Calcium Carbonate (E 170)

Last reviewed October 19, 2026

In plain words: Calcium carbonate (E 170) is a common calcium salt. In food it is used to whiten or firm foods, adjust acidity and add calcium.

What the evidence review says

Calcium carbonate is a common calcium salt used to whiten or firm foods, adjust acidity and add calcium. EFSA identified no safety concern for it at reported food-additive uses, including in foods for young infants. Very large amounts of calcium from other sources, such as antacids, have been linked with a condition called milk-alkali syndrome; that is separate from the amounts used as a food additive. EFSA also flagged aluminium impurities as a specification issue.

No safety concern identified for calcium carbonate itself at reported food-additive uses, including foods for infants under 16 weeks. Separate from additive use, large supplement or antacid intakes can push total calcium above the adult tolerable upper intake level and have been linked to milk-alkali syndrome (hypercalcemia, metabolic alkalosis, and kidney injury). EFSA also flagged unavoidable aluminium in E 170 as a specification issue.

• Source: EFSA Panel on Food Additives and Flavourings (FAF), EFSA J, 2023 · doi:10.2903/j.efsa.2023.8106
• Source: EFSA Panel on Dietetic Products, Nutrition and Allergies (NDA), EFSA J, 2012 · doi:10.2903/j.efsa.2012.2814
• Source: Beall DP et al., Am J Med Sci, 2006 · doi:10.1097/00000441-200605000-00001

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This page is for general education. It is not medical advice and does not replace advice from your doctor, pediatrician, allergist or registered dietitian. Research changes; we review these pages when new evidence or rules come out. Last reviewed October 19, 2026.