The Tryptophan Myth About Turkey

Thanksgiving is usually a blur of food, family, friends and football (or other big-screen delights). And as often as not, turkey has taken the rap for the sleepiness that takes hold after the big meal, thanks to the "tryptophan in turkey."

But it's time to call "fowl" on this power-nap play. Despite the rumors, the tryptophan in turkey isn't what is causing guests to nod off after the Thanksgiving feast. It is the overeating—and likely the heavy carbs in the side dishes and pumpkin pie—causing the post-meal food coma.

But there is tryptophan in turkey, so what role does it play? And how can you shake this sleepy feeling?

What is tryptophan?

Tryptophan, or L-tryptophan, is an essential amino acid, which means your body cannot make it. Instead, you get it from your diet (so bring on the bird!). Once you gobble up that turkey, the meat's proteins get digested into amino acids and absorbed into the bloodstream for use throughout the body. (And this is a good thing—tryptophan has many health benefits, which we'll get to in a moment; there's a reason, after all, that people supplement with tryptophan.)

These amino acids are knowns as the "building blocks" of proteins. The L-tryptophan crosses the blood-brain barrier, and some gets changed into another chemical you've probably heard of: serotonin.

What does tryptophan do to your body?

As an amino acid, L-tryptophan helps with protein synthesis. What makes tryptophan special is its important role in the formation of the neurotransmitter serotonin, a happy hormone, and melatonin, your sleep hormone.

Serotonin is also called your mood hormone, and it is associated with happiness, satisfaction, and optimism. Serotonin also supports a healthy stress response and sleep cycle. But your body can't produce and maintain healthy serotonin levels without L-tryptophan, which is why it is so important for mood health.

L-tryptophan is also beneficial for melatonin, the compound that helps you feel sleepy at night and helps manage your sleep-wake cycles so you get restful sleep and wake refreshed.

L-tryptophan's health benefits don't stop there! It also supports a healthy stress response and can help you feel fuller after eating (which you might not need after Thanksgiving dinner but may appreciate on non-feasting days).

And there's even evidence that this neurotransmitter plays a role in cognition and memory. So that Thanksgiving turkey and the amino acids (and B vitamins) it delivers may help support brain health, as well.

Don't expect turkey's protein to trigger sleepiness, though. The L-tryptophan has to compete with the turkey meat's other amino acids to make the blood-brain crossing, so it isn't the culprit. Instead, the carbohydrates in your Thanksgiving meal and the blood flow needed for digestion—and possibly alcoholic drinks—are to blame.

Is turkey high in tryptophan? Why?

Poultry in general is a good source of L-tryptophan. After all, chickens, ducks and turkeys need tryptophan for their biological processes, just like humans. But turkeys don't rule the roost when it comes to tryptophan content in meat—chickens do! That means you don't have to wait for Thanksgiving to get your fill of L-tryptophan. You can stock up today with a low-fat chicken breast or cut into other meats, such as skirt steak or pork chops.

What other foods are high in tryptophan?

Animal meat protein delivers the most of this essential amino acid, but firm tofu is also among foods high in tryptophan. If you think about what we drink to make us sleepy, you'll guess another top source of dietary L-tryptophan: milk. A warm glass of milk has been used for centuries to calm children (and adults) before bed.

Other L-tryptophan-rich foods include:

• Salmon and canned tuna

• Oats

• Cheese and yogurt

• Pumpkin seeds

• Eggs

Looking for another reason to eat dark chocolate? (Who isn't?) It can contain up to 18 milligrams of tryptophan per ounce (which is why it can help support serotonin). Some fruits, such as bananas, also have L-tryptophan as well as other necessary vitamins and minerals.

Can you get enough tryptophan from turkey?

If you only eat turkey on Thanksgiving, then it isn't a good choice for maintaining healthy levels of anything. But turkey is a good source of L-tryptophan and another amino acid, tyrosine—as well as B vitamins, protein, selenium and more—on the days you eat it. On other days, you may want to consider a dietary supplement to fill your nutritional gaps.

Tryptophan supplements are a good way to support not only your L-tryptophan levels but also your serotonin and melatonin levels. Healthy serotonin and melatonin levels promote restful sleep, encourage your mood and support your immune system. Plus, melatonin is an antioxidant, so it helps protect your cells against oxidative stress and promotes cellular DNA health.

Other ways to support serotonin levels

Want some help getting in the (good) mood? Motion is potion! Regular exercise helps support levels of serotonin—and your other happy hormones—and contributes to both physical and mental well-being. Sunshine also promotes serotonin, so spend some time outside.

Feel like a double dose of serotonin? Get a good laugh in while you enjoy the great outdoors. Laughter helps support serotonin and helps you respond better to stress.

Besides tryptophan supplementation, other nutrients may help support a healthy mood. Learn which ones might fit your lifestyle with a mood health quiz.

References

• Hajishafiee M, et al. "Suppression of Energy Intake by Intragastric l-Tryptophan in Lean and Obese Men: Relations with Appetite Perceptions and Circulating Cholecystokinin and Tryptophan." J Nutr. October 2021. https://pubmed.ncbi.nlm.nih.gov/34255069/
• Jenkins T, et al. "Influence of Tryptophan and Serotonin on Mood and Cognition with a Possible Role of the Gut-Brain Axis." Nutrients. January 2016. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4728667/
• "Health Benefits of Turkey." WebMD. September 2021. https://www.webmd.com/diet/health-benefits-turkey
• "The Truth About Turkey & Tryptophan." Medical West. https://www.medicalwesthospital.org/the-truth-about-turkey--tryptophan.php