[dentstudent (OP)]

If you drink tea etc a bit hot, you can feel it going down (as it were). The same for cold stuff - but are they at the same temperature when they hit the stomach?

[kdlynn]

that's a good question. i accidentally swallowed an ice cube once, and i felt it hit my stomach. and it did not feel good.i was very aware of my stomach until it melted. it felt weird.

[dentstudent (OP)]

It might remain unanswered though!

[SquarishTriangle]

I would think that the short amount of time it takes for something to travel from the mouth, down the oesophagus to the stomach is not sufficient to change the temperature significantly, although there would be a slight increase or decrease in temperature for colder than and hotter than body temperature food respectively. The stomach is classified as an "external environment" of the body, so the body would not be overly concerned with regulating the temperature of the stomach contents. However, regulating the temperature of the internal environment (ie. the other side of the gastrointestinal wall), is of far greater importance and the body dedicates energy to actively keeping the internal temperature within a constant range.

Enzymes, including the digestive enzymes within the stomach, have optimal ranges of temperature, acidity etc. I assume the optimal temperatures for the digestive enzymes would be similar to the normal body temp ranges (about 37-38c)...so maybe there is an importance to keeping stomach temps regulated (I realise I'm contradicting myself, but it is 1 in the morning). However, it's probably unlikely (other than for scientific purposes) that you would swallow enough ice or boiling hot water to significantly change the temp of the entire litre or so of stomach volume you have...but then you don't need enzymes to digest water anyway (yeah, now I really am muttering).

Anyway, with food, the normal way of eating (ie. the way your body is most likely to have response mechanisms for) is to chew it before swallowing, and if you haven't noticed already, chewing and mixing your food with saliva in your mouth brings it fairly quickly to a "comfortable" temperature before it even reaches your stomach.