Vitamin B2 (Riboflavin) in particular can be helpful for those with migraines. But it seems like it only effects those with migraines headaches, and not migraine auras. Did nothing for me :-(

Also N=1, but I remember coming across some research that confirmed this when I was taking the supplements.

Interesting. I still often feel like I am about to get a migraine (colours go weird, slight auras, blurry vision), but they don't eventuate.