Gastric juice N-nitrosamines in health and gastroduodenal disease.

The concentrations of total extractable N-nitroso compounds, pH, and nitrite levels were measured in fasting gastric juice, which was also cultured for bacteria, from 50 healthy volunteers and 217 patients with common upper gastrointestinal complaints. The concentrations of N-nitroso compounds and pH levels rose significantly with age. Sex and cigarette smoking had no significant effect. There was a positive correlation between pH and N-nitroso concentration, and between pH and an increase in the concentration of nitrites. A significant relation was demonstrated between raised N-nitroso and nitrite levels and growth of nitrate reductase-positive microorganisms. These results demonstrate for the first time in man the interrelations of N-nitrosamine concentration, pH, gastric juice nitrite, and nitrate-reducing bacteria. The findings are considered in relation to the risks of development of gastric cancer in man.