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Tryptophan – the sleepy turkey drug?

by jughandle

Eat Turkey, take a nap, right?  Blame it on the tryptophan in the turkey and stick your hand in your pants and fall asleep in front of the TV while the wife cleans the house and does the dishes.  No problem, except she ate the turkey too, didn’t she?

What is Tryptophan?

Trp or W is one of the 20 essential amino acids in the human diet.  That means by definition tryptophan can not be synthesized by the body and must be obtained as part of the diet.  Amino acids are the building blocks of protein biosynthesis.  Most protein based foods contain Trp and Turkey is about the same as most other poultry.

Other Sources

If you really like Trp, you can get it in pill form at your local health food store.  People use this supplement to treat low serotonin levels, depression and as a sleep aid.  But, isn’t there always a BUT.  Read this from Wikipedia

A metabolite of tryptophan, 5-Hydroxytryptophan (5-HTP), has been suggested as a treatment for epilepsy and depression, although clinical trials are regarded inconclusive and lacking. Since 5-HTP readily crosses the blood-brain barrier and in addition is rapidly decarboxylated to serotonin (5-hydroxytryptamine or 5-HT).  However, serotonin has a relatively short half-life since it is rapidly metabolized by monoamine oxidase.

Due to the conversion of 5-HTP into serotonin by the liver, there may be a significant risk of heart valve disease from serotonin’s effect on the heart.

There was a large tryptophan-related outbreak of eosinophilia-myalgia syndrome (EMS) in 1989, which caused 1,500 cases of permanent disability and at least thirty-seven deaths. Some epidemiological studies traced the outbreak to L-tryptophan supplied by a Japanese manufacturer, Showa Denko KK.  It was further hypothesized that one or more trace impurities produced during the manufacture of tryptophan may have been responsible for the EMS outbreak.  The fact that the Showa Denko facility used genetically engineered bacteria to produce L-tryptophan gave rise to speculation that genetic engineering was responsible for such impurities. However, the methodology used in the initial epidemiological studies has been criticized.  An alternative explanation for the 1989 EMS outbreak is that large doses of tryptophan produce metabolites that inhibit the normal degradation of histamine, and excess histamine in turn has been proposed to cause EMS

Turkey and drowsiness

Long story short, your drowsiness after a big Turkey meal is more likely a result of eating too many carbohydrates and not the turkey.  The consumption of large amounts of carbs that are high on the Glycemic index cause the bodies blood sugar to elevate and then the pancreas kicks in to off set the amount of sugar in the blood by producing insulin.  Insulin then stimulates the uptake of the large branch-chain amino acids, but not tryptophan into the muscles.  That increases the ratio of tryptophan to Branched-chain amino acids in the blood stream.  That increased ratio makes it possible for the tryptophan to cross the blood-brain barrier and then to be converted to serotonin.  Serotonin is later converted to melatonin by the pineal gland which then causes drowsiness.  The same thing happens when you drink or eat a lot of sweets in the morning then later “crash”.


Now that we understand that it is simple carbs and sugar that cause our sleepiness after a big meal, we need to fess up to the fact that either our wives don’t eat the same meal as we do or we are just a touch lazy.  Just my opinion, your results may vary.  – jughandle


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Tryptophan decarboxylation | Gnicdon December 23, 2011 - 12:29 pm

[…] Tryptophan – the sleepy turkey drug? | Jughandle's Fat Farm […]

Cholesterol foods December 25, 2011 - 7:28 pm

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