Vitamin Analysis Comparison Study.

Purpose: We compared and analyzed the concentrations of vitamin C, vitamin E, zinc, and copper in both national and regional brands of dietary supplements recommended for patients who are at risk for macular degeneration.

Design: Prospective cross-sectional study.

Methods: National brand name and generic multivitamin formulations for age-related macular degeneration were obtained. Comparative analysis of the vitamin C and vitamin E content was performed by gas chromatography-mass spectrometry and the zinc and copper content was analyzed by atomic absorption spectroscopy in an institutional chemistry laboratory.

Results: All national brand name vitamins, both tablet and gel capsule formulations, and generic brands in tablet form were relatively accurate in their product labeling. For most of the samples tested, the measured quantities of vitamin C, vitamin E, zinc, and copper were slightly higher than labeled but not to an amount that would cause any systemic toxicity if taken at the recommended dosages.

Conclusions: Physicians may recommend national brand name vitamins and generic brands in tablet form to their patients with some confidence; however, the content may have some inaccuracies regarding labeling.