Protective effect of vitamin C on oxidative stress: a randomized controlled trial

Although a number of reports regarding the role of reactive oxygen species (ROS) as the first step in cancer induction exist, few studies have investigated how vitamin C influences ROS in human plasma. Using the ROS assay system, a method recently established by one of the authors, we aimed to evaluate the effect of vitamin C supplementation on serum ROS among subjects diagnosed with chronic gastritis. A total of 244 Japanese subjects with atrophic gastritis were randomized to take 5-year supplementation of either 50 mg or 500 mg of vitamin C. The adjusted difference in the changes of total ROS between baseline and after 5-year supplementation was statistically significant between the intervention groups: 2.70 decrease (corresponds to 1.26% decrease) in the high-dose group and 4.16 increase (corresponds to 3.79% increase) in the low-dose group, p for difference = 0.01. Vitamin C was suggested to reduce oxidative stress among subjects with atrophic gastritis.