Other names for the additive (synonyms)
General Information
Calcium citrates are calcium salts of citric (lemon) acid, known as food additive E333. They are used as acidity regulators, stabilizers, color fixatives, and sources of organic calcium.
Calcium citrates belong to natural organic salts formed in biological systems during metabolic processes.
They can be found in plant sources, particularly in fruits and berries with high citric acid content — lemons, oranges, tangerines, grapefruits, apples, pears, plums, currants, cranberries, raspberries, strawberries. Calcium citrates are also present in some vegetables, including tomatoes, spinach, and rhubarb.
In addition, citrate compounds are intermediate metabolites of cellular metabolism in living organisms.
The general chemical formula of calcium citrate depends on the degree of neutralization of citric acid by calcium.
According to food additive specifications approved by Regulation (EU) No 231/2012 of 9 March 2012, additive E333 is divided into three main subtypes depending on chemical composition:
- E333(i) — calcium monocatecholate — mono-substituted calcium citrate. Chemical formula: (C6H7O7)2Ca·H2O;
- E333(ii) — calcium dicitrate — di-substituted calcium citrate. Chemical formula: (C6H7O7)2Ca2·3H2O;
- E333(iii) — calcium tricitrate — tri-substituted calcium citrate. Chemical formula: (C6H6O7)2Ca3·4H2O.
The most popular form of calcium citrates is calcium tricitrate.
Additive E333 is a white or slightly creamy powder without odor, soluble in water, resistant to heating and changes in pH.
The history of calcium citrate usage dates back to the 19th century, when citric acid began to be actively used in food and pharmaceutical applications. Later it was found that its salts, including calcium salts, have mild effects, are well absorbed, and can perform several technological functions simultaneously. In the 20th century, calcium citrates became widely used as acidity regulators and stabilizers in the food industry.
For food purposes, additive E333 is obtained by neutralizing citric acid with calcium-containing compounds such as calcium carbonate or calcium hydroxide. This process allows obtaining different forms of calcium citrates — mono-, di-, or tricitrate, depending on the reagent ratio.
Effects on the Body
Benefit of Additive E333
Additive E333 is considered one of the most beneficial forms of calcium supplementation due to its high bioavailability, which is 22–27% higher than traditional calcium carbonate.
Calcium is an essential mineral that contributes to the formation and maintenance of strong bones and teeth, participates in nerve impulse transmission and muscle contraction, and is critically important for blood clotting processes.
Calcium citrate effectively supports bone mineral density, especially in individuals with insufficient calcium intake from food or increased needs — such as the elderly, postmenopausal women, or those with osteoporosis.
Calcium citrate may be absorbed more efficiently than some other calcium salts due to its lower dependence on stomach acidity.
Clinical trials show that calcium citrate effectively maintains bone mineral density and prevents its loss, particularly in postmenopausal women.
Studies confirm that the combination of calcium citrate with vitamin D further reduces the risk of osteoporosis and fractures in older adults.
Calcium citrate also performs a protective function for the kidneys. Several studies have shown that calcium citrate increases urinary citrate levels, which prevents oxalate crystallization, thereby reducing the risk of kidney stone formation.
The Joint FAO/WHO Expert Committee on Food Additives (JECFA) assigned calcium citrates an ADI status of "not specified" because additive E333 does not pose a health risk under normal usage.
Risks of Additive E333
Calcium citrates are generally considered a safe form of calcium when consumed within recommended doses.
In the body, calcium citrates are broken down into calcium ions and citrates, which are involved in normal metabolic processes.
However, excessive calcium intake may lead to undesirable effects such as constipation, bloating, flatulence, or gastrointestinal discomfort.
Uses
In the food industry, additive E333 acts as a multifunctional technological ingredient that simultaneously adjusts acidity levels, stabilizes structure, and increases the nutritional value of products.
Food additive E333 is widely used in the production of fruit juices and nectars, dairy products (yogurts, processed cheeses, desserts), baby food (formulas and cereals), jams, jellies, and fruit fillings, breakfast cereals, cereal bars, as well as in sports isotonic drinks.
Additionally, additive E333 is actively used in bakery products, where it improves gluten quality and promotes even dough rising.
Legal Status
Food additive E333 is approved for use in the European Union, Ukraine, USA, Canada, Japan, and most other countries.
In the EU, the use of additive E333 is regulated by Regulation (EC) No 1333/2008. In Ukraine, E333 is also included in the list of permitted food additives in accordance with EU legislation.
In the USA, the Food and Drug Administration (FDA) recognizes calcium citrates as GRAS (Generally Recognized as Safe) for food use.
