11/26/2009 01:34 pm ET | Updated Nov 17, 2011

Turkey Doesn't Make You Sleepy. It Really Doesn't!

In honor of Thanksgiving, I'm going to take a break from health care reform - much like Congress.  Instead, please enjoy this chapter from my book:

Myth: Eating Turkey Makes You Sleepy

While not everyone stoops to the level of Seinfeld’s Jerry and George, who used tryptophan in turkey to lull
a girl asleep so that they could play with her toys, the supposed
sleep-inducing effects of tryptophan in turkey are commonly recounted at
American Thanksgiving feasts and in the popular media around the holidays. 

Scientific evidence does support a connection between tryptophan and
sleep. L-tryptophan has been marketed as a dietary supplement to aid with sleep.  Tryptophan also may have an effect on the
immune system, with possible benefits for autoimmune disorders such as multiple

The truth is, turkey is not to blame for your sleepiness.  Chicken and ground beef contain almost the
same amount of tryptophan as turkey -- about 350 milligrams per 4 ounce
serving.  While you might have heard
someone claim that turkey made them drowsy, you have probably never heard
someone say that chicken, ground beef, or any other meat made them sleepy.
Swiss cheese and pork actually contain more tryptophan per gram than turkey,
and yet the American classic, a ham and cheese sandwich, somehow escapes

The amount of tryptophan in a single 4 ounce serving of turkey (350
milligrams) is also lower than the amount typically used to induce sleep. The
recommendations for tryptophan supplements to help you sleep are 500 to 1000
milligrams. Many scientists also think the limited amount of tryptophan in
turkey would be offset by the fact that it is generally eaten in combination
with other foods and not on an empty stomach. While one clinical trial found
comparable results for tryptophan from a food protein-source and pharmaceutical
grade tryptophan, this study also used an extremely rich source of tryptophan,
deoiled gourd seeds, which have twice the tryptophan content of turkey. In this
trial, and in general use of supplements, tryptophan is taken on an empty
stomach to aid absorption. Although we did not locate any experimental evidence
to support this claim, many believe that the presence of other proteins and
food in the stomach during the feasts generally associated with turkey
consumption would limit the absorption of the tryptophan in the turkey.

There are other elements of the holiday feasts that can induce drowsiness.  Large meals have been shown to cause
sleepiness regardless of what is eaten because the body increases blood flow to
the stomach, and decreases blood flow and oxygenation to the brain. Meals both
high in proteins or in carbohydrates may cause drowsiness.  And don’t forget about the booze. One or two
glasses of wine, especially for people who only drink occasionally, can
increase drowsiness.

Have a happy Thanksgiving, everyone.  Stop blaming the turkey for your sleepiness.

DON’T SWALLOW YOUR GUM! by Aaron Carroll, MD and Rachel Vreeman, MD copyright © 2009 by the
author and reprinted with permission from St. Martin’s Griffin,
an imprint of St. Martin’s Press, LLC