The claim: Artificial sweeteners cause migraines

The facts: Artificial sweeteners have been linked in anecdotal reports to a variety of health problems for more than 30 years. But one of the more mysterious reported side effects is also among the most commonly mentioned, headaches. Migraine sufferers are often known to steer clear of sweeteners, if only to be on the safe side, and there is no shortage of medical websites spreading the claim. But according to various studies, anecdotal evidence does not exactly hold up. Since the 1980s, about half dozen studies have examined the link, and majorities have discounted it. Most of those studies looked specifically at aspartame, found in diet soda and consumed by millions.

The bottom line: Despite widespread anecdotal reports, most studies have not found an association between artificial sweeteners and headaches.
Anahad O’Connor NYT