Levels of nitrite, nitrate, N-nitroso compounds, ascorbic acid and total bile acids in gastric juice of patients with and without precancerous conditions of the stomach

Abstract

To determine the relevance of gastric juice factors to gastric carcinogenesis, 56 patients with unoperated stomachs undergoing endoscopy for dyspepsia had gastric juice aspirated and analysed for pH, ascorbic acid, total bile acids, nitrite, nitrate and total nitroso compounds (NOCs). Plasma was obtained for vitamin C estimation. Antral and body biopsies were assessed for gastritis, Helicobacter pylori, atrophy and intestinal metaplasia (IM). Patients with chronic atrophic gastritis (n = 17) had lower gastric juice ascorbic acid concentrations (P less than 0.001), higher pH (P less than 0.05) and higher incidence of H. pylori infection (P less than 0.001) than normal subjects (n = 12). Patients with reflux gastritis (n = 9) had higher total bile acids (P less than 0.01). Patients with chronic gastritis and IM (n = 11) had higher gastric juice pH (P less than 0.01) and total bile acid concentrations (P less than 0.05), and lower gastric ascorbic acid concentrations (P less than 0.01) than those with chronic gastritis and no IM (n = 24). In chronic gastritis, high nitrite concentrations were associated with high pH (P less than 0.01). However, there were no significant differences in plasma vitamin C or gastric nitrite, nitrate or total NOC concentrations in relation to gastric histology. We conclude that the premalignant condition IM is associated with H. pylori infection, low gastric ascorbic acid levels and elevated total bile acids, but not to elevation in nitrite or total NOCs in fasting gastric juice.

A Review of the Nature and Effectiveness of Nutrition Interventions in Adult Males: A Guide for Intervention Strategies

“…One of the most consistent epidemiological findings on vitamin C has been an association with high intake of ascorbic acid or vitamin C rich foods and reduced risk of stomach cancer. Considerable biochemical and physiological evidence suggests that ascorbic acid functions as a free radical scavenger and inhibit the formation of potentially carcinogenic N-nitroso compounds from nitrates, nitrite in stomach and thus offer protection against stomach cancer [85][86][87].…”

Comparison of plasma biomarkers with dietary assessment methods for fruit and vegetable intake

“…All samples were stored at À701C. The samples were analysed for ascorbic acid and the carotenoids b-carotene, lutein, cryptoxanthin and lycopene by reversed-phase high-performance liquid chromatography using modified methods from Thurnham et al (1988) for carotenoids, and Sobala et al (1991) for vitamin C. Ascorbic acid is analysed separately from total vitamin C by this method of HPLC. Total vitamin C can be measured as a result of reducing any dehydroascorbic acid present by dithiothreitol.…”

Pathogenesis of the transformation from gastritis to malignancy

“…[67][68][69] Reflux of bile into the stomach is another potential inducer of intestinal metaplasia 70 but, for this action, the synergistic influence of the underlying gastritis may also be necessary. In subjects not carrying H. pylori, intragastric bile is not capable of inducing intestinal metaplasia 71,72 even though there is evidence that bile can induce cancers in animals without other contributing factors. 73 In a study of 350 patients, 72 the prevalence of intestinal metaplasia was greatest in patients with both H. pylori and the highest concentrations (>1 mmol/l) of bile acids in the gastric juice.…”