calcium sulfate
calcium sulfate

Calcium Sulfate

Common names: Gypsum, Plaster of Paris, Alabaster, Drierite (brand name), E516 (European food additive code).
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KIDSADVISORY SAFETY RATING
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Safe
Published by Jordana Tobelem, RD, LDN — Last Updated on Apr 16, 2025
Medically reviewed by Dr. William Lin, MD
Calcium sulfate, known in the food industry by its European food additive code E516, is a naturally occurring mineral extensively utilized for its functional properties. It serves as a coagulant in tofu production, where it facilitates the formation of a firm curd by promoting protein aggregation. Additionally, calcium sulfate acts as a firming agent and flour treatment agent, enhancing the texture and quality of various food products.[1]
While generally recognized as safe for consumption, excessive intake of calcium sulfate may lead to potential health concerns. Overconsumption can cause gastrointestinal discomfort and, in rare cases, may affect calcium balance in the body. Therefore, it is essential to adhere to recommended usage levels in food products to ensure consumer safety.[1]

Safety Overview

Regulatory Bodies

FDA (US)
The U.S. Food and Drug Administration (FDA) permits the use of calcium sulfate as a food additive for various applications, recognizing it as generally safe when adhering to prescribed usage levels.[2]
Health Canada
Health Canada’s Food Directorate has conducted safety assessments of calcium-containing additives, such as calcium acid pyrophosphate, and determined that there are no health or safety concerns with their use in specified food products.[3]
EFSA (Europe)
The European Food Safety Authority (EFSA) has evaluated calcium sulfate and concluded that its use in dietary supplements poses no safety concerns, provided that total dietary calcium intake remains below the established Tolerable Upper Intake Level.[1]
WHO (World Health Organization)
The Joint FAO/WHO Expert Committee on Food Additives (JECFA) has conducted safety evaluations of calcium sulfate, determining that its use as a food additive is acceptable within specified limits.[4]

FDA GRAS

U.S. Food and Drug Administration – Generally Recognized as Safe (GRAS)
Current Status
Classified

EWG Rating

Environmental Working Group
  • EWG Rating: The Environmental Working Group (EWG) assigns calcium sulfate a low hazard rating, indicating minimal concern regarding its use in personal care products.[5]
  • Level of Caution: Calcium sulfate is not listed on EWG's Skin Deep Restricted or Unacceptable Lists, suggesting a general consensus on its safety in cosmetic applications.[5]
  • Possible Health Risks: Available data do not indicate significant health risks associated with calcium sulfate; however, as with any substance, individuals with specific sensitivities should monitor for potential reactions.[5]
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More about Calcium Sulfate

  • Baked Goods: Bread, Cakes, Crackers
  • Dairy and Dairy Alternatives: Tofu, Cheese, Yogurt
  • Fortified Foods: Breakfast Cereals, Plant-Based Milk, Meal Replacement Bars

Historical Use
Calcium sulfate, commonly known as gypsum, has been utilized since ancient times, notably in the construction of monuments like the Egyptian pyramids. In the food industry, its use dates back centuries, serving as a coagulant in tofu production and as a dough conditioner in baking.[6]
Current Exposure
Today, consumers encounter calcium sulfate in various food products, including baked goods, canned vegetables, and dairy alternatives. Its widespread application as a firming agent, flour treatment agent, and coagulant contributes to regular dietary exposure through these common foods.[6]

Respiratory Irritation
Inhalation of calcium sulfate dust may cause irritation to the respiratory tract, leading to symptoms such as coughing and shortness of breath.[7]
Skin and Eye Irritation
Prolonged or repeated contact with calcium sulfate can result in skin and eye irritation, manifesting as redness or discomfort.[7]
Hypercalcemia
Although rare, excessive exposure to calcium sulfate, particularly when used in medical applications, can lead to elevated calcium levels in the blood, potentially causing altered mental status and renal impairment.[8]
Gastrointestinal Disturbances
Ingestion of large amounts of calcium sulfate may cause gastrointestinal discomfort, including nausea, vomiting, and diarrhea.[7]

Toxicological Studies
Acute oral toxicity studies have demonstrated that calcium sulfate has an LD₅₀ greater than 2,000 mg/kg in rats, indicating low toxicity upon ingestion.[9]
Long-Term Safety
Chronic inhalation exposure to high concentrations of calcium sulfate dust may lead to respiratory symptoms such as cough and reduced lung function; however, these effects are primarily associated with occupational settings involving prolonged exposure.[10]

High-Risk Groups
Individuals with pre-existing conditions such as diabetes or those undergoing procedures involving large volumes of calcium sulfate implantation may be at increased risk for complications like serous exudation.[11]
Health Impacts
In vulnerable populations, excessive use of calcium sulfate, especially in medical applications, has been associated with rare but severe side effects such as hypercalcemia, which can lead to altered mental status and renal impairment.[8]

Recommended Intake
The Joint FAO/WHO Expert Committee on Food Additives (JECFA) has established an Acceptable Daily Intake (ADI) of "not limited" for calcium sulfate, indicating no specific numerical limit is necessary when used in accordance with good manufacturing practices.[3]

General Safety Level
Calcium sulfate is generally considered safe for use in medical applications, such as bone grafts; however, some studies have reported inflammatory reactions in a minority of cases.[12]
Sensitive Individuals
While rare, there have been instances of severe inflammatory responses, including serous drainage and allergic reactions, necessitating graft removal in certain patients.[13]

FAQ

Is calcium sulfate hazardous?

Calcium sulfate is generally considered non-hazardous but can cause irritation to the eyes, skin, or respiratory system in powder form.

Is calcium carbonate safe to eat in food?

Yes, calcium carbonate is safe to eat and is commonly used as a food additive, calcium supplement, and acidity regulator.

What is calcium sulfate for cooking?

Calcium sulfate is used in cooking as a firming agent, dough conditioner, and food additive in tofu, baked goods, and canned vegetables.

References

  1. European Food Safety Authority EFSA 2019 Reu2010evaluation of sulphuric acid and its sodium potassium calcium and ammonium salts E 513 514 (i) 514 (ii) 515 (i) 515 (ii) 516 and 517 as food additive EFSA Journal 17(10) e05868 Available at: https://www.efsa.europa.eu/en/efsajournal/pub/5868 ↩︎
  2. US Food and Drug Administration FDA n.d. Code of Federal Regulations 21 - Calcium Sulfate Available at: https://www.ecfr.gov/current/title-21/chapter-I/subchapter-B/part-184/subpart-B/section-184.1230 ↩︎
  3. Canada Gazette 2012 Regulations Amending the Food and Drug Regulations 1599 - Food Additive Part 2 1269 Available at: https://www.gazette.gc.ca/rp-pr/p2/2012/2012-06-06/pdf/g2-14612.pdf ↩︎
  4. World Health Organization 1973 Calcium Sulfate Available at: https://apps.who.int/food-additives-contaminants-jecfa-database/Home/Chemical/1360 ↩︎
  5. Environmental Working Group EWG n.d. Calcium Sulfate Available at: https://www.ewg.org/skindeep/ingredients/700979-CALCIUM_SULFATE/ ↩︎
  6. Chemondis 2024 Calcium Sulfate in the Food Industry From Tofu Production to Vegan Cheese Available at: https://blog.chemondis.com/8168/calcium-sulfate-in-the-food-industry-from-tofu-production-to-vegan-cheese/ ↩︎
  7. Solvay 2011 Product Safety Summary - Calcium Sulfate Available at: https://www.solvay.com/sites/g/files/srpend221/files/2021-01/PSS-Calcium-Sulfate.pdf ↩︎
  8. Lun DX et al. 2024 Limitations and modifications in the clinical application of calcium sulfate Frontiers in Surgery 11 1278421 Available at: https://www.frontiersin.org/articles/10.3389/fsurg.2024.1278421/full ↩︎
  9. European Chemicals Agency ECHA n.d. Endpoint summary Acute toxicity oral Available at: https://echa.europa.eu/registration-dossier/-/registered-dossier/11841/7/3/1 ↩︎
  10. Neghab M Toosi S Azad P 2016 Respiratory Morbidity Associated with Long-Term Occupational Inhalation Exposure to High Concentrations of Hydrated Calcium Sulfate Dust Occupational Diseases and Environmental Medicine 4 1-7 Available at: https://www.scirp.org/journal/paperinformation?paperid=61545 ↩︎
  11. Bing D et al. 2023 Analysis of risk factors for serous exudation of biodegradable antibiotic-loaded calcium sulfate implantation in patients with fracture-related infection Frontiers in Bioengineering and Biotechnology 11 1189085 Available at: https://www.frontiersin.org/articles/10.3389/fbioe.2023.1189085/full ↩︎
  12. Thomas MV Puleo DA Al-Sabbagh M 2005 Calcium sulfate a review Journal of Long-Term Effects of Medical Implants 15(6) 599-607 Available at: https://pubmed.ncbi.nlm.nih.gov/16393128/ ↩︎
  13. Kelly CM Wilkins RM Gitelis S Hartjen C Watson JT Kim PT 2001 The use of a surgical grade calcium sulfate as a bone graft substitute results of a multicenter trial Clinical Orthopaedics and Related Research (382) 42-50 Available at: https://pubmed.ncbi.nlm.nih.gov/11154003/ ↩︎

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