What is the potential importance of taking vitamin C?

Severe vitamin C deficiency is uncommon in people who consume Western diets, but mild insufficiency is found in 6% of healthy adults⁵⁹ and larger numbers of college studentsand smokers. On the basis of extensive analyses of published vitamin C studies, some authorities have suggested that optimal intake for disease prevention may be at least 90 to 100 mg per day. However, supplementation with over 200 mg per day of vitamin C by healthy people does not result in higher vitamin C concentrations in the body, and may be no more helpful for preventing disease than smaller amounts.