Sweet and sour: The surprising danger of peanut butter for dogs

Pet owners and caregivers should be aware that the addition of the sweetener xylitol makes peanut butter, or any other product, toxic for dogs. Photo: File photo Pet owners and caregivers should be aware that the addition of the sweetener xylitol makes peanut butter, or any other product, toxic for dogs. Photo: File photo

By now, most pet owners are well aware that chocolate can be toxic to dogs and cats. The fact has a memorable pub quiz flair to it—a simple nugget of knowledge that is simultaneously fascinating, bizarre and useful. And the publicity has no doubt saved the lives of many thousands of household pets. But when it comes to the unexpected toxicity of a seemingly innocent household staple, there’s a heavier hitter in town these days. With all due respect to chocolate, perhaps it’s time to start worrying more about peanut butter.

I should back up a bit. There’s nothing inherently wrong with peanut butter (apart, perhaps, from its astonishing calorie density). And the odds are good that the peanut butter in your own home is perfectly safe to give to a dog. But you’ll want to check the label, because those odds are a bit lower than they used to be.

The threat comes from a sugar substitute called xylitol, a naturally existing sugar alcohol that offers the same sweetness as table sugar but with a fraction of the calories and a bonus layer of protection against dental cavities. This has made it a common ingredient in chewing gum over the past decade or so. You can even buy bags of the stuff in health food stores to use in sugar-free baking. And in the last few months, it has started to quietly appear in a few niche brands of peanut butter.

While xylitol is perfectly safe for human consumption, it is terribly toxic to dogs. It fools their pancreas into releasing a dangerous surge of insulin. This causes their blood sugar to bottom out, potentially resulting in seizures, coma or death. Adding insult to injury, dogs who survive the initial crisis can find themselves contending with liver failure. In truth, xylitol is far more toxic than chocolate, but far fewer people know about it.

Xylitol caused enough trouble when it was only in chewing gum, resulting in the occasional emergency when a dog was found rummaging through a coat pocket. But those are accidents. Peanut butter is a different story entirely. People give it to dogs on purpose, smearing it inside rubber toys to keep dogs busy or even baking it into homemade treats. And, until recently, there was absolutely nothing wrong with that.

To be clear, the vast majority of peanut butters do not contain xylitol and are safe for canine consumption. It is a small number of less-common brands (including Nuts ’n More, Krush Nutrition and P28 Foods) that are of concern. Unfortunately for consumers, the labeling can be subtle. While manufacturers are quite happy to trumpet “naturally sweetened” across the front of the jar, they are less eager to append “with something that might kill your dog.” If the ingredient list contains xylitol, or if it makes a less- specific reference to “sugar alcohol,” it’s best to just leave it on the shelf.

These products entered the market without any particular fanfare, and I worry that this is the start of something bigger—that xylitol is going to gain traction in other sugar-free products as well. If the current situation is any indication, the onus will fall entirely on pet owners to make sure that they are not unwittingly putting their dogs in danger. Buyer beware, indeed.

Dr. Mike Fietz is a small-animal veterinarian at Georgetown Veterinary Hospital. He received his veterinary degree from Cornell University in 2003 and has lived in Charlottesville since.