Everything You Need To Know About Your Serotonin + Gut Health Connection

You may think you have control over your emotions, and while that is true to a certain extent, your body’s brilliant biochemistry has a lot to do with how you feel on a daily basis. More specifically, optimal levels of your “happy” neurotransmitter are necessary for keeping depression and anxiety at bay.

But did you know that serotonin controls so much more than just your happiness levels? In fact, as a functional medicine practitioner I can’t deny the connection between serotonin and gut health. Serotonin gut health is a subject that might not seem relevant to you however, understanding this connection can help you improve both your mental and physical health. 

Read on to learn more about serotonin and gut health, how to increase serotonin in the gut, and why you need to pay more attention to this overlooked connection.

What is serotonin?

Made from the essential amino acid tryptophan, serotonin helps regulate everything from your sleep to your mood because of its role as a mood stabilizer. Low levels are associated with increased rates of anxiety, depression, and seasonal affective disorder in the winter as serotonin levels in the brain tend to drop during this time of the year.

Serotonin also plays a role in a few other important functions:

• Bowel movements: Helps your bowel movements running smoothly and on a regular schedule
• Bone health: Balanced levels of serotonin are necessary for strong bones
• Nausea: Works to stimulate the area of your brain that plays a role in nausea
• Blood clotting: Serotonin is released to help your blood clot to heal wounds

The gut-brain connection

You may be thinking, “does gut health affect serotonin?” and the answer is, absolutely! While it may seem strange that these two far away systems of your body could be connected at all, their connection goes back to before you were even born!

Your gut and brain are actually formed from the same fetal tissue when you were growing in your mother’s womb, and continue their special bond throughout your whole life through what is known as the gut-brain axis. The same proteins that govern gut permeability also determine the permeability of your blood-brain barrier. Basically, what affects one, affects the other.

One of the greatest examples of this is serotonin gut health. Surprisingly, close to 95% of this neurotransmitter is made and stored in your gut - not your brain! No wonder the medical literature often refers to your gut as your “second brain”. (1)

How serotonin benefits gut microbiome

Most talk about serotonin is surrounding its impact on mental health however, it is just as important to your gut health. It controls how quickly food moves through your digestive system and how much mucus and other fluid is secreted by your intestines. And since serotonin also controls nerve receptors, serotonin levels can determine how sensitive you are to bloating and pain in your gut.

While serotonin gut health is still not fully understood, research has found that people with gut problems like irritable bowel syndrome (IBS) have lower levels of serotonin and their muscles  are less reactive to serotonin. (2) In general, low levels of serotonin are correlated with constipation and hard stools whereas higher levels of serotonin are correlated with diarrhea and watery stool.

All this to say, balance is key. You don’t want levels to be too high but you definitely don’t want them to be too low because it can impact your gut health negatively either way.

Symptoms and causes of low serotonin

If you are dealing with any of the following symptoms, serotonin deficiency might be to blame:

• Depression
• Anxiety
• Chronic fatigue
• Insomnia
• Chronic pain
• Brain fog or memory issues

So what causes low serotonin levels in the gut? There are actually quite a few reasons.

1. Nutrient deficiencies

Since tryptophan is necessary for your gut to make serotonin, deficiencies can lead to low serotonin levels, as your gut doesn’t naturally produce this nutrient on its own.

2. Gut problems

Health problems like leaky gut and imbalances in the microbiome can make it difficult to absorb tryptophan and contribute to low serotonin. It can also inhibit the proper production and storage of this neurotransmitter, leading to chronically low levels. 

3. Hormone imbalances

Certain hormone imbalances like low estrogen have been linked to lower levels of serotonin. (3) This is why women can often notice mood changes during menopause when levels of estrogen drop.

4. Chronic stress

While researchers are just beginning to understand the link between stress and serotonin deficiency, they believe chronic stress can inhibit the transportation of serotonin in the body and play a role in altering gut health, contributing to leaky gut and dysbiosis.

5. Lack of sunlight

Exposure to sunlight helps regulate melatonin and serotonin levels and also helps your body synthesize serotonin. Studies have shown that SERT (serotonin transporters) levels in people with SAD were shown to be 5 percent higher in the winter. (4) The higher levels of serotonin in the winter indicate less serotonin in the brain, which can lead to feelings of depression.

How to boost serotonin naturally?

1. Diet

I am often asked, “how can I increase serotonin in my gut?” Eating more foods that contain higher levels of tryptophan is going to be beneficial as this nutrient is necessary for your gut to produce more serotonin. Turkey is a great choice as it contains some of the highest levels of tryptophan as well as eggs, wild-caught salmon, grass-fed cheese (if you can tolerate dairy products), and nuts like walnuts and almonds.

2. Probiotics

Do probiotics increase serotonin? Not directly. While they aren’t going to automatically increase serotonin levels, they are going to facilitate a healthy gut and microbiome balance to facilitate a healthy environment for serotonin to be stored and produced.

Try increasing your intake of probiotic-rich foods like sauerkraut and kimchi while also taking a daily probiotic supplement.

3. Exercise

The more we learn about exercise, the more we see just how important daily movement is for all areas of our health, including our mental health. Studies have shown that exercise can increase the release of serotonin in the brain

4. Light exposure

If you live in a sunny climate year-round try getting outside as much as possible as sunlight has been shown to help boost serotonin levels, But if you live in a place that gets more traditional winter weather and you can’t get outside as much, a light box that mimics sunlight has also been shown to increase serotonin levels.

Seeking help from a functional medicine doctor

While researchers are still learning more about all the mechanisms by which serotonin affects your health, we can’t deny its impact on our mental and physical health. But if you are struggling with sleep, depression, or other mood problems and suspect that serotonin deficiency is a factor in your health case, it’s important to seek out help from a qualified practitioner.

In functional medicine, we are able to look at the health of your gut to determine if there is a correlation between your gut, serotonin levels, and symptoms in order to come up with the best course of action to boost serotonin naturally. Since serotonin deficiency is a complex issue, a functional medicine doctor will be able to take your entire health case into consideration - diet, stress, underlying conditions, and your lifestyle - to understand what is happening beneath the surface.

Since there is no one test to diagnose serotonin deficiency, it makes working with a functional medicine practitioner more important since they can look at the entire picture and make connections to determine if this is an issue in your health case.

Don’t know if you’re dealing with a serotonin gut health problem? We can help! As one of the first functional medicine telehealth clinics in the world, we provide webcam health consultations for people around the globe.

READ NEXT: A Functional Medicine Perspective On Microdosing