Every year people say after their Thanksgiving feast that the tryptophan in turkey is making them need a nap. There’s no doubt that many people end up groggy and sleepy after devouring loads of turkey, mashed potatoes, stuffing, and everything else that goes with Thanksgiving, but is it really the turkey that leads to the sleepiness?
An article on About.com by Anne Marie Helmenstine, Ph.D., a biology and chemistry professor, debunks the myth. Dr. Helmenstine says:
Turkey does contain L-tryptophan, an essential amino acid with a documented sleep inducing effect. L-tryptophan is used in the body to produce the B-vitamin, niacin. Tryptophan also can be metabolized into serotonin and melatonin, neurotransmitters that exert a calming effect and regulates sleep.
If you read only that passage, you may think that it’s settled .. the turkey makes you sleepy. However, Dr. Helmenstine continues, saying it’s actually much of the OTHER food on the table that makes you tired:
It’s actually a carbohydrate-rich (as opposed to protein-rich) meal that increases the level of this amino acid in the brain and leads to serotonin synthesis. Carbohydrates stimulate the pancreas to secrete insulin. When this occurs, some amino acids that compete with tryptophan leave the bloodstream and enter muscle cells. This causes an increase in the relative concentration of tryptophan in the bloodstream. Serotonin is synthesized and you feel that familiar sleepy feeling.
The article also points out that the fats in Thanksgiving food, as well as alcohol and plain old relaxation, can also lead to naptime. So, if you want to avoid feeling like you need a nap after your Thanksgiving meal, skip the carbohydrates, moderate your alcohol intake, and take a brisk walk after your meal. To read the entire article, click here.