A Misunderstood Effect of Tryptophan and Turkey
by Vin Miller
It’s common for people to experience drowsiness after the large turkey dinners that are often a part of the Thanksgiving and Christmas holidays. Although most people attribute the drowsiness to the tryptophan in turkey, this is unlikely to be the cause. Despite this somewhat negative perception of tryptophan, it’s actually an important nutrient that has considerable benefits.
Tryptophan is an amino acid that’s needed by the body to assemble proteins that are involved in numerous biological functions. Tryptophan is also an essential amino acid which means that it cannot be synthesized by the body and must be obtained through diet. When tryptophan is not consumed in adequate amounts, it can lead to a number of issues including mood disorders.
How Tryptophan Influences Your Health and Wellbeing
In addition to being an amino acid that’s needed to build the proteins that support the basic biology of life, tryptophan has an especially important effect on mental wellness. This is because it’s a precursor to the neurotransmitter serotonin which has a significant impact on mood. An inadequate intake of tryptophan can cause serotonin deficiency, and in turn, also cause depression, anxiety, low self esteem, obsessiveness, and irritability.
Because serotonin is derived from tryptophan, and because tryptophan must be obtained through diet, the food you eat has a significant influence on your mood. Someone who doesn’t eat enough food that contains tryptophan is more likely to have a deficiency of serotonin, and in turn, experience unpleasant moods.
Tryptophan is also a precursor to niacin which is a B vitamin and is involved in a number of physiological functions including metabolism, hormone production, circulation, and nervous system function. Niacin is also believed to help reduce the risk of heart disease by reducing the amount of very low density lipoproteins which are an undesirable carrier of cholesterol.
Factors that Influence the Utilization of Tryptophan
The effects of tryptophan aren’t only based on the amount of it consumed. The blood vessels that transport nutrients to the brain are lined with cells that act as filters and only allow certain substances to pass through. These cells represent what is known as the blood brain barrier and amino acids can only pass through it with the assistance of special transport proteins.
The hormone insulin is primarily known for its involvement in the absorption of glucose. It also increases the absorption of amino acids, but not tryptophan. As a result, whenever the body’s sensitivity to insulin increases, or whenever insulin production increases, more amino acids are absorbed and the ratio of tryptophan remaining in the blood increases. Because of this increased ratio, more tryptophan can bind with transport proteins and enter the brain where it can be used to synthesize serotonin. As such, anything that promotes an increase in insulin production or sensitivity can also promote an increase in serotonin production.1
Because exercise increases sensitivity to insulin, it also facilitates the transport of more tryptophan to the brain and the production of more serotonin. This is one of the primary reasons why exercise can improve mood and relieve depression and anxiety. Similarly, consumption of sugar and refined carbohydrates increases the production of insulin which also results in more tryptophan entering the brain and more serotonin production. However, sugar and refined carbohydrates are unhealthy, and for people who are suffering from serotonin deficiency, this temporary boost in mood is one of the reasons why such foods are addictive.
The Real Cause of Post Turkey Drowsiness
Because serotonin is a precursor to the sleep promoting hormone melatonin, anything that causes an excessive production of serotonin can also cause drowsiness. Since excessive carbohydrate consumption can cause too much tryptophan to enter the brain, and in turn, cause too much serotonin to be produced, this is more likely to be the cause of the drowsiness that is so common after large turkey dinners. Alcohol and blood sugar fluctuation can contribute to the drowsiness as well.
Sources of Tryptophan
Some of the best sources of tryptophan include turkey, pork, chicken, beef, salmon, cheese, and eggs. As such, most people who follow a healthy diet that’s based on natural whole foods such as these shouldn’t have to worry much about their tryptophan intake. For your diet to have the most impact, it’s best to choose pasture raised meat, minimally contaminated fish, and organic cheese made from raw milk.
For people who are genetically susceptible to serotonin deficiency or are fighting sugar addiction, supplements can be helpful. Although tryptophan is available in supplement form, 5 HTP is usually preferred because it’s a derivative of tryptophan and is a more immediate precursor to serotonin. However, some people have more success with tryptophan than 5 HTP.
If you search for additional information on tryptophan, you might come across some controversy. In response to a number of cases of a rare neurological disorder, tryptophan was banned as a supplement in the United States in 1990. The cause of this outbreak was determined to be a tainted supply of tryptophan from Japan that was improperly manufactured. Because tryptophan supplementation has been proven to help mood disorders, many people believe that the FDA was influenced to impose the ban so that doctors could be encouraged to recommend Prozac instead. Fortunately, the ban was lifted in 1995 and tryptophan is once again available as a supplement.
Learn How to Improve Your Moods Naturally
Obtaining a sufficient amount of tryptophan through a healthy diet is only one of the many factors that can greatly improve your moods. For more information on how to improve your mental wellness through diet and other natural lifestyle habits, I highly recommend that your read The Mood Cure by Julia Ross.
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Hi Vin – good post. Last Christmas I came to a similar conclusion based on my sleep experiences while feasting, although of course there are many factors to consider. My hypothesis was that eating a large, meat-rich, carb-rich meal in the evening represented the perfect timed-release sleep aid…
Here’s a link to the post if you are interested: High-Carb Feasts Could Help You Sleep
Hi Methuselah, thanks for your comment!
You were definitely on to something with what you said about tryptophan and serotonin in your article!
In fact, tryptophan and 5 HTP supplements are sometimes used to improve sleep because of their association with serotonin and melatonin.
Hi Vin
This was excellent! I just love when someone puts together good research and lays out all of the facts!
I have found myself in similar situations explaining to people that it is not the turkey so much to blame for the drowsy/tired feeling as to WHAT and HOW MUCH you ate.
Not matter what we eat, but especially high sugars and high animal protein, if eaten in large amounts, our body takes such a toll on trying to process these. So over eating is one of the first and biggest culprits of having ones energy drained.
That is why as much as some people don’t want to hear it, overeating period is just not good for us. People think they “treat” themselves during the holidays, but in reality those are some of the greatest moments of stress for the body.
Anyhow, great article!
Thanks, Evita!
I completely agree that overeating is likely to be a major factor in causing the drowsiness, especially if carbohydrates are involved. If someone were to have a meal that consisted of turkey and some low starch vegetables, it would be difficult to overeat, and it’s very unlikely that such a meal would cause drowsiness. In fact, when I eat turkey with other healthy foods it elevates my mood and energy.
My brother and I were the only two (out of the table of 19) that had a primal Thanksgiving dinner (I hit the ice cream later Ha-ha). We were also the only two not completely bonked out scattered all over the living room snoring an hour after dinner was over.
Every time someone mentioned the “turkey coma” I jumped down their throat. I get A LOT of flack and worries about my “weird diet” so I fire back hard whenever I can!
I love it! If your experiences have been anything like mine, it’s still an uphill battle convincing people of their flawed eating habits despite such obvious evidence. However, that’s not to say that firing back isn’t satisfying.
So glad you wrote this article. Tryptophan has helped me greatly. No matter how bad my insomnia, or how bad I ache at the end of the evening, within 20 minutes of taking a 500mg tablet of tryptophan, I am out cold! And I sleep soundly until the morning. Soo much better than sleeping pills, that made me feel groggy most of the next day. Needless to say, I no longer suffer from insomnia. It really, really works.
Hi Ailu, thanks for your comment!
It’s great to hear that you found a way to improve your sleep! Have you considered reducing your dosage of tryptophan while trying to obtain more of it from your diet?
Thanks for your reply, Vin.
Yes, I’ve tried eating foods high in Tryptophan, but it didn’t really do much for me. Problem is, when you ingest it with your food, other amino acids compete for uptake. So you don’t get near as big an effect as when you take it alone.
All your ’science’ aside, Vin, I know one thing for a fact. After chowing down on a massive slice of turkey breast, I felt inert and nearly comatose. In fact, if it had been for the reviving powers of home made pecan pie, I may have fallen completely asleep.
AND I ATE TURKEY JUST BEFORE THIS HAPPENED. Coincidence? Ha!
Hi Phil, thanks for your comment!
There are so many other factors to consider in addition to the tryptophan in the turkey that it would be difficult to say if it was the cause of your drowsiness, especially if you ate anything else along with it. I don’t know if I’d consider pie to be a reviving power either.
Metabolism varies from person to person and some people experience undesirable effects from eating large portions of protein, including drowsiness.