Exploring Omega-3 Fatty Acids and Eye Health
A type of polyunsaturated fat, Omega-3s are said to be "essential" because they cannot be manufactured by the body. People must obtain these important fatty acids through their diet with foods like fatty fish, nuts and plant-based oils. There are three types of Omega-3 fatty acids. These are:
1. ALA or alpha-linolenic acid Rich sources of ALA are canola oil, walnuts, soybeans and flaxseed.
2. EPA or eicosapentaenoic acid EPA can be found in fatty fish like mackerel, herring, salmon and sardines.
3. DHA or docosahexaenoic acid DHA also can be found in fatty fish and is a byproduct of algal fermentation.
Omega-3 fatty acids have been touted to offer a host of health benefits including lowering the risks for heart disease, stroke and cancer and reducing levels of LDL or "harmful" cholesterol. A number of studies have also suggested that Omega-3s may reduce risks for developing age-related macular degeneration (AMD), a disease attributed to aging that attacks the macula, the part of the eye responsible for seeing in fine detail.
One very important study from the National Eye Institute (NEI) is The Age-Related Eye Disease Study (AREDS) which was published in 2001. AREDS showed that certain nutrients can help slow the development of AMD and consequent loss of vision - namely vitamins C and E, beta-carotene, zinc and copper. The research also looked at secondary results involving lutein and zeaxanthin (carotenoids found in spinach, kale, broccoli and zucchini) and the Omega-3s, DHA and EPA.
Analysis of AREDS showed that participants receiving the most DHA experienced a 50% lower risk for developing advanced AMD. Those consuming the most EPA experienced a nearly 50% lower risk for developing advanced geographic atrophy, a severe type of "dry" AMD. Participants with the highest intake of lutein and zeaxanthin experienced a 50% lower risk for developing new AMD. In addition, this group experienced a lowered risk for dry AMD and neovascular (wet AMD).
It has been suggested that lutein, zeaxanthin, EPA and DHA may protect the macula and retina from oxidative stress associated with exposure to light. In addition, DHA is a key component of rods and cones, the photoreceptors of the eye. With the exciting results from AREDS, the National Eye Institute wanted to more carefully examine a modified combination of lutein, zeaxanthin, EPA and DHA to see if AMD and resulting vision loss can be further slowed.
They began recruiting patients in 2006 for a continuation of the original study (AREDS II). The research officially began in 2008, and results will be available upon conclusion of a five-year study period in 2013.
4000 people from the ages of 55 to 80 who have large drusen (spots under the retina) or advanced AMD in one eye are participating. They will be given one of four supplements - a combination of lutein, zeaxanthin, DHA and EPA; 1 g of DHA and EPA; 10 mg of lutein and 2 mg of zeaxanthin or a placebo. While the research is mainly focusing on AMD and cataracts, it will also examine effects of EPA and DHA on mental function.
In addition to possible effects on AMD, Omega-3 fatty acids have been shown to be helpful for dry eye in enhancing the function of glands that provide lubrication for the eye. With many substantiated health claims and further possible benefits, it can't hurt to make Omega-3 fatty acids (and lutein and zeaxanthin) a regular part of your daily diet.
One way to ensure adequate consumption is through the use of natural supplements. These can be found through your local whole foods store or through natural supplement websites.