For more than 50 years, the Food and Nutrition Board of the National Academy of Sciences has been reviewing nutrition research and defining nutrient requirements for healthy people, referred to as the Recommended Dietary Allowances (RDA). As new nutrition research is published, the importance of vitamins as vital nutrients is underscored, and new physiologic roles and applications to human health are examined and considered with regard to updating the RDA. Each year a substantial amount of new research is published on vitamins. This review examines recent research published on the importance of vitamin C with regard to general health.