Pet Article

A sugar substitute fit for humans, which can be lethal to your dog

What is xylitol and where can it be found?

Xylitol is a natural sugar alcohol that is commonly used as a sugar substitute in human foods. It is found in and extracted from corn fiber, birch trees, hardwood trees as well as other fruits and vegetables.

Xylitol is a sugar substitute most commonly found in chewing gum, candies, breath mints, baked goods, cough syrup, children’s edible vitamins, mouth wash and tooth paste (all of the sugar free variety). There are many more human products on the market that may contain xylitol. It may also be purchased in a granulated form to be used for baking, or as a sweetener over cereals and in beverages. As society’s pressure to look lean and slim, and the need to diet increases, this sugar free alternative has grown drastically in popularity over the last decade.

The German chemist Emil Fisher first identified Xylitol in 1891. During the Second World War it was first produced in large quantities as sucrose was not available. Xylitol has become more popular in recent years as it has only two-thirds the calories of sugar. Xylitol in humans does not require insulin to enter cells, making it very useful as a dietary supplement in diabetics. It is associated with very little insulin release in people.

Even though this product is safe for human consumption, and may even have a health benefit, it is unfortunately very toxic to our pets.

What does xylitol do to our pets and how much is dangerous?

There are 2 major side effects of xylitol in our dogs, namely hypoglycaemia (low blood sugar) and severe liver damage.

Hypoglycaemia: xylitol is rapidly absorbed from the intestinal tract following consumption. What then follows is a potentially life threatening series of events. As the xylitol is absorbed it stimulates the release of large amounts of insulin from the pancreas. Insulin’s function in the body is to stimulate the absorption of blood glucose (sugar) by the cells of the body for energy. Unfortunately with xylitol, there is no increase in blood glucose following the meal and the released insulin then removes all the remaining glucose from the bloodstream causing a drastic drop in the blood sugar. This may occur within 10-60 minutes after ingestion. Low blood sugar levels can result in weakness, collapse, and even seizures. If not treated quickly this may even cause the death of the dog. Insulin also decreases blood potassium levels as this is taken up with the glucose into the cells. Low phosphorus levels may also be found as insulin increases the cells’ permeability to phosphate ions allowing them to enter the cells more easily.

More recently they have found that when xylitol is consumed, a more severe and challenging complication may arise - acute liver damage. Following ingestion of xylitol, it enters the blood stream and passes through the liver. In the liver it causes cell death and destruction of the normal liver tissue which can result in acute liver failure. The exact reason why this happens is yet to be determined but the effect does seem to be dose dependent, i.e. it is proportional to the amount of xylitol consumed. This sudden and devastating liver damage can result in jaundice and bleeding tendencies along with the vomiting and lethargy commonly seen with this intoxication. This occurs within 72 hours (3 days) after consumption.

The amount of xylitol needed to cause these complications starts from only 0.1g/kg. Many of the common chewing gum brands contain as much as 1 g per piece of gum. As little as 2 pieces of gum eaten by a 20 kg dog is enough to cause toxicity. In others word, very little is needed before your pet’s life may be threatened.

What should you do if you find your pet eating something containing xylitol?

If you are lucky enough to find your pet while they are eating the offending food, stop them and try to remove as much of the substance out of their mouths as you can. Next step is to take your dog to your veterinarian. Once there, the vet will mostly induce vomiting by placing a medication in either their eye or nose. Within about 15 minutes your dog will start to vomit and hopefully get as much of what they ate out as possible. As mentioned previously, xylitol is absorbed very quickly so most likely your pet will have to be admitted to monitor the blood glucose levels.

In dogs xylitol causes the release of insulin from the pancreas within 10 to 60 minutes after ingestion and can be life threatening if not treated. Xylitol has been estimated to be 100 times as toxic as chocolate to dogs.

If caught early enough and hypoglycaemia (low blood sugar) is minor or avoided, it is still important to monitor your pet closely as they may still undergo liver damage. Blood tests done at 24, 48 and 72 hours after consumption may be necessary to check if there is any liver damage. These blood tests measure the levels of enzymes (functional proteins) that are released from the liver following a toxic insult such as xylitol ingestion.

In the unfortunate situation where you may not have been able to stop your pet from eating the xylitol containing food, here are some clinical signs too look for:

Vomiting
Lethargy
Weakness
Incoordination
Ataxia (your pet will be wobbly on their feet swaying from side to side when they walk, almost as if they are drunk)
Depression
Tremors
Seizures
Coma
Yellow gums, eyes and skin in severe cases
Buildup of fluid in the body especially the abdominal area (ascites)
Bloody diarrhea
Bleeding gums

In the event that your pet is far advanced and collapsed by the time you get them to the vet, consultation will involve assessment and treatment of the hypoglycemia by intravenous administration of glucose and careful monitoring. They may need to be placed on a drip to maintain blood pressure and to treat and prevent dehydration. Monitoring of phosphorus and potassium blood levels is important and any abnormalities will need to be corrected as needed. Should the liver be affected, unfortunately the prognosis is generally not good. The damage to the liver is irreversible and it depends on the proportion of the liver damaged. If a large area of the liver has been destroyed there is less chance of survival, and vice versa. Treatment involves intravenous fluid therapy, liver supportive medication, antioxidants, regular monitoring of liver enzymes and intensive monitoring. If a bleeding tendency develops they may require a plasma or blood transfusion.

How to prevent this from happening to my pet?

If you use xylitol or any product containing xylitol always keep it in a safe place where your dogs may never reach it. You should not share any product containing xylitol with your dog.

There are some veterinary products that contain xylitol such as mouthwashes. At prescribed doses they are safe for your pets. Just as with many other chemical compounds, the dose is critical. Many medications which are used on a daily basis in veterinary medicine can be fatal if used in too high quantities. Therefor the formulation of any medication is critically important in the safe management of many medical conditions in pets. Other sugar substitutes such as mannitol, sorbitol and aspartame have been found to be safe in dogs to date.