E-numbers / Other additives / E526
also: Slaked lime · hydrated lime · cal
A mineral alkali used to firm foods and control acidity, and to prepare maize for tortillas and corn chips.
Scan a barcode to check a food for calcium hydroxide. NutraSafe Pro · £3.99/month · iOS
Lentil Flour (77%), Rapeseed Oil, Salt, Raising Agents (Calcium Oxide, Calcium Hydroxide, Sodium Bicarbonate, Disodium Diphosphate).
Calcium hydroxide, also called slaked lime or hydrated lime, is produced by adding water to calcium oxide (quicklime).
40
of the 43,325 UK supermarket foods we checked declare E526 in their ingredients
That is under 0.1%, counted by its code or its name.
Counted by NutraSafe from UK supermarket ingredient lists, September 2026. How we counted
Calcium hydroxide, also called slaked lime or hydrated lime, is produced by adding water to calcium oxide (quicklime). It is a white powder that dissolves slightly in water to produce a strongly alkaline solution. It is a mineral compound with no organic chemistry.
In food it acts as an acidity regulator, raising pH to control sourness and prevent spoilage. It also works as a firming agent, reacting with pectin in fruit and vegetable cell walls to strengthen their structure. Its most traditional role is nixtamalisation: dried maize kernels are soaked in a lime-water solution, which loosens the outer hull, makes the grain easier to grind, and releases bound niacin (vitamin B3) that would otherwise pass through the body unabsorbed.
Most commonly in corn tortillas, tortilla chips, masa flour, and similar maize-based products. Also used in cocoa processing (to reduce acidity), in some confectionery and sugar refining, in canned tomatoes and other vegetables as a firming agent, and in some baked goods as a leavening aid. On a label it appears as 'calcium hydroxide' or 'E526'.
The traditional use of calcium hydroxide to treat maize (nixtamalisation) has been studied in populations where this practice is absent versus present. Where untreated maize forms the staple diet without nixtamalisation, pellagra (niacin deficiency disease) has historically been common. Alkaline lime treatment chemically releases niacin from its bound form, making it absorbable. This is a well-documented nutritional benefit, not a risk.
Alkaline treatment of maize during nixtamalisation significantly increases the bioavailability of niacin by releasing it from the bound niacytin form, reducing risk of pellagra in populations dependent on maize.
EFSA has assessed calcium compounds as a group of food additives. Calcium hydroxide contributes calcium to the diet, an essential mineral. No numerical acceptable daily intake has been set because intakes from food additive use are far below levels associated with any adverse effect. The main dietary concern with excess calcium is from supplements and fortified foods in aggregate, not from incidental additive use.
EFSA's Panel on Food Additives and Nutrient Sources concluded that calcium salts used as food additives, including calcium hydroxide, did not raise a safety concern at the levels used in food, and no numerical ADI was necessary.
No group needs to avoid E526 specifically. People managing total calcium intake from multiple fortified sources (including supplements) may wish to note it contributes calcium, but the amounts from its use as a food additive are small. Look for 'calcium hydroxide' or 'E526' on the label.
Calcium hydroxide is one of the oldest food-processing materials in the world: lime-treated maize has been a staple food preparation technique in Mesoamerica for thousands of years. Its chemistry in food is well understood, its regulatory history is long and stable, and it has been through a modern EFSA re-evaluation without any safety flags. The quantities present in food after processing are small, and the compound itself is simply a calcium and oxygen mineral. There is no active scientific debate about its use in food at permitted levels.
No. Calcium hydroxide is approved for use in the UK under the assimilated EU Regulation 1333/2008 and appears on the UK FSA approved-additives list.
It is used in a process called nixtamalisation, where dried maize is soaked in a lime-water solution. This softens the outer hull, makes the grain easier to grind into masa dough, and releases niacin (vitamin B3) into a form the body can absorb. The practice is thousands of years old.
Most commonly corn tortillas, tortilla chips, and masa flour. Also found in some cocoa products, confectionery, canned tomatoes and vegetables (as a firming agent), and certain baked goods.
Yes. Calcium hydroxide is a mineral compound produced from limestone. It contains no animal-derived ingredients.
It's the only app that does thisUKJaneK
You Need This AppGmac2005
Best AppGK getting skinny UK App Store reviews
NutraSafe reads the label and puts every additive into plain English, with the source, right in the app.
NutraSafe Pro · £3.99/month · iOS
