Before we understand tryptophan, its role in mood and the plant-based foods we can obtain it from, we first need to understand serotonin.
Known as the ‘happy hormone/molecule', serotonin plays a crucial role in regulating mood and also in promoting feelings of wellbeing and positivity.
Serotonin also works to support healthy brain function that includes promoting mental cognition and emotional stability.
Other body processes also greatly benefit from the presence of serotonin, such as social behavior, sex drive, a solid sleep schedule, and learning and memory.
What Happens When You Are Serotonin Deficient?
Because serotonin has such an effect on the body and the brain, a lack of serotonin in the body can lead to some unpleasant symptoms. These include:
- digestive disorders (including constipation)
- an increased sensitivity to pain
- changes in eating patterns (including binge eating bouts and an increased desire for carbohydrates)
- separation anxiety or dependency
- disrupted sleep schedule
- issues with self-esteem
- headaches and migraines
- general bad moods
Serotonin deficiency manifests differently in men and in women. Women with a lack in serotonin have a general propensity to experience depressed moods and increased anxiety.
Serotonin deficiencies in men manifest differently: men are more prone to impulse control disorders, including ADHD. Low serotonin also makes men more susceptible to alcoholism and potentially other addictive diseases.
Studies show that a decrease in serotonin can also greatly impact a person’s length of life: a lack in the molecule can lead to increased rates of many diseases, including: heart disease, Alzheimer’s, dementia, asthma, fibromyalgia, and migraines, as well as irritable bowel syndrome, anxiety, insomnia and depression.
Serotonin Produced in the Intestine Vs. the Brain
Interestingly, 90%+ of serotonin is produced in the digestive tract.
Peripheral serotonin is created in the intestines by the enterochromaffin cells and also by immune cells and certain gut neurons.
Serotonin produced in the brain is created by raphe neurons that directly supply the brain. The serotonin is molecularly the same, but the molecules are produced by different types of cells and can elicit a variety of functions.
A common misconception is that eating serotonin-rich foods will improve the amount of serotonin molecule in the brain and improve mood.
Unfortunately it isn't as simple as that, because serotonin produced in the intestine can’t cross the blood barrier to the brain.
But, with the help of a precursor, it can.
This precursor is an amino acid called tryptophan.
You see, there’s a transport protein in the brain that plucks tryptophan out of the bloodstream. So, what you eat can end up affecting your mood.
How to Get Your Trytophan – Debunking “The Turkey Myth”
Many people associate tryptophan with turkey, and while it does contain a high-level of tryptophan, turkey doesn’t have any more tryptophan than other types of poultry.
While poultry is tryptophan rich, science shows us that animal foods are not the best way to obtain tryptophan.
In fact, researchers note that
‘when tryptophan is ingested as part of a high protein meal, serum tryptophan levels rise, but brain tryptophan levels decline… due to the mechanism of transport used by tryptophan to cross the blood-brain barrier.’
In this study, the tryptophan levels in those given a high-protein turkey, egg, cheese breakfast dropped, whereas in the waffle-OJ group, their tryptophan levels went up.
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Bad Moods & Arachidonic Acid (in animal proteins)
While we're on this subject: There's a good reason vegetarians and vegans are known to experience less anxiety and better moods than their omnivorous counterparts, and that is a decreased presence of arachidonic acid, a substance that can be found in animal proteins.
Arachidonic acid is metabolized in the body to ‘produce inflammatory mediators: they convert the arachidonic acids into specific compounds that create inflammation and pain.
In fact, that’s how anti-inflammatory drugs like aspirin and ibuprofen work—by interfering with the conversion of arachidonic acid into compounds that produce inflammation, pain, and swelling.
Arachidonic acid is overwhelmingly found in chicken and eggs, though there’s also some in beef, pork, fish and other animal products.
Omnivores have more of the acid in their bodies, therefore creating more pro-inflammatory compounds that contribute to poor mood and raised levels of stress and anxiety. You'd be a bad mood too if your body was blown up like a balloon!
How Carbs Help Increase Serotonin Synthesis
Eating carbohydrates triggers a release of insulin, which forces muscles to ‘eat’ non-tryptophan amino acids as their food or fuel. This is actually beneficial to the brain — because it frees tryptophan up to be absorbed by the brain.
Interestingly, researchers found that women who suffer from PMS experience carb cravings.
This may be a message from the brain to ingest more tryptophan in order to alleviate their symptoms. The researchers note that:
consumption of a carbohydrate-rich, protein-poor evening test meal during the premenstrual period improved depression, tension, anger, confusion, sadness, fatigue, alertness, and calmness scores significantly among patients with premenstrual syndrome. The synthesis of serotonin in the brain also tied with mood and appetite — serotonin will also spike after carbohydrate intake, leading to a very understandable reason for carbohydrate cravings during PMS (Study ref).
The study followed 19 patients who suffered from severe premenstrual syndrome.
Mood was assessed by the Hamilton Depression Scale and fatigue, sociability, appetite, and carbohydrate craving were also measured.
The researchers also measured nutrient intake in the patients, noting that carbohydrate intake increased significantly during the late luteal phase (24% from meals and 43% from snacks).
The researchers also found that carbohydrate-rich, protein-poor evening test meal during the luteal phase improved PMS symptoms like depression, tension, confusion, sadness, fatigue, anger, alertness, and calmness.
They reasoned that synthesis of brain serotonin increases after intaking carbohydrates. This makes sense, as women with PMS might be trying to improve their moods through their meals.
Let's face it, we all feel good when we “carb up!”
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Fruit as a Treatment for Depression (Low Serotonin)
A recent article in the Journal of Neuropsychiatry and Clinical Neuroscience noted that fruit could be used as an effective treatment for depression, for which a low level of serotonin may be held accountable.
While most treatments for depression now hinge on SSRI drugs, such as Prozac, the side effects of such drugs are significant enough to want to choose an alternate method.
Researchers found that depression patients who supplement with fruits like plantains, pineapples, bananas, kiwis, plums, and tomatoes see reduced symptoms.
However, the best foods to eat to promote serotonin levels in the brain are those with a high protein to tryptophan ratio, as we'll find out below…
10 Tryptophan-Rich Vegan Foods
While tryptophan-rich foods are the way to go, researchers found that protein-source tryptophan paired with carbohydrates resulted in a:
‘significant improvement on an objective measure of anxiety.’ They concluded that protein-source tryptophan (in combination with a high glycemic carbohydrate) is an easy way to help those suffering from social anxiety.
Note that before studies like this, it was thought that…
a change in the composition of intact dietary protein was not seen as a possible option for the treatment of common psychological disorders associated with low serotonin levels.
However, previous studies were done using animal proteins, which as we learned above in the arachidonic acid section can make mood worse. not better. Hooray for plants!
To maximize mood-elevation, we should ideally choose foods with a high tryptophan-to-total protein ratio, which would primarily be seeds such as sesame, sunflower and pumpkin varieties. That aside, here's 10 of the best serotonin-laced plant-based foods you can consume.
- The Recommended Daily Allowance of tryptophan is .29 grams for the average adult. As you'll see, it's very easy to get this from a plant-based diet.
1. Butternut Squash Seeds
Because serotonin is best elevated with a source of tryptophan and protein, seeds are a great choice, specifically butternut squash seeds. These seeds were used during a study of those suffering from social phobia.
Significant improvement in anxiety was measured among those who consumed squash seed bars. They measure in at .04 grams per ounce of tryptophan.
2. Sea Vegetables
Veggies like kelp, seaweed, and spirulina are all fantastic sources of tryptophan, that ever-essential amino acid. These veggies contain about 3 percent of daily tryptophan value.
Soy gets a bad rap for being bland and highly processed, but choosing organic/non-GMO brands is the way to go. You can get your soy through soybeans, tofu and soymilk. Soy contains nearly 122 percent of the recommended daily tryptophan value, at .048 grams per ounce.
A great source of molybdenum, vitamin K, vitamin C, potassium, magnesium, and silica, cucumbers are the fourth most cultivated vegetable and a great source of tryptophan: .001 grams per ounce.
Containing .011 grams per ounce of Tryptophan, wheat is both a staple worldwide food and an easily accessible food source.
Walnuts are an incredible source of polyunsaturated fats, omega-6 fatty acids, and can reduce bad cholesterol. Walnuts also improve metabolism and can help control diabetes. They are quite high in tryptophan at .10 grams per ounce.
Another cheap and accessible food source, potatoes are a great source of vitamin B6, potassium, vitamin C and dietary fiber. Potatoes also contain .008 grams per ounce of tryptophan.
Closely related to broccoli, cauliflower is an excellent source of protein, fiber and also potassium. It is loaded with amino acids, including tryptophan — it contains about .0025 grams per ounce.
Mushrooms are rich in vitamin D, selenium, antioxidants, and B2 vitamins. Mushrooms contain .0025 grams per ounce of tryptophan.
10. Leafy Greens
Known for their alkalizing properties, leafy greens are high in fiber, vitamin C and phytochemicals and they’re low in fat. Leafy greens help fight chronic disease. They’re high in tryptophan at .008 grams per ounce.
Is it Safe to Supplement with Trytophan Pills?
Likewise, tryptophan pills can also be used to improve mood.
These became a popular dietary supplement some years back, until people started dying from something called eosinophilia myalgia syndrome, an incurable, debilitating, and sometimes fatal flu-like neurological condition, caused by the ingestion of tryptophan supplements.
Now, this may have been due to some unknown impurity, which has yet to be identified.
But what followed was a ban by the Food and Drug Administration (FDA) on the sale of L-tryptophan. And, just as they presumed, the incidence of EMS declined rapidly.
The ban was lifted in 2005, and no new cases were reported.
However, this study here reports a new case of L-tryptophan-associated EMS, and evidence of historical and related issues.
That said, millions of people take tryptophan supplements with no issue, and report benefits. So it's up to you. But it is advisable to go down the route of obtaining serotonin from plant-based foods first.