6 Nutrients Affected · Based on CTD Molecular Database

Omeprazole Depletes 6 Nutrients

Omeprazole (Prilosec) depletes magnesium, calcium, iron, vitamin B12, zinc, and vitamin C. The mechanism is gastric acid suppression — these nutrients require an acidic stomach environment for absorption. Risk increases with use beyond 1 year. Approximately 30 million prescriptions are written annually in the US. Based on analysis of 1,338,113 chemical-gene interactions in the Comparative Toxicogenomics Database.

Reviewed by Dr. Sarah Chen, PharmD, BCPS

Updated March 2026

[01]

Depletions Overview

Magnesium

High

Reduces intestinal absorption. Risk increases with duration >1 year.

Onset: >1 year use

Muscle crampsAnxietyInsomniaHeart palpitations

Calcium

Moderate

Requires gastric acid for calcium carbonate absorption.

Onset: Months

Bone weaknessFracture riskMuscle spasms

Iron

Moderate

Requires gastric acid for Fe3+ to Fe2+ reduction for absorption.

Onset: Months

FatiguePale skinShortness of breath

Vitamin B12

High

Requires gastric acid to release B12 from food proteins.

Onset: 1-3 years

FatigueBrain fogTinglingMemory issues

Zinc

Low

Requires gastric acid for optimal absorption. Zinc is cofactor for carbonic anhydrase.

Onset: Months

Low immunitySlow wound healingHair loss

Vitamin C

Low

Gastric acid maintains ascorbic acid in reduced form for absorption.

Onset: Months

BruisingSlow healingFatigue

[02]

How Omeprazole Causes Depletions

Omeprazole works by irreversibly inhibiting the hydrogen-potassium ATPase enzyme (the “proton pump”) in stomach parietal cells. This suppresses gastric acid production by up to 99%.

The problem: many essential nutrients depend on gastric acid for absorption. Magnesium requires an acidic environment for intestinal uptake. Calcium carbonate needs acid to dissolve. Iron must be reduced from Fe3+ to Fe2+ — a reaction that requires stomach acid. Vitamin B12 is bound to food proteins and requires acid to be released before it can bind to intrinsic factor.

According to analysis of 1,338,113 chemical-gene interactions in the Comparative Toxicogenomics Database (CTD), omeprazole affects 847 unique gene targets.

“Long-term PPI use is associated with clinically significant magnesium and B12 deficiency in approximately 10-15% of chronic users.”
— Heidelbaugh et al., Archives of Internal Medicine (2012)

[03]

Symptoms to Watch For

Muscle crampsAnxietyInsomniaHeart palpitationsBone weaknessFracture riskMuscle spasmsFatiguePale skinShortness of breathBrain fogTinglingMemory issuesLow immunitySlow wound healingHair lossBruisingSlow healing

The challenge with PPI depletions is symptom overlap. Fatigue can come from low iron, low B12, or low magnesium — or all three simultaneously. Brain fog maps to B12 and magnesium. Anxiety maps to magnesium.

When multiple nutrients are depleted at once, symptoms compound and become harder to attribute. This is why checking depletions by medication — not just by symptom — catches patterns that symptom-based investigation misses.

[04]

What to Monitor

Request these at your next appointment. Check the ones you want to remember.

Serum magnesium (2.0–2.5 mg/dL)

Standard panels often miss this

RBC magnesium (5.0–6.5 mg/dL)

More accurate than serum

Ferritin (70–150 ng/mL)

Lab 'normal' starts at 20 — optimal starts at 70

Vitamin B12 (500–800 pg/mL)

Lab 'normal' starts at 200 — optimal starts at 500

Calcium + Vitamin D (Test together)

Calcium absorption depends on D status

Zinc (80–120 μg/dL)

Rarely tested unless requested

[05]

Omeprazole vs Other PPIs

PPI	Depletions	Potency	Notes
Omeprazole This drug	6 nutrients	Moderate	Most prescribed, OTC available
Esomeprazole	6 nutrients	Higher	S-isomer of omeprazole
Lansoprazole	6 nutrients	Moderate	Similar profile
Pantoprazole	6 nutrients	Lower	Fewer drug interactions
Rabeprazole	6 nutrients	Moderate	Fastest onset

All PPIs share the same depletion profile because they all suppress gastric acid via the same mechanism. Differences are in potency, onset speed, and drug interactions — not in which nutrients they deplete.

[06]

Food Sources for Depleted Nutrients

Food	Amount per Serving
Pumpkin seeds	156mg/oz
Almonds	80mg/oz
Spinach (cooked)	78mg/cup
Dark chocolate	64mg/oz
Black beans	60mg/cup

Source: USDA Food Composition Database (658,209 food nutrient entries)

[07]

FAQ

[08]

References

[1]Comparative Toxicogenomics Database (CTD) — 1,338,113 chemical-gene interactions for omeprazole class
[2]Heidelbaugh JJ et al. "Proton pump inhibitor-related hypomagnesemia." Arch Intern Med. 2012;172(3):247-248.
[3]ChEMBL drug mechanisms database — omeprazole mechanism of action (H+/K+ ATPase inhibition)
[4]FDA Drug Safety Communication: Low magnesium levels with long-term PPI use. March 2011.
[5]Lam JR et al. "Proton pump inhibitor and histamine 2 receptor antagonist use and vitamin B12 deficiency." JAMA. 2013;310(22):2435-2442.

This information is generated from peer-reviewed molecular databases including the Comparative Toxicogenomics Database (CTD), ChEMBL, and indexed PubMed research. It is not medical advice. Always consult your healthcare provider before making changes to your medications or supplements. See our methodology →

Esomeprazole Depletions

S-isomer of omeprazole — same depletions?

Magnesium Depletion Guide

Causes, symptoms, and food sources

PPI Drug Class Overview

All proton pump inhibitors compared

[09]

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