Propylene glycol is a colorless, odorless synthetic liquid that absorbs water. This quality makes the chemical extremely versatile as an additive to everything from antifreeze to food. But though it is considered generally safe for human and animal consumption, cats have a unique sensitivity to propylene glycol and should never ingest it.
Unsafe Ingredient in Cat Food
Propylene glycol is used as a moistening agent in softer pet foods, such as chewy treats. Though the Food & Drug Administration considers the additive to be safe for most animals, it officially declared propylene glycol unsafe for cats in 1996. Most cat food makers stopped adding propylene glycol to their formulas in 1992 when it was discovered that large doses of propylene glycol can trigger a blood disease known as “Heinz body” anemia in cats.
Heinz Body Anemia
Heinz bodies damage hemoglobin, or red blood cells, and can lead to a form of anemia to which cats are particularly prone.Typically, cats contract Heinz body anemia from medications or, as do dogs, from eating onions. Symptoms include fever, sudden weakness, loss of appetite, pale mucous membrane, such as the lips and gums, discoloration of the skin and, in severe cases, reddish-brown urine.
Though propylene glycol has been ruled as an unsafe ingredient in cat food, it continues to be used in general pet food production and may find its way into cat products. In 2012 the additive triggered a pet treat recall for Catswell brand VitaKitty chicken breast with flax seed and vitamins, though no cases of poisoning were linked to contaminated treats. More commonly, propylene glycol poisoning occurs when cats lick up droplets of antifreeze, for which propylene glycol is an ingredient. The additive is, nevertheless, considered more pet-safe for antifreeze than ethylene glycol.
Treatment and Care
If you suspect your cat has ingested propylene glycol or if she exhibits symptoms of Heinz body anemia, get her to a veterinarian right away. Mild cases are not typically fatal and cats may actually have a significant number of Heinz bodies in their blood without having anemia. Treatment generally is to remove the source of the additive and let time heal the problem. Severe cases may require a blood transfusion.