Dr Borkum describes this as "a plausible unifying principle" linking all the external factors which can trigger an attack.
Free radicals have also been linked to cancer, and some scientists believe they are also the reason why our bodies age.
Dr Borkum, who published his paper in the Headache medical journal, said that a migraine might be the result of the body's attempt to protect and heal itself during a free radical attack. "Understanding migraines may ultimately teach us how we, too, can protect the brain," he added.
The discovery means that headaches could be prevented or alleviated using supplements such as beta carotene and vitamin C, which bind and shut down free radicals.
However, some treatments may be risky. One study said people on antioxidant supplements had a higher risk of early death.
An estimated one in ten people get regular migraines, which can last for hours and be so serious that sufferers cannot function. Elizabeth Loder, of the Headache and Pain Division at Brigham and Women's Hospital in Boston, who was not involved in Dr Borkum's study, said sometimes what patients think is the trigger for a headache is actually a symptom.
For example, some thought chocolate caused their headaches, but the craving for something sweet might be a sign of a coming migraine, she explained.
- Daily Mail