[luckylion]

I found that, for me at least, it kinda works to not outright disagree, but to say that you 'read an article' that disputed said fact and now you're confused about whether it's actually true. I usually see one of three things happening: they say something along the lines of "oh, I don't know a lot about that, so I can't tell you" and the conversation moves on, they tell you "it's obviously bullshit, because I read it in $magazine", or they'll engage with it to try and lift your confusion. In the latter case, you can feed them arguments and facts, but since it's not a debate ("you're wrong" - "no, YOU are wrong"), it's easier for them to see when/where their beliefs fall short.