Do the labels of vitamin A, C, and E supplements reflect actual vitamin content in commercial supplements?

This study aimed to determine the compliance between the actual levels of vitamins A, C, and E, determined by laboratory analysis, with those declared on the labels of vitamin supplements sold in an urban area in Brazil. Fifty-seven samples of vitamin supplements (tablets, sugar coated tablets, hard and soft gel capsules, suspensions, and solutions) were evaluated to determine their antioxidant vitamin contents. Vitamin A, E, and β-carotene contents were determined by high-performance liquid chromatography with diode-array detection (HPLC-DAD), and vitamin C content was determined by automatic potentiometric titration. Of the samples analyzed, 71% and 50% had lower vitamin A and E content, respectively, than the declared values. In contrast, 28% of the analyzed samples had vitamin E content greater than the declared value. The vitamin C content of 67% of the samples was consistent with the declared value. Some supplements analyzed had vitamin content ranging from “not detected” to 81% higher than that reported on the label. The wide variability observed between the stated label amounts of vitamins and those determined analytically demonstrates the need for control measures and enforcement actions to ensure that consumers have access to safe and reliable information about vitamin supplements.