Prostate cancer and folate and folic acid

http://m.cancer.gov/topics/prevention/bycancer/prostate/patient

Folate is a kind of vitamin B that occurs naturally in some foods, such as green vegetables, beans and orange juice. Folic acid is a man-made form of folate that is found in vitamin supplements and fortified foods, such as whole-grain breads and cereals. A 10-year study showed that the risk of prostate cancer was lower in men who had enough folate in their diets. However, the risk of prostate cancer was increased in men who took 1 milligram (mg) supplements of folic acid.