Foods That Boost Serotonin: The Impact on Gut & Brain Health

Foods That Boost Serotonin: The Impact on Gut and Brain Health

Using Foods to Improve Your Mood and More

Key Points:

  • Foods that may boost serotonin levels include turkey, chicken, milk, canned tuna, peanuts, oats, bananas, and apples.
  • Serotonin is important for your mental health and sense of well-being, and it’s also important for proper gut function.
  • Tryptophan, an amino acid found in protein-containing foods, is the sole precursor to serotonin and must be consumed in the diet or taken in supplement form.
  • Foods with higher tryptophan content relative to other amino acids, like poultry, canned tuna, oats, and bananas, have more potential to impact brain production of serotonin.
  • Probiotics have also been shown to impact serotonin levels.

You’ve probably heard that serotonin is important for maintaining a good mood. After all, many of the most commonly prescribed pharmaceuticals like antidepressants (including selective serotonin reuptake inhibitors or SSRIs) are designed to influence serotonin levels to treat the symptoms of a variety of psychiatric and neurological disorders (5, 1)

What you may not realize though, is most of the serotonin in your body is actually made and used by your gut to regulate gut secretions and the movement of food through your intestines (motility) (1). So, low serotonin levels don’t just impact your mood; they can also affect your energy levels, lead to disrupted sleep, behavior and appetite changes, poor gut motility, and even altered blood sugar (2, 3, 4)

Boosting serotonin levels with foods can be accomplished by eating foods high in tryptophan relative to other amino acids (turkey, canned tuna, apples, bananas, and oats), eating direct food sources of serotonin (kiwi, pineapple, potato, and tomato), and by upping your intake of foods with vitamin B6 (poultry, tuna, chickpeas, and lentils) and vitamin D (mushrooms, salmon, cheese, and sardines). But simply eating these types of foods probably won’t measurably impact your serotonin levels if your overall diet is unhealthy.

In this article, we’ll provide you with a list of foods that boost serotonin levels and discuss how poor gut health and inflammation can rob you of this happy-mood chemical. We’ll also discuss serotonin basics, like how it’s formed and what it does in the brain and the gut. 

Foods That Boost Serotonin

Before diving into the specific foods that boost serotonin levels, let’s talk about how serotonin is created.

Tryptophan, an amino acid found in protein-rich foods, is the only precursor to serotonin. Since tryptophan can’t be created by your body, you must obtain it from the foods you eat or from dietary supplements (5)

After digestion, most tryptophan is absorbed in the small intestine and then 95% is utilized for the kynurenine pathway (a biochemical pathway thought to underlie certain diseases) (6) and the remaining 5% can either (7, 8):

  1. Be converted to serotonin and remain in the gut (representing 90% of serotonin production)
  2. Cross the blood brain barrier (BBB) with the help of a transport protein and be converted to serotonin to be used in the brain (representing 10% of serotonin production)

What Are The Foods That Boost Serotonin Levels?

While eating foods that contain tryptophan can theoretically boost serotonin levels, it’s important to note that tryptophan competes with other amino acids for entry into the brain (5). So, just eating foods high in tryptophan may not necessarily translate into higher serotonin levels in the brain (9). Choosing foods higher in tryptophan when compared to other amino acids is probably the better way to boost brain serotonin levels. 

The following foods are high in tryptophan relative to other amino acids (10):

  • Turkey
  • Chicken
  • Milk
  • White or whole-grain bread
  • Semisweet or sweet chocolate
  • Canned tuna
  • Peanuts
  • Cheddar cheese
  • Oats
  • Dried prunes
  • Bananas
  • Apples

Several foods are direct sources of serotonin, but since serotonin outside the central nervous system (CNS) doesn’t easily cross the BBB, they may not have much impact on brain function and mood (11).

The following foods are direct sources of serotonin (12):

  • Bananas
  • Chicory
  • Chinese cabbage
  • Coffee powders
  • Green coffee bean
  • Green onion
  • Hazelnut
  • Kiwi
  • Lettuce
  • Nettle
  • Paprika
  • Passion fruit
  • Pawpaw
  • Pepper
  • Pineapple
  • Plantain
  • Plum
  • Pomegranate
  • Potato
  • Spinach
  • Strawberry
  • Tomato
  • Velvet bean
  • Wild rice

Of course, adding the above foods that boost serotonin levels can be important, but foods rich in vitamin B6 (required for tryptophan to be converted into serotonin) and vitamin D (helps to activate an enzyme needed to produce serotonin) may also be helpful for boosting serotonin production (13, 14)

The following table lists food sources of these nutrients:

Vitamin B6Vitamin D
PoultryRainbow trout
Beef liverSardines
CarrotsFortified orange juice
Brown RiceMushrooms

Are There Any Diets That Boost Serotonin Levels?

Adding foods that boost serotonin levels to your meal plan may be helpful to a certain extent, but your dietary pattern on the whole is probably more important. Regularly eating foods that negatively impact your gut and/or promote inflammation will make boosting your serotonin levels with specific foods difficult. 

Vegetarian diets and those high in fish tend to have the highest levels of tryptophan, whereas vegan diets have the lowest levels (25). A diet low in tryptophan can decrease your serotonin levels and increase your risk for depression or poor mood (15, 16, 13).

Different kinds of diets have been shown to positively impact serotonin in addition to their other health-promoting benefits:

  • An elimination diet, with or without probiotics, for 14 weeks resulted in a significant increase in serum (blood) serotonin levels (24).
  • Anti-inflammatory diets may help boost serotonin production (26).
  • A low FODMAP diet has been shown to increase serotonin-producing cells in the GI tract in people with irritable bowel syndrome (IBS) (27).
  • Diets higher in carbs increase tryptophan in relation to other amino acids, which can make it easier for tryptophan to cross the BBB to be converted to serotonin (4, 19).

The overall takeaway is not necessarily to try to choose the diet that’s highest in serotonin-boosting foods, but rather to choose the diet framework that best suits your body’s needs. A diet that makes you feel good and that is ideal for your own gut health will help with natural serotonin production, along with various other benefits. 

Can Nutritional Supplements Boost Serotonin Levels?

Taking tryptophan in supplement form has the potential to impact serotonin levels too. In one randomized controlled trial, participants who consumed a tryptophan-containing supplement experienced improvement in cognitive function. The researchers felt this may be due in part to increased levels of serotonin, but serotonin wasn’t specifically measured (17). In other studies, supplementing with tryptophan led to improvements in mood (18, 16).

What is Serotonin?

Serotonin (5-hydroxytryptamine or 5-HT) is a neurotransmitter created from the essential amino acid tryptophan with important implications for both gut and brain health (2). Serotonin is found in the brain, platelets (cells needed for blood clotting), and in the enterochromaffin cells (ECs) of the gut (2)

Its functions include:

The Gut-Serotonin Connection

You may think of serotonin in relation to mental health first, but the majority of the serotonin in your body is actually located in the GI tract, where ECs release it to increase gut motility (7)

The release of serotonin by the ECs impacts the gut microbiome, which in turn influences the number of ECs in the gut (11)

While neurotransmitters like serotonin are created in the gut and can travel to the brain to impact appetite, pain, mood, cognition, and more, it’s thought that serotonin created in the gut and serotonin created in the brain may act in different ways (19, 11).

Low levels of gut serotonin can alter bowel function, and IBS patients with low serotonin levels have been found to experience pain, mood disorders, and visceral hypersensitivity (a sensation of bloating despite having normal levels of gas) (20, 21).

How Does Inflammation Affect Serotonin Levels?

Inflammation in the GI tract (or the rest of the body) can affect gut serotonin levels but also disrupts the flow of serotonin from the gut to the brain along the vagus nerve (19)

Normally when your body breaks down tryptophan-containing foods, 5% of that tryptophan is used to create serotonin and melatonin (8). But if you’ve got inflammation, that 5% is instead used in the creation of inflammatory proteins (kynurenine pathway) and you’re ultimately robbed of your happy-mood chemical, serotonin (6). See the diagram from Healthy Gut, Healthy You below to visualize this process:

Diet has a significant impact on your physical health and the levels of inflammation in your gut and throughout your body. Eating a diet high in processed and refined foods (high amounts of inflammatory fat, sugar, empty calories, and salt) and low in fruits and vegetables can increase inflammation and may shunt tryptophan into the kynurenine pathway, which lowers the available tryptophan to make serotonin (22). In addition, inflammatory diets often contain high amounts of amino acids that compete with tryptophan for entry into the brain (5).

Can Probiotics Boost Serotonin Levels?

Research is limited, but probiotics may be another option for improving serotonin levels related to their impact on the tryptophan and kynurenine pathways. Humans can’t create tryptophan, but gut bacteria are capable of producing both serotonin and tryptophan, so improving the landscape of the gut with probiotics may naturally boost serotonin (23)

Let’s look at the results of some randomized controlled trials:

  • Students who drank a probiotic drink for eight weeks before a stressful exam had higher stool serotonin levels, possibly due to how probiotics impacted tryptophan metabolism (24).
  • Taking a probiotic for eight weeks significantly decreased the ratio of kynurenine to tryptophan, meaning more tryptophan was used to make serotonin. Participants had significant improvement in symptoms of depression (25).
  • People with major depressive disorder who took probiotics for eight weeks had a significant decrease in kynurenine levels (26).

Other trials have found probiotics to help boost levels of the enzymes needed for serotonin production (27) and to normalize serotonin levels in those with constipation (28).

An Anti-Inflammatory Diet and Probiotics Can Boost Serotonin Levels

Serotonin is an important neurotransmitter for gut and mental health. Tryptophan-containing foods like poultry, canned tuna, chocolate, dried prunes, and peanuts provide the building blocks of serotonin, but direct sources of serotonin like wild rice, spinach, potato, and bananas may also boost serotonin levels. 

Take a look at your diet and see if you’re consuming adequate sources of tryptophan and direct sources of serotonin. If not, add in some of those good sources and take note of your symptoms. In addition, consider adding in probiotics. The limited research on probiotics and serotonin hints at a beneficial relationship. Probiotics are safe, have no side effects for most, and have a variety of health benefits, so they’re worth trying. 

You’ll probably recognize the most benefit by following an anti-inflammatory meal pattern like the Paleo diet and working on improving your overall gut health though. Check out Healthy Gut, Healthy You for a step-by-step gut-healing guide or reach out to us at the clinic at the Ruscio Institute for Functional Medicine if you’re looking for a more personalized plan.

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