External causes gastric cancer, Japanese immigrants to the U.S. research, the first generation of significantly decreased the incidence of dollars, indicating that from an early age to exposure to pathogenic factors in the pathogenesis of this disease is very important. Because the stomach constantly in contact with food, it is believed that the substance present in food. As for what kind of material is not fully understood. Epidemiological survey of gastric cancer and eat more fat foods such as sauerkraut manufacturing, salt fish, bacon, and smoked foods, and even eat more starch was also made with the closely related substances. On the contrary, milk, fresh vegetables, fruit, vitamin C, and frozen foods can reduce the risk of gastric cancer. Excessive salt intake and gastric cancer incidence may be related to survey endemic areas, the patient most of the daily amount of salt intake over l0g.
External causes gastric cancer, gastric cancer caused by carcinogenic substances may be plastic nitrite. The lack of conclusive evidence yet of human gastric cancer, but animal experiments have proved it could be caused by stomach cancer. Plastic nitrite from nitrate reduction to nitrite and then with plastic combination. Widespread among nitrate in food may be nitrate-reducing bacteria in the stomach into nitrite. Nitrite is also widely present in foods, especially pickles, salted fish, bacon, etc., but its main source of nitrate reduction may come from. From gastric cancer often developed from chronic atrophic gastritis. The latter benefit more from lower acid nitrate-reducing bacteria colonization of the Min. In high-prone areas (such as northwest China) have proved that the nitrate content in soil and high water; Also in the gastric juice of patients also demonstrated the presence of high concentrations of nitrite. Reducing salt intake is often accompanied by intake of nitrate and nitrite reduction. Low temperature can inhibit the nitrate into nitrite
External causes gastric cancer, the country, Japan, the incidence of gastric cancer declined in recent years, extensive use of the refrigerator may be a factor. Vitamin C can inhibit the combination of nitrite and glue. In endemic areas has proved that long-term use of vitamin C in the population, the incidence of gastric vitamin C was significantly lower than those against. Although these observations provide only limited evidence to support the cause of human gastric nitrite rubber, but may be quite significant.