Tired on holiday? Don't blame turkey!
Garrison Hilliard
By Peggy O'Farrell � pofa...@enquirer.com � November 24, 2009
Don't blame the turkey when it's time for the after-dinner nap
Thanksgiving Day.
Tryptophan, an amino acid found in turkey, has long been blamed for
inducing drowsiness.
But it's probably the sheer amount of food consumed that causes the
traditional Thanksgiving Day food coma, not the turkey itself, said
University of Cincinnati obesity researcher Stephen Benoit.
"The quantity of tryptophan in turkey is really no different that what
you'd find in beef or chicken," Benoit said.
The body uses tryptophan to make two brain chemicals - serotonin and
melatonin - known to promote sleep, he said.
Researchers have shown that lab animals and human research subjects fed
large quantities of tryptophan, and nothing else, do get sleepy after the
meal.
"You're talking about animals or patients who are basically
food-deprived," he said. "Sure, if you feed them a lot of tryptophan, you
can see some effect. But we don't consume tryptophan in that large a
quantity on Thanksgiving, and we don't consume it in isolation."
The traditional Thanksgiving meal, a hefty combination of a little protein
and a lot of sugar, carbohydrates and fat, makes the body release another
hormone - insulin - to help metabolize the meal.
Insulin causes the blood sugar to dip, and when blood carries the insulin
to the digestive tract, drowsiness results.
"We probably all have very similar experiences on other days," Benoit
said. "You go out for a big company lunch and eat a huge meal and you get
back to work and what happens? You want to take a nap, but you can't.''
A couple of psychological factors also likely contribute to the holiday
nap, he said.
First, having a day off work means no one has to fight off post-meal
sleepiness.
And once the meal's over, Thanksgiving hosts get a chance to wind down
from the stress of preparing the holiday meal.
"It's a highly stressful situation leading up to the meal, and when it's
over, you have that big relief that contributes to the feeling of
drowsiness," he said.