E170 · Calcium carbonate, calcium hydrogen carbonate
- WHO
- Safe
- FDA
- Safe
- EFSA
- Safe
- FSANZ
- Safe
- Japan
- Safe
- UK FSA
- Safe
- Health Canada
- Safe
What is E170?
Calcium carbonate (CaCO₃) is a naturally occurring mineral, found in limestone, marble, and chalk, used in food as a white colorant, anti-caking agent, and calcium supplement/fortifier. It is also a common active ingredient in antacids, where it neutralizes stomach acid. Calcium hydrogen carbonate (calcium bicarbonate) is the water-soluble form that occurs when calcium carbonate dissolves in water containing carbon dioxide, and it is the main contributor to water hardness and limescale. Both forms are generally recognized as safe (GRAS) for food use by EFSA and FDA.
Also appears on labels as: Calcium carbonate, Calcium hydrogen carbonate, Calcium bicarbonate, Carbonic acid, calcium salt, Carbonic acid, monocalcium salt, CaCO3, Ca(HCO3)2, E170, E 170, E-170, E170(i), E 170(i).
What the evidence says
- Very high intakes (mainly from concentrated supplements, not typical food-additive levels) can contribute to milk-alkali syndrome, causing elevated blood calcium.
- Generally recognized as safe at typical food-use levels.
Research behind the verdict
- Calcium Carbonate (E170) – Safety Review — EFSA Panel on Food Additives, EFSA Journal (2011). Widely used mineral; ADI not specified; safe; excessive intake linked to kidney stones or hypercalcemia.[safe_in_moderation]
Frequently asked questions
Is E170 safe?
Our overall verdict for E170 (Calcium carbonate, calcium hydrogen carbonate) is “Safe”, based on the most cautious of the major regulators’ positions — FDA: safe; WHO: safe; EFSA: safe; FSANZ: safe; Japan: safe; UK FSA: safe; Health Canada: safe.
Is E170 vegan, halal or gluten-free?
According to our ingredient data for Calcium carbonate, calcium hydrogen carbonate — vegan: yes, vegetarian: yes, halal: yes, kosher: yes, gluten-free: yes, dairy-free: yes. Manufacturing sources can vary between products; check the label if it matters to you.
What is E170 and why is it used?
Calcium carbonate (CaCO₃) is a naturally occurring mineral, found in limestone, marble, and chalk, used in food as a white colorant, anti-caking agent, and calcium supplement/fortifier. It is also a common active ingredient in antacids, where it neutralizes stomach acid. Calcium hydrogen carbonate (calcium bicarbonate) is the water-soluble form that occurs when calcium carbonate dissolves in water containing carbon dioxide, and it is the main contributor to water hardness and limescale. Both forms are generally recognized as safe (GRAS) for food use by EFSA and FDA.
Does E170 contain allergens?
No known allergens are recorded for Calcium carbonate, calcium hydrogen carbonate.
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This page summarises publicly available regulatory assessments and research. It is general information, not medical advice. Sources: EFSA, FDA, WHO and the studies linked above.