H2 Blockers (Acid Reducers)
Common brand names: Pepcid (Famotidine), Zantac (Ranitidine), Tagamet
Two nutrients listed against this medication. The most severe is marked moderate.
At a glance
One of the two is marked well documented. The other one carries its own evidence level.
At a glance
- Vitamin B12Moderate · Well documented
- ZincModerate · Traditionally cited, limited evidence
Color shows how serious each listed effect is. The label beside it shows how strong the evidence is. The cards below explain each one and show its evidence.
Nutrients it can lower
Mechanism, H2 blockers reduce gastric acid, impacting food-bound B12 absorption (though less severely than PPIs).
Common signs, Fatigue, cognitive changes, elevated homocysteine An amino acid in the blood that rises when vitamin B12, folate or B6 are low. with long-term use
Lam et al. (JAMA, 2013; PMID PubMed ID: the permanent number the US National Library of Medicine gives a published paper. Each one links to that paper's record on PubMed. 24327038): 2+ years of H2-blocker use was associated with incident vitamin B12 deficiency in a large case-control study.
Methylcobalamin 500–1,000 mcg sublingual daily is a range in common use, not from a trial cited on this row. Lam reports B12 deficiency associated with two or more years of H2-blocker use and tested no repletion dose or route.
Mechanism, Reduced gastric acid from H2 blockade impairs zinc ionization and absorption.
Common signs, Immune suppression, taste changes, skin issues
Sturniolo et al. (1991; PMID 1894892): zinc malabsorption with acid suppression
Zinc 15 mg daily with food is a figure in common use, not from a trial cited on this row. The cited paper measured zinc absorption under acid suppression and tested no repletion dose or form.
For your next appointment
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Disclosure
These statements have not been evaluated by the Food and Drug Administration. Any grade on this page describes the strength of published human trial evidence in the populations studied. It is not a recommendation for any individual and is not medical advice. Starting, stopping or changing any supplement or medication is a decision for your physician.
Grades move when new trials publish. A free monthly email lists every grade EBL moved, with the reason and the trial behind it: the sign-up is on the Evidence Log →