For those interested in pursuing this angle, you may want to check out the
book, Excitotoxins, the Taste that Kills, by Russell Blaylock, MD.

In my own case, I sometimes had migraines whose cause I couldn't pinpoint,
but often the source was a smoked/fermented/preserved food, such as bacon,
ham, commercial beef jerky, lox, blue cheese, sun dried tomatoes, canned
fish, etc. Some of these foods might be consumed as part of a Paleo diet. I
suggest a trial period of a month or so eating only fresh foods with NO
ingredient labels, to be absolutely sure of no contamination with any
potential Excitotoxin.

Additives such as carageenan, other vegetable gums, hydrolyzed vegetable
proteins, soy sauces or extracts, natural flavorings, vegetable broths (in
every can of water packed tuna fish, for example) can be sources of MSG which
can trigger migraines in susceptible people. And there are scores of other
ingredients as well. The scary thing is that many foods that state, "Contains
NO MSG" actually DO contain it in an indirect form.

A Google search will bring up lots more information. When my diet is
perfectly "clean", I have no migraine headaches.

Maddy Mason
Hudson Valley, NY