Wolfie and Sonya
Photo by Andrew Holycross
The Holycross family got Wolfie, shown here snuggling with Sonya Sass Holycross, as a puppy early in the pandemic. Andrew Holycross said losing the dog to xylitol toxicosis one year later was very difficult.
One night in July, an exuberant Samoyed named Wolfie nosed his way into his owner's purse perched on a countertop, where he found and devoured 30-plus pieces of Wrigley's Juicy Fruit gum. The sortie was noisy enough to attract the attention of Sonya Sass Holycross and her 13-year-old daughter, Alessandra. They came across the dog gulping the last of the gum, according to Andrew Holycross, Sass Holycross' husband, who was out of town at the time.
At first, they weren't alarmed, he said. His wife thought she'd bought regular gum containing sugar. From the time Wolfie joined the household early in the pandemic, the family made a practice of avoiding the artificial sweetener xylitol because it was on a list Alessandra had compiled of foods the new puppy shouldn't eat. A naturally occurring alcohol sugar, xylitol is safe for humans but can be toxic for dogs because of differences in their metabolisms.
Alessandra double-checked the mangled package and discovered to her alarm xylitol was the first item on the ingredient list. After a call to a poison control hotline, Sass Holycross raced Wolfie to a VCA hospital near their Arizona home. It had been less than an hour since he ate the gum, but by the time they reached the clinic, he was "wobbly," a sign of hypoglycemia. Within 36 hours of consuming the gum, Wolfie died in the hospital from liver failure.
Losing Wolfie spurred Holycross to begin campaigning for warning labels on xylitol products, including by showing up unannounced on the home doorstep of his congressman. At first, Arizona Rep. David Schweikert was guarded, but soon he invited in his constituent, and they talked in the kitchen for nearly two hours. That conversation culminated three months later in the Paws Off Act of 2021 (H.R. 5261). Introduced in the U.S. House of Representatives this fall by Schweikert, the bill would require a dog safety warning label on food products containing xylitol. A label is needed, proponents say, because many pet owners aren't aware that xylitol is toxic to dogs or that it is used in many products.
"The PAWS Off Act is a necessary piece of legislation that will positively impact nearly half of American households who own a pet," said Schweikert, a Republican, in a statement emailed to the VIN News Service. "As a pet owner, I know that I revere my own dogs as members of my family. That is why it is crucial that this legislation is passed so that all dog owners, myself included, are able to keep their pets safe."
The American Veterinary Medical Association supports the bill and urges members to ask their representatives to co-sponsor the legislation.
The bill has six bipartisan co-sponsors so far, and Schweikert's staff said that to date, they are unaware of any opposition to the bill.
Why xylitol harms dogs
While veterinarians have known for years about the risks of xylitol, the public is less aware; cases of xylitol poisoning have risen steadily over the past two decades. The Animal Poison Control Center operated by the American Society for the Prevention of Cruelty to Animals received its first xylitol-related call in 2002, according to Dr. Tina Wismer, a veterinary toxicologist and medical director at the center. It logged two reports that year. In 2011, call volume reached 3,045. Last year, the center received 7,811 xylitol-related calls. It is on track to exceed that record this year, with 8,213 calls logged as of Oct. 31.
Wismer said cases are increasing for two reasons. "Number one, we are finding it in more products," she said. "It really seemed to take hold when the whole Atkins low-carb craze happened. And [second], veterinarians are becoming more cognizant of this being a problem."
In humans, xylitol does not affect insulin or glucose levels, making it a popular sweetener among people with diabetes. There is no evidence it causes problems in cats. In dogs, however, xylitol stimulates the pancreas to release a flood of insulin that causes a sudden drop in blood sugar, a condition called hypoglycemia. Signs of hypoglycemia include unsteadiness, anorexia, vomiting, lethargy, restlessness, dilated pupils and in severe cases, seizures. If a dog ingests xylitol in quantity, it may lead to liver failure. Exactly why liver failure sometimes occurs is not well understood, according to the xylitol entry in the VINcyclopedia of Diseases, a reference developed by the Veterinary Information Network, an online community for the profession. Signs of liver injury include jaundice, vomiting, diarrhea and abdominal pain.
Originally created through extraction and processing of xylan in hardwood trees, xylitol now is often produced more cheaply using corncob remnants from ethanol plants. It can be found in breath mints, baked goods, cough syrup, chewable vitamins, mouthwash, toothpaste, peanut and nut butters, over-the-counter medicines, dietary supplements and many more food and non-food products.
"It hides places," Wismer said. Unlike other foods that are toxic for dogs, such as macadamia nuts, garlic, chocolate, grapes and raisins, xylitol is usually not in the name of the offending item.
Small amounts aren't dangerous to dogs. It is used in small concentrations, in fact, in some canine dental products because xylitol has antibacterial properties. As the saying goes, the dose makes the poison.
"We know that at about 75 to 100 milligrams per kilogram [of a dog's weight], we can start to see an increase in the release of insulin in the body," Wismer said. "Typically, we send dogs into the veterinarian at anything over 100 milligrams per kilogram, and then we get concerned about the liver at about 500 milligrams per kilogram."
The amount used in gum varies from less than a milligram to one gram (or 1,000 milligrams) per piece, she said. Knowing the concentration of xylitol helps veterinarians anticipate what will happen to a dog that's ingested it, and avoid overtreating the patient. Ten years ago, some companies declined to disclose xylitol content to veterinarians or pet owners, saying it was proprietary information. That's changed.
Although many companies still do not put the amount on the label, Wismer said, "Most companies will give you that amount if you call their customer service number and tell them what is going on."
Because their bodies rapidly absorb xylitol after ingestion, dogs must be treated quickly. Interventions for xylitol toxicity can include inducing vomiting and administering IV dextrose to stem hypoglycemic seizures. Supportive care is given while patients' blood chemistry is tracked.
About the Paws Off Act's prospects, Wismer didn't venture a prediction. "Is it going to go anywhere? We don't know, but at least it's getting people talking even if it doesn't pass," she said. "I think it's kind of where we were with chocolate 40 years ago. Now, everybody knows chocolate can be poisonous to dogs. I think it's just education."
Dr. Michelle Ward, who works at an emergency veterinary hospital in Eastern Washington, anticipates pushback to the legislation from companies that use xylitol in their products. "They want people to think of the product as a healthier alternative," Ward said. "[A warning] makes it seem like poison."
For her part, Ward has promoted warning labels on a local scale. Twice, she convinced managers at food co-ops where she shopped to put a warning next to bulk bins of xylitol powder, which is used in baking and sometimes is labeled "birch sugar."
Ward said she's seen many cases of xylitol poisoning, including during the last weekend in October when a dog was brought to the hospital after eating a container of sugar-free Ice Breakers Ice Cubes gum. His heart rate was elevated, but he wasn't tremoring. The veterinary team was able to induce vomiting. He survived.
She warns clients that just one piece of sugarless gum can kill a small dog.
Holycross calls on Mars Inc. to help
Photo by Sonya Sass Holycross
Wolfie managed to extract from his owner's purse an almost-full container of Juicy Fruit gum that initially contained 40 pieces. Because the gum is labeled "original," Wolfie's owner thought it was the old-style sugary formulation. But the gum contained xylitol, a sugar substitute that can be toxic to dogs and proved fatal to Wolfie.
For Holycross, a herpetologist, biology professor at Mesa State Community College and adjunct faculty at Arizona State University Biodiversity Knowledge Integration Center, enlisting support for the Paws Off Act from pet owners and veterinary and animal welfare groups is just the beginning of his campaign. Next, he's turning his attention to industry, in particular, Mars Inc.
Privately held Mars, headquartered in Virginia, is probably best known for selling candy, including many products with xylitol, such as Wrigley's Juicy Fruit gum. Mars is also the largest owner of veterinary clinics in the world, with more than 2,500 locations, including VCA hospitals, in North America alone. In addition, it owns a large share of the U.S. market for pet foods and other pet products.
Holycross didn't know much about Mars before Wolfie died. It wasn't until he called Mars Wrigley to complain about the lack of a warning label about xylitol, then reached out to VCA to see if they'd support the labeling legislation that he discovered Mars was on both ends of his ordeal.
As he put it, "They sold me an unlabeled canine poison. Then, they profited from treating my dying dog."
He described the gum canister his wife bought as being the classic yellow color of the sugary Juicy Fruit of yore, and the word "original" appearing in prominent lettering. Beneath that, in smaller type, the label reads "artificially flavored sugarfree gum." Holycross said the label leads a shopper to believe they are buying the original formulation of sugared gum.
"I also think that Mars is deliberately not including a visual icon on their products to warn of xylitol's toxicity to dogs," he said. "The few folks aware of the xylitol epidemic have been petitioning these companies for a while now."
When he and his wife emailed and called Wrigley's to complain about the lack of warning labels, he said the representative gave each of them the same "scripted response" that, to his ear, deflected responsibility. (Holycross provided a copy of one email.)
"Eventually, they start gaslighting you," Holycross said, "telling you it's up to you to know what you are bringing into your home." He asks: How realistic is it to suggest that the many millions of busy Americans who own dogs are going to read the ingredient list of every item they purchase?
"These companies have an obligation to put a clear symbol on the label," he said. He believes Mars' public messaging that they care about public and pet health is inconsistent with the company's failure to alert dog-owning consumers to the real risk presented by its products containing xylitol.
Holycross sent a letter to Mars CEO Grant Reid asking him to support the bill "because they are an industry leader and have tremendous influence," he said, adding: "I want them on board. I want them to do the right thing." He also posted a plea on Facebook for others to join him in writing to the company.
The VIN News Service asked Ryan Bartholomew, director for global corporate communications at Mars Veterinary Health, if anyone in that division would comment on the legislation or Holycross' experience and concerns. She emailed the following statement:
"As part of our dedication to pet health and wellbeing, Mars Veterinary Health supports education about common foods and products that pose a danger to pets, including xylitol. While Mars is not engaged in this legislation, we encourage more conversation and awareness of the dangers of xylitol for pets to help ensure pet owners are aware of the risks."
Bartholomew clarified that not engaging means "neither supporting nor opposing" the legislation, and that the position applies to all of Mars, including Mars Wrigley.
The Paws Off Act is in the House Energy and Commerce Committee. The legislation would direct the FDA to require a warning label but doesn't dictate what labeling would look like. If the bill is signed into law, the FDA will have a year to determine specific requirements.
VIN News Service commentaries are opinion pieces presenting insights, personal experiences and/or perspectives on topical issues by members of the veterinary community. To submit a commentary for consideration, email firstname.lastname@example.org.