December 11 2013. The December 11, 2013 issue of the Journal of the American Medical Association reports an association between the use of drugs that inhibit excess stomach acid and deficient levels of vitamin B12. By suppressing the production of the stomach’s acid, the drugs, which include proton pump inhibitors (PPIs) and histamine 2 receptor blockers used by patients with gastroesophageal reflux disease (GERD), reduce the amount of the vitamin that is absorbed.
"Vitamin B12 deficiency is relatively common, especially among older adults; it has potentially serious medical complications if undiagnosed,” write Jameson R. Lam, MPH, of Kaiser Permanente and coauthors in their introduction. “Left untreated, vitamin B12 deficiency can lead to dementia, neurologic damage, anemia, and other complications, which may be irreversible."