Just this week, Blue Buffalo issued a recall on some cat treats because propylene glycol was found in them. This sparked my curiosity, because I have seen this as an ingredient in many dog treats (and some foods).
- Why did it necessitate a recall in cats but it’s okay in dog foods?
- What exactly is it used for in food anyway? (I know it’s the main ingredient in antifreeze!)
- Should we be avoiding products with propylene glycol in them for dogs, just in case?
I set out to get these questions answered to help all of us keep our pets healthy.
Why did it necessitate a recall in cats but it’s okay in dog foods?
Susan Thixton, Pet Food Consumer Advocate and founder of TruthAboutPetFood.com, pointed me in the direction of the Food & Drug Administration (FDA) for the answer to this question.
On their site, they actually use propylene glycol as an example of how an ingredient cannot be used it if has been shown through scientific research to cause health risks to animals:
“If scientific data are presented that show a health risk to animals of an ingredient or additive, the FDA’s Center for Veterinary Medicine (CVM) can act to prohibit or modify its use in pet food. For example, propylene glycol was used as a humectant in soft-moist pet foods, which helps retain water and gives these products their unique texture and taste. It was affirmed Generally Recognized As Safe (GRAS) for use in human and animal food before the advent of soft-moist foods [emphasis added]. It was known for some time that propylene glycol caused Heinz Body formation in the red blood cells of cats (small clumps of proteins seen in the cells when viewed under the microscope), but it could not be shown to cause overt anemia or other clinical effects. However, reports in the veterinary literature of scientifically sound studies have shown that propylene glycol reduces the red blood cell survival time, renders red blood cells more susceptible to oxidative damage, and has other adverse effects in cats consuming the substance at levels found in soft-moist food. In light of these new data, CVM amended the regulations to expressly prohibit the use of propylene glycol in cat foods. [emphasis added]” (www.fda.gov)
So the answer to the first question is that while it’s deemed safe for dogs and humans, research has shown propylene glycol can cause adverse effects in cats, so the FDA has banned its use in their food products, including treats.
What exactly is it used for in food anyway?
While we know now why our cats can’t have it (and by the way, this means you should be making sure any cats in your house are not being fed. or have access to, dog products with this ingredient in it), it still begs the question why something that is used to make antifreeze, is in our food.
For those unfamiliar with the substance, here is the data on propylene glycol from the The Agency for Toxic Substances & Disease Registry (TATSDR):
“Propylene glycol is a synthetic liquid substance that absorbs water. Propylene glycol is also used to make polyester compounds, and as a base for deicing solutions. Propylene glycol is used by the chemical, food, and pharmaceutical industries as an antifreeze when leakage might lead to contact with food. The Food and Drug Administration (FDA) has classified propylene glycol as an additive that is “generally recognized as safe” for use in food. It is used to absorb extra water and maintain moisture in certain medicines, cosmetics, or food products. It is a solvent for food colors and flavors, and in the paint and plastics industries. Propylene glycol is also used to create artificial smoke or fog used in fire-fighting training and in theatrical productions. Other names for propylene glycol are 1,2-dihydroxypropane, 1,2-propanediol, methyl glycol, and trimethyl glycol. Propylene glycol is clear, colorless, slightly syrupy liquid at room temperature. It may exist in air in the vapor form, although propylene glycol must be heated or briskly shaken to produce a vapor. Propylene glycol is practically odorless and tasteless.”
Steve Pelletier is the Vice President of Food for Petnet.io and CEO of Slimdoggy.com, a website created to inform and inspire pet owners on raising healthy, fit pets. They have a food database where they have complied thousands of dog and cat foods along with their calories, ingredients, macronutrients, etc., so pet owners can feed their best friends better.
Pelletier explained to iHeartDogs.com that propylene glycol is commonly used as a sweetener in dog products because “it’s cheap and readily available.” As mentioned in the TATSDR report, it’s also used as a preservative and to remove moisture in dry foods.
And do dog’s like sweet?
“Yes, they do, their palate is very similar to humans,” Pelletier explains. “It is for this reason that some of the lower quality Brands load up their foods with sweeteners (sugar, sucrose, propylene glycol, etc.) —to increase the palatability and to mask the low quality ingredients that make up their formulations. Some dogs can even develop a type of addiction to sweetness and the result is that they refuse, at first, to eat a healthier food when their owner upgrades.”
Should we be avoiding products with propylene glycol in them for dogs, just in case?
So the big question…..it seems that this might be a matter of personal opinion. I am pretty sure the companies that use it will swear up and down that it’s safe and use the FDA guidelines as proof.
Of course, we all know the FDA approves things and then later we find out it causes cancer or something, they are not always correct. In fact, at first they thought propylene glycol was safe for cats, if you read the excerpt carefully you will notice it says later research proved it wasn’t.
According to the SlimDoggy.com database, the following is the percentage of dog foods and treats that contain propylene glycol and propyl gallate (a form of this ingredient):
- No wet foods contained this ingredient
- 4.2 % of the treat recipes contained this ingredient
- 1.9 % of the dry foods contained this ingredient
Pelletier does not think dogs should be fed this ingredient. Here is his argument:
“Propylene glycol is generally recognized as safe by the FDA for use in human foods like salad dressing. This is how Purina et al justify it as being fine for our pets. However, the FDA has missed the boat on this with pet foods. Why? Because unlike salad dressing which is used occasionally, pets tend to eat the same food for each meal, day after day, month after month, even year after year. Although an occasional use might be ‘safe’, the cumulative effect is what is most concerning.”
And since their database shows that it should be relatively simple for you to avoid this ingredient, without limiting your choices of food or treats for your dog, you may feel it’s “better to be safe than sorry,” and avoid foods with this ingredient moving forward.
