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Tryptophan: characteristics and functions of this amino acid

Tryptophan: characteristics and functions of this amino acid

May 9, 2021

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

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

Characteristics of tryptophan

As has been said, tryptophan is an essential amino acid. But what does this mean? Well, your own body can not synthesize it and you have to get it through food . Luckily, tryptophan is found in a wide variety of foods, including meats, nuts, eggs or dairy products.

The body uses tryptophan to synthesize proteins, vitamin B niacin and the chemicals serotonin and melatonin. However, to be able to acquire serotonin thanks to niacin, it is necessary to consume, in addition, iron, riboflavin and vitamin B6.

A good dietary supplement

In recent years, This amino acid has begun to be marketed as a dietary supplement for its supposed benefits for the state of mind . In any case, with regard to this type of products, it has not been shown that they significantly affect blood levels of tryptophan. So their results are more than questioned.

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

The excess stimulation of serotonin on postsynaptic 5-HT1A and 5-HT2A receptors at the central and peripheral levels can have negative consequences for the organism. This is known as Serotonin syndrome and it can be deadly. Although this syndrome can be caused by taking drugs (for example, Prozac) or the use of drugs (for example, LSD, MDMA, methylphenidate, bath salts ...), it is unlikely to happen due to the consumption of drugs. Tryptophan supplements. However, when combining different substances, special care must be taken.

  • Learn more about this subject in our article: "Serotonin syndrome: causes, symptoms and treatment"

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

Tryptophan is necessary to live, but some studies indicate that consuming too much can be counterproductive to health . For example, because it causes a decrease in life expectancy, organ damage and increased insulin resistance.


Next we will know what are the main functions of tryptophan. This amino acid is intimately linked to the correct functioning of the brain and our neurons.

1. The role of this amino acid in the brain

The blood-brain barrier determines which substances that are found in the blood can reach the brain. At least nine amino acids, including tryptophan, compete with each other to access the same support that transports them through this barrier.

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

2. The role of tryptophan in the synthesis of serotonin

Serotonin is a chemical substance with which neurons communicate, that is, a neurotransmitter. Although many think that serotonin is only found in the brain, the Central Nervous System (CNS) only contains 5% of 5-HT. It is in the small intestine where the rest is produced. This serotonin never reaches the brain, because it has other functions, such as regulating the state of contraction of the smooth muscles of the blood vessels.

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

3. Its influence on sleep cycles

After becoming serotonin, the body can use this chemical to produce the hormone melatonin . In this sense, tryptophan helps regulate the sleep-wake cycle, because melatonin regulates the biological clock. The amount of melatonin produced is determined by ambient light: during the day, melatonin levels decrease. Instead, during the night, they increase.

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

4. The role of tryptophan in the production of niacin

The body can transform tryptophan into niacin, also known as vitamin B3 , which is essential to convert food into energy and maintain a healthy nervous system.

Another important vitamin, which helps convert tryptophan to 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 take care of brain health"

Bibliographic references:

  • Afifi, A.K. and Bergman, R.A. (1999). Functional neuroanatomy. McGraw Hill.
  • Hammond (2001). Cellular and Molecular Neurobiology (with CD-ROM). Academic Press.
  • Rodriguez, F .; L√≥pez, J.C .; Vargas, J.P. and Salas, C. (1998). Fundamentals of Psychobiology. Laboratory manual. Seville: Kronos.
  • Streit, W.J. and Kincaid-Colton, C.A. (nineteen ninety six). The immune system of the brain. Research and Science January. 16-21.

Memorize amino acids | amino acid easy tricks to remember (May 2021).

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