Bought and paid for
But conflicts of interest are always interesting. I recently came across a paper that concluded that slight dehydration has important effects on mood and cognition (Armstrong). I was taking it seriously for a few minutes until I discovered that it was funded in part by a giant corporation that sells bottled water, which made me roll my eyes and get a lot less interested in the results (which were minor anyway, I thought).
So now what to believe? Who knows: the data may be perfectly good, or hopelessly corrupted. We just can’t tell without more information. We’ll simply never know what’s true without more research … which will probably be hard to get anyone but another water bottling company to pay for!