Calcium carbonate absorption with antacids questioned
What it found
The advice to give calcium citrate instead of calcium carbonate to people taking antacids is not backed by convincing scientific evidence.
Whether calcium carbonate needs stomach acid to be absorbed is also unproven.
What they found
Guideline advice
American guidelines and UpToDate recommend prescribing calcium citrate to patients who use antacids. The reason given is that water-insoluble calcium carbonate needs acid for adequate absorption.
Evidence for the advice
No convincing scientific evidence supports prescribing calcium citrate instead of calcium carbonate to patients who also take antacids. The authors say this deserves further investigation.
Acid-free absorption
The idea that calcium carbonate does not need acid to be absorbed has also not been proven. The authors note this as a gap in the evidence.
Taking with meals
In clinical practice, it appears important that calcium is taken with meals to improve its absorption. The authors highlight this as a practical point.
What the authors conclude
“No convincing scientific evidence supporting the advice to prescribe calcium citrate instead of calcium carbonate to patients who also take antacids is available, and therefore deserves further investigation.”
Also in their conclusions
- They say no convincing scientific evidence supports the advice to prescribe calcium citrate instead of calcium carbonate to patients who also take antacids.
- They state that this question deserves further investigation.
- They note that in clinical practice it appears important that calcium is taken with meals to improve its absorption.
How it was done
American guidelines and UpToDate recommend calcium citrate for patients who use antacids, because calcium carbonate is water-insoluble and thought to need acid for absorption. The authors say no convincing evidence supports this advice and it deserves further investigation.
What it can’t tell you
- We summarised it from the abstract only.
- This paper does not report any new measurements in people, animals or cells.
- It cannot show whether calcium carbonate or calcium citrate is better absorbed by people who take antacids.
- It cannot show whether calcium carbonate needs stomach acid to be absorbed.
Who paid
- Authors work at
- Universitair Medisch Centrum Groningen, the Netherlands
The paper
- Title
- [Calcium suppletion for patients who use gastric acid inhibitors: calcium citrate or calcium carbonate?]
- Type
- ReviewThe authors read earlier studies and describe what they found. It isn’t a new study.
- Summarised from
- Abstract only
- Cite
- de Jonge HJ, Gans RO, Huls G (2012). [Calcium suppletion for patients who use gastric acid inhibitors: calcium citrate or calcium carbonate?]. Nederlands tijdschrift voor geneeskunde.PubMed 22914054
Summary written 26 Sep 2026. Check it against the paper before it changes what you eat. How we summarise papers · Report an error