Tryptophan is an amino acid found in foods. Many amino acids combine to make a protein. These proteins are then digested and broken down into the amino acids. Amino acids are carried by the blood throughout the body. When we think about sleep, the important organ is the brain. There is a “blood-brain barrier,” which substances in the blood need to be transported across. Tryptophan uses the same transporter as several other amino acids. If those amino acids are in the blood at the same time, they will compete with tryptophan, so less tryptophan will cross into the brain.
Why is tryptophan relevant to sleep?
Several of the neurotransmitters (brain chemicals) of sleep rely on tryptophan for their production. Among these are serotonin and melatonin. Melatonin has been discussed in other blog posts here. Increasing tryptophan by taking tryptophan supplements does help treat insomnia. These supplements provide higher doses of tryptophan than can be found in food. Cottage cheese has the most tryptophan per serving, at 400mg tryptophan in 1 cup. A 3oz serving of turkey provides 283mg of trytophan, and 1 cup of milk 110mg.
Does the tryptophan in our Thanksgiving turkey help sleep?
Thinking about the tryptophan basics we first discussed above, the tryptophan in turkey probably doesn’t help you sleep. This is because there are other amino acids in the turkey, some of which may compete with tryptophan to be taken into the brain. That said, enjoy the sleepy reverie that often follows the Thanksgiving feast!