October 1, 2012 — Lutein and zeaxanthin supplementation could improve early functional abnormalities of the central retina in patients with early age-related macular degeneration (AMD), according to a randomized, double-masked, placebo-controlled trial. that studied the effects of 48 weeks of lutein and zeaxanthin supplementation on retinal function by multifocal electroretinography (mfERG) in patients with early AMD.
Le Ma, from the Department of Nutrition and Food Hygiene in the School of Public Health at Peking University in Beijing, People's Republic of China, and colleagues studied the effects of 48 weeks of lutein and zeaxanthin supplementation on retinal function by multifocal electroretinography (mfERG) in patients with early AMD. They published their findings in the October issue of the American Journal of Ophthalmology.
"We found that lutein and zeaxanthin supplementation for patients with early AMD resulted in significant increases in N1P1 response densities in the central retina associated with early abnormalities of retinal function," write the authors.
The researchers randomly assigned 108 patients with early AMD to receive 10 mg of lutein per day (n = 27), 20 mg of lutein per day (n = 27), 10 mg of lutein per day plus 10 mg of zeaxanthin per day (n = 27), or placebo (n = 27) for 48 weeks. Patients were excluded from the study if they had late AMD; unstable chronic illness; or other eye disorders, including macular edema, macular holes, central serous chorioretinopathy, or macular epiretinal membrane.
The investigators also enrolled 36 age-matched controls without AMD to compare baseline data with those of patients with early AMD. They measured and analyzed MfERG responses and macular pigment optical densities at baseline (week 0) and at 24 and 48 weeks.
In the first 24 weeks, the 3 treatment groups experienced increased N1P1 response densities in ring 1, but this finding was not statistically significant in the 10 mg lutein group. Analysis of variance (ANOVA) found that patients in the 20 mg lutein group experienced a much greater increase compared with the placebo group (0.3 vs 20.3; between-group difference, 19.9; 95% confidence interval [CI], 0.03 - 39.6; P < .05).
After 48 weeks, ring 1 N1P1 response densities demonstrated a mean (± standard error) increase of 18.0 (7.5) in the 10 mg lutein group, an increase of 22.4 (7.4) in the 20 mg lutein group, and an increase of 23.5 (6.9) in the lutein and zeaxanthin group (all P < .05); densities were maintained in the placebo group.
Ring 1 changes in N1P1 response densities for the 20 mg lutein group (22.4 vs –0.3; between-group difference, 22.7; 95% CI, 3.1 - 42.3; P = .02) and the lutein and zeaxanthin group (23.5 vs –0.3; between-group difference, 23.8; 95% CI, 4.2 - 43.4; P = .02) were significantly greater than those found in the placebo group.
In repeated-measures ANOVA, lutein and zeaxanthin supplementation had a significant treatment effect (P = .02) as well as a significant time effect (P < .001) on increasing N1P1 response densities in ring 1.
Ring 2 N1P1 response densities also increased progressively in the 3 active treatment groups. At week 48, significant within-group differences from baseline were seen only in the 20 mg lutein group (10.6; 95% CI, 1.7 - 19.5; P < .05).
The ring 2 changes in N1P1 response densities for the 20 mg lutein group (10.6 vs 0.3; between-group difference, 10.9; 95% CI, 0.2 - 21.7; P = .05) showed a significantly greater increase than those seen in the placebo group.
The researchers found a significant time effect (P = .03) with only a tendency for a treatment effect (P = .19) for ring 2 N1P1 response densities. There were no longer significant changes in N1P1 response densities in ring 3 to ring 6 in any of the groups. Changes in N1P1 response densities did not significantly differ between the groups.
There was a positive correlation between the change in macular pigment optical density and the changes in N1P1 response densities in ring 1 and ring 2 for most active treatment groups. No significant associations were seen between the change in macular pigment optical density and the changes in N1P1 response densities in ring 3 to ring 6 (P > .05 for all).
No significant changes in P1 peak latencies were found in any group at any time point in the study. Macular pigment optical density changes were unrelated to P1 peak latency changes in various rings during the study.
"[T]he improvement of N1P1 response densities was positively associated with the elevation of macular pigment optical density, suggesting a causative effect of macular pigment level on health of retinal function," the authors write. "These findings provided evidence that lutein and zeaxanthin might reverse the impairment in retinal function, and ultimately prevent the progression of AMD."
Too Early to Tell
Abdhish Bhavsar, MD, a clinical correspondent for the American Academy of Ophthalmology and the director of clinical research at the Retina Center of Minnesota, Minneapolis, commented on the study in a telephone interview with Medscape Medical News.
"It’s a very early study that supports some biologic activity of these antioxidants…given certain parameters," said Dr. Bhavsar. Because the study had very specific entry criteria and exclusion criteria, the study is not generalizable to the general population, or to other populations, Dr. Bhavsar explained.
"The study is very short-term, and even though there could be real changes in the macula pigment optical density and/or the multifocal ERG findings, there’s a big leap yet to hypothesize or to state that these vitamins/antioxidants do have a clinically significant impact on the disease process," said Dr. Bhavsar.
Publication of this article was supported by the National Natural Science Foundation of China in Beijing, People’s Republic of China. The authors and Dr. Bhavsar have disclosed no relevant financial relationships.
Am J Ophthalmol. 2012;154:625-634. Abstract
Medscape Medical News © 2012 WebMD, LLC
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Cite this: Lutein, Zeaxanthin Supplementation May Help Early AMD - Medscape - Oct 01, 2012.