Effect of increased intake of vitamin C on the mutagenic activity of gastric juice and intragastric concentrations of ascorbic acid.

Mutagenic activity, ascorbic acid levels and pH were measured in fasting gastric juice from eight patients given oral supplements of vitamin C (1 g qid X 7 days). Supplementation significantly reduced mutagenic activity and increased intragastric ascorbate levels without altering gastric pH. These results demonstrate for the first time the relation between intragastric ascorbate levels, mutagenic activity and oral supplements of vitamin C. The findings are discussed in relation to the possible chemoprevention of gastric cancer.