The Cochrane Collaboration (http://www.cochrane.org/) is an organization that provides systematic meta-analysis of the current medical literature.
Systematic means they consider all reports and not just cherry-pick one or the other (which can be used to distort scientific findings).
Meta-analysis means they integrate and analyze the data and findings from many individual scientific papers.
Further, they are not funded by industry, and therefore are less biased than any industry sponsored literature.
There is a handy search engine for their site to make the data more accessible.