The Association for Research in Vision and Ophthalmology (ARVO) has presented at the Annual Meeting in Seattle, Wash., May 5 to 9, 2013, the results from AREDS2. In summary, it reports that daily usage of eye health supplements containing 10 mg of lutein and 2 mg of zeaxanthin as compared to a formula containing vitamins C and E, beta-carotene, zinc and cupric oxide (referred to as original AREDS formulation, which gave a 25 to 30 percent reduction in AMD) did not reach additional significant reduction in risk to the original AREDS formulation of progression to advanced AMD, a leading cause of adult blindness. However, in a subgroup analysis comparing 10 mg lutein and 2 mg of zeaxanthin with the groups given the original AREDS supplement, a statistically significant reduction in the progression to advanced AMD of 9 percent was seen for lutein and zeaxanthin in the entire study group. Details are published in the Journal of the American Medical Association.
A subgroup analysis in 1,055 eyes indicates that subjects with the lowest quintile of dietary intake of lutein and zeaxanthin (median 0.7 mg per day) but supplemented with 10 mg lutein and 2 mg of zeaxanthin had a significant risk reduction of 26 percent for progression to advanced AMD. These findings affirm the role of lutein and zeaxanthin as important contributors to risk reduction of AMD progression and the authors acknowledge the role of lutein and zeaxanthin in disease development and suggest further investigations. They also mention that the results of this study may not be generalizable to the wider U.S. population, as the highly selected group studied was well nourished with a diet high in carotenoids and vegetables. In the U.S., dietary intake of lutein and zeaxanthin is typically less than 1 mg per day.
AREDS2 is a randomized trial conducted in more than 80 sites across the U.S. by the National Eye Institute (NEI) of the National Institutes of Health (NIH). This study follows AREDS1, which was published in 2001 and found that people at high risk of developing advanced stages of AMD lowered their risk by 25 to 30 percent when treated with a high-dose combination of vitamin C, vitamin E, beta-carotene, zinc and copper. AREDS2 assessed the effects of oral supplementation of certain eye nutrients in more than 4,000 participants ranging from 50 to 85 years of age, most of whom at the time of enrollment had intermediate AMD. It is the largest trial to date testing the effectiveness of lutein, zeaxanthin and omega-3 in adults with AMD. The AREDS2 study also found that circulating blood levels of lutein and zeaxanthin increased significantly in those receiving supplements, which may have a protective effect in eye disease.
The results of AREDS2 also addressed the role of beta-carotene as this was a part of the original AREDS formulation. A subgroup analysis of lutein and zeaxanthin and the original AREDS formulation without beta carotene as compared to the group lutein and zeaxanthin and the original AREDS formulation with beta carotene resulted in a significant risk reduction of 18 percent for progression to advanced AMD for the group receiving no beta carotene.
No beneficial or harmful effects of DHA-EPA for treatment of AMD could be demonstrated in this study. The authors comment on this finding that dose, duration of treatment and possibly the DHA-EPA ratio may have been inappropriate.
In summary, the effects observed in this study for its main study supplementation are consistent with other study reports on the beneficial roles of lutein and zeaxanthin in eye health. Finally it has to be noted that diseases such as AMD, with their long patho-etiological time-course and many genetic and environmental factors, are complex to study with an intervention of modest changes of nutrients.