Does chocolate cause cancer or protect against it? Are a few glasses of wine everyday a terrible habit or one that will add a couple of extra years to your life? Is coffee going to save you or kill you? Every other day there's a new study out assuring you that specific dish that you love, whether it is curd rice or butter, is going to give you cancer. Followed up, of course, the very next day by a news story telling you that the very same thing actually is good for you.

So who's right? News reports about medical studies are all over the place and make for an easy headline, but they usually fail to mention the important context: most studies end up failing, or not having enough information, and the way they are reported can often be misleading. That's what leads to contradictory headlines that can show up one day after the next.

Fifty common ingredients

To examine just how prevalent this is, researchers Jonathon D Schonfeld and John P.A. Ionnidis looked at 50 common ingredients from a specific cook book, and checked whether reported studies suggested they caused cancer or protected against it. The results, turned into this perfect chart put together by Vox.


Essentially, everything we commonly eat both causes and prevents cancer. As the researchers conclude in their piece in the American Journal of Clinical Nutrition, "associations with cancer risk or benefits have been claimed for most food ingredients. Many single studies highlight implausibly large effects, even though evidence is weak," they write.

So the next time you get startled by a report in the morning paper saying your cup of coffee is going to turn you terminally ill, just Google it and see if there's another study that says just the opposite.