Well, I mean I would guess so, huh? But yet it doesn't seem to happen every single time, but when it DOES, it's immediate. I mean the same way people get a 'brain freeze' when they eat ice cream or something.
I just had a small handful and hadn't even finished chewing the last one and - man!oh man! - the headache was right there!
I use Almond Breeze almond milk occasionally in my smoothies; and in my hot oat bran cereal and don't get a headache..just when I'm eating them raw.
I even tried soaking them first..
Well, I'm going to have to guess that you're right.