When nutrient enter the stomach, they are combined with Hydrochloric acid (HCL), Pepsin and a host of other enzymes. The HCL breaks down the nutrients, into a thick liquid mass, called Chyme. The HCL also assists the Peptic enzymes, in converting proteins, into peptones. Many proteins are allergens and will cause allergic reactions, if they are not broken down and destroyed, by the action of the HCL and Peptic enzymes.
Pepsin is most active in the conversion of proteins, when the strength of the HCL is at 1.0 pH. When the strength of the HCL diminishes, the peptic enzymes, become less active, in the conversion process. At pH 5.0, the peptic enzymes are no longer active, in the conversion process.
The reduction in the strength of the HCL is called Hypochlorhydria, in extreme cases it is called Achlorhydria.
As part of the aging process, the acid producing cells in the stomach (parietal cells) wane in their ability to produce sufficiently strong acid. When this occurs, nutrients are no longer completely sterilized and the peptic enzymes can no longer break down protein allergens. Hypochlorhydria will allow raw nutrients to enter the small bowel, resulting in allergic reactions. Many people as they age develop food allergies that they never had when they were younger. The development of food allergies as a person ages is caused by Hypochlorhydria. Strong hydrochloric acid, in the stomach, is absolutely necessary, for sterilization and conversion, of the nutrients consumed. Hypochlorhydria will allow bacteria, fungus and pathogens to enter the small bowel. It will also cause the overgrowth of bacterial in the digestive tract. The use of antibiotics, proton pump inhibitors (PPIs) and other medication will stop the parietal cells in the stomach from producing acid. There is a lot of information on the web about food allergies, check out digestiveblog.com, or search for pH diagnostic test, pH gastrogram, or pH capsule test.