Diet/nutrition and stomach cancer in Japan

Incidence rates of stomach cancer in Japan are much higher than in other countries, but have shown a large decline in the past 20 years. Incidence rates among the Japanese in Hawaii are only one third or less of the indigenous Japanese in Japan. Epidemiologic studies indicate that consumption of salt or salty foods is associated with increased risk of stomach cancer, in concert with the results of experimental studies in rodents. In contrast, consumption of vegetables and fruit is associated with decreased risk. Accumulated evidence is strong that a reduction in salty food intake and an increase in vegetable and fruit intake is important to primary prevention of stomach cancer. Possible protective roles of tea and allium vegetables and supplemental use of micronutrients, interaction between salty food intake and H. pylori infection and other factors need further investigation. Occurrence of stomach cancer in Japan may be reduced by two thirds or more via dietary changes, as seen in the population of Japanese ancestry in Hawaii.