FOLLOWING TAKEN FROM ARTICLE ON MEDSCAPE WEBSITE WRITTEN BY LINDA ROACH MARCH 23, 2013
Adults with "dry" age-related macular degeneration (AMD) developed a denser macular pigment layer after taking a daily oral supplement of carotenoid compounds and omega-3 long-chain polyunsaturated fatty acids, a German research group has found.
However, the clinical importance of this is unknown, Christin Arnold, Dipl-Troph, and colleagues from Friedrich Schiller University, in Jena, Germany, report in a paper published March 21 in JAMA Ophthalmology.
The researchers report that after 1 month, plasma concentrations of the 2 carotenoids increased significantly in the treated groups and this level was maintained throughout the trial. In addition, optical density of the macular pigment increased significantly (P < .05) in the treated groups, rising slowly through 12 months, but was nearly unchanged in the placebo group.
The pigment's density was slightly higher in the double-dose group than in the other treated group, but the difference was insufficient to support use of the higher doses of these nutritional supplements.
In an interview with Medscape Medical News, Arnold, who is a doctoral-degree candidate in nutritional sciences, pointed to the latter finding as most clinically relevant to physicians whose patients with dry AMD ask about taking supplements.
"Our patients responded to the supplementation in both groups, but we found that you did not need 20 mg of lutein. As a nutritionist I feel better about the lower dose, because I prefer for people to get their nutrients from food as much as possible," Arnold explained. "There are toxicological studies showing that 20 mg is safe. But now that we know 10 mg is effective, we can say that patients should not be using the higher dose."
Rather than looking at structural changes after supplementation, it is more important to determine whether the right nutritional supplements, in the right doses, prevent development and/or progression of AMD, Dr. Chew said.
She is chair of the second Age-Related Eye Diseases Study (AREDS2), the National Eye Institute's large randomized, controlled, multicenter clinical trial that is expected to report results this spring. AREDS2 tested the same supplements as were used in the German study, but at different doses and in different combinations. The AREDS2 dosing was 10 mg lutein, 2 mg zeaxanthin, 650 mg EPA, and 350 mg DHA.