Nitrate consumption and the incidence of gastric cancer in Singapore

The nitrate content of a wide variety of vegetables, fruits and meat purchased in Singapore were determined by high-pressure liquid chromatography. From the 1982 statistical figures of retained imports and local production of these items the average per capita daily consumption of nitrates was calculated and found to be 215 mg, one of the highest reported figures in the world. Two vegetables in particular, Chinese flowering cabbage and kale, contributed to almost half of this intake. These two vegetables are not so popular with the Malays and Indians who comprise 21% of the population. If their consumption of these vegetables is ignored then the per capita daily nitrate consumption of the Chinese population amounts to 250 mg and those of the Malays and Indians to 113 mg. Although these may be overestimates they do appear to show an association with the male gastric cancer incidence rates (age-adjusted) of 44.8 for the Chinese, 10.3 for Malays and 19.4 for the Indians. This could, however, be a chance association.