Sugar Substitute May Be Dangerous to Dogs
October 1, 2006
CONTACT: David Kirkpatrick
SCHAUMBURG, Ill. - If you think it's no big deal that your dog just ate some sugar-free gum or a cookie or two, think again. You may want to make an immediate trip to your veterinarian.
While veterinarians have suspected that the sugar substitute xylitol can make dogs sick, there is now further clinical evidence of an association between the product and possible liver failure in dogs. A clinical report appearing in the Oct. 1 Journal of the American Veterinary Medical Association (JAVMA) discusses the sometimes fatal conditions developed by dogs that have ingested xylitol. Xylitol, a sweetener found in many sugar-free chewing gums, candies, baked goods and toothpastes, is a naturally occurring ingredient that may have far-reaching negative health effects on dogs.
"Not all things that are natural are safe," said veterinary toxicologist Sharon Gwaltney-Brant, who along with veterinarian Eric K. Dunayer co-authored the report. "There are plenty of things in the environment that are toxic to pets."
While not all pets become ill after eating xylitol, Dr. Gwaltney-Brant said the public—and especially dog owners—needs to be aware of the potential dangers. She added that pet owners should make sure that products containing xylitol are kept away from dogs. If an owner suspects that their dog has eaten products containing xylitol, they should contact their veterinarian immediately.
"The potential for severe illness is very high," she said. "People don't think sugar-free gum can kill their dog. I didn't before I got into this. But this is something people should be aware of."
In the report, Drs. Dunayer and Gwaltney-Brant, staff members at the Animal Poison Control Center of the American Society for the Prevention of Cruelty to Animals in Urbana, Illinois, used the Control Center's data base to gather information on eight dogs that were treated between 2003 and 2005 after eating products containing xylitol. Each dog became ill, and while three of the dogs survived, five of the pets either died or had to be euthanized because of liver failure possibly stemming from xylitol ingestion.
Dr. Gwaltney-Brant said three additional dogs that ingested xylitol after the study was conducted either died or had to be euthanized after becoming ill. All three, Dr. Gwaltney-Brant said, had liver failure.
Dr. Gwaltney-Brant described the potential negative xylitol effects on dogs as a "species difference."
"People only absorb a certain percentage of xylitol," she said. "The human body doesn't even notice it. However, in dogs, xylitol triggers significant insulin release, which drops the blood sugar. It is definitely a species difference. People aren't in danger from sugar-free gum containing xylitol; dogs are."
The number of xylitol-related pet exposures is on the rise, according to Dr. Gwaltney-Brant, partly because of increased awareness, but more so because xylitol is being used in more products. The incidence of reported xylitol exposures climbed from 70 in 2004 to 170 in 2005. As of August, the Poison Control Center reported 114 cases of xylitol exposure this year.
"This is the tip of the iceberg now," she said. "Anything that is sugar-free could potentially have substituted xylitol for the original sweetener."
The extent of xylitol's potential effects on the liver are new—and certainly not good news—for dogs, their owners and veterinarians.
"The fact that xylitol-containing products can cause problems in dogs is a relatively new find," Dr. Gwaltney-Brant said, explaining that the sweetener had already been tied to low blood sugar in dogs—but not liver failure. "Once you start looking at something, you see a lot more of it."
Some sugar-free chewing gums, Dr. Gwaltney-Brant said, are as much as 70 percent xylitol, depending on the brand and whether the product is used as a primary sweetener.
"A 22-pound dog who consumes 1 gram of xylitol should be treated," she said. "This can equate to 3 to 4 pieces of some gum products."
One dog in the study that had to be euthanized because of its condition had eaten four large, chocolate-frosted muffins that contained about 1 pound of xylitol.
"They use it like sugar," Dr. Gwaltney-Brant said. "Baked goods can easily contain a large amount of xylitol."
There is no information on whether severe xylitol poisoning has occurred in cats, Dr. Gwaltney-Brant said.
"If we get exposures, we have blood sugar checked as a precaution," she said.
Dogs, however, are potentially at risk. And while further studies need to be conducted to definitively establish a cause-and-effect relationship between xylitol ingestion by dogs and liver damage and bleeding disorders, Dr. Gwaltney-Brant hopes the message gets out.
"Liver failure is one of our main concerns when dogs get into this," she said. "The low blood sugar we can deal with. But the liver damage, even with aggressive treatment, can make it difficult to save these animals."
For more information, a copy of the study, "Acute hepatic failure and coagulopathy associated with xylitol ingestion in eight dogs," or an interview with author Dr. Sharon Gwaltney-Brant, contact David Kirkpatrick at 847-285-6782.
UT College of Veterinary Medicine