But many people are unaware of the ever-expanding list of consumable products that contain xylitol. This sweetener is now being added to human vitamins and prescription drugs, including pediatric elixirs once considered safe for dogs.
According to Patty Khuly, DVM, the increasing use of xylitol presents a risk that veterinarians, pharmacists and pet owners must be made aware of.
“I used to recommend Flintstones vitamins for my patients,” says Khuly. "Now I have to caution my clients to stick to pet-only brands and to be very diligent about reading labels."
Xylitol is a sugar alcohol extracted from corn and corn fiber, birch, raspberries and plums. It is used to sweeten many products, including:
- Sugar-free gum, mints and other candy
- Nicotine gum
- Chewable vitamins
- Certain prescription drugs
- Dental hygiene products
- Baked goods
Xylitol can also be purchased in granulated form as a sugar replacement to sweeten beverages, cereals and other foods.
The Number of Products Containing Xylitol is Diverse and Growing
The use of xylitol is increasing because it is as sweet as sucrose, but with only two-thirds the calories of sugar. It’s less expensive than other sugar substitutes, tastes better, and causes little if any insulin release in humans.
Just a few years ago, xylitol could be found in less than a hundred products in the U.S., primarily limited to sugar-free gums, candy and foods. Today it can be found in a wide range of health and beauty products, food products, over-the-counter drugs and supplements, and prescription medications.
A fairly comprehensive list of families of products as well as some specific products containing xylitol can be found at Wikia.com.
Response to Xylitol is Species-Specific
While xylitol appears safe for human consumption, the same can’t be said for pets. In fact, the FDA recently released a consumer alert on the dangers of xylitol ingestion in certain animals.
The sweetener’s effect seems to vary by species. In people, rhesus monkeys, rats and horses, intravenous (IV) xylitol causes little to no insulin release. However, it has the opposite effect on baboons, cows, goats, rabbits, dogs, and ferrets. Its effect on cats is unknown.
Humans absorb xylitol slowly, and the sweetener ingested orally is absorbed at from about 50 to 95 percent.
In dogs, xylitol is rapidly and completely absorbed within about 30 minutes. Just a small amount of xylitol can cause a dangerous insulin surge and a rapid drop in blood sugar. Symptoms of xylitol intoxication include:
- Loss of coordination
If you suspect your pet has eaten a product containing xylitol and is experiencing any of these symptoms, immediate veterinary care is needed to save your dog’s life.
Xylitol and Liver Failure in Dogs
A more recent discovery than the connection between xylitol and hypoglycemia is the incidence of acute liver failure in dogs that have ingested the sweetener.
According to a 2006 case report of xylitol-related liver failure in eight dogs, five of the eight died or were euthanized despite treatments that included IV administration of fluids, blood transfusions, and administration of dextrose.
Six of the eight dogs with liver failure did not develop hypoglycemia first, and no symptoms were present for from 12 to 24 hours after they ingested the xylitol. So it isn’t safe to assume, if you suspect your dog has ingested xylitol that signs of toxicity will show up quickly. Your pet could appear fine for up to a day after getting into some xylitol, only to then develop liver failure.
The cause of xylitol-related liver failure in dogs is not well understood, but scientists suspect it has to do with the fact that xylitol and its metabolites deplete adenosine triphosphate stores in the liver. Adenosine triphosphate is a chemical substance that gives cells energy. Without a sufficient amount of this chemical, the cells in the liver die off.
Interestingly, neither other sugar alcohols (mannitol, sorbitol) nor artificial sweeteners like saccharin are known to cause illness in canine companions.
How Much Xylitol Does It Take to Make a Dog Sick?
Generally speaking, dogs ingesting over 0.1 g/kg of xylitol are considered at risk for hypoglycemia. Amounts above .5 g/kg can poison the liver.
Since it is almost impossible to figure out how much xylitol is contained in a particular product, I strongly recommend that dog owners avoid anything containing xylitol.
I urge you to inspect the labels on any sugar-free gum, candy or processed food you have on hand, as well as oral hygiene products (toothpaste, mouth rinse, teeth whiteners, etc.).
Also check all your OTC medications and supplements, for example, chewable vitamins, as well as your prescriptions – especially any drug in liquid form.
Stick only with veterinary drugs and supplements for your pet, and if your veterinarian prescribes a new medication, make sure he or she can confirm for you the preparation is xylitol-free. You can also consult your local pharmacist about new prescriptions as well as any drugs you, your pet, or other family members are currently taking.
How Sick Can My Dog Get?
If your pet is treated promptly by a veterinarian, an uncomplicated blood sugar drop brought on by ingestion of a relatively small amount of xylitol can be reversed.
A minor increase in liver enzymes, meaning the sweetener is affecting your pet’s liver, should also resolve in a few days with proper veterinary care.
However, if dramatic elevation of liver enzymes occurs, as well as increased levels of bilirubin and lack of blood clotting activity, your dog is in serious trouble.
Hyperphosphatemia, which is an abnormally high level of phosphate in the blood, is also an indicator of a very poor prognosis for dogs that have ingested a significant amount of xylitol.
Because xylitol intoxication can create a dangerous downward spiral in your dog’s body very quickly -- and because it has such deadly potential -- if you suspect your dog has ingested even a very small amount of this sweetener, you should seek immediate veterinary care.