What is tryptophan?
Tryptophan is an essential amino acid that’s a vital building block for protein in the body. There are 20 known amino acids, nine of which cannot be created within the body and must be consumed in the diet, thus considered “essential.” Tryptophan fits under this umbrella. Research has found that tryptophan also plays an important role in the gut microbiome-brain connection. This is because it’s a precursor to serotonin, a neurotransmitter that is key for main functions, including healthy sleep, hunger, pain recognition, and emotional processing. It’s also involved in the synthesis of melatonin, a hormone that helps with circadian rhythm regulation and sleep. These functions combine to potentially leave you feeling mighty sleepy after a tryptophan-heavy meal, as tryptophan is linked to increased tiredness and decreased time needed to fall asleep. Tryptophan can also be used by the liver to create niacin, or vitamin B3, in the body. Niacin is pivotal in energy metabolism and DNA production.
Does tryptophan actually make you sleepy?
Tryptophan is certainly linked to sleep—some research has found that a tryptophan-rich diet, which promotes serotonin and melatonin activity, may help contribute to better sleep. However, consuming a turkey dinner (or other tryptophan-laden meal) doesn’t immediately put you under a magic sleep spell as we’ve come to believe. This is because it’s also been found that the absorption of tryptophan is reduced by the presence of additional amino acids (also present in turkey). Oftentimes, foods contain multiple amino acids, lessening tryptophan’s effects. So after, say, a large, filling holiday meal with many different foods, it’s more likely that a surge of blood flow to the gut, and away from the brain, is what causes feelings of tiredness—rather than the tryptophan found in turkey.
Tryptophan Foods
The recommended intake for tryptophan is between 250 milligrams (mg) and 425 mg per day. Below are some of the highest tryptophan food sources that can help you get there, whether or not you’re a meat-eater (and that you’re likely already eating year-round, not just on Thanksgiving!).
