Prostate cancer has become a major public health burden worldwide with an estimated number of 679,000 new cases in the year 2002. This represents 11.7% of all new cancer cases in men (19.03% in developed countries and 5.3% in developing countries) (Ferlay et al. 2004). Diet has been implicated in prostate cancer risk. Studies suggest that men can reduce their risk of prostate cancer by a healthy diet. People in countries such as China and Japan are far less likely than Westerners to develop prostate cancer. Notably, when people migrate to the US, their rates of prostate cancer rise greatly and, since their genetic make- up is the same, there appears to be something about living in America that increases these men’s chances of developing prostate cancer. Diet is the number one suspect.
An interesting observation is that although the incidence of latent (occult, histologically evident) prostate cancer is similar throughout the world, clinical prostate cancer varies from country to country by as much as 20-fold (Wynder et al. 1971). Previous ecologic studies have demonstrated a direct relationship between a country’s prostate cancer-specific mortality rate and average total calories from fat consumed by the country’s population (Armstrong and Doll 1975, Rose and Connolly 1992). Studies of immigrants from Japan have demonstrated that native Japanese have the lowest risk of clinical prostate cancer, first generation Japanese-Americans have an intermediate risk, and subsequent generations have a risk comparable to the U.S. population (Haenszel and Kurihara 1968, Shimizu et al. 1991). Animal models of explanted human prostate cancer have demonstrated decreased tumor growth rates in animals fed a low-fat diet (Wang et al. 1995, Connolly et al. 1997).