I have advanced prostate cancer, and been wondering why has it happened to me. I have just found that folic acid, which gives vitamin B9 in the body, increases risk of PCa several fold. I have been on folic acid (5mg per day) for the last 15 years since I had a stroke in 2000. Its a massive amount and its known to cause methylation in DNA, which gives rise to cancer, I was prescribed it as there was one study in the USA that suggested it cut down stroke. When I think of the number of times my medications have been reviewed by my GPs, you would think they might have come across the dangers. Folic acid is also added to cereals that come from the USA, and flour, to prevent neural tube defects in babies. I wonder how many men on this forum, have been prescribed folic acid in the past?