Friday, November 25, 2005

No, eating turkey doesn't make you sleepy

It's a myth. (See also Snopes)

There's reportedly good Thanksgiving news for turkey lovers: Contrary to popular belief, tryptophan in turkey doesn't cause drowsiness.

In fact, scientists told National Geographic News the substance could possibly aid in the treatment of depression and multiple sclerosis.

Purified tryptophan is a mild sleep-inducing agent and that probably led to the idea that foods containing heavy doses of the chemical cause drowsiness. But tryptophan can't function well as part of a meal.

"Tryptophan is taken to the brain by an active transport system shared by a number of other amino acids and there's competition among them -- like a crowd of people trying to get through a revolving door," Simon Young, a neurochemist at McGill University in Montreal, Canada, told National Geographic News.

He said consuming tryptophan-rich foods may cause blood levels of the amino acid to rise, but not enough tryptophan will reach one's brain to have a sedative affect. And, scientists told NGN, turkey isn't even unusually high in tryptophan. Many other foods, such as beef or soybeans, have higher concentrations.

And while we're on the subject of turkeys, here's a link to a wonderful thread of comments illustrating that turkeys can engage in navel-gazing just like people...
The turkey that laid a golden egg


Scott Ferguson said...

I think people get sleepy from Thanksgiving dinner because of all the simple carbohydrates they consume at one sitting -- rolls, sweet corn, pie, mashed potatoes with cornstarch-laden gravy, stuffing. Thirty minutes after you push yourself away from the table, you're in insulin shock!

Hoots said...

You're right. Even after a regular Sunday dinner I'm ripe for a nap.
I remember from grade school that the alimentary canal from throat to the other end is some twenty or thirty feet long. After we eat the whole thing gears up to start processing the food. That means a lot more of our blood supply is put to use in one place. As much as a pint or two of blood is redirected to digestion, leaving less for the brain and other functions. Getting sleepy is a narural response to less blood to the brain. At least that's the way I remember it from school.