As we began clearing the plates
it slowly started to spread around the table…the post-Thanksgiving meal sleepiness.
Along with it, I began to hear mumbles of, “I feel the tryptophan kicking it,”
and just then it hit me. Could tryptophan
really be responsible for the overwhelming tiredness people feel after eating a
Thanksgiving meal? Turns out the best
answer is “maybe.”
Tryptophan is an essential amino
acid, meaning the human body cannot produce it and so it must come from our
diets. Tryptophan is metabolized in the
body, and is used in both the production of niacin (a B vitamin essential for
nerve function and digestion) and serotonin (a neurotransmitter which helps regulate
mood, sleep cycles, appetite, and behavior).
Serotonin can be further metabolized to melatonin, which aids in the
regulation of circadian and seasonal rhythms (Galano, Tan, and Reiter,
2011). So, with an increase in
tryptophan which is a precursor to regulators of sleep cycles and circadian
rhythms it would make sense that those who overstuff themselves with turkey,
which contains tryptophan, would be sleepy right? Well, research suggests otherwise.
Turns out, chicken and milk actually
contain more tryptophan than turkey (Milagres et al, 2013). So why do people only seem to be sleepy after
eating their Thanksgiving turkey and not their regular Saturday night chicken
dinner? Research suggests it is
primarily the amount of turkey and other foods consumed on Thanksgiving and not
tryptophan itself, which causes the sluggishness (Zamoski, 2013). As we know from physiology, the
parasympathetic nervous system is responsible for “resting and digesting.” Well, when people consume large amounts of
calories (an average of 4,400 more on Thanksgiving Day), they activate this
division of the nervous system. In
addition, digesting that many additional calories is actually a lot of work for
the body. So, you essentially are using
a lot of energy just to digest all the food you ate, which tires your body out,
and induces that ever infamous “turkey coma” (Park et al, 2011).
So, next year (or later this week
when you eat too many leftovers) just remember it is partially the turkey that
makes you sleepy, but it’s also the large quantities of rolls, green bean
casserole, mash potatoes, cranberry sauce, sweet potatoes, and of course those
several slices of pie that are all going to work in combination to put you to
sleep.
Galan
A, Tan D, and Reiter R. 2011 Jul. Melatonin as a natural ally against oxidative stress: a physicochemical
examination. Journal of Pineal Research 51(1): 1-16.
Milagres M, Minim V, Minim L, Simigueli A,
Moraes L, and Martino H. 2013 Nov. Night milking adds value to cow’s milk.
Journal of Science of Food and Agriculture. DOI: 10.1002/jsfa.6480
Zamoski L. 2013. Does tryptophan really make you sleepy—and
is turkey to blame? Experts set the record straight. http://www.webmd.com/food-recipes/features/the-truth-about-tryptophan
Park S, Kang K, Lee SW, Ahn MJ, Bae JM, and Back K. 2010
Oct. Production of serotonin by dual expression of tryptophan decarboxylase and
tryptamine 5-hydroxylase in E. coli. Applied Microbiology and Biotechnology.
89: 1387-1394.
Megan,
ReplyDeleteThat is really interesting! I had always wondered exactly how it was that tryptophan would cause that sleepy feeling. It is amazing how many extra calories are actually consumed on Thanksgiving. I wonder if people who are vegetarian or vegan and still consume extra calories but not turkey would still report feeling that same feeling? Did you come across anything like that in your research?
Megan, I think you are spot on with the notion that the increase in caloric intake taking a toll on the the body and hence the lethargic feeling. I'd like to bring up that fact that for some reason, most families seem to eat their thanksgiving dinner much earlier in the day. Some as early as 2pm. So on top of the turkey and the all the carbs and calories, I think that most people feel much more tired in their minds because they just ate a "dinner" and still have the rest of the day to go. This is not even considering the all wine. So I think it is a perfect storm that leads to nap time.
ReplyDeleteAlso, because your body has to work much harder to process all the food that you ate on thanksgiving and even a day or two after that, I firmly believe that such a binge is not THAT bad for a person's overall healthy diet. You said it yourself that the body expends a lot of energy to process the food that it was forced fed on turkey day. I think that sustained intake of high calories is much worst, in the same vein as a sustained caloric deficit is the best way to lose weight--it might even make you live longer too (see cite). This is just a long, winded way of me justifying how much I ate in the last few days.
Cava E, Fontana L. Jul 2013. Will calorie restriction work in humans? Aging (Albany NY).;5(7):507-14.
Must be pretty standard pre-Thanksgiving discussion, because I somehow found myself looking into this after a discussion somewhere about tryptophan in turkey making you sleepy. One of the reasons for turkey comas might be a combination of excessive tryptophan consumption during a large carbohydrate rich meal. This apparently upsets the proportions of tryptophan to other amino acids in the body and encourages its blood-brain barrier transfer, leading to greater serotonin/melatonin. The reason a chicken dinner might not have the same effect could be due to not eating in excess as one is likely to do during Thanksgiving, leading to less tryptophan utilization.
ReplyDeleteI'd imagine this working in conjunction with what you've proposed with parasympathetic nervous system activation and energy expenditure during a large meal.
Wurtman RJ, Wurtman JJ, Regan MM, McDermott JM, Tsay RH, Breu JJ. 2003. Effects of normal meals rich in carbohydrates or proteins on plasma tryptophan and tyrosine ratios. American Society for Clinical Nutrition. 77(1):128-132.
Kelsey, I did not come across that specifically in my research; however, as a vegan I can affirm that while everyone at the table was beginning to nod off I felt awake. Of course, this could have been too because my meal was primarily vegetables, which studies show lead to a feeling of fullness faster, and in turn prevent one from consuming excess calories (1).
ReplyDeleteBilly, my research did also mention the wine that people consume as a contributor to the sleepiness one experiences after a Thanksgiving meal.
Erik, that makes a lot of sense about the increased amount of tryptophan associated with Thanksgiving, opposed to a regular chicken dinner. Thanks.
1. Zhou B, Yamanaka-Okumura H, Adachi C, Kawakami Y, Inaba H, Mori Y, Katayama T, and Takeda E. 2013 Sep. Age-related variation of appetite sensations of fullness and satisfaction with different dietary energy densities in a large, free-living sample of Japanese adults. Journal of the Academy of Nutrition and Dietetics 113(9):1155-1164.