Calcium Sulfate

It is used to firm up the texture of wet foods, and it also supplies calcium and sulfur.

Calcium sulfate is a mineral salt, also known as gypsum, used in foods as a calcium source and as a firming agent. In cat food it adds calcium and sulfur. The Merck Veterinary Manual notes that calcium deficiencies are uncommon in cats on complete and balanced diets. Ask your veterinarian about mineral intake for a cat with a urinary or kidney condition.

Source: merckvetmanual.com

Calcium sulfate in cat food is a mineral ingredient that supplies calcium. In some recipes it also helps bind or firm the texture. It is the same compound that is used to set tofu, though food and feed grades are purified for that use.

Yes, calcium sulfate is the chemical name for gypsum. The food and feed grades used in cat food are purified versions, not construction material. Labels list it by its chemical name because AAFCO requires each ingredient to be listed by its appropriate name.

Source: aafco.org

Calcium sulfate is not a filler. It is added in small amounts as a calcium source or as a texture aid, and it usually appears low in the ingredient list. Fillers are ingredients that add bulk; calcium sulfate is used in amounts too small to add bulk.

Pettings gives calcium sulfate 3 out of 5 and lists it as a mineral. It appears on 33 of the 149 dry cat foods we list. Our How We Score page explains how ingredient scores are set. Each food's page shows how it scores overall.