Serotonin: Definition, Function, & Boosters

Serotonin: Definition, Function, & Boosters

Read this article to learn the definition and function of serotonin as well as how to increase your well-being by boosting your serotonin levels.

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Serotonin is one of the most important neurotransmitters in our bodies – important enough that you’ve probably heard of it before, probably in the context of discussions of mental health concerns such as depression or anxiety. But you may not be aware of just what serotonin is and how essential it is to the healthy functioning of your body.​

What Is Serotonin? (A Definition)

Serotonin Function

Serotonin in the Gut

Perhaps you have read some of the new research describing how closely related our brains and our guts are. Serotonin is no exception to this finding! Fully 95% of the serotonin in your body develops and is stored in your gut (Furness & Costa, 1982). Your gastrointestinal tract creates serotonin by converting tryptophan, an amino acid in the foods that you eat, into serotonin.
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In addition to impacting how much serotonin the rest of your body gets, the serotonin in your gut is important for healthy gut functioning (Gershon & Tack, 2007). In experiments with animals, changing the amount of serotonin in their intestines has caused changes in their gut microbiome and caused inflammation in the gut (Ghia et al., 2009).

Serotonin vs Dopamine

Serotonin and dopamine are both very important neurotransmitters, but their roles and functions in the brain and body are different. For the brain, dopamine is a “reward” chemical, involved in telling us what to pay attention to and work toward (Conio et al., 2020). Having more dopamine in your system generally means you are going to easily concentrate on what would be rewarding to you.

By contrast, serotonin’s role in the brain seems to be related to the regulation of negative thoughts and emotions (Dayan & Huys, 2008). Serotonin’s role may be to help us shift away from negative patterns – without enough serotonin in key regions of our brain, we may have a hard time saying to ourselves, “I’m really stuck in a spiral of negative feelings. I should go talk to a friend or do something to distract myself.”
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In summary, you can think of dopamine and serotonin as the “happy” neurotransmitters. Just keep in mind that one of them – dopamine – enables us to feel pleasure, while the other – serotonin – helps us avoid negative thoughts and feelings.

Serotonin and Depression

Serotonin Deficiency

Where does this serotonin deficiency come from? As you might have expected, there is some evidence that suggests that our genes play a role. People whose genetic code features less effective versions of certain serotonin-related genes may have a harder time generating, maintaining, and moving around serotonin (Zhang et al., 2005). If you have heard that depression runs in families, well, that’s right – less effective serotonin processing can be hereditary.

Serotonin deficiency can also result from an invalidating, stressful, or consistently negative environment (Cowen & Browning, 2015). And as with almost all biological and psychological topics, serotonin deficiency can grow through epigenetic pathways.

What does this epigenetic pathway look like? Imagine you are born with a risk of low serotonin because of your genes. You find it hard to transition out of negative thought patterns and feelings. This makes it harder to have positive and meaningful experiences over time. Without those positive experiences, your serotonin levels are unlikely to go up – in fact, they may even go down further.
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Unfortunately, this pattern is experienced by many people with depression. Knowing this can help us understand how brain chemistry makes it so hard for people with mental health disorders to heal. Nobody can force themselves, just of their own will, to have more serotonin where they need it. Thankfully, there are many tools available to people who might be experiencing abnormal levels of serotonin.

Serotonin Reuptake Inhibitors

Psychiatric drugs that increase the amount of available serotonin are the best available form of medication for addressing depression and anxiety (Hoffman & Mathew, 2008). Of these, selective serotonin reuptake inhibitors (SSRIs) are the most commonly prescribed and used. SSRIs get their name from their function: they stop the reuptake of only serotonin, and not other neurotransmitters.
 
What does reuptake mean? Remember how neurotransmitters can either stay with the new neuron, return to the old neuron, or hang out in between them? SSRIs make sure that reuptake – going back to the original neuron – happens less often, and that serotonin stays in the space between the neurons instead. This makes it easier for communication between the neurons to keep happening.
 
SSRIs were first introduced as a psychiatric drug in the 1980s, and since then, many research studies have attested to how effective they can be in treating depression and anxiety, even to the point of causing permanent, positive changes in the brain’s serotonin pathways (Sharp & Cowen, 2011). However, they are often less effective for people who are severely depressed or who have many genetic risk factors for low serotonin (Uher et al., 2014).
 
For a visual demonstration of how SSRIs work, watch the following video:

Video: Selective Serotonin Reuptake Inhibitors (SSRIs)

Serotonin Boosting Foods

Serotonin Supplements

Serotonin Overdose

Outside of consuming psychiatric medications, it is extremely unlikely for a person to have too much serotonin in their system. But people who are taking SSRIs can experience what is called “serotonin syndrome”, which typically involves symptoms such as shivering and diarrhea, but can also include fever, tightening of the muscles, and even seizures.
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However, serotonin syndrome occurs mostly when individuals increase their SSRI dosage or are prescribed other drugs to take at the same time as their SSRIs, such as during a hospital visit (Isbister et al., 2007). In other words, a serotonin overdose won’t be a concern for most people, and even people taking SSRIs should be fine, as long as they follow their doctor’s orders and don’t take drugs (legal or illegal) that they haven’t been prescribed.

Articles Related to Serotonin

Books Related to Serotonin

Final Thoughts on Serotonin

The more we learn about serotonin, the clearer its vital role in regulating our minds and bodies becomes. If you think you might be experiencing the symptoms of somebody with low serotonin levels, I encourage you to talk to your primary care physician. If you are curious about serotonin supplementation, know that the risks appear to be minimal, and the upsides considerable.
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Either way, talk to a healthcare professional you trust. Serotonin is far from the only factor in depression, anxiety, gut health, and the other health concerns discussed in this article. Only a professional can best determine whether your needs are best met by addressing your serotonin levels or by some other intervention.

References