Migraines are an unfortunately common occurrence for many women — we're around three times more likely than men to have them, which is extremely not cool. Even less cool is that experts still don't know very much about why they happen (or even how they happen). According to new research, though, one possible cause of migraines may be bacteria in your mouth.For the study , published online today in the journal mSystems, researchers used data from the American Gut Project to analyze 172 samples of bacteria taken from participants' mouths — and 1,996 taken from their poop. All participants had previously taken a survey about any health issues, including migraines.They found a couple of significant differences between the bacteria from participants with migraines and those without — and the biggest differences were actually in the bacteria that came from their mouths.Specifically, people with migraines tended to have more bacteria that process nitrates, compounds found in many foods (e.g. leafy vegetables and processed meats). Normally, those nitrates eventually get turned into nitric oxide — which can be good for your heart health , but which has also previously been linked to migraines . So, if migraine sufferers have more nitrate-processing bacteria, those could be fueling the creation of more nitric oxide and triggering those hellish headaches."There is this idea out there that certain foods trigger migraines — chocolate, wine, and especially foods containing nitrates," said the study's first author Antonio Gonzalez in a press release . "We thought that perhaps there are connections between what people are eating, their microbiomes, and their experiences with migraines."Although this study does show an association between larger amounts of those nitrate-related bacteria and migraines, it doesn't prove that one necessarily causes the other. The researchers say the next step will be to correlate specific types of migraines with levels of those bacteria to nail down the ways in which they're connected.For now, though, we wouldn't suggest trying to get rid of those bacteria in an effort to help your headaches; they exist within the complex, balanced ecosystem of your mouth, which is there for a reason. But if you're one of those unfortunate few who find that meals trigger your migraines, this study might at least help explain why.