Did you know that serotonin influences virtually every process connected to human behaviour? Emotions, digestion and even motor skills—this powerful chemical affects our lives and bodily functions in so many ways. That’s why increasing your serotonin levels is a great natural remedy for depression and mood swings, especially during the long winter months.


Serotonin: definition and roles

Serotonin, also known as 5-hydroxytryptamine (5-HT), is a neurotransmitter: a chemical compound responsible for transmitting messages from one neuron to another. Serotonin helps regulate body temperature, appetite and digestion, sexual function, the sleep-wake cycle, pain, anxiety and motor control, among other key bodily functions. Also considered a hormone by many, serotonin plays an important role in embryonic development.

That is why a disruption of serotonergic neurons, together with a drop in serotonin levels (as in some cases of depression), can affects any number of neural networks and the functions they control, such as the sleep-wake cycle, food intake, nociception, psychomotor activity, impulse control and many other aspects. Antidepressants of the selective serotonin reuptake inhibitor (SSRI) class, such as Prozac, stimulate the production of serotonin by preventing its reabsorption—or reuptake—by the serotonin transporter (SERT) at the neuronal junction or synapse. But antidepressants aren’t the only solution. Here are some natural methods to boost serotonin levels.

Serotonin is often called the “happiness hormone” and is opposed to dopamine, which is linked to risk-taking behaviour.


Where is it produced?

At first glance, it might seem logical that all neurotransmitters are generated in the brain. But nothing could be farther from the truth! 95% of the body’s serotonin is produced in the intestine, where it is also synthesized thanks to an amino acid called tryptophan. Therefore, to increase your serotonin levels, you should:

  • Ensure adequate intake of essential nutrients (B vitamins, vitamin D, omega-3, etc.);

  • Promote good digestion;

  • Get sufficient levels of sunlight;

  • Practice mindfulness meditation.

1 – Ensure you’re getting all the essential nutrients

Tryptophan is one of the eight essential amino acids that is obtained from diet. You can get it from bananas, eggs, nuts (almonds, cashews, walnuts), pumpkin, sesame and chia seeds, parsley, dates, avocados, wheat germ, buckwheat, quinoa, chickpeas, lentils and spirulina.

Serotonin production in the brain is directly influenced by the transport of tryptophan in the brain (across the blood-brain barrier). The rate of transport is itself inversely proportional to concentrations of the other large neutral amino acids (leucine, isoleucine, valine, tyrosine and phenylalanine), which compete with it at the entrance to the brain. These concentrations vary according to the proportion of carbohydrates and proteins consumed. Consuming sugar or meals high in sugar will indirectly (and momentarily) increase tryptophan levels in the brain, while high-protein foods (which, paradoxically, contain all the amino acids in higher quantities, including tryptophan) will lead to a drop in tryptophan and, most likely, serotonin levels. This explains why we crave a sugar rush when we’re depressed!

Increasing vitamin B3 intake allows tryptophan not to be used for the synthesis of vitamin B3—the body’s chosen route—but rather for the production of serotonin. Other types of vitamin B, including vitamin B12, are also essential. Vitamin B12 can be found in peanuts, almonds, brewer’s yeast, wheat germ, sesame seeds, raw mushrooms, dried apricots, prunes and some types of fish.

Vitamin B6 also plays a crucial role in serotonin synthesis. It is found in foods such as pistachios, bananas, shiitake mushrooms, chickpeas and prunes.

Omega-3 fatty acids positively influence the growth of neurons and the myelin sheath. They support nervous system function and, by extension, the transmission of information via 5-HT (serotonin) receptors. Omega-3s can be found in hemp, ground flaxseed linseed, chia seeds, Grenoble walnuts and egg yolks. Naturopaths recommend consuming 45 ml (3 tablespoons) of oil rich in omega-3 per day: flaxseed, linseed, camelina, hemp, safflower, walnut, etc.


Avoid gluten and dairy products as much as possible: a study has linked wheat gliadin (the protein found in wheat, barley, rye, spelt, kamut and oats) to depression. The same applies to zein, which is the protein found in maize, and hordein, the protein in barley. What’s more, casein, a protein found in dairy products, has negative side effects that can lead to mood disorders and impair brain function.


2 – Support intestinal function and proper digestion

Since 95% of serotonin is produced in your intestine, it’s important to ensure optimal gut health and function so that food is properly digested. And that means knowing how to choose the right food combinations! For example, digestive issues such as excessive gas, bloating, constipation, diarrhoea and stomach pain are likely to impact the metabolism of serotonin.


3 – Get sufficient exposure to sunlight

Serotonin acts on the circadian cycle, and neurons are only active during the day. Exposure to sunlight—or light therapy—stops serotonin from converting to melatonin, thus ensuring it is able to function properly.

“...serotonin synthesis, release, and function in the brain are modulated by vitamin D and the 2 marine omega-3 fatty acids, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). Brain serotonin is synthesized from tryptophan by tryptophan hydroxylase 2, which is transcriptionally activated by vitamin D hormone. Inadequate levels of vitamin D (∼70% of the population) and omega-3 fatty acids are common, suggesting that brain serotonin synthesis is not optimal. Excerpt from Vitamin D and the omega-3 fatty acids control serotonin synthesis and action, part 2: relevance for ADHD, bipolar disorder, schizophrenia, and impulsive behaviour (2015).

Sunlight is the single most important factor in ensuring adequate vitamin D intake. However, our current way of life makes it challenging to achieve optimal levels. Keeping covered up, applying sunscreen and spending much of our time indoors all prevent the body from producing enough vitamin D.

And from October to March, solar radiation in the northern hemisphere is not strong enough to stimulate the body’s production of vitamin D. That’s why we are generally told to take vitamin D supplements (one high-quality natural option is boreal lichen). Pregnant and breastfeeding women, young children and the elderly are at particular risk of vitamin D deficiency.


4 – Be mindful

Mindfulness meditation is a type of meditation that helps boost serotonin levels. As a meditation practice, it focuses on the awareness of bodily sensations, emotions, inner lives and conscious movements. The practice is aimed at consciously focusing your attention on the present moment by welcoming any thought or emotion that arises with grace and openness. The approach is non-judgmental and embraces the candid perspective of a child.

Mindfulness meditation is ideal for stimulating serotonin receptors and serotonin production. This is correlated by findings of increased serotonin metabolites in the urine after meditation (Walton, et al., 1995).

Excerpt from Neurobiology of Spirituality (E. Mohandas, 2008).

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3190564/?report=classic

Studies have shown that therapeutic massage leads to a 31% decrease in cortisol levels, with an increase in serotonin and dopamine levels of 28% and 31%, respectively. When cortisol production is slowed or even inhibited, our brain is in a state of boosted serotonin production. In short, book a massage and stay away from stressful situations whenever possible!

Sarah Juhasz
Biological engineer, Naturopath, Raw chef