title: A systematic review on zinc for the prevention and treatment of age-related macular degeneration.
abstract: OBJECTIVE
  The objective of this systematic review was to examine the evidence on zinc intake from foods and supplements in the primary prevention and treatment of AMD.
  
  
  METHODS
  Randomized controlled trials (RCTs), prospective cohort, retrospective cohort, and case-control studies that investigated zinc intake from foods and/or supplements, and AMD in men and women with a mean age of 50 years or older were included. Medline and Cochrane Central were searched from inception to February 2012 and November 2012, respectively. Data extraction and quality appraisal were done on all eligible studies.
  
  
  RESULTS
  TEN STUDIES WERE INCLUDED: four RCTs, four prospective cohort, and two retrospective cohort studies. Age-related Eye Disease Study (AREDS) showed zinc treatment to significantly reduce the risk of progression to advanced AMD. The risk of visual acuity loss was of similar magnitude, but not statistically significant. Two RCTs reported statistically significant increases in visual acuity in early AMD patients and one RCT showed no effect of zinc treatment on visual acuity in advanced AMD patients. Results from six cohort studies on associations between zinc intake and incidence of AMD were inconsistent.
  
  
  CONCLUSIONS
  Current evidence on zinc intake for the prevention of AMD is inconclusive. Based on the strength of AREDS, we can conclude that zinc treatment may be effective in preventing progression to advanced AMD. Zinc supplementation alone may not be sufficient to produce clinically meaningful changes in visual acuity.
authors: Carotenoids and Health Lab, Jean Mayer United States Department of Agriculture Human Nutrition Research Center on Aging at Tufts University, Boston, Massachusetts.
authors: Rohini
authors: R
authors: Vishwanathan
authors: Mei
authors: M
authors: Chung
authors: Elizabeth J
authors: EJ
authors: Johnson
mesh_terms: D000368:Aged; D016022:Case-Control Studies; D016208:Databases, Factual; D004032:Diet; D019587:Dietary Supplements; D018450:Disease Progression; D005260:Female; D006801:Humans; D008268:Macular Degeneration / Q000175:diagnosis / Q000517:prevention & control*; D008297:Male; D008875:Middle Aged; D016032:Randomized Controlled Trials as Topic; D014792:Visual Acuity; D017967:Zinc Compounds / Q000008:administration & dosage*
chemical_list: D017967:Zinc Compounds
keywords: age-related macular degeneration; systematic review; zinc