Bacteria in our mouths may hold clues about why people get migraines
Caterina Cestarelli doesn't always know what will trigger an excruciating migraine. Sometimes it's skimping on sleep or missing a meal. Other times it's smelling a powerful perfume.
Whatever the trigger, it usually leads to the same place: Her tiny New York City bedroom, with lights off and blinds drawn, as she waits for the painful throbbing, waves of nausea and distorted vision to subside.
"Some days I feel like staying in bed is all I can do," said 21-year-old Cestarelli, who is a Mashable intern.
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Scientists and doctors still don't fully understand why people get migraines and what sets them off. Around 38 million people in the U.S. suffer from migraines, each with their own mix of triggers and symptoms.
Our microbiomes, it turns out, may hold some of the clues, according to researchers at University of California, San Diego's School of Medicine.
People who get migraine headaches have significantly more nitrate-reducing microbes in their mouths and guts compared to people who don't get migraines, the team found in a study published Tuesday in the journal mSystems.
This finding marks a small but important step toward understanding migraines, and the researchers said they plan to expand on the study in future research.
"We think it will be possible to... classify different migraine sufferers' status based on these bacteria," Antonio Gonzalez, the study's lead author and a programmer analyst at UC San Diego, told Mashable.
By classifying migraine types, scientists could better understand how to prevent or treat different triggers, he said.
For the study, Gonzalez and his colleague Embriette Hyde used publicly available data from UC San Diego's American Gut Project.
They looked at 172 oral samples and nearly 2,000 fecal samples from healthy participants, who had previously filled out surveys indicating whether they suffered from migraines.
Second, Gonzalez and Hyde used a bioinformatic tool called PICRUSt to study the gene content of the oral and fecal bacteria. From there, they looked specifically for genes that are reducers of nitrates, nitrites and nitric oxide.
Nitrates are commonly found in green leafy vegetables, processed meats and certain medicines. For some migraine sufferers, these foods can trigger severe headaches, although for other people they're not a trigger.
Nitrates are reduced to nitrites by bacteria found in a person's mouth. The nitrites can be further converted into nitric oxide when circulating in the blood, which can improve blood flow and reduce blood pressure.
In the oral samples, the researchers found "significantly more abundant" genes that reduce nitrates, nitrites and nitric oxide in migraineurs -- people who suffer from migraines -- compared to non-migraineurs.
The fecal samples showed a slight but statistically significant increase in the abundance of these genes.
Gonzalez and Hyde said they next plan to study large groups of migraine sufferers to determine how strong the connection is between people's oral bacteria and their migraines — and whether that has any bearing on how frequently or severely these headaches occur.
"Eventually, we could have some kind of gradient based on the oral bacteria and this specific gene content, and then we can start thinking about probiotics and other [treatments]," Gonzalez said by phone.
"This is still an open question, and it's a puzzle we're trying to fit together," he added.
As scientists search for answers about migraines, people suffering from the disorder must similarly work to find — and avoid — their own triggers.
Cathy Glaser, co-founder and president of the Migraine Research Foundation in New York, said that, generally speaking, sticking to a routine can help lower the chances of a migraine attack.
"Try to keep things as regular as possible: Go to sleep at the same time every night, get the same amount of sleep every day, make sure you don't skip meals, hydrate properly," she said. "The brain of a migraine sufferer doesn't like change."
Cestarelli said she tries to hold down a routine as best she can. Her roommate has also stopped wearing strong perfumes. Sometimes the migraines come anyway. She tried medications to prevent migraines, but the side effects, such as hair loss, outweighed the benefits.
"I don't really know what triggers it," she said. "I'm constantly working that out."
Maria Gallucci was a Science Reporter at Mashable. She was previously the energy and environment reporter at International Business Times; features editor of Makeshift magazine; clean economy reporter for InsideClimate News; and a correspondent in Mexico City until 2011. Maria holds degrees in journalism and Spanish from Ohio University's Honors Tutorial College.
