Oral bacteria linked to onset of migraines

Surveying the food in the Fresh Food Café, you see that juicy sausage and mouth-watering bacon. All these processed meats, containing high levels of nitrates and nitrites, are commonly known to be correlated with cancer and heart diseases. On top of that, these nitrate-containing foods have been recently identified as triggering headaches.

Researchers at the University of San Diego School of Medicine recently found that migraine sufferers, or migraineurs, have a significantly higher amount of nitrate-reducing bacteria in collected oral samples and a slight but significant difference in stool samples when compared to samples from those who did not suffer from migraines. Their work was published on in the Oct. 18 issue of mSystems, an open access journal from the American Society of Microbiology.

“Many of the 38 million Americans who suffer from migraines report an association between consuming nitrates and their severe headaches,” first author Antonio González, a programmer analyst in The Knight Lab, said according to a press release.

Gonzalez and his group explained that there are two ways that nitrates in cardiac medicine can induce headaches.

First, there are immediate headaches that have mild to medium severity that arises within an hour of consumption. This type concurs due to nitric oxide-mediated vasodilation or the widening of blood vessels, which decreases blood pressure. Second, there are delayed headaches that are more severe but arise three to six hours after consumption. This type of headache is triggered by actions such as CGRP release or changes in ion channel function.

An example of nitrate-causing headaches is seen by analyzing cardiac patients. Because nitric oxides are capable of improving the blood flow in arteries and veins throughout the body, cardiac patients often take nitrate-containing drugs. Roughly four in five cardiac patients who take nitrate-containing drugs for chest pain or congestive heart failure report severe headache as a side effect.

González and his group hypothesized that nitrate, nitrite and nitric oxide-reducing genes would be significantly higher in the oral and stool samples of migraineurs than those of non-migraineurs. They used data from the American Gut Project’s crowd-sourced repository and a bioinformatics tool called Phylogenetic Investigation of Communities by Reconstruction of Unobserved States to observe the differences in these genes.

In their results, oral samples showed significant difference between migraineurs and non-migraineurs for all three genes. Fecal samples only showed significant difference for nitrate and nitrite reductase genes but not for nitric oxide.

“We definitely think this pathway is advantageous to cardiovascular health. We now also have a potential connection to migraines, though it remains to be seen whether these bacteria are a cause or result of migraines or are indirectly linked in some other way,” Embriette Hyde, project manager of the American Gut Project, said in a press release.

González and his group’s research provide the first potential link between migraines and nitrate-reducing bacteria. They plan to further explore the relationship between nitrate-reducing bacteria and migraines by looking into more specific groups of patients.