Tryptophan: characteristics and functions of this amino acid

the tryptophan (L-tryptophan) is an essential amino acid found in different foods, for example turkey. Its molecular formula is C11H12N2O2, and in the human body it performs many functions.

In this article we will review its characteristics, functions and foods that contain it.

Characteristics of tryptophan

As mentioned, tryptophan is an essential amino acid. But what does that mean? so that the body itself cannot synthesize it and this has to be achieved through food. Fortunately, tryptophan is found in a variety of foods, including meats, nuts, eggs, and dairy products.

the body uses tryptophan to synthesize protein, vitamin B, and niacin and the chemicals serotonin and melatonin. However, to acquire serotonin from niacin, it is also necessary to consume iron, riboflavin, and vitamin B6.

A good dietary supplement

In recent years, this amino acid began to be marketed as a dietary supplement due to its purported benefits for mood.. In any case, with regard to this type of product, it has not been shown to significantly affect the levels of tryptophan in the blood. Their results are therefore more than questioned.

However, some studies claim that tryptophan supplements may be effective as a sleep remedy and as an antidepressant. These results are associated with its role as a serotonin and melatonin synthesizer.

Excessive stimulation of serotonin on postsynaptic 5-HT1A and 5-HT2A receptors at the central and peripheral level can have negative consequences for the organism. This is known as serotonin syndrome and can be fatal. Although this syndrome can be caused by taking medication (eg Prozac) or the use of medication (eg LSD, MDMA, methylphenidate, bath salts …), it is unlikely that it occurs due to the consumption of tryptophan supplements. However, when combining different substances, special care should be taken.

  • Read more on this topic in our article: “Serotonin Syndrome: Causes, Symptoms and Treatment”

Is it possible to get a lot of tryptophan through food?

Tryptophan is necessary to live, however some studies indicate that excessive consumption can be counterproductive for health. For example, because it leads to decreased life expectancy, organ damage and increased insulin resistance.

the functions

Below we will find out what are the main functions of tryptophan. This amino acid is closely linked to the proper functioning of the brain and our neurons.

1. The role of this amino acid in the brain

The blood brain barrier determines which substances in the blood can reach the brain. At least nine amino acids, including tryptophan, compete for access to the same carrier that transports them across this barrier.

Amino acids that are present in greater amounts in the blood are more likely to cross the barrier. In most foods, tryptophan is found in small amounts, so it has serious difficulty crossing the blood-brain barrier. however, it is possible to increase the possibility of crossing the barrier if it is consumed with carbohydrates. These cause the release of insulin, which reduces the amount of other amino acids in the blood without affecting tryptophan levels.

2. The role of tryptophan in the synthesis of serotonin

Serotonin is a chemical that neurons communicate with, that is, a neurotransmitter. Although many believe that serotonin is only found in the brain, the central nervous system (CNS) contains only 5% 5-HT. The rest is in the small intestine. This serotonin never reaches the brain, as it has other functions, such as regulating the state of smooth muscle contraction in blood vessels.

In the brain, serotonin is essential. Once tryptophan reaches the brain, it is converted into serotonin. As a neurotransmitter, serotonin plays an important role in memory, by regulating mood or appetite. Low levels of this neurotransmitter are associated with various pathologies (depression, obsessive-compulsive disorder, etc.).

3. Its influence on sleep cycles

Then convert to serotonin, the body can use this chemical to produce the hormone melatonin. In this sense, tryptophan helps regulate the sleep-wake cycle, since melatonin regulates the body clock. The amount of melatonin produced is determined by ambient light: during the day, melatonin levels drop. Instead, overnight they increase.

Melatonin supplements help improve sleep problems, such as those caused by jet lag.

4. The role of tryptophan in the production of niacin

The body can convert tryptophan into niacin, also known as vitamin B3, Which is essential for converting food into energy and maintaining a healthy nervous system.

Another important vitamin, which helps convert tryptophan into serotonin, is vitamin B6. Vitamin B6 deficiency can cause confusion, depression, memory loss, a faster rate of brain degeneration, difficulty paying attention, fatigue, and insomnia.

  • Learn more about the relationship between vitamins and the brain in our article: “6 Vitamins to Support Brain Health”

Bibliographical references:

  • Afifi, AK and Bergman, RA (1999). Functional neuroanatomy. McGraw Hill.
  • Hammond. (2001). Cellular and molecular neurobiology (with CD-ROM). Academic press.
  • Rodriguez, F .; Lopez, JC; Vargas, JP and Sales, C. (1998). Fundamentals of psychobiology. Laboratory manual. Seville: crowns.
  • Streit, WJ and Kincaid-Colton, CA (1996). The brain’s immune system. Research and science. Gener. 16-21.

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