nutrients, such as Vitamin E and Vitamin C. Some experts suggest that a combination of nutrients may be more beneficial to most people than a single nutrient alone.
Zeaxanthin, Lutein and Cataracts
The crystalline lens in the eye is known for primarily collecting and focusing the light that is gathered by the eyes onto the retina. In order for images to remain clear and the information transferred to your brain to provide a clear image, the lens itself must remain clear. Unfortunately, frequent exposure to free radicals and oxidation of the lens is a significant cause of cataracts, which end up clouding the lens and obscuring a person’s vision.
Antioxidant nutrients such as zeaxanthin work to neutralize the free radicals in the eye that are associated commonly with retinal damage and oxidative stress. That is why many experts advise using these nutrients in the fight against cataracts and other eye problems. In fact, studies have found that a higher intake of zeaxanthin, lutein and vitamin E was associated with a more significantly decreased risk of formation of cataracts.
Zeaxanthin and AMD
In most cases, people mention zeaxanthin when referring to AMD, as there is a great deal of evidence suggesting that this nutrient helps to reduce the risk of age related macular degeneration. The NEI has even discovered that taking nutritional supplements such as zeaxanthin every day can help to reduce the risk of developing late AMD. Beyond the risk of eye disease, various studies have shown that zeaxanthin and lutein can improve visual performance in AMD patients, cataract patients and other people who are otherwise in good health.
A number of studies have also found that zeaxanthin or lutein can help to prevent AMD or slow down the progression of the disease. For instance, research published in Nutrition and Metabolism has discovered that a supplement containing meso zeaxanthin lutein and zeaxanthin helped to increase the optical density of the macular pigment in the eyes of the majority of the human subjects. The macular pigment is also believed to offer some protection against the development of AMD. What’s more, studies published in the American Journal of Ophthalmology found greater amounts of zeaxanthin and lutein in the diet are generally associated with lower incidences and risks of AMD. Two studies published in Investigative Ophalmology and Visual Science also found that eyes with greater levels of macular pigments were far less likely to develop macular degeneration.
What Is the Recommended Daily Intake of Zeaxanthin?
At present it’s hard to know exactly how much zeaxanthin should be included in any individual person’s diet. Some people respond differently to this nutrient, and it may be that you require more of it in your system than someone else in your social circle or family. If you are not getting enough zeaxanthin and lutein in your diet alone, your doctor may recommend that you consider taking daily supplements. Although there isn’t a specific recommended dosage for zeaxanthin, many experts recommend taking at least 2mg a day.
The majority of western diets are naturally low in zeaxanthin and lutein which can be found in a range of different foods including:
- Collard Greens
- Turnip Greens
It’s important to note that zeaxanthin supplements have usually been tested extensively on humans and animals at levels far above the maximum daily amount that is recommended by most health experts. That means that it’s quite safe to take a supplement even if you aren’t sure how much zeaxanthin you are getting in your diet from natural sources. What’s more, there are currently no known side effects or negative interactions when taking zeaxanthin alongside other drugs and supplemental substances. Some individuals who have taken very high doses have noticed a golden coloration of the skin, but the number of instances weren’t large enough to ensure a constant correlation.
Many experts suggest that zeaxanthin supplementation should be a process that is carried out during the course of a person’s life to ensure good health on a consistent basis. If you take zeaxanthin for a while, having the substance in your system should help, but building the levels of this product in your eyes can take a long time. In volunteer experiments, it took months of zeaxanthin supplementation to see any measurable increase in the macular pigment of the eye.
Resources and References:
- Zeaxanthin Information – Covers Some of the Benefits of Zeaxanthin to Eye Health (Visivite.com)
- Lutein and Zeaxanthin – Insight Into Many of the Studies That Have Shown the Connection Between Zeaxanthin And Eye Health (AllAboutVision.com)
- Lutein and Zeaxanthin – Effect of Lutein and Zeaxanthin on Eye Health (WebMD.com)