E170iColour · Stabiliser

Calcium carbonate

What the research shows

Prototype

Conflicting

studies in people disagree or haven’t settled it

6 health findings on this page · See the findings

A chemical compound found in rocks, chalk, limestone, eggshells, shells and pearls.

Written from Open Food Facts and English Wikipedia¹²

May not be vegan
May not be vegetarian

What research says

Studies in people

Benefit

Phosphate control in dialysis patients⁴

In people on dialysis, cheese with added calcium carbonate led to lower phosphate rises between sessions than regular cheese.
No harm found

Bone density in teens⁵

In teens with HIV, calcium carbonate plus vitamin D did not change bone density overall.
Concern

Thyroid hormone absorption⁶

Taking calcium carbonate within two hours of thyroid pills raised TSH and cholesterol in women.
Open question

Bone health in children⁷

In children with HIV, scientists are testing whether calcium carbonate plus vitamin D helps bones grow stronger.
Benefit

Calcium absorption in teen girls⁸

In teen girls, calcium carbonate supplements helped the body hold onto more calcium than a placebo, but smaller particles were no better.
Open question

Calcium absorption after stomach surgery⁹

In people who had stomach-shrinking surgery, calcium citrate got into the body better than calcium carbonate.

Study type not stated

Open question

How well calcium is absorbed¹¹

Scientists do not yet know whether calcium carbonate needs stomach acid to be absorbed well.
Concern

Aluminium in a food additive¹²

Calcium carbonate can contain small amounts of aluminium, which scientists say is a concern.

How it’s made and used

How much calcium the body absorbs³

In people, calcium from calcium carbonate was absorbed about as well as from another calcium supplement.
What it does in food¹⁰

Calcium carbonate is used in food to carry nutrients and hold mixtures and gels together.

The signal at the top counts the findings in people and in animal and lab studies. A concern in studies of people outranks animal and lab studies, and “No concerns” needs at least two findings in people. Findings whose study type is not stated are shown but not counted. This page is a reference, not medical advice. It describes what regulators and published research say. Talk to a doctor or dietitian about your own diet.

Regulatory status

Checked Sep 2026

United States Permitted FDA 21 CFR 73.70
Canada Permitted Health Canada · Colouring Agents

Status reflects the named register on the date checked. It is not a safety rating. A country appears here once we've found this ingredient on its official list.

How we check

Products

The 6 most-scanned of 17,212 products on Open Food Facts that list calcium carbonate.

Geröstete Mandel Ohne Zucker alpro · 1 l 3 additives
White Ciabatta Sourdough Bread Jason's Sourdough · 580 g 0 additives
Sliced White Sourdough Bread with Grains & Seeds Ciabattin Jason's · 580 g 0 additives
sourdough bread jason's sourdough · 450 g 0 additives
Seeded Sourdough Bread Specially Selected · 500 g 0 additives
JASON'S SOURDOUGH JASON'S SOURDOUGH · 450 g 0 additives

References

1Calcium carbonate: ingredient taxonomy entry. Open Food Facts.
2Calcium carbonate. Wikipedia. Accessed September 25, 2026.
3Wiria M, Tran HM, Nguyen PHB, Valencia O, Dutta S, Pouteau E. Relative bioavailability and pharmacokinetic comparison of calcium glucoheptonate with calcium carbonate. Pharmacol Res Perspect. 2020;8(2):e00589. doi:10.1002/prp2.589
4Ardissino G, Matta R, Patricelli M, et al. Calcium carbonate-enriched cheese to improve nutrition, compliance and phosphorus control in patients on kidney replacement therapy. J Nephrol. 2022;35(1):305-309. doi:10.1007/s40620-021-01102-1
5Ferrand RA, Dzavakwa NV, Bandason T, et al. Impact of high-dose vitamin D and calcium carbonate supplementation on bone density in adolescents living with HIV: a randomised, placebo-controlled trial. Lancet Child Adolesc Health. 2026;10(2):111-121. doi:10.1016/S2352-4642(25)00301-3
6Morini E, Catalano A, Lasco A, Morabito N, Benvenga S. L-thyroxine malabsorption due to calcium carbonate impairs blood pressure, total cholesterolemia, and fasting glycemia. Endocrine. 2019;64(2):284-292. doi:10.1007/s12020-018-1798-7
7Dzavakwa NV, Chisenga M, McHugh G, et al. Vitamin D(3) and calcium carbonate supplementation for adolescents with HIV to reduce musculoskeletal morbidity and immunopathology (VITALITY trial): study protocol for a randomised placebo-controlled trial. Trials. 2022;23(1):78. doi:10.1186/s13063-021-05985-0
8Elble AE, Hill KM, Park CY, Martin BR, Peacock M, Weaver CM. Effect of calcium carbonate particle size on calcium absorption and retention in adolescent girls. J Am Coll Nutr. 2011;30(3):171-7. doi:10.1080/07315724.2011.10719957
9Tondapu P, Provost D, Adams-Huet B, Sims T, Chang C, Sakhaee K. Comparison of the absorption of calcium carbonate and calcium citrate after Roux-en-Y gastric bypass. Obes Surg. 2009;19(9):1256-61. doi:10.1007/s11695-009-9850-6
10Dong Y, Liu Z, Lan T, Zhang Y, Sui X. Calcium carbonate particles: Template-driven structural design and functional innovation applications in food systems. Food Chem. 2025;485:144447. doi:10.1016/j.foodchem.2025.144447
11de Jonge HJ, Gans RO, Huls G. [Calcium suppletion for patients who use gastric acid inhibitors: calcium citrate or calcium carbonate?]. Ned Tijdschr Geneeskd. 2012;156(34):A4343.
12Younes M, Aquilina G, Castle L, et al. Re-evaluation of calcium carbonate (E 170) as a food additive in foods for infants below 16 weeks of age and follow-up of its re-evaluation as food additive for uses in foods for all population groups. EFSA J. 2023;21(7):e08106. doi:10.2903/j.efsa.2023.8106