Researchers followed more than 36,000 Japanese men older than 40 for an average of 13.2 years. They found that those that consumed culinary mushrooms three times a week had a 17 percent lower chance of developing prostate cancer compared to those that ate mushrooms less than once a week. Participants that ate mushrooms once or twice a week had an 8 percent lower risk. The trend was even greater for those men over the age of 50 and was unrelated to other dietary habits.