There is a bit of a myth surrounding Thanksgiving: the Thanksgiving coma, which is basically when everyone nods off after the big meal. So what causes it?

It’s quite an elaborate story, even with scientific roots. According to general wisdom, turkey meat contains an amino acid called tryptophan (true), and in the body tryptophan is used for making serotonin (true), a hormone associated with sleep (also true). So the myth tells us that turkey has a lot of tryptophan, and eating lots of it makes your body produce a lot of serotonin, and you feel sleepy. Right? Nope; it’s nonsense!

You see, turkey contains as much tryptophan as a similar piece of chicken or beef. In fact, all meats contain a little bit of tryptophan, and we don’t dose off after eating chicken, now do we? Also, heavy meals full of fat and carbohydrates tend to make us sleepy anyway, regardless if they contained turkey or not.

And if life wasn’t turkey enough (sorry for the pun), tryptophan has been implicated in helping people sleep sometimes. For example, last year, Dutch researchers reported on a small and (very) short study that suggested a link between better sleep and tryptophan. But don’t rush and buy tryptophan supplements just yet: in 1989, a link between consuming supplements containing very high levels of tryptophan and Eosinophilia Myalgia Syndrome (EMS), which resulted in 38 deaths was uncovered in the USA. As of 2001, the FDA is still worried about dietary supplements containing tryptophan.

So, really, why do you feel sleepy after a heavy meal? It’s because of the fatty and starchy meal you just ate, so the blood is diverted to your digestive system to help absorb all the nutritional goodies. This diversion makes you feel tired and lethargic, but only temporarily. Sorry, no magic involved.

[tags]thanksgiving, thanksgiving coma, turkey, sleep, tryptophan[/tags]