Cold water. To drink or not to drink.
There is a popular meaning that drinking cold water slows down digestion. The question raised in comments and I’ve decided to answer. As usual, the answer is easy as a piece of cake - if you don't see the logic, the logic is usually absent.
Briefly - you can drink cold water it has nothing to the digestion.
Also, the question can be subdivided into 2 parts. Is it true that digestive juices are water soluble and thus digestion slows down? And is it true that cold water and drinks decrease the digestion time and as a result, we are not receiving the needed macronutrients?
The first part at first :) In digestive process is used the following: acid (hydrochloric acid and digestive ferments - pepsin and rennin) and bile]. Acid is needed for proteins and carbs digestion, while bile is used for digesting fats.
The paint is that acid solution is water-based, which means that additional water won’t change anything - our stomach can regulate the acidity. Moreover, water has several supplementary functions: flushing food parts from the oesophagus; - helps to beat big parts of food to provide the access for ferments and acid (every food even in the cold water changes its structure, for instance, super-healthy buckwheat, which can be put into cold water for night to became ready-to-go breakfast in the morning)
The second part - Is it true that cold water and drinks decrease the digestion time?
We have several reliable researches: «Gastric emptying of liquid and solid meals at various temperatures: effect of meal temperature for gastric emptying» - hot food digests faster than the cold one. «Effect of test meal temperature on the gastric emptying of liquids» - food with a temperature lower than the body ones digests slowly because there is needed additional energy to “heat” the food to the needed temperature.
And one more interesting research - «Cold pain prolongs gastric emptying of liquid but not solid meal: an electrical impedance tomography (EIT) study». It says that cooling prolongs the digestion time, even if you just put your hands into the cold water ))
Also, there are several researches where no significant difference between hot and cold food was founded. And I haven’t found anything saying that cold food can be digested faster than the hot one.
Preliminary conclusions: «Gastrointestinal Regulation of Water and Its Effect on Food Intake and Rate of Digestion» - consuming water with food does not affect digestion in any way...
Conclusions: Drink water - it’s needed. It really helps.