Turkey, Tryptophan, and sedation.

I am sure everyone has heard claims that the reason people get sleepy after a thanksgiving meal is that turkey contains a lot of L-tryptophan.

Question one: Is this True? Or is it simply overeating.

I understand the molecular basis for L-tryptophan’s theoretical effect . But is it true that this can result from the levels of typtophan in a turkey dinner?

Question two: If this is true… Why do turkeys have so much damned tryptophan anyway. Do they have tons of a particular tryptophan rich protein in their muscles that other animals (which we also eat) do not?

Most proteins have very similar (if not identical) homologues or orthologues in other species. I would not expect these to have altered trytophan levels to such a significant amount.

Question three: If turkeys have so much tryptophan, how do they stay awake?

AHHH, I assume this is a quip.

However, I will take it seriously just in case.

There is a difference between, containing a lot of tryptophan in the form of long polypeptides (proteins) and “free” tryptophan. Tryptophan containing proteins would not have this affect. Free tryptophan-absorbed by the body from the digestion of high tryptophan containing proteins… in say, turkey… could cause this sedation, theoretically.

However, I was not interested in discussing the molecular basis for the proposed drowsiness. I would like to know:

If the amount of tryptophan in a turkey dinner could cause such effects?..

And what makes the turkey so tryptophan rich?