Over at another question I commented that cold water is traditionally thought to be hard on digestion. I wrote "Drinking ice water is a ridiculous idea that is uniquely american. Enzymes work in a very narrow temperature range so if you throw cold fluids on them it headers their ability to perform. This forces the digestive tract to use energy heating food rather than digesting it."
This prompted Dr. The Quilt to respond with a study that showed that cold water increases full body metabolism.
Me: "Just because it increases metabolism doesn't mean it's a good thing. I didn't say it doesn't increase metabolism. What I was saying is that it is a stupid way to increase metabolism. Stressing the gut so the body freaks out so that it can digest doesn't sound like a good idea to me and a lot of traditional medicine agrees with that diagnosis. Reams of n=1 also confirm this."
Jack/Dr. Quiltness: "you said it was an American thought......it was german. And it works too. You can call BS if you choose but it works. Many studies have confirmed this too. NASA showed that 40 degree water is the ideal water temp for their training for spacewalk weight loss prevention...Nasa actually heat water up in space because of this. The astronauts shred weight in space like mad. So any savings they look for so they do not have to send up more payload on trips requiring long space exposures"
Me: Cooling your digestive track shouldn't be a weight loss strategy. Not because it doesn't cause weight loss but because it interferes with digestion both by moving enzymes outside of their optimal temperature range and by causing vasoconstriction in the GI. In the short term it might not be a bloody huge deal but long term it can wreak havoc on the gut. And what I said was that drinking ice water is more of an American culture idea not that Germans didn't do studies on it.
Primallykosher: I would think the food would warm up in the stomach anyway.
Me: yeah, it doesn't seem like a big deal at first glance. Most people already have a low core temp. Throw a bolus of cold on top that and you're stressing the core temp even more often. There is very little research out there that I can find on the bodies ability to warm cold food so I've got to go with physiological plausible mechanisms and n=1 stories. Try removing cold from your diet and see if your digestion improves. Easiest thing the world to try and 3000 years of Chinese medicine will support your decision to try it. They'd actually prefer that you only drink liquid body temperature and above but I'm a bit of softy and am not an oriental medicine doc so I allow room temperature beverages into my body.
What side of the fence do you fall on?
I'm on the fence about this particular idea. I can see a number of ways it could go, and why traditional medicine would encourage the drinking of water that had been boiled and steeped with medicinal herbs, especially when drinking from wells in crowded cities and villages. Cholera certainly isn't worth the glass of cold water, and over time it was probably observed that folks who drank hot beverages didn't keel over from water borne illnesses as often. In times of food scarcity, especially agrarian food scarcity, you would want to hold on to every calorie possible, and if warm drinks are less taxing on the body and use less energy to digest that would be a good thing.
Going further back historically, drinking water sources in colder climates probably would have been just above freezing, and if that drastically impaired digestion I don't think there would be as many of us around today. Perhaps we have compromised our digestive enzymes so much with a modern diet that cold water can have this serious of an impact on our digestive abilities.
Third thought, modern day lab setting, maybe cold water is the new Olestra. Perhaps part of the noticed short term "benefit" is from impairing enzymatic activity, and not being able to digest food as well and losing weight from that combined with the thermodynamic effect.
I must be missing something. Consuming warm or cold food or beverages may give a certain feeling when they go down the hatch, but everything equalizes to body temperature. I can't imagine food, or especially liquids, maintaining their temperature for very long after hitting the stomach, so I guess that's the side of the fence that I'm on.
What a timely post for me!
I've never liked drinking cold water (or showering in it for that matter) but just this week I've been giving cold water a try, as I thought it was more logically 'paleo' ! The idea being that when hunters and gatherers were out for the day, and come upon a stream or whatever, they'd just drink the water without bothering to stop and make tea. And honestly I'm not disliking it as much as I thought I would. I've put this down to my paleo diet, as since going paleo I have noticed other temperature (or circulation) related improvements. I used to always have ice cold feet and hands for example but no more.
Whether drinking cold or warm water is 'optimal' for health or not would surely be very difficult to determine conclusively. And perhaps what is best for one person on any particular day might change the next day.
My limited understanding of Ayurveda for example, would lead me to think that I may currently be adjusting from being Vata (always cold, needing warmth) to Pitta (easily heated, prefers cool). It's summer here in Australia and I'll be interested to observe if I adjust back to Vata in the winter.
So my personal opinion, based on no real science at all, would be that the body runs optimally when the temperature of the food or drink consumed is assisting (if required) to keep the inner temperature of the body at its optimal level. So cold drinks and food if you are feeling hot, and warm drink and food if you are cold.
And I think the pleasurable invigoration from a glass of cold water (similar to the invigoration you feel with a cold shower) is more positive for the body than negative.
I don't know how it affects digestion, but drinking cold water with food will give you cancer. I got this helpful email from a coworker last year; he was kind enough to forward it to the entire company-
"Cold Water = CANCER
Drinking cold water after meal = Cancer! (this is not a joke)
For those who like to drink cold water, this article is applicable to you. It is nice to have a cup of cold drink after a meal. However, the cold water will solidify the oily stuff that you have just consumed. It will slow down the digestion.
Once this "sludge" reacted with the acid, it will break down and be absorbed by the intestine faster than the solid food. It will line the intestine.
Very soon, this will turn into fats and lead to cancer. It is best to drink hot soup or warm water after a meal."
My seventeen year experience with Ayurveda leads me to sit on the warm side of the fence. The ice water thing is so American.( Like pasturized milk.) I just ordered eight more bottles of PQQ, so I 'm a big Quilt fan. But I'll go with David Frawley(Ayurvedic Mavin) on this issue. I also NEVER mix fruits and veggies. Instant stomach ache every time. The East has lots of things to teach us. This anti-East ethos is one of the weaker aspects of Paleohacks. Just saying......
When it is cold outside, I like hot drinks. When it is hot outside, nothing beats a glass of water with ice cubes. I think it can be as simple as that- there is only a small window where the liquid is going to stay at it's original temperature before it gets diluted and cooled/heated to your internal temperature. Unless you are shooting back a liter of ice water at a time, I really can't conceive that this could have a large effect on the gut, particularly in regards to the vasoconstriction that you mentioned.
Just because Americans drink their liquids colder on average (though ice water is very very accessible in many other countries) doesn't mean this is the cause of all of the problems. Regularly mountain hiking and filtering my own water from streams tells me that drinking fresh, cold water is a pretty nice experience. 3000 years of Chinese medicine doesn't mean that it's auto-legit- my Chinese grandma fed me all kind of weird herbs that I now know have little to no efficacy.
Hot or cold, we can handle it either way. Whatever floats your boat when the weather outside is frightful or delightful...
Here are some (unorganized) thoughts, I've had about this over the years.
The Ahrennius (check the spelling) equation gives a rule of thumb about chemical reaction rates. The basic result of that is that every 10 degrees (Celcius) you increase a reaction's temperature, you double the reaction rate. So your body is at 37 degrees, and it's nothing to drink ice water at 0 degrees, so that's nearly 40 degrees, which would be slowing down the reaction rate of digestion by 16 times. So until the water warms up, you will be slowing down any (temperature dependent) reactions with the stomach acid and your food.
You're also diluting the stomach acid, so that will affect digestion rates too
Those two statements above are true statements as they deal with the underlying physics and chemistry of the situation; however, the real question we should be asking is "does it matter?". I don't know. My guess is that the water should be warmed up pretty quickly, so the reaction rates should come up pretty quickly. And we should be able to pump more acid to make up for the dilution. I'd say that most of it is personal experience and for you to try it and see how your body reacts to it.
One more thought, a (food) Calorie is defined as the energy required to heat 1 kg (1 L) of water 1 degree Celcius. So just drinking one liter of ice water would require you to burn 37 calories just to warm it up to body temperature.
Also, see my other post on drinking too much and diluting stomach acid.
I do like ice cold water when I'm doing an intense exercise or warm. Warm water doesn't sound appealing though. Vasoconstriction of the GI blood vessels could also slow digestion speed, which would result in harder bolus.