In natural health care we often talk about hypochlorhydra, or decreased production of hydrochloric acid in the stomach. It is a concept that seems to escape traditional medical thinking. There is some research that supports some of the ideas we have about stomach acid.
One study, published in the Journal of The American College of Nutrition ( 1991;10(4):372-375), looked at the role of acid secretion on zinc absorption. It was a small study, utilizing 11 subjects. The acid inhibitor cimetidine was given (one gram/day) by mouth for three days. Zinc absorption was reduced after cimetidine administration. To ensure that the reduction in zinc absorption was not specific to cimetidine, another H2 antagonist ranitidine was also tested 300 mgs per day for 3 days and 300 mgs before the test meal). It also reduced zinc absorption.
Another study, published in the American Journal of Medicine (May, 1998;104:422-430), looked at B12 levels in patients with Zonninger-Ellison Syndrome who were being treated by suppressing stomach HCl production. The 131 subjects had been treated with either omeprazole (mean duration of therapy was 4.5 years), or with an H2 receptor antagonist (mean duration of therapy was 10 years). Vitamin B12 levels, but not serum folate or any other hematological parameters, were significantly lower in those treated with omeprazole, especially in those who had omeprazole-induced sustained hyposecretion or complete achlorhydria. The duration of omeprazole treatment was inversely correlated with vitamin B12 levels, but not folate levels. Six percent of the patients developed subnormal vitamin B12 levels during follow-up. Patients with Zollinger-Ellison syndrome treated with H+-K+-ATPase inhibitors should have serum vitamin B12 levels monitored since they may be at risk for developing vitamin B12 deficiency.
Stomach HCl production may be a factor for anemic patients who do not respond to therapy. In some older studies (Lancet, [April 16, 1966:845-848] and Br J Haematology [1966;12:728-736]) both showed a connection between low stomach acid production and iron deficiency anemia. Granted, these are old studies, but there are not many studies that look into the underproduction of stomach HCl and they are worth mentioning.