Deep-fried foods may increase the risk of prostate cancer, suggested a 2013 study of more than 3,000 men by researchers at the Fred Hutchinson Cancer Research Center in Seattle. Men who ate fried chicken, fried fish, fried potatoes or doughnuts (but not chips) more than once a week had a 30 to 37 percent increased risk of prostate cancer, compared to men who ate these foods less than once a month. The study was published in The Prostate.
High-heat cooking produces advanced glycation end-products (AGEs), which are associated with increased oxidative stress and inflammation. In particular, when oils are fried, they form potentially carcinogenic compounds. On the other hand, a high intake of deep-fried foods could also just be a marker for high intake of fast foods in general or other unhealthy habits that could increase prostate cancer risk.