Stomach Cancer Risk Factors

A diet high in salt, especially when accompanied by a long term H. pylori infection of the stomach appear to be the two most important environmental factors promoting stomach cancer worldwide. Both these insults damage to the stomach lining reducing the production of protective mucous and acid resulting in a atrophic gastritis. This precancerous state is seen in 15-20% of older Americans. Nitrites from cured meats and other sources can react with other chemicals in the stomach to form known cancer promoting N-nitroso compounds. However, these compounds form more readily when stomach acid is low and can get to the stomach lining more easily when mucous production is reduced. The consumption of vitamin C can also inhibit the formation of N-nitroso compounds and this may be one reason many population studies find a reduced risk of stomach cancer in those who consume the most fresh fruits and vegetables. Other antioxidant phytochemicals, such as carotenoids and polyphenols, may also inhibit the formation of N-nitroso compounds in the stomach and so cut the risk of stomach cancer.Inconsistent data suggests that a diet high in citrus fruits, leafy vegetables, and/or cruciferous vegetables reduce the risk of stomach cancer. Garlic and onions may also reduce the risk of stomach cancer.1 2 Certainly replacing pickled vegetables with N-nitroso products with more fresh fruits and vegetables cannot hurt and is likely to at least modestly cut the risk of gastric cancer in older people with atrophic gastritis. Smoked foods and tobacco smoke contain cancer causing substances and most data suggest those who smoke and/or eat more smoked foods are at higher risk of developing stomach cancer. Again this increased risk is more likely in those who have atrophic gastritis. Alcoholic beverages have not been inconsistently associated with an increased risk of stomach cancer. It may be that some types of alcoholic beverages promote stomach cancer while others do not. For example a recent study of beer drinkers in Spain presented at the American Cancer Society meeting this past April found a 75% increased risk of stomach cancer in those who drank 2-3 or more beers daily for many years. Beer does contain a fair amount of N-nitroso compounds not seen in significant amounts in wine and distilled spirits. Finally a study in Mexico found stom- ach cancer patients had a history of consuming much higher levels of hot chili peppers than control subjects.3 Again it may be the loss of healthy mucous producing cells due to salt toxicity and H. pylori that set the stage for the carcinogenic impact of the chili’s capsaicin.By James J. Kenney, PhD, FACNReferences: 1. Int J Cancer 2006;118:2559-66 2. Am J Clin Nutr 2000;72:1047-52 3. Am J Epid 1994;139:263-71