Why Thanksgiving Makes You Sleepy

In the spirit of Thanksgiving, today’s post will deal with tryptophan and if it makes you sleepy.  We all know thanksgiving as a holiday of food.  A veritable cornucopia of various dishes.  What most people complain about is the feeling of sleepiness after eating lots of turkey.  Most of us like to blame the copious amounts of food we consume on causing what we colloquially call “food coma.”   However there is known evidence over the last 20 years that shows that in fact its turkey’s higher levels of L tryptophan (an essential amino acid) that creates that sleepy feeling. Tryptophan is converted into Serotonin via a biochemical pathway. Since serotonin is a neurotransmitter often responsible for sleep/ tiredness one can infer that more turkey = more tryptophan = more serotonin= more sleepy.

So now, knowing what we know, lets take a look at these two molecules.  When you look at the molecular structure of Tryptophan and the structure of Seratonin, its not suprising that one turns into the other.

A molecule of Tryptophan

A molecule of seratonin

Seratonin can be found in neurons of the central nervous system (CNS) where it functions in several ways.  Its been found to process in  regulation of mood, appetite, sleep, muscle contraction, and some cognitive functions including memory and learning.   When excess tryptophan is eaten more seratonin is produced by the body.  This means that more serotonin is present in the neuronal synapses and thus with a constant level of neurotransmitter reuptake more neurotransmitter is creating action potentials (or firing of neurons) at the post synaptic gap.  In other words you can state that more seratonin means an increase in mood,a decrease in appetite, an increase in sleep and relaxed muscles in the sympathetic nervous system and an increase in the para-sympathetic nervous system leading to digestion.

So this thanksgiving lets all go eat some turkey, and while we sit an begin to doze off we can think about how tryptophan and serotonin are playing a role in our drowsiness.


Posted on November 25, 2009, in Uncategorized and tagged , , , , , , , . Bookmark the permalink. Leave a comment.

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