Age‐related macular degeneration and nutritional supplementation: a review of randomised controlled trials

Abstract

Age-related macular degeneration (AMD) is the leading cause of severe vision loss in the developed world. The lack of effective treatment modalities, coupled with evidence supporting an oxidative pathogenesis, has increased interest in the potential preventative role of nutritional supplementation. This article reviews seven randomised controlled trials (RCTs) that have investigated the role of nutritional supplementation in AMD. Three of these trials reported a positive effect of nutritional supplementation on AMD; the Age-related eye study (AREDS), the Lutein Antioxidant Supplementation Trial (LAST), and the oral zinc trial by Newsome et al. (1988). However, the oral zinc trial by Newsome et al. (1988) was unlikely to detect any difference between treatments smaller than 72%, and the AREDS results were based on a subgroup of their study population. Lutein was considered for the AREDS formulation, but was not commercially available at that time. The findings of the LAST support a possible therapeutic role of lutein in AMD.

α-Tocopherol is an effective Phase II enzyme inducer: protective effects on acrolein-induced oxidative stress and mitochondrial dysfunction in human retinal pigment epithelial cells

“…A small study involving 25 AMD patients and 15 AMD-free controls found statistically significant lower serum levels of vitamin E and Zn in the AMD subjects than in the AMD-free subjects, and a negative correlation between AMD grading of both the patients' eyes and serum vitamin E levels [47]. On the other hand, supplementing antioxidants such as vitamin E, the carotenoids, vitamin C, glutathione, SOD and catalase may be useful in preventing RPE damage and AMD [17,48,49]. AREDS was a large multicenter study of the natural course and clinical prognosis of age-related cataract and AMD.…”

“…The strongest evidence showing a preventive effect of antioxidants on AMD is the Age-Related Eye Disease Study (AREDS). Compared to supplementation with placebo, researchers found a statistically significant reduction in the development of advanced AMD by antioxidants (vitamin C, 500 mg; vitamin E, 400 IU; and beta carotene, 15 mg), plus zinc (80 mg, as zinc oxide) by as much as 25% (Pb.01) [16,17]. A pilot study showed that a combination of antioxidants and mitochondrial metabolites (acetyl-L-carnitine, polyunsaturated fatty acids, coenzyme Q10 and vitamin E) improves retinal function in early AMD [18].…”

Reduced Metabolic Capacity in Aged Primary Retinal Pigment Epithelium (RPE) is Correlated with Increased Susceptibility to Oxidative Stress

“…Thus, it is likely that aged RPE cells are more susceptible to oxidative stress (Zarbin 2004). In support of this notion, the NEI-sponsored AREDS study demonstrated that subjects at risk for AMD and those with early AMD benefited from supplements containing high levels of antioxidants and zinc (Bartlett and Eperjesi 2003). While cellular bioenergetics (i.e., ATP production) have been assessed at baseline in human RPE cells (He and Tombran-Tink 2010), little is known about cellular bioenergetics under stress conditions.…”

Protection by polyphenol extract from olive stones against apoptosis produced by oxidative stress in human neuroblastoma cells

“…To perform the assay, cells were seeded into 24-well plates at a concentration of 20,000 cell/ well and were incubated at 37 °C and 5% CO 2 ) in a medium with 1% FCS for 6 days, changing the medium every three days. One day before the experiment, the medium was replaced with specific medium without serum and 1% N 2 (Invitrogen) supplement.…”

“…Antioxidants can prevent the harmful effects of free radicals in cells in the same way that a diet rich in polyphenols can decrease the risk of cancer (1), heart disease, and some neurological diseases (2), and prevent neurodegeneration caused by oxidative stress, among others (3).…”