Happ(ier) Holidays – Any Connection with Tryptophan?

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As we roared past Thanksgiving in the express lane to Christmas, many of us may have spent a post-turkey moment lolling on the couch, our bellies protruding, unable to keep our eyes open in food coma bliss (or discomfort). Tryptophan has long taken the blame for our post-holiday dinner sleepy states, but what exactly is this mysterious and omnipresent Thanksgiving substance we often attribute to turkey?

“We use [tryptophan] to make vitamin B3 and serotonin, and our gut microbes turn the substance into a large number of chemicals which can influence the brain.”

It turns out that tryptophan is an essential amino acid that we need, since we don’t make it ourselves. We use it to make vitamin B3 and serotonin, and our gut microbes turn the substance into a large number of chemicals which can influence the brain. But, since it hasn’t actually been shown to be a sleep aid itself, is tryptophan what’s making us so tired after a holiday meal? Do we feel the same fatigue while grabbing a quick turkey sandwich or soup? Not always.

If the tryptophan in turkey isn’t the sleep-inducing agent many claim it is, what is making us so sleepy after we’ve given thanks? Many experts suggest that the overeating and accompanying carbohydrate overload on our holiday plate is the actual culprit.

Tryptophan tricks.

Either way, the interesting thing about tryptophan, other than the fact that insufficient amounts of it can lead to depression, anxiety, irritability, impulsiveness, poor concentration and insomnia to list a few, is that we not only use it to make the aforementioned vitamin B3, but that we also process it into serotonin, often thought of as the ‘happy hormone’. (Now the possible side effects of having too little start to make sense).

“…the great majority of our serotonin is produced and stored in special cells in our gut, regulating a multitude of gut functions, in addition to sending signals to our brain via the vagus nerve.”

Many of us associate serotonin with brain health and mood. We are right to do so, but our brain is not serotonin’s only home, and its modulating effects on mood, body temperature, sleep and hunger are not the only effects on our well being. In fact, the great majority of our serotonin is produced and stored in special cells in our gut, regulating a multitude of gut functions (such as contractions and secretions) in addition to sending signals to our brain via the vagus nerve. This gut based conversion of tryptophan into serotonin is heavily influenced by molecules produced by our gut microbes, in particular the short chain fatty acid butyrate.

Tryptophan supplements have been shown to have mild antidepressant effects in some studies, but due to serious side effects with the original formulation have quickly fallen out of vogue and should not be taken in combination with antidepressant medications, in particular the serotonin uptake inhibitors.

In addition to the king of the Thanksgiving table, canned tuna, milk, beef, pork and chicken also contain significant amounts of tryptophan. Importantly, as eggs, soy, oats, cheese, sunflower and pumpkin seeds and nuts like peanuts pack a trypto-punch as well, you certainly don’t need be carnivorous to get your dose of this essential amino acid.

“Even veggies like spinach, peas, broccoli and sweet potatoes supply ample amounts of tryptophan.”

Chocolate contains up to 19 milligrams of tryptophan per ounce and fruits like bananas, apples and plums contain a bit as well. Fish (sardines in particular), and shell fish like crab and oysters win the competition, supplying us with sometimes more than a day’s requirement. Even veggies like spinach, peas, broccoli and sweet potatoes supply ample amounts of tryptophan.

Keep in mind that like with the majority of food related natural sources for essential nutrients, sticking with a diverse largely plant based diet, including dark chocolate and certain fruits, with meat coming largely from small fish shell fish and some poultry may be your best bet.

“Too much serotonin is not a good thing either.”

Those with too much of it can experience the opposite of the happy affect we attribute to this miracle neurotransmitter. Keep in mind that tryptophan is not only absorbed by your small intestine, but that it is also processed into a myriad of molecules by your gut microbes which can enter the blood stream and ultimately the brain. It is therefore no surprise, that an excess of serotonin can lead to irritability, agitation, restlessness, and anxiety. Contact your physician if you’re experiencing any of these syndromes while taking any medications or supplements affecting serotonin levels.


Katharine Jameson is a graduate of Syracuse University and a Certified Health Counselor. Her growing interest and research in nutrition solved her own weight problems. A mother of two, she is compelled to share the ease with which good health is obtained through the integration of good foods and proper nutrition. Based in Los Angeles, Katharine writes a weekly column where she discusses pivotal health topics and interviews cutting edge experts. She can be found on Instagram at @foodforthoughtwithkat.