Recently, high-dose supplementation with beta carotene, vitamins C and E and zinc has been shown to slow the progression of age-related macular degeneration (AMD). Researchers from the Netherlands initiated a population-based cohort study to investigate whether regular dietary intake of antioxidants is associated with a lower risk of incident AMD.

Dietary intake was assessed at baseline in the Rotterdam Study (1990-1993) using a semiquantitative food frequency questionnaire. Investigators determined incident AMD, defined as soft distinct drusen with pigment alterations, indistinct or reticular drusen, geographic atrophy or choroidal neovascularization, until final follow-up in 2004 by grading fundus color transparencies in a masked technique according to the International Classification and Grading System.

Of 5,836 persons at risk of AMD at baseline, 4,765 had reliable dietary data and 4,170 participated in the follow-up. Subjects in the study were drawn from all inhabitants aged 55 years or older in a middle-class suburb of Rotterdam, the Netherlands.

Incident AMD occurred in 560 participants after a mean follow-up of 8.0 years (range, 0.3 to 13.9 years). Dietary intake of vitamin E and zinc was inversely associated with incident AMD. The hazard ratio (HR) per standard deviation increase of intake for vitamin E was 0.92 (95 percent CI, 0.84 to 1.00); for zinc it was 0.91 (95 percent CI, 0.83 to 0.98). An above-median intake of all four nutrients, beta carotene, vitamin C, vitamin E and zinc was associated with a 35 percent reduced risk (HR, 0.65; 95 percent CI, 0.46 to 0.92) of AMD. Exclusion of supplement users did not affect the results. The authors concluded that a high dietary intake of beta carotene, vitamins C and E and zinc is associated with a substantially reduced risk of AMD in older people.