19 replies to this topic

[scientistsahai]

Globally a lot of people eat rice as a part of their staple food. I have felt that I feel sleepy after consuming rice. I have personally observed this and a lot of peoples views have confirmed the same.

Can anyone please throw light on this ...

• What (factors) in rice induces sleep?
• Is the variety/quality of rice linked to this? Has it been scientifically proven?
• Does the glycemic load/glycemic index of rice play a role in triggering sleep?
• What is the mechanism of action of factor(s) that induce sleep?
• Does the brain need to concentrate on digestion of rice and switches off the other signals which make us lethargic?

Please help me uncover the mystery behind this
Any nutritionists, physicians, dieticians ....

[iNow]

My suggestion is that we often feel sleepy after eating most heavier meals, regardless of what food we have ingested. Most times when we eat, we get sleepy. If I'm not mistaken, this is because much of the blood previously in our brain is diverted to our belly to assist in digestion.

Since rice is a grain, it is harder to digest, and takes more time and energy to do so. That energy which would normally be used to keep you awake, alert, and productive is now being used to digest the grains of rice you have ingested.

I don't think it has anything to do with chemicals in the rice, or rice quality, but more to do with the fact that digestion changes the energy usage pattern in our body and rice is somewhat more difficult to break down.

That's my guess. I will apologize now if I am mistaken or wrong about anything above.

[CharonY]

I do not think that rice should have any particular stronger effect than any other foodstuff. For a big part it is simply starch.

[StringJunky]

I checked it out on a few sites and it would appear that rice (especially brown) is rich in tryptophan. This is an amino acid that can have calming properties in the presence of a lot of carbohydate Pumpkin seeds contain a lot of tryptophan as well and had this effect on me some years ago. Heating milk also releases tryptohan, hence, giving it a mild sedative effect

http://www.askdrsear...l/4/t042400.asp

[iNow]

Interesting. That same chemical is in turkey, and is well known for causing sleepiness (like after a Thanksgiving dinner here in the US).

[StringJunky]

Interesting. That same chemical is in turkey, and is well known for causing sleepiness (like after a Thanksgiving dinner here in the US).

I think that same phenomenon is replicated all over G.B. at Christmas!

It is`a useful substance to exploit when you have the odd bout of insomnia. I heat a mug of milk with a good amount of sugar and a minimal amount of coffee to give it a bit of taste...relaxes me enough to sleep.

[CharonY]

Actually according to most papers tryptophan content in rice is rather low. In livestock with rice based diets tryptophan is supplemented. There are GM versions with high tryptophan content around, but I do not think that they are used for human food yet.
Also tryptophan itself is not calming, but serotonin (of which tryptophan is a precursor).

According to Comai et al (International Congress Series Volume 1304, 1 November 2007, Pages 227-232). Rice had the lowest (non-protein) trp concentration.
To have any effect you would have to eat rather enormous amounts of rice and rice cake.
The same is for milk btw. The amount is too low to have any true effect. It is likely that having any drink that relaxes you will have the same effect. And yes, the same is true for turkeys. There are estimations out there that one need gallons of milk and around 30 pounds of turkey to get trp concentrations with any physiological effects.
And that is only if you are able to utilize all that is present in the meat/milk/rice. The bioavailability (the amount that can be actually utilized by your body) is only a fraction thereof. In addition for the sleepiness part only the tiny remaining amount that actually passes the blood-brain barrier will have any effect. This fraction (given that in about any protein containing food trp will have the lowest abundance), is so incredibly low that even those vast amounts underestimate things.
Sounds like urban myths to me, I am afraid.

Edited by CharonY, 28 August 2009 - 08:58 PM.

[Dudde]

Speaking strictly from 15 years of cooking for 4-25 people on a regular basis, I can say that heavier foods make you tired. I always guessed it was energy being sapped to digest, as opposed to any chemical attributes - if you put a bunch of raw vegetables or fruit into some rice, you probably won't experience the weariness as much as if you had steak and potatos mixed in with rice.

kinda makin' myself hungry

[Mokele]

It's pretty obvious from an anatomical POV - once you eat, your body diverts blood and energy to the gut to process the food. And not a small amount, either.

You have 3 major gut arteries - celiac (stomach and that general area), superior mesenteric (midgut, including most of the small intestine), and inferior mesenteric (part of the large intestine). The former and latter are big enough to stick a pencil into, and the superior mesenteric artery is big enough to put a finger in. By comparison, your

So when folks say 'increased blood flow to the gut', we're talking about a LOT of blood.

[Mr Skeptic]

Look what I found:

http://en.wikipedia....in#Biosynthesis
Melatonin is also synthesized by various plants, such as rice, and ingested melatonin has been shown to be capable of reaching and binding to melatonin binding sites in the brains of mammals.[14][15]

Melatonin being one of the major factors for sleep. What temperature is necessary to destroy melatonin?

[Mokele]

No food has been found to elevate plasma melatonin.

[StringJunky]

I've found this that seems to support the wikipedia article linked by Mr Skeptic. It seems to show that rice contains melatonin which is capabe of binding to the receptor sites but does not indicate the amount one would need to eat to have the sleep inducing effect.

http://www.ncbi.nlm..../pubmed/7773197

[Mr Skeptic]

No food has been found to elevate plasma melatonin.

What of the reference in wiki (#15) where it specifically says it does raise plasma melatonin?

[Mokele]

Meh, perhaps I'm wrong. Still, IMHO, this or that chemical in food is likely to be minimal in effect compared to simply re-routing blood flow and increase in parasympathetic nervous system output.

[Capita]

I dont know exactly what kind of rice you are eating but keeping the glycemic index in mind the white rice will make your blood sugars rise high and then crash as it is not complex and will be broken down quickly as compared to something like brown rice. Both high and low blood sugars from diabetes makes me rather tired. Not to mention like every one else said more energy is used for digestion rather than to your head.

[insane_alien]

carbohydrates found in rice are exactly the same as carbohydrates found in other foodstuff.

[iNow]

Same spammer, different username, I_A. Check the sig. Mods have already deleted like 5 posts of the exact same format from this thread.

[insane_alien]

i really need to start reading sigs

[iNow]

Hey... Look. Yet another post to this thread from a brand new user with the EXACT same format of spam in the signature. That's GOT to be a coincidence. It's only happened nine times now. First post. New user. This thread. Two links in the sig. Good stuff.

[swansont]

Man apparently does not live by rice alone. One needs spam, too.