Effect of omeprazole on plasma zinc levels after oral zinc administration.
Level 3 - non-randomized controlled study
Non-randomized, self-controlled before-and-after interventional trial in humans
What was done
Fourteen healthy volunteers were evaluated before and after 7 days of oral omeprazole (60 mg/day). Fasting gastric pH, gastric volume, and basal and maximal acid outputs were measured. Plasma zinc levels were measured at baseline and at 1, 2, 3, and 4 hours after oral administration of 300 mg zinc sulfate to determine zinc absorption before and after omeprazole.
What was found
Omeprazole significantly increased fasting gastric pH from 2.4 to 5.5 (p < 0.001). Mean basal acid output decreased from 8.0 to 1.6 mEq/h (p < 0.001) and maximal acid output decreased from 106.6 to 20.6 mEq/h (p < 0.001). Zinc absorption decreased from 245 (35) mg/dL/h pre-omeprazole to 141 (34) mg/dL/h post-omeprazole (p < 0.01).
Why it matters
This study demonstrates that gastric acid suppression from proton pump inhibitors significantly reduces the intestinal absorption of orally administered zinc.
Limits
The study is limited by a very small sample size (n = 14) and an unblinded, non-randomized before-and-after design lacking a parallel control group. It tested a short duration (7 days) of high-dose omeprazole (60 mg/day) in healthy subjects, leaving chronic effects, clinical deficiency endpoints, and lower typical therapeutic doses unassessed.
Cited by
- supports Proton pump inhibitors and reduced gastric acidity impair zinc absorption.