Here's what's helped for me. I had strong headaches that would persist for weeks, with some auras, which my doctor called migraines. (They don't seem to be as bad as what people usually mean by the word.) A flaxseed oil supplement keeps them away. When I don't take enough, they come back; it needs to be at least 15g/day or so (many times more than the 2-3 gelcaps/day that supplement bottles direct you to take). I've taken fish oil occasionally instead.

I found this by (non-blinded) experimenting with different allegedly anti-inflammatory supplements. I'm not a doctor, etc.