I've read mixed results in the research on black pepper. (By the way, black, white, and green peppercorns all come from the same plant.) Some research states that the black pepper has protective effects, while others say it may create carcinogens, particularly when heated.
I use black pepper lightly, just a few black peppercorns in my pepper mill. The rest, I've replaced with pink peppercorns, which are unrelated to the above. They have a nice taste which is not overly spicy. I've seen them in more and more supermarkets.
Lisa
http://www.pinkkitchen.info