The human brain is one of the most complicated structures in the known universe. Despite only weighing an average of three pounds, the human brain is capable of several tremendous feats.
While neuroscientists will tell you there is still so much to be learned, we have good data on how our brains work now, and how we can support our most valuable organ.
For one, we know that serotonin is essential to both brain and bodily functions. An imbalance of serotonin can contribute to both mild and major conditions that can negatively impact our physical well-being and quality of life.
The good news is that serotonin can be positively impacted by dietary choices, and sometimes, even cutting out certain foods can help bring levels closer to normal.
Here is why serotonin is essential, and five foods that can deplete it.
What Is Serotonin?
Serotonin is a neurotransmitter that helps send chemical signals between the brain and nerve cells. The brain naturally produces the neurotransmitters that it needs to function, but neurotransmitters in the GI tract can also contribute.
Serotonin is one example, but other important neurotransmitters include glutamate, dopamine, glycine, gamma-aminobutyric acid (GABA), norepinephrine, and acetylcholine. Each of these various neurotransmitters plays differing roles in the function and regulation of your brain (and body) activity.
The intestines are also capable of producing some of these neurotransmitters. It’s estimated that 90 percent of the body’s serotonin is produced in the gut instead of the brain.
The serotonin produced in the gastrointestinal tract won’t have the same effects as the ones working in the brain. Although the chemical composition is virtually identical, serotonin from the gut doesn’t have anything to do with the central nervous system.
The body uses two different points of origin because serotonin is incapable of passing the blood-brain barrier. The tight-knit and heavily regulated network of blood vessels and tissues is designed to protect the brain from harmful substances, and only select types of molecules can pass through.
Even something as useful as serotonin produced in the body isn’t allowed to enter the brain from the outside. This means that serotonin produced in the gut typically won’t be able to bind to receptors in the brain.
What Does Serotonin Do?
Serotonin is essential to healthy living as it impacts a majority of critical bodily functions, most centering around homeostasis and overall bodily balance. The exact functions can vary depending on where it was produced, but serotonin is involved with the following:
Mood Stabilizer. Serotonin is often called the “feel good” chemical of the body as it helps you feel calm, happy, emotionally stable, and focused. This is why low levels of serotonin are often associated with mood disorders.
Body Temperature. Serotonin affects the hypothalamus, which controls a lot of homeostatic processes, including regulating our body temperature.
Learning and Memory. Serotonin plays several roles in cognitive function and is involved with learning speed and memory recall.
Wound Healing. Blood platelets utilize circulating serotonin to help speed up the healing of wounds.
Bowel Movements. The GI tract uses serotonin to speed up the digestion and expulsion of irritating, toxic, or non-nutritional foods.
Nausea. Serotonin can trigger nausea and vomiting in the stomach when it’s released faster than it can be digested.
Appetite. Serotonin helps to regulate appetite to ensure you’re getting the right amount of food.
- Sleep Cycle. Serotonin, dopamine, cortisol, and melatonin all play crucial roles in regulating your sleep-wake cycle.
How Is Serotonin Produced?
The brain and the gut use the same biochemical process for serotonin synthesis. The key ingredient to serotonin production is an essential amino acid called tryptophan.
The body is incapable of creating its own supply of tryptophan, which means it must come from dietary sources. Several foods contain large amounts of tryptophan, but more on that later.
When tryptophan is absorbed into your blood, it circulates throughout the body. The brain, intestines, and liver can all use tryptophan to produce different chemicals. The cells will use a chemical reactor called tryptophan hydroxytryptamine to create serotonin.
Combining these with the help of iron, riboflavin, and vitamin B6 will result in a new chemical called 5-hydroxytryptamine (5-HTP). Folate combines with the 5-HTP, and the result is serotonin.
What Foods Contain Tryptophan?
Tryptophan is the sole precursor to serotonin. There’s no way for the body to substitute another amino acid in its place.
The good news is that most meat, dairy products, beans, and seeds have plenty of tryptophan.
Because serotonin is also produced in the gut, probiotic foods promoting balanced gut bacteria can support serotonin production. As a plus, many of them are also tryptophan-rich foods.
Here are a few examples of foods that are good sources of tryptophan:
- Adzuki Beans
- Black Beans
- Brown Rice
- Cheddar Cheese
- Chia Seeds
- Cottage Cheese
- Peanut Butter
- Pinto Beans
- Pumpkin Seeds
- Red Kidney Beans
- Sesame Seeds
- Squash Seeds
- Sunflower Seeds
- White Beans
- Whole Grain Bread
Which Foods Deplete Serotonin?
Eating more foods containing tryptophan is a good start toward ensuring that you have sufficient serotonin levels. However, some foods have the opposite effect and can actually lower your serotonin levels.
These are the five foods that can deplete your serotonin:
It should come as no surprise to see alcohol on this list. It's fairly well known that alcohol is a depressant that limits the abilities of the brain and central nervous system.
The bizarre thing about alcohol is that a small to moderate amount of it may actually boost serotonin in your brain.
These feelings of being “buzzed” can largely be attributed to serotonin release. That might explain why alcohol is such a popular beverage during times of celebration.
The problem with alcohol is that too much can have the opposite effect. Heavy consumption or regular use can severely disrupt the way the brain produces serotonin, as well as serotonin’s overall effectiveness. The serotonin pathways can be disturbed, which can slow down the production and breakdown of serotonin in the brain, leading to lower serotonin levels.
Aspartame is a fairly common artificial sweetener used in place of sugar. Its purpose is to provide something that offers the sweetness of sugar with none of the calories. While aspartame can achieve this goal, it doesn't come free of unwanted side effects.
Roughly 50 percent of the chemical composition of aspartame is an amino acid known as phenylalanine. A few negative effects can come from consuming too much phenylalanine.
One of the most prominent downsides of phenylalanine is that it contains tyrosine. Tyrosine is another essential amino acid that plays a role in the production of several neurotransmitters. While that might sound like a benefit, tyrosine is often in direct competition with tryptophan.
Tyrosine can limit the amount of tryptophan that crosses the blood-brain barrier. The brain won’t be able to get as much tryptophan, which can hinder its overall serotonin production.
Caffeine also affects the central nervous system, like alcohol. The key difference is that it’s a stimulant rather than a depressant. The presence of caffeine can increase the activity in your brain and central nervous system, which is how it boosts your energy levels.
The ensuing boost does result in a temporary boost to serotonin levels. However, caffeine is much like alcohol — drinking caffeine can naturally increase adrenaline and cortisol levels in your body. These stress hormones are a big reason caffeine can help you stay alert. Serotonin has a soothing effect and acts as a counterbalance to these hormones.
Quite simply: generally, the more cortisol and adrenaline in your blood, the more serotonin is necessary for balance.
Excessive and frequent consumption of caffeine can also result in other side effects. Caffeine can hinder your body’s ability to absorb iron from food, and can decrease the amount of B vitamins in your blood. Remember that iron and vitamin B6 are both essential to serotonin production. A lower supply of these essential nutrients can make it much harder for your body to meet the increased demands for serotonin.
Fructose is a natural sugar found in various carbohydrates like fruits, vegetables, and honey. Generally, fructose isn’t viewed as negatively as high fructose corn syrup or even table sugar, and can be an excellent energy source. The problem is that too much of a good thing can quickly become a bad thing.
For most people, fructose is quickly digested and turned into glucose (blood sugar). For these individuals, fructose isn’t likely to cause problems with their serotonin levels. However, fructose can be a big problem for the roughly 40 percent of people in the Western hemisphere that have fructose malabsorption.
Fructose that isn’t properly digested can sit in the lower bowels and ferment. These symptoms are bad enough as they mirror the symptoms of irritable bowel syndrome (IBS).
In addition, fermented fructose can hinder your body’s ability to absorb tryptophan. Serotonin cannot be produced anywhere without a steady supply of tryptophan. Without it, you’re likely to experience serotonin depletion.
Fat is an essential macronutrient that’s used for a variety of crucial functions throughout the body. However, there are a few different types of fat, some considered “good” and others considered “bad.”
Trans fat is an example of a “bad” fat as it provides little nutritional value while also contributing to negative health outcomes like high cholesterol. Trans fat has two distinct negative impacts on the brain.
The primary issue is that excess levels of trans fat can reduce the production of serotonin in the brain. For this reason, diets that feature foods with high levels of trans fats are commonly associated with depression.
The second issue is that trans fat can increase inflammation in the brain. Neuroinflammation can prevent the production of omega-3 fatty acids, one of the “good” types of fat.
Your Diet Can Help Maintain Healthy Serotonin Levels
Serotonin plays a crucial part in several essential bodily functions. A life without sufficient serotonin can result in depression, anxiety, insomnia, and other health conditions.
There are a few ways that you can naturally boost your serotonin levels. Sunlight, stress management, and getting regular exercise are a few examples.
You can also support healthy serotonin levels by eating foods containing tryptophan. Tryptophan is the precursor to serotonin, and has to enter your system through food since your body can’t make it on its own.
You can also limit foods that can negatively affect serotonin levels. Alcohol, aspartame, caffeine, trans fat, and fructose can be limited or eliminated from your diet to support healthy serotonin levels.
Visit the MOSH Pit for more tips on how to support mind and body wellness!