From Johns Hopkins University
Based on epidemiological studies, in which researchers use food diaries, diet recalls, or questionnaires to closely examine what people eat, it's now believed that diet is one of the most important lifestyle factors that can influence cancer rates of many organs. The problem is that researchers haven't been able to specifically identify which components of the diet have the most effect.
Cancer experts estimate that diet accounts for up to 90% of cancers of the prostate, large bowel, breast, and pancreas—even lung cancer may have a dietary link. And we do know that people who consume plenty of vegetables, fruits, and grains and who exercise regularly, are less likely to develop various cancers—possibly including cancer of the prostate—than those who don't.
Scientific evidence suggests that differences in diet and lifestyle may account in large part for the variability of prostate cancer rates around the world. Researchers are now hard at work examining the foods we eat to see exactly what they contain and what affect they have on the prostate.