Ben Goldacre (of Bad Science fame) and some colleagues have done some research into the reliability of health claims made in UK newspapers. The results suggest that newspapers have a lot of misleading information.
The vast majority of these claims were only supported by evidence categorised as “insufficient” (62% under the WCRF system). After that, 10% were “possible”, 12% were “probable”, and in only 15% was the evidence “convincing”. Fewer low quality claims (“insufficient” or “possible”) were made in broadsheet newspapers, but there wasn’t much in it.