Vet’s advice: artificial sweeteners
Vet’s advice Neil Mcintosh SG’s gundog health expert
“I think you have written before about the danger chewing gum poses to dogs. What is the problem?” KEVIN POILE, OXFORDSHIRE
This issue comes up time and time again and it is well worth a reminder, as danger lies almost everywhere. Apart from getting stuck between the toes, chewing gum can contain xylitol.
Xylitol
Xylitol is best known as an artificial sweetener, or sugar replacement, but it also occurs naturally in low levels in some fruit and vegetables. It is a five-carbon sugar that is involved in glucose metabolism. Xylitol is not altered by baking or cooking and it lowers the calorie content of products. It is important to note that, on packaging, xylitol may not be mentioned by name but by its food additive code, which is E967. Indeed, any medicine or product that is labelled ‘sugar free’ should be treated with suspicion, as it is likely to contain the substance.
So what’s the problem?
Xylitol stimulates insulin release in dogs, which can result in a rapid reduction in blood glucose. In one study, oral administration of xylitol caused an increase in insulin after only 20 minutes and blood glucose started to fall after half an hour. Liver enzymes had increased within four hours. When dogs swallow (rather than chew) chewing gum, however, it can be up to 12 hours before effects are seen, making diagnosis of the problem rather troublesome.
Hypoglycaemia (low blood glucose) is manifest in dogs by increased heart rate, unsteadiness on the feet, lethargy, weakness, vomiting, seizures, low blood pressure and ultimately coma, permanent brain damage and death. The reduction in blood glucose seen after xylitol ingestion is ‘dose dependent’.
How much is too much?
50-100mg/kg causes mild hypoglycaemia, which can be treated by giving small, frequent meals or sugar, along with medication to stop vomiting (anti-emetics). 100-500mg/kg causes significant hypoglycaemia, which should be treated at a vet, as monitoring of blood glucose and administration of intravenous dextrose is usually required.
More than 500mg/kg can cause profound, prolonged hypoglycaemia and liver damage, so urgent treatment should be sought. Low potassium levels can be detrimental to heart function and bleeding disorders can occur.
Unknown dose
Of course, this sounds all well and good, but the ingested dose is generally unknown, as product packaging rarely contains the actual xylitol content. (And dogs often eat the packaging as well.)
The most common source of xylitol poisoning is chewing gum, with different products containing between 1% and 90% xylitol. A relatively new range of Starburst Gums, called Starburst Fruity Mixies, Starburst Strawberry Cubes and Starburst Red Berry Sticks are described as a cross
“When dogs swallow gum, it can be 12 hours before effects are seen”
between a gum and a sweet and contain more than 50% xylitol. These have been implicated in recent poisoning cases, as most people are unaware of the danger.
To date, I am not aware of any veterinary products or canine water additives, which reduce plaque formation, causing toxicity. In the latter, xylitol is present in very low concentration and it reduces dental plaque and tartar formation by inhibiting bacterial growth, which is beneficial to health, so don’t stop using them.
Where accidental ingestion of xylitolcontaining products is discovered within the hour, it is worthwhile inducing vomiting to empty stomach contents. This requires owners to phone ahead to their vet and announce they are coming in and why. There is no point in sitting waiting, as time is of the essence.
Although xylitol does not bind well with activated charcoal, its use can still be beneficial. Dogs that are showing clinical signs of hypoglycaemia should not be given emetics due to the increased risk of aspiration.
What else could it be?
Hypoglycaemic-type clinical signs can be seen with a number of disorders, from pancreatic tumours to hypothyroidism and Addison’s disease. They also occur with insulin overdose (of course) and the ingestion of other drugs and toxins. Severe exertion and Hunting Dog Hypoglycemia should also be considered.
I hope that this has given you something to chew over…