Tryptophan: The Sleepy Culprit?

With the holidays approaching you may have heard someone mention tryptophan (pronounced “trip-to-fan”). Tryptophan is an essential amino acid (building block of protein) that is found in turkey and other foods. Since tryptophan cannot be synthesized by the human body, we must obtain tryptophan from food sources or supplements. Because of tryptophan’s role in producing the neurotransmitters serotonin and melatonin in the body, it is often blamed for a person’s post Thanksgiving “food coma”. Interestingly enough, it is not that simple. Let’s dive in and learn more about tryptophan!

As I mentioned before tryptophan plays a role in producing serotonin and melatonin, two neurotransmitters that regulates a person’s sleep cycle. There are actually many foods other than turkey that contain tryptophan, such as salmon, eggs, and chocolate to name a few. Turkey does not contain an overabundance of tryptophan compared to other protein rich foods. Protein rich foods contain a variety of amino acids, which are all looking to be absorbed by the body. As the various amino acids travel the bloodstream, they must be shuttled via specialized transporter proteins in order to reach the brain. Tryptophan and the other amino acids are essentially in a competition when attempting to reach the brain. Because of the transport process, the brain usually does not receive enough tryptophan at one time to induce the sleepiness it often gets blamed for. However, if a person takes tryptophan supplements, melatonin production will increase which may cause sleepiness. Since the supplement is pure tryptophan, it has no competition with other amino acids in reaching the brain.

So now you might be wondering, what does make me sleepy after a large, delicious holiday meal if tryptophan is not necessarily the culprit? There can be many reasons based on the person’s health status and types of food eaten. One of the most common reasons the average person may feel tired after consuming a large meal is because the digestive system requires a large amount of blood to function adequately when lots of food is present. The amount of blood allocated to the digestive system in addition to the digestion system working hard to digest food may make a person feel tired. A meal full of carbohydrates may also cause a person to feel tired. Certain carbohydrates cause a rapid rise in blood glucose levels. The body responds by secreting insulin quickly in order to store or prepare the glucose for the body to use. Once the insulin addresses the glucose, the person’s blood glucose levels drop rapidly, causing tiredness. Simple carbohydrates or an overabundance of carbohydrates causes blood sugar levels to vacillate compared to complex carbohydrates.

While tryptophan may cause a person to be tired after a meal, it is not the only culprit. Some recommendations for not feeling tired after eating include eating a well balanced meal with carbohydrates, proteins, and fats and exercising portion control.