The Truth about Tryptophan

Does this really make you sleepy?

A couple of years ago a friend told my husband and I about his nightly ritual of eating a “big turkey sandwich” and a glass of milk before he went to bed – claiming it helped him sleep.  He repeatedly emphasized the big turkey sandwich. I finally asked him why he kept repeating that. He said it was because the tryptophan in the turkey helped him get to sleep.

I had to break the news to him: it wasn’t the turkey that helped him get to sleep so much as it was the “big” sandwich, no matter what kind he made. The large amount of food was probably doing it to him and NOT the turkey. He didn’t believe me: it was in a Seinfeld episode (The Merv Griffin Show, season 9) … Jerry Seinfeld the comedian vs. Shelley the Nutrition Expert.

Here are the facts:

  • Turkey contains tryptophan.
  • Tryptophan is an essential amino acid (one of the building blocks of protein).
  • Tryptophan, the dietary supplement (specifically L-tryptophan) is marketed as a sleep aid.
  • Chicken and ground beef contain about the same amount of tryptophan as turkey. Sunflower seeds and soybeans contain more, as does milk.
  • To affect our brain, and make us sleepy, tryptophan needs to be consumed on an empty stomach with no protein present to have an effect on our brain, which tells us we are sleepy.

So does turkey make us sleepy? No. there isn’t enough tryptophan in turkey for it to affect us, it has protein, and generally we aren’t eating it on an empty stomach. If the tryptophan in turkey made us sleepy, then the chicken dinner and the dinner with beef would have the same effect. It just doesn’t add up.

Why do you feel the need for the nap after Thanksgiving? If you ate a lot of food, had many carbohydrates (potatoes, rolls, stuffing, and the pie) along with any alcohol, and then you have found your answer! Even if you don’t consume alcohol, the likelihood of you getting sleepy is higher if you have more carbohydrates.

So, even if take the nap after dinner, don’t blame the turkey or the tryptophan!