Vitamin C: working on the x-axis.

摘要

Before 2000, Recommended Dietary Allowances (RDAs) for vitamin C (ascorbic acid) had a simple premise: prevention of frank vitamin C deficiency (scurvy) with an additional margin of safety. For many iterations, the central criterion for all RDAs was ‘‘the amount of nutrient required to prevent the appearance of signs and symptoms caused by a lack of the nutrient’’ (italics in original citation) on the basis of nutrient intakes from foods (1). This approach was faulted by chemist and 2-time Nobel Laureate Linus Pauling. Pauling contended that optimum concentrations of some nutrients could be larger than amounts provided by diet alone (2).