Do pistachio nuts cause insomnia

Answer 1

Yes. In my experience, pistachio nuts can indeed cause insomnia, assuming the brand I purchased has an accurate ingredient label, which lists only roasted pistachios and salt. The latter has no noticeable effect on my sleep, but the nuts unquestionably do if I consume a few ounces of them in the afternoon or evening. I haven't noticed any sleep disruption secondary to other nuts (walnuts, pecans, almonds, or peanuts), so I was surprised that something which seemingly should not trigger insomnia did that. After several bags of them over the past few months, I experienced a clear correlation between pistachio consumption at the aforementioned times and poor sleep quality that night, with overly vivid dreams.

I asked three friends, and all noticed the same effect of pistachio nuts. That's obviously not scientifically conclusive, but it is interesting nonetheless. I checked the PubMed database and found no directly relevant studies, but scientists have yet to study other things that cause insomnia, too. I found some interesting indirectly relevant studies. Putting 2 and 2 together might provide an answer to this mystery that makes physiological sense; I'll update this answer with the additional information when I have time.

Incidentally, genetic and other differences between people explain why everyone doesn't experience this effect. If they did, it would likely be well-documented by now.

-- answer by Kevin Pezzi, MD