drink water, orange juice or Cola before eating?

[daniel.kurz]

It is a complete untruth that you should not drink water with a myth. It is an urban myth that was started that has no factual basis. If you drink water, the stomach has the ability to detect pH. The actual process is much more complex mechanically, but that doesn't need to brought into the discussion. Pepsin is the active form of a protein called a zymogen which is enzyme that has to be cleaved to be activated. Pepsin as well as other enzymes (enzymes are all proteins but not all proteins are enzymes) such as trypsin start off with -ogen at the end of their name. Pepsinogen and trypsinogen. They are cleaved by the hydrochloric acid secreted by parietal cells in the stomach to pepsin and trypsin (both secreted by chief cells).

Regardless of acidity in the stomach, the acid is neutralized in beginning by bicarbonate because the acid will damage the enyzmes and the lining of the intestine. Now, only in specific cases such as chronic heart burn or ucler conditions will acidity be a problem. There can also be problems with not secreting enough acid in some individuals. Only found in the elderly but relatively not frequent. For the most part, people do not have a problem secreting enough acid into their stomach. Drinking soda and juices can just add to unwanted many calories in the diet for some people.

If you withhold water during a meal, the stomach has to make more mucus and water into the stomach which can be a major problem for those that suffer hypertension and other blood volume conditions. The stomach cannot mix properly if it does not have the fluidity to mix problem. You can try this by eating a very heavy fatty cake where the water will not mix with the fat (trust me it doesn't feel good). The enzymes in the intestine have to find their destination in the food in order to breakdown the food that you have consumed. If you have a nice "dry" stomach, where everything is really super viscous your enzymes will not find what they are looking for as easily and will result in improper digestion. This can result in digestive problems further down the line. Now, there is some validity to not drinking as much water because it might slow down stomach emptying and as a result keep you full longer. This is advantageous in those that want to lose weight by doing less snacking.

The moral of this story... drink water with your meal or any other beverage in moderation (not too much and not too little) because your body is extremely adaptive. Unless you have instructions from your physician or evidence to say that you have an acid secretion problem, don't worry too much and enjoy your meal. Like others have said, try eating without a drink and its quite hard.

[JackBean]

not all enzymes are proteins, e.g. the ribozyme is RNA
trypsin is not cleaved by HCl since it is not in stomach
why should be the acid neutralized? Where does the bicarbonate come from?