Zinc oxide, the most biologically form of Zinc available, is a mineral with powerful antioxidant properties. In high doses, zinc must also be taken with a small quantity of copper (cupric oxide) to prevent the Zinc from displacing copper off the hemoglobin molecules and causing a form of anemia, or low red blood cell count. The recommended zinc to copper ratio is 40 to 1.
The National Eye Institute's Age Related Eye Disease Study (AREDS) demonstrated that ingestion of 80 mg of Zinc oxide, even without other antioxidants, had a beneficial effect in preventing the progression of macular degeneration. AREDS found also that there was a 6% incidence of adverse side effects, including urinary tract and gastrointestinal symptoms.
For this reason, the National Eye Institute announced in late 2006 that in AREDS2, the upcoming study looking at an updated nutritional formula for the treatment of macular degeneration, that Zinc oxide would be reduced to 40 mg daily, in hopes of finding similar efficacy with a lower incidence of side effects.
One macular degeneration supplement company already offers supplements with these new reduced zinc levels. For more information, see www.visivite.com.