Tryptophan

Contrary to popular belief, Thanksgiving turkey does not induce sleep. Overdosing on carbohydrates is more likely the cause behind after-dinner drowsiness.

Tryptophan is an amino acid found in turkey, as well as chicken, pork, cheese, milk, nuts, fish, eggs and several vegetables. Tryptophan produces the vitamin niacin, which in turn produces serotonin, a neurotransmitter that helps regulate sleep. However, scientists have discovered that tryptophan must be ingested on an empty stomach without any other amino acids or proteins in order to cause drowsiness.

The more likely reason for those Thanksgiving naps is the meal's high level of carbohydrates -- potatoes, yams, bread, pumpkin pie and other starchy, sugary items. Carbohydrates stimulate insulin production, and as a result, other amino acids leave the bloodstream. Tryptophan then accumulates in the bloodstream and triggers serotonin production in the brain. Carbohydrates are more closely linked to tryptophan's sleep-producing qualities than high protein foods such as turkey.

In addition, the digestive system becomes overworked from so much food to process. Therefore, blood flow is diverted to the stomach and away from the brain and other parts of the body, causing you to feel lethargic.

Resources:

Learn more about tryptophan, and why a big Thanksgiving dinner can make you sleepy.

KidsHealth explains tryptophan and turkey tiredness in language that kids can understand.

Several varieties of food can either help you to sleep, or keep you awake. Discover their hidden sources before you have another unwanted restless night or lethargic afternoon.

November 29, 2003