The digestive process takes place as food passes through the mouth, stomach, small intestine, and large intestine. A low level of gastric acid increases the likelihood and severity of certain bacterial and parasitic intestinal infections. A normal stomach's level of gastric acid is sufficient to destroy bacteria. In one study, most fasting people who had normal gastric acid in the stomach had virtually no bacteria in the small intestine. Some bacterial colonization of the stomach occurred in individuals who had low levels of hydrochloric acid.
Gastric acid is produced by the parietal cells of the stomach.
The acidity is quite strong in a normal stomach. In fact, the stomach can be between 100,000 and almost 1,000,000 times more acidic than water. Betaine HCl is the most common hydrochloric acid-containing supplement. Normally it comes in tablets or capsules measured in grains or milligrams. This form of betaine is different from betaine HCl.