Translating AREDS 2 Results
Making sense of the study’s outcomes
KIMBERLY K. REED, O.D., F.A.A.O.
While the AREDS 2 study did not provide ground-breaking results, we can learn much from it.
The five-year study was designed to determine whether adding lutein (10mg) and zeaxanthin (2mg), long-chain omega-3 fatty acids (650mg EPA and 350mg DHA as ethyl ester), or both, and eliminating beta-carotene or reducing zinc (from 80mg to 25mg) from the original AREDS formula would strengthen it against advanced AMD or cataract.
More than 4,200 patients (96% white, average age of roughly 73) at risk for advanced AMD participated. They were randomized to differing AREDS formulation groups. Only non-smoking or former smokers could receive the original beta-carotene-containing formula, as beta-carotene is a high risk for lung cancer in smokers.
More patients in the original AREDS formula group vs. the other groups developed lung cancer. Most formerly smoked. Substituting lutein/zeaxanthin (L/Z) for beta-carotene in the original AREDS formulation is recommended for these patients.
Those in the L/Z formula sans beta-carotene group had a slight, but not significant, decrease in their advanced AMD risk vs. those in the beta-carotene-containing formula group. Also, those who entered the study with the lowest L/Z levels and were in the L/Zadded formula group were 26% less likely to develop advanced AMD vs. participants who had similar levels, but weren’t in this group. Since participants tended to be more well nourished vs. the general population of the same age, the average intermediate AMD patient may have lower L/Z levels vs. the study participant.
Beta-carotene (shown here) and former and current smokers don’t mix.
Finally, those with the lowest L/Z dietary intake in the L/Zadded formula sans beta-carotene group reduced their risk of progression to cataract surgery by 32%.
More patients are in the at-risk or early stages of AMD: Don’t draw over-broad conclusions regarding this study’s implications.
Also, compliance in AREDS 2 was defined as 75% of pills taken.
With a long-term nutritional intervention study, it is not possible to isolate the studied substances. Supplements are not the only source of these nutrients in the body. So, studies like AREDS 2 strongly suggest trends and statistical probabilities, but the results might not be transportable to every patient. For example, a 73 year-old white, blue-eyed female who smokes, has never worn UV protection, has a BMI of 35, a family history of AMD, never exercises and admits to a diet of mainly fried foods and refined carbohydrates requires different management than a 73 year-old white, browneyed female who has never smoked, has a BMI of 22, exercises regularly and eats foods rich in carotenoids and omega-3 fatty acids.
Inter-patient differences aside, AREDS 2 researchers recommend intermediate AMD patients take a supplement containing: 10mg lutein, 2mg zeaxanthin, 80mg zinc, 2mg copper as cupric oxide, 500mg vitamin C and 400 IU vitamin E. OM
DR. REED IS AN ASSOCIATE PROFESSOR AT THE NOVA SOUTHEASTERN UNIVERSITY COLLEGE OF OPTOMETRY IN FORT LAUDERDALE, FLA., A MEMBER OF THE OCULAR NUTRITION SOCIETY AND AUTHOR OF NUMEROUS ARTICLES ON OCULAR NUTRITION, DISEASE AND PHARMACOLOGY. E-MAIL DR. REED AT KIMREED@NOVA.EDU, OR SEND COMMENTS TO OPTOMETRICMANAGEMENT@GMAIL.COM.
Optometric Management, Volume: 48 , Issue: July 2013, page(s): 30