Calcium can delay age-related macular degeneration via enhanced copper metabolism.

Secondary analyses of data from the Age-Related Eye Disease Study (AREDS) revealed that higher calcium intakes were associated with slower progression to age-related macular degeneration (AMD). Earlier, primary analyses had revealed that a supplement containing copper reduced the odds of developing AMD while lengthening life. Because ocular lesions are being reported increasingly in neuropathy from copper deficiency and because higher dietary calcium can have beneficial effects on copper metabolism, it is hypothesized that the association of calcium intakes with better vision was mediated by improved copper utilization of study participants who were eating too little copper. Nutrition surveys reveal that amounts of copper proved insufficient for men and women in controlled studies are readily available to the general population. Observations on eye anatomy of animals deficient in copper and on decreased retinal superoxide dismutase, an enzyme dependent on copper for activity, in people with AMD support this hypothesis. Eradication of AMD will require new approaches based on hypotheses that fail falsification.