There is always talk of post-turkey feast sleepiness from the tryptophan in turkey at this time of year, but what is tryptophan?

Tryptophan is an essential amino acid best known for its role in producing the precursors for the hormone melatonin and the protein 5-hydroxytryptophan (5HTP), which is a precursor for serotonin.  Serotonin is a neurotransmitter that affects many facets of human behavior, such as mood, stress response, appetite, and sexual drive. Melatonin and serotonin are involved in the regulation of the body’s sleep-wake cycle.

Up to 90% of the body’s serotonin is produced by the gut microbiome (the collection of healthy bacteria in your gut) with the bacteria converting the lion-share of tryptophan into serotonin. This is why having a healthy gut has gotten so much attention in recent years. It plays a huge role in the production of neurotransmitters and other co-factors that affect brain health. ( This article by the American Psychological Association addresses the relationship  between healthy gut bacteria and mood states. )


Is it really the turkey that make you sleepy? 


There are about 450-500mg mg of tryptophan in a 6oz piece of roasted turkey breast, a same sized portion of chicken breast has 650-700mg of tryptophan. Dairy products like cottage cheese are also a source of tryptophan with 300-350mg. Three scrambled eggs and bacon for a keto-friendly Sunday morning breakfast and you’ll have about 600mg of tryptophan. If you eat more like a pescatarian, you are in luck! Most fish is high in tryptophan. A 6oz fillet of Salmon, for example, is not only rich in omega-3, but it has around 575mg of tryptophan. And no worries if you are a vegan or vegetarian, a cup of firm tofu has about 600mg of tryptophan and a cup of edamame has about 400mg.

Most likely the sleepiness we have after enjoying such a large turkey feast is due to the shunting of blood to the stomach to help digest a full belly. It could also be that with such a huge carbohydrate load, we are simply sleepy from the sugar load. It left me wondering though what other nutritional value turkey has?

Turkey provides us with B6 (pyridoxine), an essential water soluble vitamin that helps the body create red blood cells, as well as B12 (cobalamin) which is needed for proper brain function. The liver uses tryptophan to produce Niacin (B3) for needed energy, DNA production, and metabolism. B3 is used in the conversion of food to energy. Minerals, like selenium and zinc are also found in turkey. Selenium is an amazing antioxidant that helps reduce inflammation and supports mental function.   Zinc is an important co-factor in thyroid hormone synthesis, function and metabolism.  And last, but certainly not least, is choline. Choline is an essential nutrient needed for the production of phospholipids which are important for brain development, nervous system stability, cellular structural integrity, and healthy liver function.


Good food is good medicine.

As we gather this Thanksgiving season, let’s remember to be thankful for the nourishment that we receive in the food that we eat and in the company we keep.

May you have a wonderful Thanksgiving and enjoy what the day brings.