Frequently referred to as the body’s “happy” or “feel-good” chemical, serotonin actually has a broad range of roles beyond its contribution to wellbeing and happiness.
Serotonin is certainly key to mood regulation, with normal levels of this neurotransmitter or hormone helping to ensure you remain happy, calm, focused and emotionally stable.
But it would also be selling serotonin short to not acknowledge how it impacts on various other bodily functions, ranging from bowel movements and nausea to blood clotting and sexual function.
How and where is serotonin made?
Nerve cells produce serotonin, the scientific name of which is 5-hydroxytryptamine or 5-HT, via a unique biochemical conversion process. Tryptophan, a component of proteins, is combined with the chemical reactor tryptophan hydroxylase, resulting in serotonin.
Tryptophan is a building block to proteins and an essential amino acid that can only be obtained through the diet; good food sources include the likes of cheese, nuts and red meat.
Inadequate levels of tryptophan in the body can lead to reduced serotonin levels. This, in turn, has been linked to mood disorders like anxiety and depression, as we explore in greater detail below.
What does serotonin do?
Although serotonin is mainly present in the brain, bowels and blood platelets, it also occurs throughout the body. It is thought to be key to the central nervous system (CNS) and general bodily function, influencing most of the brain’s cells both directly and indirectly, as well as every other part of the body.
This neurotransmitter’s impact on mood is surely its “headline” effect; while it is by no means the only brain chemical that provides vital support to your all-round wellbeing, its role in regulating mood is an important one. Indeed, medications designed to treat mood disorders often target serotonin.
But serotonin is also influential in digestion, for example, by supporting normal bowel function and lowering your appetite as you eat to indicate that you’re full. Furthermore, there is a link between serotonin and nausea, as the gut produces more serotonin if you eat something irritating or toxic, in order to accelerate its transit and expel the irritant in diarrhoea.
The chemical also contributes to the formation of blood clots, being released by the blood’s platelet cells to help heal wounds, and past research has even pointed to a potential influence on bone density – in other words, the strength of your bones.
As aforementioned, serotonin is also associated with sexual function, due to the influence it can exert on the intensity and frequency of your sexual feelings. Indeed, there is thought to be a connection between elevated levels of serotonin and decreased libido.
So, what about serotonin’s link to depression?
It has long been thought that serotonin is associated with depression in some way, given its status as a “happy chemical” and the fact that various risk factors for depression – such as experiencing difficult life events and having a family history of mental illness – can cause an imbalance of serotonin in the brain.
Sure enough, research has suggested that higher levels of serotonin in the brain are associated with happiness and elevated mood, while lower levels can often co-exist with common symptoms of depression, such as feeling sad and upset.
This is not necessarily to suggest that low serotonin causes depression, or that depression causes lower serotonin levels. The relationship between the two is still being studied in the hope of making important breakthroughs in how we seek to prevent and treat mood disorders like depression and anxiety.
Nonetheless, if all of the above should suggest something to us, it is that serotonin is highly influential in the body, and ensuring we have adequate levels of it ought to be one of our most pressing health priorities.