This article was originally published on November 24, 2014.
It's truly the season for talk of tryptophan, which is often blamed for the drowsiness we feel after the gluttony of our Thanksgiving feast. But, it turns out turkey isn't all that special. Lots of other foods contain comparable amounts of tryptophan. And, we eat them all the time.
Tryptophan (a.k.a. L-tryptophan) is an amino acid necessary for growth and the production of niacin and serotonin. Serotonin is a neurotransmitter known to play a role in the regulation of appetite, mood, sleep, and many other important physiological processes. But, since the body doesn't make its own, you've got to gobble up specific foods to get your trypto-fix.
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It's about this time of year — every year — that we hear about tryptophan in turkey. But, it turns out turkey doesn't actually contain much more tryptophan than most other poultry. And, there are so many sources of this particular amino acid that we're eating it all the time. We kind of have to.
In a 200-calorie serving, roasted light meat turkey has about 433 mg of tryptophan. And, other meat and fish have comparable amounts: 474 mg in rotisserie chicken breast and 384 mg in salmon. You can also get tryptophan from eggs (208 mg if they're hard boiled), milk, and seeds.
So, if tryptophan is not to blame, why do we get so sleepy after our T-Day meal? Many have offered speculations, but it seems like it's down to a couple factors: the excessive amount of food we eat and the carbs involved. Combined, the tryptophan-rich meat and carbs may create a complicated insulin response that causes drowsiness. Of course, you could also just blame it on the wine.