Serotonin is a neurotransmitter and hormone found mostly in the digestive system, but also in the brain. It helps with numerous bodily functions, such as sleeping, eating, and digestion. It is also known as the happiness horm one, as it regulates various moods and neurotransmitters in the brain, and a serotonin deficiency can be linked to depression.
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Effect of serotonin
Serotonin is a neurotransmitter and also a hormone. It is found primarily in the digestive system, although it is also found in platelets and throughout the central nervous system, and thus the body. About 95 percent of serotonin production in the body occurs in the gastrointestinal tract, with the remaining 5 percent produced in the brain, where it transmits signals between nerve cells.
Serotonin owes its name to its existence in platelets and blood serum and its effect on the tone of blood vessels, or blood pressure.
It is produced from the essential amino acid tryptophan. This amino acid must be supplied through the diet and is commonly found in foods such as nuts, cheese and red meat. Tryptophan deficiency prevents serotonin production and can lead to serotonin deficiency. This in turn leads to mood disorders such as anxiety or depression.
Serotonin affectsevery part of thebody. It affects emotions and overall performance, is considered a natural mood stabilizer, and is therefore also known as the happy hormone. It is the substance that helps with sleeping, eating and digesting.
Serotonin performs the following tasks in the body and brain:
Mood: Serotonin is responsible for regulating anxiety, happiness, and other feelings. Low levels or lack of serotonin are associated with depression. It is found primarily in the stomach and intestines of the body and helps regulate your bowel movements and related functions. It is the reason why we feel nauseous. Production increases to get rid of harmful or irritating foods faster when you have diarrhea. Furthermore, it can be converted into the sleep hormone melatonin. Melatonin controls the day-night rhythm and a serotonin deficiency can therefore possibly lead to sleep problems.
Blood clotting: platelets release serotonin to heal wounds. It causes small arteries to narrow, causing blood clots to form.
Bone health: it also plays a role in bone health. Significantly high levels of serotonin in the bones can lead to osteoporosis, which makes the bones weaker.
Serotonin syndrome is a potentially life-threatening syndrome that can be triggered by the use of serotonergic medications and drugs. A variety of combinations can lead to serotonin syndrome. It can occur when very high levels of serotonin are induced over a long period of time by misuse of medications or drugs. The very sensitive serotonin system then no longer functions properly with a normal serotonin level. Depression, insomnia, anxiety, panic attacks and much more can then be the result.
Serotonin and depression - serotonin deficiency
A 2007 study found that people with depression often have low serotonin levels, which leads to a serotonin deficiency. Anxiety and sleep disturbances are seen as symptoms of serotonin deficiency.
Minor disagreements exist about the role that serotonin levels play in mental health. Some researchers in older studies question whether an increase or decrease in serotonin can affect depression. However, recent research claims that there may very well be an influence. A 2016 animal study examined mice that lacked serotonin autoreceptors. These inhibit serotonin secretion and without these receptors, the mice had higher levels of serotonin in their brains. Researchers found that these mice exhibited less anxiety and depression behaviors than, for example, mice that were serotonin deficient.
Influence on cognition
Cognition refers to all thought and perception processes, such as the functioning of long-term and short-term memory, conscious learning and remembering, language and speech recognition, or the making of decisions and judgments.
The serotonergic system forms a diffuse network within the central nervous system and plays an important role in the regulation of mood and cognition. Some studies show that serotonin deficiency is associated with poor memory and depression.
Clinical studies have shown that serotonin improved reaction times, attention levels, and both abstract visual memory - and face recognition memory. Furthermore, in elderly patients suffering from mild cognitive impairment, serotonin levels were increased by administration of serotonin precursors such as tryptophan. They reported significant improvements in cognitive function. However, it cannot be proven that the positive effect is only due to serotonin levels.
Serotonin and sleep
A 2016 study shows that serotonin levels have direct effects on sleep. Improved sleep quality is also associated with improved cognitive abilities, improved morning alertness, and higher brain attention spans.
Prolonged REM sleep has also been demonstrated, with further animal studies demonstrating the importance of serotonin in this context. Thus, it is also a precursor to melatonin in the pineal gland.
Serotonin deficiency occurs when the body does not have enough of it. The serotonin deficiency cause is different for each person and is associated with a range of physical and psychological symptoms.
It is important to remember that the role of serotonin deficiency, especially the psychological ones, is not fully understood. For example, the association of serotonin deficiency with depression is often still debated. However, it is certain that the function of serotonin is much more complex than previously thought and has an influence on, among other things, nerve cells and the body as a whole.
You can detect a serotonin deficiency by a range of psychological and physical symptoms:
Psychological serotonin deficiency symptoms can include:
Physical symptoms of serotonin deficiency can include:
Furthermore, serotonin deficiency seems to affect men and women differently. It was found in a 2017 study that reduced serotonin levels caused depression and other mood swings in women. Male participants, however, became more impulsive and did not notice mood swings.
The normal range of serotonin levels in the blood should be 101-283 nanograms per milliliter (ng / ml). However, this benchmark may vary slightly depending on the measurements and samples tested. It is best to discuss this with a medical specialist. However, measuring your own serotonin can also be done from the comfort of your own home.
The serotonin level is determined via the urine and is also used in modern laboratory diagnostics. A keyword for this is neurostress profile.
The urine test is an important instrument especially in cases of depression and burnout syndrome.
The results serve as a basis for an individual therapy with serotonin precursors (L-tryptophan or 5-HTP) and the co-factors.
The idea that changes in thinking - either by oneself or through psychotherapy - can alter metabolism in the brain is not new. Numerous studies have already shown changes in blood flow under such circumstances. In a recent study, meditation was reported to increase the release of dopamine. The study by Perreau-Linck and his colleagues is the first to report that self-induced mood swings can affect serotonin production. This raises the realization that the interaction between serotonin synthesis and mood may be two-way. That is, serotonin deficiency affects mood and this in turn affects serotonin levels. Obviously, more research is needed to answer all the questions in this area - for example, whether mood improvement associated with psychotherapy is accompanied by an increase in serotonin synthesis. When more detailed information is available on how to remedy serotonin deficiencies and stimulate production, this will help improve modern therapeutic techniques.
Light is a standard treatment for seasonal depression, but some studies also suggest that it can be an effective treatment for non-seasonal depression. Many studies show a link between light and serotonin levels, and it is independent of the time of year. The determining factor is the number of hours of sunlight, which of course is usually higher in the summer. In rats, serotonin is highest during the light part of the light-dark cycle. In humans, there is certainly an interaction between bright light and the serotonin system.
Just a few generations ago, most of the world's population was farming and outdoors all day. This had led to a heavy exposure of the body to bright light even in winter. Even on a cloudy day, the light outside can exceed 1000 lux. This is a level that is normally never reached indoors. In a recent study conducted at about 45 ° N, daily light exposure at more than 1000 lux averaged about 30 minutes in the winter and only about 90 minutes in the summer for people who worked at least 30 hours a week - weekends included. In this group, summer bright light exposure was probably still much lower than the winter exposure of our agricultural ancestors.
Lamps providing more lux than normal indoor lighting designed to treat seasonal serotonin deficiency are now available. However, using them in a daily routine presents challenges. Public strategies are now available, e.g. "Light Cafes" pioneered in Scandinavia are now available in the UK and an Austrian village that gets no sunshine in winter because of the surrounding mountains is building a series of giant mirrors to reflect sunlight down into the valley. Better use of daylight in buildings is a big issue that architects are becoming increasingly aware of.
Regular exercise is another way to offset serotonin deficiency. A comprehensive study reviewing the relationship between physical exercise and mental well-being found that antidepressant effects have been clearly demonstrated. In the United Kingdom, the National Institute for Health has published a guide to the treatment of depression. The guide recommends treating mild clinical depression with a variety of strategies, including exercise as an antidepressant, because the risk-benefit ratio for using antidepressants in patients with mild depression is poor.
Exercise improves mental well-being, as demonstrated by a group who were given regular aerobic exercise in an environment and level familiar to them. However, scepticism remains about the antidepressant effects of exercise and the National Institute of Mental Health in the US is currently funding a clinical trial into the antidepressant effects of exercise. Several lines of research suggest that exercise increases brain serotonin function. As noted by Jacobs and Fornal, motor activity increases the firing rate of serotonin neurons and this leads to increased release and synthesis.
Whether motor activity increases the firing rate of serotonin neurons in humans, as it does in animals, is not known. However, it is clear that aerobic exercise is mood enhancing. As with exposure to bright light, there was a big change in the intensity of physical activity as humans were hunters or gatherers or engaged primarily in agriculture.
Another factor that may play a role in increasing brain serotonin is diet. According to some evidence, tryptophan, which increases brain serotonin in both humans and experimental animals, is an effective antidepressant for mild to moderate depression. In healthy people with high irritability, it also increases empathy and decreases argumentativeness.
However, whether tryptophan should be considered as a monopreparation or rather foods containing tryptophan is a point of contention. Although purified tryptophan increases serotonin levels, foods with tryptophan do not. This is because tryptophan is transported to the brain by a transport system that is active for all major neutral amino acids, and tryptophan is the least abundant amino acid in protein. There is competition between the different amino acids for the transport system, so that after eating a meal containing protein, the increase in plasma levels of the other major neutral amino acids will prevent plasma tryptophan from increasing brain tryptophan.
The popular culture idea that a high-protein food like turkey will boost tryptophan and serotonin is unfortunately false. Another popular myth circulating on the internet is that bananas improve mood because of their serotonin content, which does not cross the blood-brain barrier. Α-Lactalbumin, a small component of milk, is a protein that contains relatively more tryptophan than most proteins. Ingestion of α-lactalbumin may improve mood and cognition in some circumstances, presumably due to increased serotonin levels.
5-Hydroxytryptophan (5-HTP) is an amino acid that the body produces naturally. 5-HTP is the direct precursor of serotonin and requires so-called co-factors for conversion. For this reason, 5-HTP supplements have become increasingly popular.
5-HTP in supplements can either be synthetically produced or, and this is the rule, extracted from the Griffonia simplicifolia (African black bean) plant. There are extracts with varying dosages. The highest dosage is a 98% extract - so it contains 98% 5-HTP.
The effects of 5-HTP on depression symptoms have been well studied. While the exact cause of depression is largely unknown, some researchers believe that a serotonin deficiency or excess can affect mood in a way that leads to depression. It is believed that 5-HTP supplements can positively affect depression by increasing serotonin levels. In fact, several small studies have shown that 5-HTP can reduce symptoms of depression. Similarly, another study concluded that 5-HTP may help treat depression.
However, much of the research suggests that the potential antidepressant effects of 5-HTP are stronger when combined with other substances or antidepressants than when used alone. This means that combination supplements may be more effective than a mono-supplement. It has been concluded that there may be great potential in 5-HTP and further, larger studies are needed. Bottom line: supplements increase serotonin levels in the body, which may improve depression symptoms, especially when used in combination.
If ingested, none of it would reach the brain because it cannot cross the blood-brain barrier. This is a natural protective mechanism of our body.
Many compounds act as co-factors in basic metabolic pathways.
Vitamin B6 (pyridoxine) is necessary for the biosynthesis of several neurotransmitters. Its concentration in the brain is usually about 100-fold higher than in the blood. The active coenzyme is the phosphorylated derivative pyridoxal phosphate. This coenzyme is involved in decarboxylation reactions that, for example, converts 5-hydroxytryptophan to 5-HT.
Zinc influences numerous cellular functions, including immune mechanisms, effects of several hormones, and enzyme activities. More than 200 enzymes are known to depend on it. Together with pyridoxal phosphate, it is involved in many metabolic processes - including decarboxylation reactions in serotonin synthesis.