How important are ejaculations to prostate health?

How important for male prostate health is routine ejaculations or is this just a myth? I have read that having frequent ejaculations can help prevent prostate cancer, but I don’t know whether or not that is true. I don’t want to have problems with my prostate.

Dr. Katz on Prostate Health

Columbia University’s Dr. Aaron Katz on the importance of maintaining prostate health and preventing cancer.

What supplements are good for prostate health?

Other than zinc which I already know of what supplements are good for a man’s prostate health? I’m going to put my father on something to try to prevent him from getting prostate problems.