Vitamin C
This article was originally published in The Tan Sheet
Executive Summary
RDA for women should be increased to 90 mg based on new depletion-repletion study data, NIH researchers say in Aug. 14 Proceedings of the National Academy of Sciences. Mark Levine, MD, National Institute of Diabetes & Digestive & Kidney Diseases, et al., note current RDA of 75 mg was based on extrapolated data for men. Levine and colleagues evaluated long-term intake in 15 women who received doses ranging from 30 mg-2,500 mg daily, finding a "steep sigmoidal relationship between vitamin C doses and resulting [plasma] concentrations for doses of 30 mg-100 mg daily." Current RDA "is on the steep linear portion" of the curve, "where small dose changes cause large changes in plasma concentration," Levine et al. say. They also suggest current 90 mg RDA for men may be too low