Prophylactic vitamin C: misplaced zeal.

C supplements had 61% more URT infections than the runners who took vitamin C. Further, we are asked to believe that during a 2-wk period after a race in which they did not compete, 36 of 73 (49%) sedentary control subjects experienced URT infections with an average duration of about 5 d. Because the investigators did not infect their subjects with virus, it would appear to me that the subjects overreported their symptoms and that the validity of this study is questionable. Stanley N Gershoff School of Nutrition Tufts University Medford, MA 02155