What is Tryptophan?

You may have heard reference to tryptophan around the holiday season when post-dinner naps are especially common. But what is tryptophan? It is an essential amino acid that is found in protein-rich foods. There are two types of tryptophan, L-tryptophan and D-tryptophan, which serve the same purpose but differ in molecular orientation. The body does not produce tryptophan, so we rely on food and supplements for this amino acid. Tryptophan produces niacin when combined with enough iron and vitamins B6 and B2. Niacin then converts into serotonin, which plays an important role in producing melatonin. Serotonin also affects mood, sleep quality, and overall health and wellness. As a result, having enough tryptophan in your diet is an important part of your wellbeing. Read on for more about this essential amino acid.


roasted turkey

What Foods Contain Tryptophan?

Foods that are high in protein often contain tryptophan. It can be found in cheese, yogurt, eggs,  fish, chicken, and other meats, but is not exclusive to animal products. Tryptophan is also present in nuts, seeds, spinach, and tofu.

The body is able to absorb more tryptophan when these foods are combined with carbohydrates. Without carbohydrates, tryptophan competes with all other amino acids in your food and is less likely to be absorbed. You can combine ingredients to make a healthy, balanced meal that is rich in protein, carbohydrates, and tryptophan.

Gut health is also an important part of overall wellness. Taking care of your gut health with fiber and probiotics can encourage proper absorption of nutrients and boost serotonin levels.

Does Tryptophan Really Make Us Sleepy?

Most foods - including turkey - actually have fairly low levels of tryptophan. So while you may repeatedly hear the sentiment that Thanksgiving turkey is making you sleepy, this claim is actually misleading. Tryptophan may contribute to sleepiness, but it is not acting on its own.

In order to affect sleepiness, tryptophan must first be absorbed and used to create niacin. Niacin is then converted into serotonin, which also affects melatonin levels. So it is not an immediate effect of tryptophan entering the bloodstream. In fact, there are several components that determine whether or not the tryptophan is absorbed by the body to begin with. Tryptophan competes with all the other essential amino acids present in food and is the least represented. In order to make it to the brain, tryptophan relies on insulin produced from carbohydrates to remove the competing amino acids.

Since the amount of tryptophan in foods like turkey is low, it is not necessarily these foods that are making you sleepy. Rather, it is the combination of foods high in carbohydrates paired with the foods that contain tryptophan that leads to an increase in niacin, serotonin, and melatonin.

What are L-Tryptophan Supplements?

Since most foods are relatively low in tryptophan, some turn to tryptophan supplements for a boost of the amino acid. L-tryptophan supplements are designed to increase tryptophan levels in the body and should be paired with foods high in carbohydrates and low in protein for effectiveness.

Tryptophan supplements are commonly used to offset symptoms of mild insomnia, physical pain, premenstrual syndrome, and seasonal affective disorder. Since tryptophan is connected to serotonin and melatonin levels in the body, it is an option for those with mood and sleep disorders.

Dosing for these oral supplements is typically measured in grams. Typical recommended doses range from 1 to 12 grams, with a generally recommended dose of 8 to 12 grams for depression in adults divided into 3 to 4 doses. Double dosing is not recommended if you miss a dose. Individuals should consult with their doctor prior to taking any supplements, as they may interfere with current medications. Care should be taken to follow package instructions and professional medical advice.

Are Tryptophan Supplements Safe?

It is safest to absorb tryptophan through food, as there are fewer risks and possible side effects involved. However, tryptophan has been used as a supplement for decades and has been studied in numerous clinical trials with beneficial results.

In the late 1980s, tryptophan was banned due to 30 extreme cases of eosinophilia-myalgia syndrome, which affects multiple organs and can cause muscle pain, weakness, fatigue, and death. This EMS outbreak was likely caused by a contaminant in the supplements from one manufacturer, making the banning of all tryptophan supplements controversial. As a result, the U.S. Food and Drug Administration conducted extensive studies with the Life Sciences Research Office of the Federation of the American Societies for Experimental Biology. Proper guidelines and recommendations were put forth for safety in amino acid supplements and tryptophan supplements were reintroduced in 2005.

The availability of Tryptophan supplements is still limited by the FDA in the United States. There are additional precautions to take to ensure the tryptophan supplements you select are safe. First, consult with your doctor or trusted medical professional. Ensure that the supplements are purchased from a reliable source. Avoid purchasing supplements that are manufactured internationally, as they do not have to comply with FDA regulations.

It is especially important to consult with your doctor if you are taking other medication that may have negative interactions with tryptophan, if you have kidney or liver problems, or if you are pregnant or trying to become pregnant. Possible side effects include nausea, vomiting, headaches, and a suppressed appetite.

Should You Use Tryptophan Supplements for Sleep?

Before self-prescribing tryptophan supplements, it is important to consult with your doctor. There are many factors to consider before taking a new supplement, including your overall health and wellness as well as any medications you are currently taking. Studies have shown tryptophan to be beneficial for those with mild insomnia, as it may help you fall asleep faster. For those with more serious conditions, including chronic insomnia, it may be beneficial to start with a medical consultation. There are many components to getting a good night’s sleep, and tryptophan’s effect on serotonin and melatonin is just one factor to consider.

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