Xylitol is an organic chemical in a class of compounds called polyalcohols. It was discovered more than 100 years ago. It is now widely produced and used in the developed world for one simple reason: It tastes sweet. It is therefore used as an artificial sweetener in gums, candies, medicines, and many foodstuffs.
In humans, xylitol is touted as being beneficial for health. When consumed, xylitol releases dramatically fewer calories than sugar. It does not raise blood sugar. And it helps to prevent cavities. For the last reason, most sugarless gums are now made with xylitol. This practice enables gums to claim that they are good for teeth.
No adverse effects from xylitol have been widely reported in humans. Sadly, the same cannot be said for pets. Xylitol toxicity is one of the most common toxic exposures I treat in dogs.
Dogs’ bodies (yes, I know this is Catster — bear with me) react differently to xylitol. The compound tricks their bodies into believing that blood sugar is too high. Insulin is released by the pancreas, causing actual blood sugar to drop to dangerous levels. Dogs who have consumed xylitol must be hospitalized for up to several days so that intravenous dextrose (sugar) can be administered to prevent fatal hypoglycemia.
Dogs who consume xylitol also are at risk of idiopathic hepatic necrosis. In other words, xylitol causes liver failure for unexplained reasons in some dogs that consume it.
Long story short: Xylitol is really bad news for dogs. And dogs tend to be drawn to minty, sweet, or aromatic things. They regularly consume packs of gum and wind up in the hospital for days.
Cats, it turns out, are relatively more sensitive to many things than are dogs. For instance, there are doses of acetaminophen that are sometimes used to treat pain in dogs. (Note: It is illegal and dangerous to give your dog over-the-counter Tylenol. Don’t do it!) Such a dose of acetaminophen would be fatal to a cat. Cats are unique creatures with special metabolisms.
It had therefore long been assumed that xylitol would be as toxic to cats as it is to dogs, if not more so. In this arena, however, cats have one big advantage: They don’t, in general, like gum or sweets. Xylitol exposure in cats is almost unheard of. Of course, the key word is almost.
Several days ago a client brought a cat to me. He reported that she may have consumed sugarless gum. He suspected this because the cat vomited at home, and in the vomit he had found a gum wrapper. He had used his iPhone to take a picture of the wrapper, and he showed it to me. It said, “Trident, Good for Teeth.” I Googled what I had read and discovered, as expected, that many Trident gums contain xylitol.
I evaluated my patient. She was bright, alert, and responsive. She was very friendly. Her eyes, ears, nose, and throat were unremarkable. I ausculted normal heart and lung sounds, and I palpated a normal abdomen. Her lymph nodes, pulses, neurological function, and musculoskeletal system appeared normal. In other words, the entire exam was normal.
However, low blood sugar can occur in cats with normal physical exams. The only way to know whether blood sugar is low is to test it, so we did. It was normal.
I spoke with the owner. He did not know the source of the gum. The cat lived exclusively indoors, and he hadn’t purchased any gum in recent memory. I asked more about the vomit. Had any gum been seen in the vomit? Had any food coloring been seen? The answer to both questions was no.
We spoke for a moment longer. I pointed out that cats, in general, don’t like gum. They do, however, like paper. Was there any chance that the cat had merely consumed an empty gum wrapper? The owner and I both came to the conclusion that this was probably what had happened.
But what if the cat had consumed gum? Given that they are very sensitive little creatures, might she be in serious trouble? I couldn’t state with certainty, but I knew someone who could: The on-duty veterinarian at the ASPCA’s Animal Poison Control hotline.
Animal Poison Control is an amazing resource. It is always open, and always staffed with a veterinarian or toxicologist. They have a massive database of animal poisons and are able to recommend treatments or, sometimes, to put owners’ (and vets’) minds at ease. The service is not free, but the fee charged is low and, relative to the value of the service provided, it is practically nominal.
I explained the situation to the toxicologist. She did some calculations while I was on the phone, and then she asked to put me on hold. I was on hold for quite some time, which means that the situation was a challenging one for her, too. But when she got back on the line, she gave me a surprise — a happy surprise.
She advised me that recent information has revealed that xylitol is not known to be toxic to cats. They do not develop low blood sugar, nor do they develop liver failure. Prior to this the presumption was made, based upon extrapolation from dogs, that cats would suffer similar effects. Due to the fact that cats don’t frequently expose themselves to xylitol, it apparently took quite a while for all of the information to come out.
So now we know. This does not mean that cat owners should tempt fate by force feeding xylitol to their cats, or even by leaving xylitol lying around. But it does mean that folks who own cats but not dogs needn’t take drastic measures such as the ones in place in my home. We are completely xylitol free; perhaps you needn’t be.
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