Serotonin, the hormone of good mood

Serotonin is involved in many biological processes that have both physical and psychological repercussions.

Isolated for the first time in the 30s of the last century by the Italian scholar Vittorio Erspamer, this substance has been, and continues to be, the subject of research and analysis of science and medicine. Since the day of its discovery, its importance has grown progressively: today researchers investigate its effects at the level of the central nervous system, in an attempt to reconstruct its functioning mechanism and thus understand the causes of various pathologies and disorders.

What is serotonin

Often called the hormone of well-being or happiness, serotonin is a neurotransmitter synthesized in the brain and other tissues from the essential amino acid tryptophan, a protein molecule taken primarily through the diet.

Present in various areas of the central nervous system, it is a sedative substance produced by some so-called serotonergic neurons, which shows a direct relationship with mood levels and other functions of the body.

As with all chemical mediators, serotonin, to allow the transmission of information from one neuron to another, binds to various receptors so as to play a different role depending on the cells with which it interacts, and the part of the body in which it is present. Many of the biological functions of serotonin (as well as the functions of as many as 14 serotonin receptors) are not yet fully understood.

The following table shows the main physical and psychological effects of this hormone.

How serotonin acts on the body

Variously distributed between the enterochromaffin cells of the intestine (in which the highest concentration is found, almost 90%), platelets, the pineal gland and obviously brain cells, serotonin performs various functions both physically and mentally.

On the organic level, it is mainly involved in bone metabolism, appetite and the regulation of the sleep-wake rhythm.

Here are some of its main functions:

– regulates appetite, as it acts in the control of appetite and eating behavior, contributing to the sense of satiety;

– regulates circadian rhythms: as a precursor of melatonin, serotonin synchronizes the sleep-wake cycle with daily endocrine fluctuations, so an excessive level of this neurotransmitter can cause insomnia;

– regulates body temperature;

– safeguards bone health: in fact, people who take serotonin reuptake inhibitor antidepressants (so-called “selective serotonin reuptake inhibitors” or SSRIs) may see their bone density reduced;

– during childhood, regulates the production of growth hormones;

– regulates motility and intestinal secretions, improves digestion and reduces nausea. Serotonin is mainly produced by the intestine, in which there is a large amount of cells that secrete it (the aforementioned enterochromaffin cells). An excess of serotonin causes nausea, vomiting and diarrhea, while a reduced amount produces constipation: this also explains why psychic stress often shows repercussions on intestinal motility. Moreover, in case of intestinal inflammation the production of this hormone is altered with important psychophysical consequences;

– acts on the contraction of the arteries, contributing to the control of blood pressure and thus preventing hypertension;

– stimulates the contraction of the smooth muscles of the bronchi and bladder;

– stimulates the aggregation of platelets, exerting a vasoconstrictor activity;

– reduces sensitivity to pain and prevents migraines.

Action on stress and well-being

The most well-known effects of serotonin are those on mood and in general on the psyche.

Changes in the levels of this substance are associated with mental imbalances such as, for example, schizophrenia.

Here are some psychic effects of serotonin:

– if it is present at adequate levels, it produces a feeling of pleasure and well-being. It is no coincidence that some drugs that increase the release of serotonin or target the activity of its receptors, such as ecstasy, induce euphoria, make sociable and increase the sense of self-esteem. When, on the other hand, levels are reduced, for example in times of stress, anxiety disorders and episodes of psychophysical tension can be triggered.

– at moderately high levels it increases sexual desire, while at low levels it is responsible for its decrease.

– regulates anger and aggression.

In case of stress, the body is activated by increasing the secretion of certain hormones and inhibiting that of others. To undergo the first effects of this alteration are substances such as dopamine, norepinephrine and serotonin, whose reduction influences all the processes in which this substance is involved.

Protects our neurons

Serotonin also performs a protective function against neurons: this was illustrated by a study by the University of Pisa published in the journal eNeuro. In practice, the researchers have shown how, by inactivating the synthesis of serotonin in the brain of an adult individual, evident alterations are produced that, when the production of serotonin is restored, disappear. These results explain once again how an imbalance in the levels of this important neurotransmitter can contribute to the onset of neuropsychiatric diseases such as mood disorders.

Serotonin affects memory and mood

It is no coincidence that another study, conducted in the United States at Johns Hopkins University, has shown that in patients with a mild loss of thought and memory in the early stage of Alzheimer’s disease, lower amounts of serotonin are identifiable.

According to the researchers, who used positron emission tomography (PET) brain scanning to examine serotonin levels, the results suggest that serotonin deficiency may be a factor linked to the onset of the disease.

The research, published in Neurobiology of Disease, therefore hypothesizes that preventing serotonin loss may slow or stop the progression of Alzheimer’s and other dementias.

Many other studies have already shown how different cognitive disorders can be involved in these mechanisms. Even autism (a complex neurodevelopmental disorder characterized by impaired social interaction, deficits in the ability to communicate, and repetitive behaviors) seems to be linked to serotonin levels. During the 60s of the last century, scholars had found that, in at least one case out of three, this disorder was accompanied by an abnormal increase in serotonin production; while, in recent years, to verify this hypothesis, some American researchers have analyzed mice lacking brain serotonin, in which they have observed the presence of typical symptoms of this pathology.

What to do to stimulate serotonin production

If, therefore, many biological factors affect the levels and production of serotonin, so much so that with the same environmental stimuli some people are more likely than others to develop mood disorders, it is still possible to do something to regulate the levels of this substance.

In terms of lifestyle it can be useful:

– practice regular relaxation exercises, which help us eliminate stress, such as yoga;

– carry out pleasant activities that make us feel good;

– sunbathing;

– sleep well, constantly and uninterrupted as it helps maintain the right balance of our serotonin levels;

– practicing sports: for some time numerous studies have shown that sport (when it is practiced recreationally, with fun and pleasure, and never as an imposition) stimulates the production of molecules that promote good mood, such as endorphins or serotonin. Physical activity directly counteracts stress also because it reduces cortisol levels in the blood: an excellent idea is to practice it outdoors, thus benefiting from sunlight so important to ensure good mood levels. It is therefore no coincidence that many studies have shown a higher risk of anxiety, panic disorder and depression in sedentary people, in whom a lower ability to uptake serotonin is identifiable;

– Practice meditation: relaxing trying to let the mind free is beneficial for mood and stimulates the production of serotonin.

Healthy life and physical activity, therefore, are able to stimulate the release of serotonin and, thus, contribute to the maintenance of health and well-being of the psycho-physical system, but can be considered insufficient, if they are not accompanied by adequate diets.

Keep an eye on nutrition

A first step to feeling good by regulating serotonin levels is to take care of the diet.

Improving mood by acting on serotonin is possible, introducing foods with low caloric density, rich in tryptophan, but poor in other amino acids. However, there are few foods of this type: for example, these are some fruits, such as papaya, bananas and dates, but milk, eggs (especially yolks), cocoa and dark chocolate are also rich in them.

In general, foods rich in proteins or carbohydrates such as vegetables, nuts, legumes and whole grains are fine: the brain requires sugars to synthesize tryptophan.

On the contrary, we should avoid foods rich in saturated fats and simple sugars, such as snacks and sweets, while foods rich in omega3 (whose main source is fish) that guarantee proper brain functioning are excellent. Finally, limit the consumption of caffeine.

Natural remedies and supplements

A help also comes from phytotherapeutics, such as extracts of Rhodiola Rosea that improves mood, promotes the synthesis of serotonin, increases resistance to psychophysical stress and reduces stress tachycardia while promoting weight loss. Griffonia, on the other hand, can be a natural ally in the treatment of intestinal disorders or in particularly intense periods. Rich in a precursor of serotonin, this plant is useful in case of fatigue and gastrointestinal neurodysbiosis, or an alternation of intestinal bacterial flora caused by an imbalance of serotonin.

Under medical supervision, to avoid possible side effects and undesirables, it is also possible to take tryptophan supplements: useful as antidepressants, they are a valid aid against insomnia. Alongside these supplements, other more specific ones can help rebalance serotonin levels, for example those based on chromium, which helps metabolize food and acts precisely on serotonin and melatonin, regulating emotions and mood. Chromium is abundant in broccoli, grapes, potatoes and turkey meat.

Even folic acid (i.e. vitamin B9), whose properties are increasingly appreciated, helps regulate serotonin: in fact, low levels of this vitamin can cause fatigue and, at the same time, lower those of serotonin. It is no coincidence that folic acid together with vitamin B12 are often used as supplements in depressed patients. In nature they are mainly found in vegetables of green color: spinach, asparagus, avocado and Brussels sprouts.

Magnesium, whose deficiency can cause irritability, fatigue, mental confusion and predisposition to stress, is useful for brain functions, ensures good sleep quality and plays an important role in the production of serotonin. It is found in almonds and peanuts, as well as in many supplements on the market today.