By now most of us have heard that turkey contains “Tryptophan” which may make us drowsy after a big Thanksgiving or Winter Holiday dinner, but what is it and why does it does it make us sleepy?
Tryptophan is an amino acid. Amino acids chain themselves together to make proteins. Protein is the primary cellular component of our muscles, skin and organs. Our bodies continually use protein to make our tissues and to repair them in times of illness or injury. Patients in the process of healing accidental or surgical wounds require increased protein in their nutrition.
In our food, protein in the form of amino acids is found in meat, poultry, fish, milk and eggs. Amino acids can also be found in beans or lentils, and in grains like rice and corn, but these foods are not considered “complete” proteins for supplying human nutrition because they are missing some essential amino acids. “Essential” means that our bodies cannot make these amino acids needed to make our body proteins, thus they must be supplied in our diet. Twenty amino acids are needed to make complete proteins, nine of the amino acids are essential to our diet and “Tryptophan” is one of the nine. By eating combinations of beans with rice or lentils with corn, we can still ingest a complete protein because together they contain all of the amino acids needed to build the proteins of the body. An exception to the incomplete bean protein rule is soybeans, and to the incomplete grain rule is quinoa. Soybeans and quinoa do contain all essential amino acids.
Turkey meat is a protein with a higher than normal amount of the essential amino acid Tryptophan. Tryptophan is not only rare in foodstuffs, it is difficult to digest. As an amino acid it is usually found in protein foods but our body does not absorb it well unless our meal is also high in carbohydrates. During a holiday meal carbohydrates are usually present: mashed potatoes, yams, cranberry sauce and pumpkin pie all supply the high carbohydrates that increase the absorption of the Tryptophan found in the turkey.
Now that we have an idea of what Tryptophan is, what is its relationship to the post-prandial, (after-the-meal) nap? The answer is found in our Pineal Gland.
A hormone is a chemical messenger. Once released into the blood stream by a gland, hormones search out a target tissue and communicate a command to perform a function. The hormones that communicate to our body to wake-up or to fall asleep, both are composed of the amino acid Tryptophan. Insufficient amounts of Tryptophan in our diet can contribute to either insomnia or to fatigue from a lack of alertness. The wake-up hormone is called “Serotonin” to tone the blood-serum. The fall-asleep hormone is called “Melatonin”. You can remember it by the term “mellow-out” however the word actually comes from a Greek word-root that means darkness, “melan”.
The Pineal Gland is a tiny pine-cone shaped gland in the center of our brain. It is symbolized by the “pine-cone” ball at the top of the medical emblem of the double-twined winged rod, the “caduceus”. The Pineal Gland contains light sensing tissue. As the sun rises and light spreads across the earthly globe at dawn, the Pineal Gland senses this light which triggers it to make Serotonin to release into our blood stream and this Serotonin informs us that it is time to wake-up and become active. Conversely, in the evening as light decreases while forming the night, the Pineal Gland changes the Serotonin to Melatonin. Once Melatonin levels are high enough in our blood stream we become drowsy and eventually fall asleep. Artificial light can impair sleep patterns due to its interference in the natural Melatonin release and lack of Winter sunlight can contribute to a type of Depression due to insufficient amounts of Serotonin.
So in the late afternoon with the daylight decreasing, if we celebrate with turkey on the platter which is high in Tryptophan, and combine this with a meal topped by a high carbohydrate bolus of pumpkin pie that will increase our nutritional absorption of the Tryptophan; we provide just the recipe for a holiday snooze.