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Further propelling interest in the burgeoning nutraceuticals category are studies that have determined that healthy eating augmented with nutritional supplements can not only help prevent age-related eye disease but in some cases may reduce its progression, according to the Ocular Nutrition Society (ONS).

One of the more prominent clinical trials that has proven a link between nutrition and eye health is the National Eye Institute’s (NEI) 2001 landmark Age-Related Eye Disease Study (AREDS) that found nutritional supplementation can reduce the risk of developing advanced age-related macular degeneration (AMD). The original AREDS formulation contained vitamin C, vitamin E, beta-carotene, zinc and copper. Those who took the formulation were 25 percent less likely to progress to advanced AMD.

In 2006, NEI began a second study, AREDS2, to improve the original AREDS formulation. Researchers substituted lutein and zeaxanthin for beta-carotene, which was associated with an increased risk of lung cancer in smokers. AREDS2 concluded that formulation of the following ingredients were beneficial for ocular health: vitamin C (500 mg.), vitamin E (400 IU), lutein (10 mg.), zeaxanthin (2 mg.), zinc (80 mg.) and copper (2 mg.). This formulation has become the standard of care for many optometrists in reducing the risk of AMD.

Jeffrey Anshel, OD, FAAO, president of the Ocular Nutrition Society, pointed out that these nutrients aren’t only beneficial for age-related conditions. For example, lutein shouldn’t be limited to individuals over age 50. “It has been found that lutein is actually in breast milk, which kids stop getting prior to two years old. Thus, it’s important to continue to add lutein throughout childhood and into adulthood, and not wait until some signs of eye disease appear,” he said.

Zeaxanthin and lutein are actually both primary macular pigments found in the fovea that act as “internal sunglasses,” filtering harmful high-energy blue wavelengths of light and helping protect and maintain healthy cells. Without proper nutrition, macular pigment levels can decrease. Lutein and zeaxanthin supplementation can help increase macular pigment levels, protecting against certain eye diseases.

A recent study also found that zeaxanthin supplementation can improve visual processing speed. The study from the University of Georgia Vision Sciences laboratory measured the impact of high levels of dietary zeaxanthin (20 mg. and above) on processing speed, or the speed at which a person’s eyes and brain communicate to identify, process and respond to stimuli. Participants experienced statistically significant improvements in reaction time.

In addition, omega-3 fatty acids from fish oil have also been shown to be essential to the healthy structure and function of ocular tissue. Unfortunately, as Monique Wellise, the education and professional sales manager at Nordic Naturals pointed out, an estimated 91 percent of Americans are deficient in omega-3 fats. “If a patient is deficient in omega-3, they are lacking nutritional support for optimal eye health,” she said. “DHA is the omega-3 fat responsible for protecting the eyes from light, heat and age-related damage. It is critical to the development, function, and maintenance of the light-receiving cells found in the eye.”

Further, the anti-inflammatory omega fatty acid GLA has been shown to benefit dry eye in several randomized, controlled clinical trials, said Pamela Damsen, marketing consultant to ScienceBased Health. The benefit of GLA has been found for a wide range of dry eye-related causes, including: Sjögren’s syndrome, tear-deficient dry eye, contact lens wear, post-PRK, meibomian gland dysfunction, and most recently for post-menopausal women.

Supplement Safety Concerns

On the whole, with rare exceptions, nutritional supplements have proven in published studies to be safe. But as with any product that is ingested, there are precautions one should take. For example, nutritional supplements meant to slow the progression of age-related macular degeneration may actually accelerate the disease in people with certain genotypes, according to research recently published in the Journal of the American Academy of Ophthalmology.

It is also important for ECPs to partner with a reputable manufacturer, as quality can widely vary. WebMD also advises consumers to read the labels. For example, avoid supplements containing fillers, ingredients used to bulk up products so they “look like more.” These include wheat, corn, and dairy products, which could cause digestive or allergic problems in patients. Also, if fish oil is listed as a source of omega-3 essential fatty acids, the label should state that it has been produced in a manner that eliminates contaminants, particularly mercury.

AllAboutVision.com recommends following these guidelines when choosing eye supplements: check for the expiration date and make sure the seal has not been broken, check the serving size, and remember that the best eye supplements contain quality ingredients that have high bioavailability making them easily absorbed by the body.

Other factors to bear in mind include the fact that taking vitamins/minerals in mega doses can cause toxicity; “natural” does not always mean “safe”—plants, after all, can produce some powerful poisons; and even if dietary supplements are deemed safe, they can still interfere with the function of other medications someone might be taking.

Similar to other products ECPs consider offering to patients, they need to do their due diligence in learning about any possible adverse effects in the nutritional supplement.

Nutrition Science at AAO

The Ocular Nutrition Society will continue its tradition of assembling top researchers in nutrition science to present at its 13th educational symposium, to be held Nov. 11, 2014, at the Denver Convention Center in conjunction with the American Academy of Ophthalmology meeting. Scientists from several prestigious institutions will present the latest science, ranging from dietary influences on ocular disorders to the role of carotenoids in ocular function to recent ocular research studies.