B12 must be cleaved from its protein carriers by an acidic pH of the stomach. If you take antacids or use any acid-blocking medications, such as Nexium, Prilosec, AcipHex
, or Zantac, you will not free vitamin B12 for absorption Also, a protein, called intrinsic factor, must be produced in the stomach to bind with vitamin B12
to aid in its absorption. Patients who take acidblocking medications will not produce intrinsic factor and are destined to become B12-deficient.