You Ask, I Answer: Tryptophan

I am writing to you so you can hopefully help me prove a point.

My cousin claims the reason why people feel tired after Thanksgiving dinner is because of the tryptophan in turkey.

I say that's a myth.

She insists it has been "scientifically proven" that tryptophan makes you sleepy.

What do you have to say?

-- Lori Narth
(Location withheld)

Ah, yes, the "turkey makes you sleepy" myth. Let's break this one down.

Tryptophan is one of twenty amino acids (and one of nine essential amino acids which we must get from food.)

Tryptophan also happens to be a pre-cursor for serotonin (a neurotransmitter) and melatonin (a hormone), which play significant roles in the regulation of sleep.

That might make you think there is a direct link between the tryptophan in your turkey dinner and your desire to nap a short while later.

Not so much.

First of all, although tryptophan is one amino acid in turkey, it is also found in other foods.

In fact, chicken breast, tuna, soybeans, and beef contain more tryptophan than turkey! Snapper, black beans, and cod are also good sources of this amino acid.

More importantly, tryptophan is one of many amino acids contained in a Thanksgiving dinner.

This means tryptophan is competing with other similar compounds for absorption by the brain. Simply put, you aren't getting enough of it to make you sleepy.

Research has shown you would have to eat a significant amount of turkey -- almost the entire bird! -- on an empty stomach to feel any sleep-inducing effects.

A much more accurate theory for the sleepiness after Thanksgiving dinner has to do with the sheer amount of food eaten.

With that much food to digest, the body sends as much blood as it can to the intestinal tract, resulting in an energy zap.

This is the main reason behind the "small meals throughout the day" recommendation -- by not overworking your digestive system at any given time, your energy level is more likely to remain steady.

Remember, too, that most Thanksgiving meals consist of white bread, mashed potatoes, and cranberry sauce.

Those are precisely the kind of carbohydrates that make blood sugar levels rise and fall rather sharply, making for a more noticeable "energy crash."

It is also a known fact that meals high in carbohydrate increase insulin levels, consequently increasing the amount of serotonin produced by the body.

I also think people forget that the buildup to such events (traveling to someone's house, preparing the food, and being soecially "on") can be rather tiresome.