Safety grading GREEN – SAFE
Calcium carbonate (E170) receives a GREEN – SAFE safety grade based on its natural origin, extensive regulatory approval, and lack of demonstrated toxicity at permitted levels. Both the European Food Safety Authority (EFSA) and the U.S. Food and Drug Administration (FDA) consider calcium carbonate safe as a food additive. EFSA’s assessments conclude that calcium carbonate, whether mined or precipitated, poses no safety concern for consumers when used as a colorant or pH regulator in foods, provided it meets purity specifications limiting heavy metals and other impurities.
Calcium carbonate is designated as GRAS (Generally Recognized as Safe) by the FDA (21 CFR §184.1191), allowing its use in foods, beverages, and supplements under good manufacturing practice. The Acceptable Daily Intake (ADI) is “not specified,” which indicates a very low toxicological concern at typical use levels. It is metabolically inert – most passes through the gastrointestinal tract unchanged, while absorbed calcium contributes to normal dietary intake.
Independent studies, including from India and Japan, support its favorable safety profile in food and pharmaceutical contexts. For example, an Indian study in Food Bioscience (2018) evaluated precipitated calcium carbonate and reported no cytotoxic or genotoxic effects even at high test concentrations. Japanese investigations of calcium fortification in infant formula report good gastrointestinal tolerance. Considering the regulator baseline and global evidence sweep, E170 is safe for the general population, including vulnerable groups, when used within specifications.
Should you avoid additive?
There is typically no reason to avoid E170 in everyday diets. Individuals who must restrict overall calcium (e.g., due to hypercalcemia or a history of certain kidney stones) should monitor total calcium intake from all sources. However, the amounts contributed by E170 at food-use levels are small compared to dietary calcium from milk, yogurt, or leafy greens.
Common uses
- White colorant in confectionery, chewing gums, coatings, and bakery items.
- Acidity regulator / buffer to neutralize excess acidity and stabilize flavor and texture.
- Calcium fortifier in foods and beverages, and as an excipient in tablets and supplements.
- Anti-caking agent in powdered foods and spice blends.
Common names / Synonyms
- Calcium carbonate
- Chalk
- Limestone
- Precipitated calcium carbonate (PCC)
- Ground calcium carbonate (GCC)
- Calcite
What is it?
Calcium carbonate is an inorganic mineral with the formula CaCO₃ that occurs naturally as calcite, aragonite, and vaterite. Food-grade material is obtained by grinding high-purity limestone (GCC) or by controlled precipitation (PCC). Both routes must meet stringent purity and particle-size specifications. The mineral provides a bright white appearance, which is why it is widely used as a colorant. As a buffer, it neutralizes acids, helping maintain product stability and a desirable mouthfeel. It can also provide supplemental calcium.
Calcium carbonate is poorly soluble in water and does not readily react under normal food conditions, which explains its benign biological profile. Toxicological evaluations report no evidence of genotoxicity, carcinogenicity, or reproductive toxicity at permitted use levels. The body regulates calcium absorption. Excess intake is excreted through the gastrointestinal tract or urine. These characteristics support its classification as low-risk and suitable even for applications like infant formula, where tolerance is closely monitored.
Where it’s allowed (EU vs US)
In the EU, E170 is authorized under Regulation (EC) No 1333/2008 and has purity criteria in Regulation (EU) No 231/2012. It is permitted in many foods at quantum satis (as needed for the intended effect). In the US, calcium carbonate is affirmed as GRAS (21 CFR §184.1191) and allowed in a broad range of foods under good manufacturing practice.