I tried Natto and really really wanted to get to eat it every day. However, one portion gave me huge long lasting headaches. The flavour was good, and I am used

I tried Natto and really really wanted to get to eat it every day. However, one portion gave me huge long lasting headaches. The flavour was good, and I am used to eat ferments (I make my own vegan yoghurt). I was really sad because Natto is supposed to have so many great properties.