Scientists in the US believe they may have found a possible link between bacteria found in the mouth and painful migraines.
A study, published in journal mSystems, found that the mouths of migraine sufferers harbour significantly more microbes, or bacteria, with the ability to modify nitrates than people who do not get migraine headaches.
Nitrates are compounds found naturally in some foods like vegetables but are also added to processed foods as a preservative.
It's already known that certain foods trigger migraines, such as chocolate and wine and those containing nitrates.
Lead researcher, Professor Antonio Gonzalez from the University of California San Diego School of Medicine says their study gives a possible explanation as to why this might be.
"We thought that perhaps there are connections between what people are eating, their microbiomes and their experiences with migraines," Prof Gonzalez said.
When nitrates are consumed they are reduced to nitrites by bacteria found in the mouth. These nitrates are then converted to nitric oxide, which can improve blood flow and reduce blood pressure.
In fact, nitrate containing drugs are used to treat cardiac patients, however many report severe headaches as a side effect.
As part of the US study, scientists analysed oral and fecal samples from more than 2000 patients and found there was significantly more bacteria linked to the breaking down of nitrates in those from migrane sufferers.
These results show for the first time a potential connection between bacterial nitrate, nitrite, and nitric oxide and migraines, the authors of the paper wrote.
Prof Gonzalez admits, however, there is no evidence to suggest these bacteria cause or result in migraines.
