Tryptophan is an amino acid, meaning it is a building block of protein fibers in the body. While it helps to build nerve fibers, it often is better known for producing a neurotransmitter known as serotonin in the body. Serotonin is responsible for a number of possible changes in your mental function, including helping you feel more relaxed and/or sleepy. If you have a diet low in tryptophan, you may experience a number of adverse symptoms.
Research
To study the effects tryptophan has on the brain, researchers at the University of Groningen in the Netherlands tested the effects of a low-tryptophan diet on lab rats. The rats were fed varying diets and tested for their responses to stressors, including noise. The rats with low-tryptophan diets had less serotonin in their brains, which researchers theorized made them more affected by stressors. Over time, the rats on the low-tryptophan diet proved more vulnerable to stress than their counterparts that consumed tryptophan. The researchers found increasing levels of inflammatory hormones in the low-tryptophan rats. However, the researchers did note that rats on each diet were able to adjust to the changes in sound, a process known as habituation. This means you may experience greater stress reactions on a low-tryptophan diet, but that you will still retain coping mechanisms that help you deal with stress.
Foods That Have Tryptophan
Tryptophan because this amino acid found in proteins, so it is found in high-protein foods including fish, eggs, chicken and red meat. Other high-tryptophan foods include dairy products, nuts, seeds, bananas, soybeans, tuna and shellfish.
Tryptophan Deficiency
If you do not eat a lot of protein in your daily diet, it is possible to have low levels of tryptophan in your body. This can be troublesome because of tryptophan's relation to serotonin production in the body. Without enough tryptophan and therefore serotonin, you may notice disturbances in your mood and are more likely to experience increased incidences of depression and impulse control problems. Because serotonin helps to induce quality sleep, a low tryptophan diet also may affect your sleep quality, including in going and staying asleep (see reference 3).
Considerations
If you are eating a low-tryptophan diet to avoid its sleep-inducing effects, there is another method you can employ that does not involve eliminating tryptophan-containing foods entirely. For example, eating high-protein, high-tryptophan foods with carbohydrates -- like a turkey sandwich -- makes tryptophan more available in the brain. This is because your brain uses carbohydrates to release insulin, which allows your cells to take in more tryptophan. However, if you eat a protein source alone, the tryptophan is less likely to enter your cells. This is because tryptophan-containing foods also tend to have tyrosine, an amino acid that helps make you feel more energized. Therefore, you do not have to avoid tryptophan-containing foods entirely -- just avoid carbohydrates when you eat them if you are concerned with feeling sleepy.
References
- MyFit.ca; What Is Tryptophan?; 2011
- ScienceDirect; Low Tryptophan diet Increases Stress-Sensitivity, But Does Not Affect Habituation in Rats; Marit Tanke; January 2007
- MedlinePlus; Tryptophan; February 2010
- Ask Dr. Sears; Foods That Help You Sleep; Dr. Barry Sears
- Kids Health; Does Eating Turkey Make Me Sleepy?; August 2009
