NutriStack
Lansoprazole and Vitamin C, a caution.
Lansoprazole reduces the bioavailability of dietary vitamin C by raising intragastric pH, which destabilizes ascorbate. A four-week trial of a PPI lowered plasma vitamin C by about 12% in healthy volunteers despite stable intake. The effect is usually subclinical but matters for patients with marginal vitamin C intake.
One pair, every claim cited. The two substances, the type, the mechanism, the recommendation, and the primary literature.
Same shape as the other 1,729 pairs in the public database.
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What the row says.
Every entry follows the same shape: what is happening, the mechanism, the recommendation, and the primary literature.
At a glance
- Substances
- Lansoprazole and Vitamin C
- Pair type
- Caution
- Evidence (highest tier)
- Moderate
- Source citations
- 2 sources
- Stack Score effect
- −5 to your Stack Score (per scored caution row).
- Scope
- Supplement × Prescription
- Last verified
- May 30, 2026
Caution · Moderate evidence
Caution
What is happening. Lansoprazole reduces the bioavailability of dietary vitamin C by raising intragastric pH, which destabilizes ascorbate. A four-week trial of a PPI lowered plasma vitamin C by about 12% in healthy volunteers despite stable intake. The effect is usually subclinical but matters for patients with marginal vitamin C intake.
Mechanism. Vitamin C is actively secreted into gastric juice as ascorbate, the bioactive form, which oxidizes rapidly to dehydroascorbate at elevated pH. Lansoprazole-induced hypochlorhydria shifts this equilibrium toward the less-absorbable oxidized form.
Recommendation. Eat vitamin C-rich foods daily while on lansoprazole. A 250-500 mg vitamin C supplement with a meal is reasonable; no special timing is needed.
Sources (2)
- Henry EB, Carswell A, Wirz A, Fyffe V, McColl KE. Proton pump inhibitors reduce the bioavailability of dietary vitamin C. Aliment Pharmacol Ther. 2005;22(6):539-45. PMID 16167970
- Freedberg DE, Kim LS, Yang YX. The Risks and Benefits of Long-term Use of Proton Pump Inhibitors: Expert Review and Best Practice Advice From the American Gastroenterological Association. Gastroenterology. 2017;152(4):706-15. PMID 28257716
Stack Score
How this pair moves the number.
Effect on the composite score
If both Lansoprazole and Vitamin C are in the same stack, this pair applies −5 to your Stack Score (per scored caution row).
The full algorithm, the clamping rules, and four worked stacks are documented at /methodology/stack-score.
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