A review and meta-analysis of prospective studies of red and processed meat intake and prostate cancer

Worldwide, prostate cancer is the second most common cancer among men, with only lung cancer accounting for more cancer diagnoses annually, although the incidence of prostate cancer varies considerably by geographic region [1]. Indeed, adopting a "Western" lifestyle has been hypothesized as contributing to the geographic variation in incidence rates. Studies of populations migrating to the United States (U.S.) from Japan and China have shown that the rate of prostate cancer increased compared to those in their native countries, independent of early detection [2-5], suggesting that lifestyle and dietary habits may contribute to the increasing rates of disease [6-11]. In the U.S., prostate cancer is the most commonly diagnosed cancer among men, accounting for approximately one-quarter of all new cancer cases, and this malignancy ranks as the second most common cause of cancer mortality, particularly among black males [12].Although diet and prostate cancer has been investigated in numerous epidemiologic studies, few foods have been identified as potentially contributing to increasing or decreasing the risk of this malignancy. High intake of foods containing lycopene and selenium may decrease risk of prostate cancer while diets high in calcium may increase risk [3,13], although the epidemiologic evidence is not entirely clear. Some early studies have suggested that fat intake may be associated positively with prostate cancer [7,14,15], but recent prospective studies have reported no associations with fat consumption [16,17].Over the last decade, several large cohort studies of meat intake and prostate cancer have been published, and in a recent systematic review of dietary factors, it was suggested that high meat consumption may increase the risk of prostate cancer, although the authors did not quantify the relationship [3]. In their 2007 report on diet and cancer, the World Cancer Research Fund/American Institute for Cancer Research concluded that there was "limited ev