Applying the AREDS2 Findings in Practice
By Leo Semes, OD, FAAO
The long-awaited results of the Age-Related Eye Disease Study 2 (AREDS2) were released in May (AREDS2 Research Group, 2013). The study was undertaken as a result of the carotenoids lutein and zeaxanthin gaining scientific standing as beneficial supplements for those who have age-related macular degeneration (AMD).
The randomization of groups in AREDS2 was somewhat unique in that unlike the original AREDS, there was no true placebo group. That cohort was represented by those assigned to the original AREDS formula. The complete study design and results can be found at http://www.nei.nih.gov/areds2.
In some ways, the results of the study confounded the picture on supplements for patients who have AMD. A short version of the results includes the recommendation that lutein and zeaxanthin be substituted for the beta-carotene in the original AREDS formula. The complete AREDS2 formula is 25mg zinc as zinc oxide, 2mg copper as cupric oxide, 400 IU vitamin E, 500mg vitamin C, 10mg lutein, and 2mg zeaxanthin, which reflects the new recommendation.
One reason for the recommendation is that beta-carotene has been suggested to be detrimental to those who are current or former smokers (i.e., a marginally increased risk of lung cancer) (Palozza et al, 2008). Another is that, in the study population, the lutein and zeaxanthin in the AREDS2 formula were found to be beneficial against progressive vision loss.
In addition, the reduced dosage of zinc (to 25mg from 80mg daily) did not enhance the protective effect against vision loss. Finally, even though there has been support from other studies for the beneficial effect of the omega-3 component (Merle et al, 2013), which is somewhat controversial, no additional benefit of these was demonstrated in AREDS2.
Considering the Findings
It is important to recognize the “asterisks.” The population on which the AREDS2 study was conducted included a relatively well-nourished cohort, which may not resemble the majority of our patients who have AMD. All-in-all, there was about a 20% to 25% reduction in AMD progression of AMD. Those who initially had the lowest intake of carotenoids benefited the most. The groups that benefited most in each study (AREDS and AREDS2) were those who had more advanced disease—another conundrum.
Also, what about additional benefits of carotenoids? These have been touted for a number of disease prevention strategies (see http://lpi.oregonstate.edu/infocenter/phytochemicals/carotenoids).
An area of neglect in ophthalmic health preservation is cataracts. Previous studies generally have failed to show beneficial effects on cataract formation and progression from the application of supplements. Mounting evidence now suggests a benefit of lutein and zeaxanthin against the progression of cataracts as well (Chew, 2013). Perhaps overshadowed in the AMD frenzy was the accompanying report suggesting a significant risk reduction against cataract progression from the AREDS2 formulation (AREDS2 Research Group, 2013). Now we can more confidently recommend lutein and zeaxanthin as weapons in the fight against cataracts to our patients.
For patients who are not eating a healthy diet, these alternatives represent a viable substitute, and now allow for patient-specific recommendations. CLS
For references, please visit www.clspectrum.com/references.asp and click on document #219.
Dr. Semes is a professor of optometry at the UAB School of Optometry. He is a consultant or advisor to Alcon, Allergan, B+L, Sucampo, and Zeiss and is a stock shareholder in HPO and Arctic DX.