medical researches do not convince me too much. I have experience of medical researches changed after 20 years with opposite conclusions. Just to mention, coffee is good or bad, sugar is good or bad, fat is good or bad, telephone radiations are dangerous for the brain or not( at this purpose I could bring some studies and documentaries really interesting), tobacco in the 50es, climate change now etc.
http://goo.gl/CjYEMa