Tryptophan: characteristics and functions of this amino acid

What are the characteristics of tryptophan and what is its function in the central nervous system?

The tryptophan (L-tryptophan) is an essential amino acid found in various foods, e.g. turkey. Its molecular formula is C11H12N2O2, and it has many functions in the human body.

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

Characteristics of tryptophan

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

The body uses tryptophan to uses tryptophan to synthesize proteins, the B-vitamin niacin and the chemicals serotonin and melatonin. However, in order 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 has begun to be marketed as a dietary supplement for its supposed benefits for mood.. In any case, with respect to this type of product, it has not been demonstrated that it affects tryptophan levels in the Blood in a notable way. Therefore, their results are more than questioned.

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

Excess serotonin stimulation of postsynaptic 5-HT1A and 5-HT2A receptors at central and peripheral levels can have negative consequences for the organism. This is known as serotonergic syndrome and can be life-threatening. Although this syndrome can be caused by taking drugs (e.g. Prozac) or using drugs (e.g. LSD, MDMA, methylphenidate, bath salts...), it is unlikely to be caused by taking tryptophan supplements. However, when combining different substances, special care must be taken.

• Learn more about this topic in our article: "Serotonergic syndrome: causes, symptoms and treatment".

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

Tryptophan is necessary for life, but some studies indicate that too much can 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.

Functions

Let us now learn about 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 found in the blood can reach the brain. At least nine amino acids, including tryptophan, compete with each other 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 pass the barrier. In most foods, tryptophan is found in small amounts, so it has serious difficulties in passing the blood-brain barrier. Now then, it is possible to increase the possibility of crossing the barrier if it is consumed together with carbohydrates.. The latter provoke 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 serotonin synthesis

Serotonin is a chemical substance with which neurons communicate, i.e. a neurotransmitter. Although many think that serotonin is only found in the brain, the central nervous system (CNS) contains only 5% of 5-HT. It is in the small intestine that the rest is produced. This serotonin never reaches the brain, as 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 into serotonin.. As a neurotransmitter, serotonin plays an important role in memory, regulates mood or appetite. Low levels of this neurotransmitter are associated with various pathologies (depression, obsessive compulsive disorder, etc.).

3. Its influence on sleep cycles

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

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

4. The role of tryptophan in niacin production

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.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 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.; López, J.C.; Vargas, J.P. and Salas, C. (1998). Fundamentals of Psychobiology. Laboratory manual. Sevilla: Kronos.
• Streit, W.J. and Kincaid-Colton, C.A. (1996). The brain's immune system. Research and Science. January. 16-21.