Why Serotonin Is Important for Happiness

Photo by Jackson David on Unsplash

Serotonin is a neurotransmitter, a chemical that moves back and forth in the space (called the synapse) between two nerve cells, or neurons. When one neuron is ready to send a message to another, it sends an electrical signal to its end, which causes a neurotransmitter such as serotonin to communicate that message to another cell. Once that message has been communicated, the neurotransmitter can stay with the new cell, return to the old cell, or hang out in the space between them.

​Certain neurons are programmed to interact with certain neurotransmitters, and neurons that communicate with other cells via serotonin are found throughout your central nervous system – throughout your entire body (Fuller and Wong, 1990). Neurons that use serotonin are also found in especially high amounts in your gastrointestinal tract – commonly called the gut (Furness and Costa, 1982).

Since the role of a neurotransmitter is to help neurons communicate with each other, having just the right amount of serotonin where it’s needed is key to the healthy functioning of any organism, including humans. Serotonin facilitates communication throughout our central nervous system, helping to regulate many different body functions. While you might already be aware that serotonin levels affect our mood and emotions, serotonin is also involved in the regulation of our sleep, memory, appetite, digestion, body temperature, and how awake and alert we are (Jacobs and Azmitia, 1992).

Your body’s goal in regulating itself is to reach homeostasis or a balanced “just right” place for each body function. Serotonin plays a critical role in trying to find that balance, and when the balance isn’t there, problems result. If there is too little or too much serotonin reaching the part of the brain called the hypothalamus, for example, it may be harder to keep your body temperature regulated. If serotonin levels are off in your hippocampus, you may focus too much or too little on certain negative emotions or thoughts (Yabut and colleagues, 2019).

Ways To Boost Serotonin

Since our bodies cannot naturally produce tryptophan, the amino acid that is converted into serotonin, we rely on getting tryptophan from our food. The foods we eat affect how much serotonin is in our brains and where specifically it is found (Haleem and Mahmoud, 2021). Just as important, research tells us that eating foods high in tryptophan can improve our moods and decrease our anxiety (Lindseth and colleagues, 2015).

• Dairy: Cow milk provides large amounts of tryptophan, with whole milk having the highest concentration. Since cheese comes from the same source, it’s no surprise that it also has tryptophan, although at a lower concentration than milk.
• Meat: You might have heard before, correctly, that turkey provides plenty of tryptophan. But chicken also contains high amounts of tryptophan, as do chicken eggs.
• Fish: You can also get tryptophan from canned tuna, but you’ll also get a huge boost from eating salmon.
• Oats: If you want to start your day off with a healthy dose of tryptophan, a bowl of oatmeal is an effective place to start.
• Nuts and Seeds: Peanuts provide a good supply of tryptophan, as do walnuts and pumpkin seeds.
• Dark Green Leafy Vegetables: Kale and spinach are also good sources of tryptophan.
• Supplements: Scientific research has shown that at least one serotonin supplement, 5-Hydroxytryptophan (5-HTP), has positive effects. In clinical trials, people who are given a pill containing 5-HTP have experienced less appetite, better sleep, and decreases in their anxiety and depression (Halford and colleagues, 2011; Maffei, 2020).

The more we learn about serotonin, the clearer its vital role in regulating our minds and bodies. If you think you might be experiencing the symptoms of somebody with low serotonin levels, talk to your primary care physician. If you are curious about serotonin supplementation, know that the risks appear to be minimal, and the upsides are considerable.​

By Charlie Huntington, M.A., Ph.D. Candidate and Tchiki Davis, M.A., Ph.D.

A version of this post also appears on The Berkeley Well-Being Institute website.