Can Mouth Bacteria Explain This Common Food Trigger?

Many people report that nitrate-containing foods are a migraine trigger. The reports are so frequent that many headache specialists recommend all patients avoid processed meat altogether. Many of us have sworn off sausage, pepperoni, salami, hot dogs, and even cold cuts in an attempt to reduce the number of migraine attacks.

New results from the American Gut Project were published in October that may begin to explain why foods containing nitrates are such a common migraine trigger.

Nitrates are commonly found in processed meat such as hot dogs, sausages, bologna, and cold cuts. Nitrates are converted to nitrites by bacteria found in the human digestive system. No human cell can accomplish this breakdown. Nitric oxide and nitrite therapies used to treat cardiovascular disorders induce severe headaches in over 80% of patients who take them.

These headaches manifest in 2 ways:

Immediate headaches have mild to medium severity. They develop within 1 hour after ingestion, and are connected to nitric oxide-induced vasodilation.

Delayed headaches are severe and accompanied by migraine-like symptoms. They develop 3-6 hours after ingestion and are more likely to appear in patients with a family history of migraine. These delayed headaches are activated by CGRP, glutamate, and other neurochemicals.


According to this study, subjects who reported a history of migraine had a greater concentration of bacteria that convert nitrates to nitrites than their healthy counterparts. They recommend future studies to determine the exact nature of this link.

The results of this study offer no new insights into the potential cause of migraine or even an explanation as to why nitrate-containing foods are a trigger for some patients and not for others. However, it does provide valuable insight for researchers in future studies.

The report also mentions that the presence of nitrites in the body are beneficial to cardiovascular health. I do wonder about this. If higher levels of nitrites correlates to a decrease in cardiovascular risk, then why would someone with migraine also have an increased risk of cardiovascular disease? One would think that will all that extra nitrite floating around in our bodies, migraine patients would have a decreased risk of cardiovascular disease. The statistics still don’t add up.  Obviously, more research is needed to explain this.

Design flaws

One of the fundamental design flaws with this study is that it relies on patient reports rather than a thorough medical evaluation. Given that nearly half of all people with migraine have never seen a doctor to confirm the diagnosis or get treatment, it is likely that their results are flawed. They failed to ensure the validity of the results by not confirming each subject’s diagnosis. It is impossible to know if the mouth bacteria of each subject actually came from a true migraine patient.

Any researcher looking to explore this topic further should, at the very least, confirm the diagnosis of each participant using the ICHD-3. This is accomplished by a medical exam and patient interview by a qualified headache expert.

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