Xylitol, also known as wood sugar, birch sugar, and birch bark extract, has a similar sweetness as regular sugar but contains 40% fewer calories.
Table sugar: 4 calories per gram.
Xylitol: 2.4 calories per gram.
Furthermore, chemically, it is a sugar alcohol, and is found naturally in berries, plums, corn, oats, mushrooms, lettuce, trees, and some other fruits.
Commercially, most xylitol is extracted from corn fiber or birch trees, and is approved by the U.S. Food and Drug Administration (FDA) as food additive.
Although it has been used as a sugar substitute for decades, its popularity has increased dramatically in the last decade due to its low glycemic index (GI), a scale that ranks carbohydrate-rich foods by how much they raise blood sugar levels, compared to glucose.
While xylitol may be unharmful to humans, it is toxic and potentially lethal to dogs. Indeed, Pet Poison Helpline, a 24/7 animal poison control center, at 1-800-213-6680, received 5,846 calls involving dogs ingesting xylitol, in 2020. One of the most common causes of xylitol poisoning in dogs is eating sugar-free chewing gum.
Tipically:
▪ breath mints.
▪ baked goods.
▪ cough syrup.
▪ children’s and adult chewable vitamins.
▪ mouthwash.
▪ toothpaste.
▪ some peanut and nut butters.
▪ over-the-counter medicines.
▪ dietary supplements.
▪ sugar-free desserts, including “skinny” ice cream.
In people, xylitol does not stimulate the release of insulin from the pancreas. However, when dogs eat something containing xylitol, the xylitol is more quickly absorbed into the bloodstream, and may result in a potent release of insulin from the pancreas.
This rapid release of insulin may result in a profound decrease in the level of blood sugar or hypoglycemia, an effect that can occur within 10 to 60 minutes of eating the xylitol. Untreated, this hypoglycemia can quickly be life-threatening.
A dog only needs to eat as little as 0.045 grams/pound or 0.1gram/kilogram of body weight to experience hypoglycemia from xylitol ingestion.
Liver damage occurs at a much higher dose of 0.11 to 0.22 gram/pound (0.25 to 0.5gram/kilogram).
Most chewing gums contain 0.2 to 1.0 grams of xylitol per piece. That means, only one piece of gum can cause low blood sugar in a 20-pound dog, and as few as 2 to 4 pieces of gum can cause liver damage and failure.
They may include:
▪ Vomiting.
▪ Weakness/Loss of balance.
▪ Stumbling/Lack of coordination.
▪ Lethargy/Depression.
▪ Tremors/Seizures.
▪ Collapse/Coma.
Signs of hypoglycemia may appear as early as 30 minutes after xylitol ingestion, but may be delayed up to 12 hours. If you notice any of these symptoms, and believe your dog may have ingested xylitol, contact your local veterinary emergency hospital immediately.
If your dog is not showing symptoms of poisoning, and the ingestion occurred fewer than six hours prior, your vet will likely induce vomiting.
In all cases, your dog will require hospitalization for blood glucose monitoring, maropitant, dextrose administration, intravenous fluids, phytonadione, metronidazole, and fresh frozen plasma, liver protectants, and any other supportive care that may be needed. N-acetylcysteine (NAC) and S-adensoyl-l-methionine (SAMe) provide hepatic detoxification.
Early diagnosis and aggressive treatment are crucial in treating xylitol poisoning in dogs, as in the following example of successful treatment of acute hepatic failure and coagulopathy in a dog after xylitol ingestion.
A 9-year-old 4.95 kg (10.9 lb) male Chihuahua was evaluated at a veterinary clinic for vomiting after ingesting 224 g (45 g/kg, 20.5 g/lb) of granulated xylitol. Hypoglycemia developed within 1–2 h, elevated liver values, suggesting the development of acute hepatic failure, within 12 h and coagulopathy less than 24 h after ingestion.
With quick treatment, the dog survived and liver values returned to normal within 1 month post ingestion. No adverse effects to hepatic function have been identified 2 years after acute xylitol toxicity.
Finally, even though cats, rabbits, ferrets, and horses do not appear to develop hypoglycemia or liver failure from ingestion of xylitol, it is still best to keep them away from products containing this sugar substitute.
