Serotonin is a natural chemical in the body that facilitates communication between nerve cells (neurons). Serotonin is made from the amino acid tryptophan and can only be acquired through diet in red meat, nuts, and cheese. Also referred to as 5-hydroxytryptamine, serotonin naturally occurs in the body and is mostly present in the digestive system. The intestines produce most of the body’s supply, since it aids in digestion. The brain is also responsible for 10 percent of all production.
Serotonin is known for its mood-regulating functions. It promotes happiness and a feeling of well-being. It also helps manage anxiety and depression, and aids in sexual function, sleep, blood clotting, and bone health.
Serotonin’s function in the brain is perhaps its defining role. In fact, it’s commonly called the “feel-good” hormone and is one of the chemicals that help regulate brain chemical activity. So profound is its effect on the brain that some medications that treat anxiety, depression, and other mood disorders directly target serotonin. These include SSRIs (selective serotonin reuptake inhibitors), which are antidepressants.
The hormone also controls bowel functions. It helps trigger the brain when someone has taken in enough food so that they don’t overeat. Besides, it helps to flush out harmful elements in the gut. It does this by making the intestines produce more of it to eliminate the unwanted food. Notably, too much serotonin has a nauseating effect, so drugs targeting serotonin receptors are used to treat vomiting and nausea.
Again, increased serotonin levels can elevate sexual desire. Hence, some antidepressants that trigger serotonin production are known to affect libido. Additionally, its mood-altering effects ease tension, which is key to sexual arousal. This effect on libido is linked to serotonin’s relationship with dopamine, another hormone that affects how human beings experience pleasure.
The parts of the brain responsible for sleep function have serotonin receptors, meaning the hormone affects sleep behavior. However, scientists are not clear about the precise role serotonin plays in falling asleep, waking up, and sleep patterns. Nonetheless, researchers believe that serotonin affects the quality and quantity of sleep, working with dopamine and melatonin to facilitate sleep function. Melatonin is well known to control sleep cycles, and the body needs serotonin to produce it. Therefore, melatonin deficiency means there is also a likely serotonin deficiency.
Blood clotting involves several physiological processes. Among them is blood vessel narrowing, also known as vasoconstriction. When a person gets a cut and begins bleeding, the body must stop the blood flow to enable the wound to heal. Serotonin causes the arterioles, which are small arteries, to narrow, leading to decreased blood flow.
Serotonin also affects bone health, though in a negative way. Increased levels have been linked to low bone density and osteoporosis, a health condition where the bones become fragile and susceptible to fractures. Studies have also reported that SSRIs may lead to insufficient bone minerals. For a patient taking such medication, it is important to continue with their dosage and discuss with a doctor regarding other risk factors, including family history and smoking.
Serotonin deficiency may lead to depression and other mood disorders. However, other factors can of course come into play. Nonetheless, insufficient serotonin may affect mood, sleep, and digestive disorders. There is no sole reason for serotonin deficiency. It may be caused by the body not producing enough of it. It may also result from ineffective serotonin usage, such as when the brain has few serotonin receptors. Finally, tryptophan deficiency leads to low serotonin levels.
