Interesting question: is it academic researchers overselling their findings, or journalists hyping their story?
The researchers found that 33 to 40 percent of the academic press releases exaggerated causation, advice, or inference in some way, and that the news articles took those claims and published them as is, or, in some cases, exaggerated them even more. Now, to be fair, 10 to 18 percent of news articles did some sort of embellishment even with accurate press releases, news needing to be newsworthy and all.
Also, the research was all done with United Kingdom where the media are notoriously aggressive. But studies like this suggest that academic institutions, far from being the arbiters of caution when it comes to research, might actually contribute to the misinformation that plagues medical journalism.