Chocolate Toxicity

With the Christmas and Halloween seasons surrounding us, it is important to talk about chocolate. Frequently we will get calls at the clinic asking how much chocolate is too much for a pet to eat. Chocolate may be one of my favourite flavours. Canadians consume a significant amount of chocolate bars, ice cream, chocolate drinks, chocolate cakes, etc. Most of us know that it isn’t a good idea to share these treats with our pets although we don’t always know why so with some help from the Veterinary Information Network I will explain why.

There are many types of chocolate: milk, dark, white, unsweetened, cocoa powder etc. It turns out each type has a different potential for toxicity. How chocolate is made often determines how toxic it will be to our pets.

Cacao trees that grow in tropical climates around the equator are farmed in orchards. The fruit of the cacao tree called a cacao pod, the pod is sweet and attracts monkeys or other wildlife who eat the fruit but not the bitter seeds. The seeds are discarded in the natural setting, allowing new trees to grow. The seeds cannot be released naturally from the fruit unless some animal breaks the fruit open. It is the bitter seeds, packed with theobromine and caffeine, which are used to make chocolate.

The pods are harvested by hand so as not to damage the tree. The pods are split and the seeds are scooped out and left to ferment under banana leaves for about a week. This process turns the cocoa seeds the rich brown colour with which we are familiar and creates the chocolate flavour.
The seeds are then dried out, packed in sacks, and shipped to chocolate manufacturers. The seeds are roasted, ground, pressed to remove the seed oil. This oil is called cocoa butter, which is used in sunscreens, white chocolate, and cosmetics etc. The hulled cocoa beans are then ground to make chocolate liquor. Cocoa powder is the solid that remains after the cocoa butter is removed from the chocolate liquor.

Unsweetened (baking) chocolate is basically straight chocolate liquor containing 50% to 60% cocoa butter.

Dark chocolate (also known as semisweet chocolate) is chocolate that is 35% chocolate liquor (the rest being sugar, vanilla, or lecithin).

Milk chocolate is chocolate that is at least 10% chocolate liquor, the rest being milk solids, vanilla or lecithin.

As far as pets are concerned, the first potential problem with these sweets is the fat. Most often the fat and sugar in chocolate can create temporary upset stomach and urgent diarrhea, but a more serious sequel of eating a sudden high-fat meal (such as demolishing a bag of chocolate bars left accessible at Halloween time) can create a lethal metabolic disease in dogs called pancreatitis. Vomiting, diarrhea, and abdominal pain are just the beginning of this disaster. In the case of pancreatitis, it is the fat that causes the problem more than the chocolate itself.

Chocolate is also directly toxic because it contains theobromine and caffeine, the more chocolate liquor there is in a product, the more theobromine there is. This makes baking chocolate the worst for pets, followed by semisweet and dark chocolate, followed by milk chocolate, followed by chocolate flavoured cakes or cookies. White chocolate contains no theobromine and is only a concern because of the fat content.

Theobromine causes vomiting, diarrhea, hyperactivity, tremors, seizures, racing heart rates, abnormal heart rhythms and in severe cases death.

The amount of chocolate, the type of chocolate and the size of your pet all play a role in how what your pet ingests will affect them. Please call the clinic with an estimate of your dog’s size and the amount and type of chocolate they have consumed so we can let you know if this is something that we will need to address immediately or perhaps we will tell you it is a small enough dose that you don’t need to bring your pet in. If the chocolate was only just eaten, it is possible to induce vomiting; otherwise, hospitalization and support could be needed.

Prevention is the best way to prevent a sick pet, keep your treats out of your dog’s reach and avoid ever giving any chocolate to your pets.

Written by: Jane Corkum, DVM

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