This month’s Brain Food is L-tryptophan (tryptophan).

BRAIN FOODS is an ongoing educational tool for integrative and holistic resources for mental well-being. This tool is designed to share research on how food and holistic lifestyle practices have the potential to boost your mood, combat fatigue and insomnia, reduce your stress, and improve your memory and concentration.

BRAIN FOODS has explored topics such as the impact of gut health on your mental health and how dietary deficiencies in omega-3 fatty acids can increase depression, anxiety and an ability to handle stress. No single post in this series is intended to be viewed in isolation or to provide direct medical advice, rather the series covers a wide variety of non-pharmaceutical approaches designed to educate you on a wide-variety of factors that may contribute to mental health.

Brain Foods and Tryptophan

 What is L- Tryptophan?

Tryptophan is an essential amino acid that is a precursor to the brain neurotransmitter serotonin, which regulates mood. It is an essential amino acid because the body can't make it on its own; it must be acquired via food or supplementation. The synthesis of serotonin from tryptophan is a two-step process with the rate of serotonin synthesis dependent on tryptophan concentrations in the brain (source).

Low-levels of tryptophan can reduce serotonin production in the brain and can lead to depression, anxiety, insomnia, and poor memory and concentration.

mental health tryptophan

Tryptophan, Mood, and Anxiety

Several studies have consistently shown depressed individuals may have depleted tryptophan levels (source). In a meta-analysis of studies from 1966 through 2006, tryptophan depletion showed decreased mood states in participants with major depressive disorders, a family history of depressive disorders, or with major depressive disorders in remission (source). In another study, there was significant improvement in the mood states of individuals who had experienced depression and received a product containing tryptophan compared to those who received the placebo (source).

Other research has examined the effects of low-levels of tryptophan on anxiety and stress levels. One such study exposed 15 healthy adults to a stressful environment twice — once when they had normal tryptophan blood levels and once when they had low levels (source). The researchers found that anxiety, tension and feelings of nervousness were higher when the participants had low tryptophan levels.

It can be difficult to change plasma tryptophan levels through diet alone; therefore, most studies have focused on tryptophan supplementation. However, one study of 25 healthy young adults found that participants’ mood indicated significantly more positive affect scores after consuming a high tryptophan diet as compared to a low tryptophan diet (source). The same study found that consuming more dietary tryptophan resulted in less depressive symptoms and decreased anxiety.

 Tryptophan and Sleep

Research also shows that tryptophan plays are role in improving sleep. One study found that increasing tryptophan in the blood directly increases both serotonin and melatonin (source).

Another study found that a tryptophan-rich breakfast combined with daytime light exposure improved melatonin secretion and sleep quality (source).

Review of Existing Research

For the purpose on this blog post, mostly due to length, I’ve chosen to highlight a number positive study outcomes in both supplementation and increased dietary intake of tryptophan as this data is important. The findings here however are not an exhaustive view of all available research data. Current research results on tryptophan’s role in improving mental health are mixed. Research is more conclusive in the impact tryptophan depletion has on mood; yet, produces mixed results on how to improve tryptophan level, with most studies showing positive results with supplementation.

Foods containing the amino acid tryptophan are whole, unprocessed foods; and the general population is typically encouraged to consume these foods as a part of a healthy, well-rounded diet. For this reason (as well as some positive study outcomes on dietary interventions as noted above), I’ve chosen to highlight foods that contain tryptophan along with supplementation options.

tryptophan and mood, anxiety and depression

Sources of Tryptophan

Turkey likely comes to mind first when you think of tryptophan, but this brain nutrient also can be consumed via other food sources along with supplements. Quality sources of tryptophan include:


Dark green leafy vegetables, such as spinach, are a source of tryptophan.
Spinach is also a good source of iron. Iron helps the body to make healthy red blood cells. A lack of iron in the diet can lead to anemia, low energy, or difficulty breathing (source).


Poultry is one of the best sources. A serving of poultry is also a rich source of complete protein, supplying about half your recommended daily intake. No matter what type of poultry you like to eat, you’ll get 250 to 310 milligrams of tryptophan in a 3-ounce serving (source).


The Terra Origin Sleep supplement contains a mix of powerful and effective herbs and ancient remedies to prepare your system for deep, restorative sleep. Key ingredients including L-tryptophan, passionflower, chamomile, melatonin and GABA to promote relaxation and higher sleep quality. Terra Origin products are inspired by the ancient practice of Ayurveda, are scientifically supported and do not contain any empty fillers or confusing preservatives.

While developing good sleep hygiene is important for ongoing quality sleep, I personally tested this product during finals last semester as a way to reduce stress and ensure I was getting a good night’s sleep during a short-term busy time period. I loved how I could use this product intermittently during a short-term high stress period to get a restful night sleep without feeling groggy the next day.


Veggies like kelp, seaweed, and spirulina are all good sources of tryptophan, that ever-essential amino acid. These veggies contain about 3 percent of daily tryptophan value (source).

Thank You Terra Origin for sponsoring this post and thank you for supporting the brands that make this blog possible. As always, opinions are my own. 

An important message 
The entire Brain Food Series is designed to be a guide, to share educational information that empowers you in your own wellness journey. The information in this series in not designed to take the place of a medical doctor and nor is this series designed for you to act on every single topic I share each month. Some topics may be more relevant for you than others. Lastly, the field of nutrition and nutritional psychiatry are a rapidly evolving fields, with research updated frequently.

All information is intended to motivate readers to make their own nutrition and health decisions after consulting with their health care provider. Readers should consult a doctor before making any health changes, especially any changes related to a specific diagnosis or condition. No information on this site should be relied upon to determine diet, make a medical diagnosis, or determine treatment for a medical condition. The information on this website is not intended to replace a one-on-one relationship with a qualified health care professional and is not intended as medical advice. No information on this site should be used to diagnose, treat, prevent or cure any disease or condition.