[thedoc (OP)]

What is tryptophan? Does eating turkey really make you sleepy?

Asked by Rick Shepp

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[thedoc (OP)]

[img float=right]http://www.thenakedscientists.com/HTML/uploads/RTEmagicC_800px-Thanksgiving_Turkey.jpg.jpg[/img]We put this to John Fry, consultant in food science, nutrition and dietetics.

There's been a question about sleepiness caused by tryptophan in turkey and this is a popular myth in the United States that a feeling of sleepiness arises after the Thanksgiving meal and it's caused by the Thanksgiving turkey having a high content of a substance called tryptophan. Tryptophan is an amino acid, one of the building blocks of protein which means that pretty much all proteins contain some Tryptophan but turkey's not unusual in its tryptophan content. It has about the same amount as chicken or beef. Tryptophan is involved in the desire to sleep after a heavy meal but only indirectly. The root cause of the drowsiness but only indirectly. The root cause is the large carbohydrate intake that usually accompanies a celebratory festive meal. All those roast potatoes, the stuffing, not to mention sugar-rich puddings. They all result in a burst of insulin in the blood stream as the body tries to cope with this influx of sugars. One of the side-effects of this secretion of insulin is that tryptophan gets into the brain more easily and once there part of the tryptophan is transformed into a substance that's called melatonin. Melatonin is a hormone involved in sleep regulation and it can encourage sleep. But really it's the carbohydrate in a heavy meal that triggers drowsiness and tryptophan is just a bit player in the biochemical consequences of over-indulgence in carbohydrates.

[chris]

Tryptophan is an amino acid, a building block of protein, although what it has to do with turkey I haven't a clue!

Chris

[RD]

Association being mistaken for a causal relationship ...

the sleepy-turkey myth lingers around each year because it sounds so logical.

Alas, it is only marginally true. What's making you sleepy after Thanksgiving dinner is any combination of booze, bad conversation and a carbohydrate-heavy meal, but not the turkey itself.

The tryptophan trip

Tryptophan is an essential amino acid crucial for good health. Human bodies need tryptophan to build certain kinds of proteins. There is a sleep connection, though. The body uses tryptophan in a multi-step process to make serotonin, a neurotransmitter in the brain that helps regulate sleep.

Turkey does have tryptophan. But all meat has tryptophan at comparable levels. Cheddar cheese, gram for gram, has more. While cheddar isn't the most exciting cheese in the cheese cellar, no one connects it with sleep. Turkey gets singled out for no other reason than being eaten during the biggest meal of the year.

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[JP]

I think RD pretty much has it.  In addition, L-Tryptophan used to be marketed in the US as a dietary supplement to promote (among other things) sleep.  After an outbreak of eosinophilia-myalgia syndrome related to the supplement, the FDA banned its sale in 1989, but overturned the ban in 2001.  I'm not sure what its supplement status is elsewhere in the world.

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[scigirence]

And so goes any lingering awkward silences over the Christmas Dinner table!

[JnA]

"Cheddar cheese, gram for gram, has more. While cheddar isn't the most exciting cheese in the cheese cellar, no one connects it with sleep."


everything I've read about cheese and sleep talks about how cheese makes you dream more vividly. I don't know how true it is.. but the connection is starting to form in my head...

[chris]

Researchers have shown that people put on tryptophan-deficient diets get depressed. This is because tryptophan is an essential amino acid, meaning that it cannot be made in the body, and is also the precursor of 5HT (5-hydroxytryptamine or serotonin), the brain's feel-good chemical.

So self-inflicted depression is feasible, by eschewing trytophan in food.

Chris

[srobert]

So is that why when I'm feeling a bit down mac and cheese always makes me feel better? If not please don't tell me 'cos I like the idea of having to eat loads of the stuff for the good of my mental health, and forget the diet!

[chris]

Maybe part of the satisfaction that accompanies consumption of said junk food might be relief at the fact that you've survived the experience without developing BSE, salmonella or cholesterol poisoning...

C

[RD]

So is that why when I'm feeling a bit down mac and cheese always makes me feel better?

Possibly due to positive associations with McDonald's, e.g. childhood birthday parties at McD's.

alternatively ...sorry, you cannot view external links. To see them, please REGISTER or LOGIN,
 if so addicts would feel better immediately after their fix.


[Old McDonald has come a long way: when I was at school he only had one farm  [] ]

[yor_on]

Well, 'wild turkey' might get you sleepy.
But that you don't eat, more like ahh.
Let me put it this way:)
'gulp gulp gulp'
Aahhhhhhh:)

[Atomic-S]

In my experience, eating beans induces drowsiness, as does eating yogurt, Eating both together affects me powerfully, I can hardly keep my eyes open.