Propylene glycol in dog food: what it is and is it safe?

You may see propylene glycol on a bag of soft dog food. It is also on a list of things not allowed in cat food. That sounds odd. Here is what it is and what the rules say.

What is propylene glycol in dog food?

Propylene glycol, a clear liquid made in a lab, helps keep food moist. It is used in soft food. The same stuff is allowed in people food. It does not come from a plant or an animal. It is made from other chemicals.

The FDA says it does not occur in nature. EU experts say it is made from propylene oxide by adding water. It is then cleaned up.

Why is propylene glycol in dog food?

It holds on to water. That keeps soft food soft. It also helps keep germs from growing.

For soft cat food, the FDA said it was used to hold water, keep the food soft, and slow germs. In people food, the FDA lists a long set of jobs. Holding water and thickening are two of them.

Want to know how wet, soft and dry food differ? See wet vs dry dog food.

Is propylene glycol safe for dogs?

US rules list it as safe in animal food, but not in cat food. EU experts looked at a long test in dogs. They saw no harm except at the highest dose. At that dose, there were blood changes. If you have a question about your own dog, ask your vet.

The FDA rule says it is safe in animal food (except in cat food), when used with good practice.

EU experts looked at a test that lasted two years. Dogs were fed 2,000 or 5,000 mg per kg of body weight each day. The only change was at the top dose, where more red blood cells broke down and the body made more to keep up. The lower dose showed no harm.

Why is propylene glycol not allowed in cat food?

In tests, it harmed cats’ red blood cells. The cells broke down faster than normal. So the FDA took it off the safe list for cat food. The rule is about cats only.

The FDA proposed the change in 1995. The rule took effect on June 3, 1996.

Here is what the tests found. Cats fed it had more Heinz bodies, and their red blood cells did not last as long. Heinz bodies are small clumps of broken protein in red blood cells. The FDA said the cells were more easily harmed because of it.

Today the rule says it has not been shown by good enough data to be safe in cat food. The FDA papers on this rule do not say it harms dogs.

Is propylene glycol allowed in people food?

Yes. The US and the EU both allow it in people food. Each has limits on how much can be used.

In the US, many kinds of people food can have up to 2 percent. In the EU it is called E 1520. EU experts kept a daily limit for people of 25 mg per kg of body weight.

How can you spot propylene glycol on a label?

Look at the ingredient list. The word is propylene glycol.

For a full walk through the label, see how to read a dog food label. Other items on the list can keep food fresh too, like mixed tocopherols (forms of vitamin E) or BHA (a lab-made thing that keeps fat fresh) and BHT, a close cousin. Vague words can show up as well, like natural flavor.

If you want to check a label fast, you can scan it with Altie.