E170 - Calcium carbonates

At a glance

• What it is: Purified forms of the natural mineral calcium carbonate.
• What it does: Whitens foods, prevents clumping, controls acidity, carries flavors, and adds calcium.
• Where it’s found: Chewing gum, confectionery, icings, powdered mixes, bakery items, and some fortified drinks and plant milks.
• Forms: E170 covers E170(i) calcium carbonate and E170(ii) calcium hydrogen carbonate.
• Labeling: May appear as “E170,” “calcium carbonate,” or “calcium carbonates.”
• Regulation: Authorized in the U.S. and EU when used as intended.

Why is Calcium carbonates added to food?

Calcium carbonates are used because they are bright white, stable, and versatile. In foods, they serve as a color additive to whiten products and improve opacity.¹ They also act as an anticaking agent to keep powders free‑flowing, a pH control agent (acidity regulator), a carrier/bulking agent, and a nutrient supplement to add dietary calcium.²

In the U.S., the Food and Drug Administration (FDA) lists calcium carbonate as Generally Recognized as Safe (GRAS) for direct use in food with these functions when used in line with good manufacturing practice (GMP).² For coloring foods, calcium carbonate is also an FDA‑approved color additive exempt from certification.¹

What foods contain Calcium carbonates?

You’ll most often see E170 in:

• Chewing gum, mints, and sugar confectionery (for whiteness and structure)
• Icings, fondants, and bakery decorations
• Powdered mixes such as drink bases, dessert mixes, and instant soups (anticaking)
• Baked goods, tortillas, crackers, and snacks (bulk and pH control)
• Fortified beverages like some orange juices and plant‑based milks (calcium source)
• Processed cheeses and dairy powders

Product labels may list “calcium carbonate,” “E170,” or the specific sub‑entry such as E170(i).

What can replace Calcium carbonates?

Possible alternatives depend on the job it does in a recipe:

• For white color/opacity: titanium dioxide (where permitted), talc
• For anticaking: silicon dioxide, microcrystalline cellulose
• For calcium fortification: tricalcium phosphate or other calcium phosphates

Food makers choose based on taste impact, cost, labeling needs, and local rules.

How is Calcium carbonates made?

Food‑grade calcium carbonates come from two main routes:

• Natural: Mined mineral sources (such as limestone or chalk) that are cleaned, finely ground, and purified.
• Precipitated (PCC): Calcium oxide is produced by heating limestone, then hydrated to calcium hydroxide. Carbon dioxide is bubbled through to precipitate very pure calcium carbonate with controlled particle size.

EU specifications cover both natural and precipitated forms and set purity limits for E170(i) and E170(ii).³

Is Calcium carbonates safe to eat?

Yes, when used as intended. The FDA permits calcium carbonate as a GRAS food ingredient for roles such as nutrient supplement, anticaking agent, and pH control agent.² It is also an approved color additive for foods under GMP.¹

The European Food Safety Authority (EFSA) re‑evaluated E170 and found no safety concern for calcium carbonate used as a food additive at reported use levels, and did not set a numerical Acceptable Daily Intake (ADI).⁴ As a nutrient, calcium does have tolerable upper intake levels; very high intakes from supplements can cause effects like constipation and may raise kidney stone risk in some people.⁵

Does Calcium carbonates have any benefits?

• Adds dietary calcium when used as a fortificant.
• Improves appearance by whitening and increasing opacity in confectionery and coatings.¹
• Helps powders stay free‑flowing by reducing clumping.
• Buffers acidity to help with taste and stability.²

Who should avoid Calcium carbonates?

Most people can consume foods containing E170 without issues. Consider extra care if you:

• Have hypercalcemia or are on a doctor‑prescribed low‑calcium plan.
• Have a history of kidney stones and use high‑dose calcium supplements; discuss total calcium intake with your clinician.⁵
• Take certain medicines. Calcium can interfere with absorption of some antibiotics (like tetracyclines and fluoroquinolones), thyroid hormone (levothyroxine), and bisphosphonates. Separate dosing as advised by your healthcare provider.⁵

Myths & facts

• Myth: “It’s just chalk, so it’s unsafe to eat.” Fact: Food‑grade calcium carbonate is highly purified and used under strict regulations in both the U.S. and EU.²³
• Myth: “It’s only a colorant.” Fact: Beyond whitening, E170 also controls acidity, prevents caking, carries ingredients, and can add calcium.²¹
• Myth: “Europe is unsure about its safety.” Fact: EFSA reviewed E170 and found no safety concern for its intended uses at reported levels.⁴

Calcium carbonates in branded foods

You can find E170 on ingredient lists for:

• Chewing gum, mints, and pressed candies
• White coatings, icings, and decorative sprinkles
• Powdered drink mixes and instant soups
• Crackers, tortillas, and other baked snacks
• Fortified beverages and dairy powders

In the EU, labels may show “E170,” “E170(i)” or “E170(ii).” In the U.S., it typically appears as “calcium carbonate.”

References

Footnotes

1. Calcium carbonate color additive for food (21 CFR 73.70) — U.S. Food and Drug Administration. https://www.ecfr.gov/current/title-21/chapter-I/subchapter-A/part-73/subpart-A/section-73.70 ↩ ↩² ↩³ ↩⁴ ↩⁵

2. Calcium carbonate (21 CFR 184.1191) — U.S. Food and Drug Administration. https://www.ecfr.gov/current/title-21/chapter-I/subchapter-B/part-184/section-184.1191 ↩ ↩² ↩³ ↩⁴ ↩⁵ ↩⁶

3. Commission Regulation (EU) No 231/2012, E 170 Calcium carbonates — European Union. https://eur-lex.europa.eu/eli/reg/2012/231/oj ↩ ↩²

4. Scientific Opinion on the re‑evaluation of calcium carbonate (E 170) as a food additive — European Food Safety Authority (EFSA). https://efsa.onlinelibrary.wiley.com/doi/10.2903/j.efsa.2011.2318 ↩ ↩²

5. Calcium Fact Sheet for Health Professionals — National Institutes of Health, Office of Dietary Supplements. https://ods.od.nih.gov/factsheets/Calcium-HealthProfessional/ ↩ ↩² ↩³