I’ve been eating sauerkraut or kimchi daily for the past fortnight – and for roughly the same period of time I’ve been waking up too early, unable to get back to sleep. Sometimes that happens, so it took me a while to make a link, but I’ve finally got round to doing a quick Google (for example, https://www.alternet.org/story/149722/5_unexpected_foods_that_prevent_insomnia_and_5_foods_that_promote_it), and it seems that sauerkraut, kimchi and kefir (I see someone else has posted about kefir) contain an amino acid called tyramine – which inhibits sleep.
So much as though I like the effect they’ve been having on my guts, I think I’m going to have to try knocking them on the head, to confirm if the link is genuine.
Thought it might be useful to post on this, just in case anyone else has been having similar problems …