NAGOYA, JAPAN. Lung cancer is the leading cause of cancer deaths in Japan even though the incidence and mortality is still less than two-thirds of that found in the USA and the UK. Japanese researchers have just completed a study aimed at determining the association between lung cancer and diet. Their study involved 748 men and 297 women aged 40 to 79 years who had been diagnosed with lung cancer and 2964 male and 1189 female cancer-free controls. Fatty fish contain the omega-3 fatty acids eicosapentaenoic and docosahexaenoic (EPA and DHA, respectfully).
The researchers found that both men and women who ate cooked or raw fish, which contain essential omega-3 fatty acids, five times a week or more had half the incidence of lung adenocarcinoma when compared to participants who ate cooked or raw fish less than once a week. Women who consumed tofu (soybean curds) five times a week or more were found to have half the risk of adenocarcinomas, as compared to women who consumed tofu less than once a week. Frequent consumption of carrots was found to be beneficial for women, but detrimental for men especially smokers. Green vegetables were found to be highly beneficial for men, but not statistically so for women. There was also some evidence that increased coffee consumption is associated with an increased risk of squamous cell and small cell lung carcinomas in men. Increased consumption of dried or salted fish was not beneficial for men or women. The researchers speculate that this is because the processing destroys the healthy omega-3 oils EPA and DHA present in raw and cooked fish.
Takezaki, T., et al. Dietary factors and lung cancer risk in Japanese with special reference to fish consumption and adenocarcinomas. British Journal of Cancer, Vol. 84, No. 9, May 4, 2001, pp. 1199- 1206