My Aged P ("aged parent") was here visiting last night. He is a retired family practice physician, so I told him about my recent research on retinol metabolism pathways, immune tolerance, and diet differences that appear implicated in various undesirable immune and autoimmune reactions. Specifically, we discussed the Israeli peanut snack, Bamba and its ability to help keep at-risk children from developing peanut allergies. As I talked about the chloride ions provided by the dissolved salt in Bamba, my father pointed out that people already have chloride ions in their stomachs because gastric acid's most important constituent is hydrochloric acid, which dissociates into hydronium and chloride ions.
Not having gone to medical school, I appreciated his insight. And then I thought, well, then people with low hydrochloric acid, i.e., "hypochlorhydria," should be more likely to suffer from food allergies than people with adequate stomach acid. I did a little research, and found that over 80 years ago, researchers were noticing an association between low gastric acidity and various allergic conditions. Recent research still finds this association. For example, a study published three years ago found that children with GERD who were given gastric acid suppressing medications were more likely to develop food allergies than children with GERD who were not given gastric acid suppressing medications.
I grew up hearing from TV ads that stomach acid is a bad thing that must be neutralized. I don't think that's generally true. It's bad to have the acid get into the esophagus--we call that "heartburn"--but stomach acid performs many important functions, including perhaps helping our bodies not become allergic to foods.