E170I - Calcium carbonate

At a glance

Here is a quick overview before we dive deeper.

• What it is: a purified form of chalk, also known as CI Pigment White 18
• What it does: adds white color, helps control acidity, and supplies calcium
• Where it shows up: many fortified foods, candies and chewing gum, and some baked goods
• Label names: calcium carbonate, E170, E170i
• Safety: permitted in the U.S. and EU; people on certain medicines or with some health conditions may need advice first

Why is Calcium carbonate added to food?

Food makers use calcium carbonate because it works in several roles at once: it colors foods white, acts as a buffering and neutralizing agent to steady acidity, can firm or stabilize some textures, and serves as a calcium nutrient source.¹ In the European Union it is approved as a white color under the name E170 (calcium carbonates).²

What foods contain Calcium carbonate?

You can find calcium carbonate in many everyday products:

• Fortified foods where extra calcium is desired, such as some cereals and flours
• White-colored confectionery like mints and some chewing gums for brightness and texture
• Certain bakery and snack items where it helps control acidity or provides calcium
• Powdered mixes and other dry foods where a neutral, white mineral is useful

Always check the ingredient list for “calcium carbonate,” “E170,” or “E170i.”

What can replace Calcium carbonate?

The best substitute depends on the job it does in the recipe.

• For white color: where permitted, titanium dioxide is a common alternative.
• For calcium fortification: tricalcium phosphate or other calcium phosphates are often used.
• For pH control and neutralizing acids: sodium bicarbonate or other sodium carbonates can play a similar role; acids like citric acid adjust pH in the other direction.
• For stabilizing or thickening: gums such as xanthan gum or pectins may be chosen, depending on the food.

No single replacement fits every product; formulators pick based on taste, texture, color, and nutrition goals.

How is Calcium carbonate made?

Food-grade calcium carbonate comes from two main routes. It can be finely ground from natural sources like limestone or chalk, with careful purification. It can also be made as “precipitated calcium carbonate” by reacting calcium hydroxide with carbon dioxide to form very pure, small white crystals that are filtered and dried.²

Is Calcium carbonate safe to eat?

In the United States, calcium carbonate is “Generally Recognized As Safe” (GRAS) when used in line with good manufacturing practice, and it may be used as a nutrient, buffering, and neutralizing agent in foods.¹ The European Food Safety Authority (EFSA) has re-evaluated calcium carbonate (E170) and found no safety concern at reported use levels.² As with any calcium source, very high intakes can be a problem; the National Institutes of Health notes a tolerable upper intake level for adults of about 2,000–2,500 mg of calcium per day from all sources.³

Does Calcium carbonate have any benefits?

Yes. When used to fortify foods, calcium carbonate provides calcium, an essential mineral for bones and teeth and for normal muscle and nerve function.³ This can help people reach daily calcium goals if their diet is low.

Who should avoid Calcium carbonate?

Some people should be cautious or speak with a healthcare professional:

• Those who form calcium-containing kidney stones or have high blood calcium may be advised to limit calcium intake.
• Calcium carbonate can reduce the absorption of certain medicines (for example, some antibiotics like tetracyclines and fluoroquinolones, and thyroid hormone). Take these medicines at a different time from calcium-containing foods or supplements as directed by your clinician or pharmacist.⁴

Myths & facts

• Myth: “It’s the same as construction chalk, so it must be unsafe.” Fact: Food-grade calcium carbonate is purified and tested for quality before use in foods.
• Myth: “It’s added only to make food look white.” Fact: It also helps control acidity and can add useful calcium.
• Myth: “It builds up in the body.” Fact: The body tightly regulates calcium; unabsorbed calcium passes through, and absorbed calcium goes into normal calcium stores.

Calcium carbonate in branded foods

On labels, look for “calcium carbonate,” “E170,” or “E170i.” You may see it in bright white mints and gums, in fortified staples like some flours and cereals, and in various baked or snack items. The exact amount and purpose vary by brand and recipe.

References

Footnotes

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

2. Re-evaluation of calcium carbonate (E 170) as a food additive — EFSA Journal. European Food Safety Authority. https://www.efsa.europa.eu/en/efsajournal/pub/2318 ↩ ↩² ↩³

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

4. Calcium carbonate: Drug information. MedlinePlus, U.S. National Library of Medicine. https://medlineplus.gov/druginfo/meds/a601032.html ↩