Ascorbic acid has been shown to decrease nitrosation in vivo, and epidemiological data suggest that the consumption of foods rich in this
vitamin is associated with a reduced risk for
gastric cancer. In order to study this suggestion further, fasting gastric juice samples were obtained from 62 high-risk patients (seven with
atrophic gastritis, ten with pernicious anaemia, ten with partial
gastrectomy, 21 with
vagotomy and drainage and 14 with
highly selective vagotomy), before, during four weeks' treatment with 1 g
ascorbic acid four times daily, and four weeks
after treatment. Samples were analysed for pH, total and
nitrate-reducing bacterial counts,
nitrite and N-
nitroso compounds. Treatment with
ascorbic acid lowered the median pH only in the vagotomized patients (p less than 0.001) but resulted in a reduction in median
nitrate-reducing bacterial counts and in
nitrite and N-nitroso compound concentrations in all groups, except for an increase in the
nitrate-reducing bacterial count in
atrophic gastritis patients and in
nitrite in those with pernicious anaemia. These data suggest that treatment with a high dose of
ascorbic acid reduces the intragastric formation of
nitrite and N-
nitroso compounds.