How Does It Actually Work?
Every Thanksgiving, we get to hear countless debates about tryptophan.
Someone will yawn at the Thanksgiving Dinner table and your aunt might say something like, “All that tryptophan from the turkey is making you sleepy!” And then your uncle might respond with, “You know that’s not actually true, right?”
But does Tryptophan actually make you fall asleep? Does turkey actually contain higher levels of tryptophan than most other foods? There are lots of urban myths about tryptophan, but today, I’m going to teach you the scientific truth.
What is Tryptophan?
Tryptophan is officially called L-Tryptophan, and it’s an essential amino acid. Amino acids are building blocks of proteins.
We call L-Tryptophan an essential amino acid because our bodies can’t produce it naturally, which means we must get it from our diet.
Our bodies use tryptophan to produce niacin and serotonin. Niacin is a B vitamin which is responsible for aiding digestion, healing our skin, and facilitating neurotransmission.
Serotonin, on the other hand, is a chemical in the brain which promotes a feeling of wellbeing and relaxation. The brain releases serotonin when we need to fall asleep. Serotonin is required in order to make melatonin, which is the chemical released by our brains to promote a natural sleep cycle.
Our bodies actually cannot produce serotonin without tryptophan. In other words, Tryptophan plays a critical role in helping us get a healthy, natural sleep.
Which Foods Contain Tryptophan?
Yes, turkey contains tryptophan. However, before your aunt starts walking around saying, “I told you so”, I should warn you that turkey contains no more tryptophan than most other types of poultry.
In fact, turkey has slightly less tryptophan than chicken and certain other types of poultry. So you’re more likely to feel sleepy after eating a chicken breast than you are after eating a turkey wing.
Here are some of the most common foods which contain tryptophan:
— Most types of poultry, including chicken and turkey
So Why Do We Feel Sleepy After Eating Turkey?
Most people don’t feel sleepy after eating a chicken breast. But if chicken contains more tryptophan than turkey, then we should feel sleepy, right?
Top scientists have actually looked into this issue. We likely feel sleepy after eating turkey because we stack turkey with lots of carbohydrates.
Many researchers believe that tryptophan needs assistance from carbohydrates to have a noticeable effect on our serotonin levels.
What causes us to fall asleep is consuming carbohydrates and tryptophan at the same time. Even as little as 30 grams of carbohydrates will interact with the tryptophan stored in your body in powerful ways. This creates a serotonin boost in the brain, which leads to higher melatonin levels and increased drowsiness.
If you’re eating Thanksgiving dinner, you’re probably consuming lots of carbohydrates. The pie, the potatoes, and the bread in the stuffing all contain high levels of carbs.
Why Do We Need Carbs to Feel Sleepy from Tryptophan?
Scientists have actually identified the exact reason why we need carbs to feel sleepy from tryptophan.
Specifically, our bodies are flooded with amino acids after a big turkey dinner (or any meal). These amino acids basically “line up” at the blood-brain barrier waiting to affect your brain.
Tryptophan has to compete with all of these other amino acids for entry. Just like when you wait to get into a really popular nightclub, sometimes you might end up waiting for a few hours.
But what happens if you know the bouncer? You get in right away, right? (Assuming the bouncer knows you for good reasons).
That’s how carbohydrates work. Tryptophan latches onto carbohydrates, facilitating transmission across the blood-brain barrier. These carbs let tryptophan enter the brain before many other amino acids, which causes sleepiness. Source: MIT.edu
Overeating Also Contributes to Tryptophan Sleepiness
Overeating is as much of a Thanksgiving Day tradition as cooking a turkey. When we overeat on Thanksgiving Day, our bodies have to use a lot of energy to digest all that food.
When we burn energy, we feel more tired.
Oh, and you’re probably also having a few drinks on Thanksgiving Day. Alcohol is a depressant, which helps us feel relaxed.
Plus, you’re off work, so you feel even more relaxed, and it’s understandable that your body and mind feel sleepy.
So why are we sleepy during Thanksgiving Day? It’s a potent combination of tryptophan, carbohydrates, alcohol, and overeating. Tryptophan, by itself, does not make us feel very sleepy. Pass that message along to your aunt.