Food is nourishing but often species-specific. Whilst dogs evolved scavenging from humans, we now eat many things that are toxic to dogs and need to keep them safe.
Feeding a dog food that is intended for human consumption could be fatal. The human food industry is well aware that it needs to produce so-called “clean labels” for food and it is increasingly difficult to decode ingredients to understand exactly what processed food contains or how non-processed food has been grown, harvested, stored and packaged.
There are many foodstuffs that are enjoyed by humans that are toxic for dogs. Even if not fatal, some foods can cause serious illnesses in dogs, with some breeds being more susceptible than others.
Looks like a healthy bowl of fruit? Not for your dog. All the fruits in the bowl can cause serious illness and even prove fatal if eaten. Stoned fruit and pips such as those found in apples contain cyanide; although a small amount may not cause noticeable effects, if eaten regularly, toxins can accumulate to lethal effect. Dogs can also choke on stones and are likely to get an upset stomach from eating fruit flesh. Fermenting fruit such as windfalls can also cause alcohol poisoning. Avocados contain persin which can damage heart, lung and other tissues. They are high in fat and can cause an upset stomach, vomiting and pancreatitis. After ingesting, a dog may have difficulty breathing, abdominal enlargement, abnormal fluid accumulations in the chest, abdomen and the pericardium that surrounds the heart. The amount that needs to be ingested to cause problems is unknown. The same is true of grapes, whether fresh or dried as raisins and sultanas.
The hamburger may contain onion powder and garlic, both of which cause anaemia in dogs, so the onion rings are off limits too. All the onion family (allium) destroy red blood cells in dogs and, when ingested may produce weakness and breathing difficulty. As with fruit toxins, small amounts can cause cumulative damage over time irrespective of whether eaten raw, powdered or cooked. Garlic is not as toxic as onions and can be used in very small quantities therapeutically for its antibiotic, antiseptic and anti-viral properties with veterinary supervision.
Foods that are high in fat can cause stomach upsets and even pancreatitis. Some breeds are more susceptible than others, but best to avoid for all dogs. High salt is also not good for dogs and fast food usually contains a great deal of salt as well as any that may be added after serving.
Most dairy products cause digestive problems because dogs lack lactase, the enzyme required to digest food such as milk and ice cream. Some cheeses, including mild cheddar, have a lower lactose content and can be consumed in small quantities as a treat. The high sugar is not advisable either. Chocolate can be fatal to dogs if it contains high cocoa solids (70%+) and even poorer quality chocolate can trigger fatal pancreatitis if consumed in sufficient quantity.
Click here to see the effects on dogs consuming of chocolate containing different levels of theobromine, the alkaloid that is toxic. Dogs metabolise theobromine much more slowly than humans and, although it is also lethal for cats, dogs are more likely to take an interest in chocolate because they, unlike cats, are attracted to the sweetness of the sugar content. Approximately 1.3 g/kg (0.02 oz/lb) is sufficient to cause symptoms of toxicity. 1 oz of milk chocolate per pound of body weight is a potentially lethal dose in dogs and again, small amounts an cause cumulative problems.
Symptoms of theobromine poisoning include nausea, vomiting, diarrhoea and polyuria which can progress to cardiac arrhythmias, epileptic seizures, internal bleeding, heart attacks and eventually death.
Alcohol is metabolised much faster in dogs than in humans and can cause low blood sugar, low blood pressure and a drop in body temperature. Intoxicated animals can experience seizures and respiratory failure. Some people actually give their dogs alcohol but food containing alcohol or even fermenting yeast in dough can be fatal. be careful to keep proving dough away from your dog if you are baking bread.
The fizzy drink is a problem too. High sugar is bad but the caffeine content is much worse. Anything containing caffeine including coffee, tea, energy drinks and some confectionary can affect the heart, stomach, intestines and nervous system. Symptoms include restlessness, hyperactivity, muscle twitching, polyuria, excessive panting, increased heart rate and blood pressure and seizures.
All of the food in the above meal could contain artificial sweeteners. Increasingly common is xylitol which is present in many “sugar-free” products, including “gummy” sweets, and in some human toothpaste. In dogs, xylitol causes hypoglycaemia, which can produce seizures, and liver damage within 30 minutes – 18 hours. Hepatic failure can occur within 9-72 hours at doses >1.0 g/kg. In dogs that do develop acute liver failure, the mortality rate is 70-80%.
Nuts of all types can cause problems to dogs and some are toxic. Almonds are poorly digested and can result in gastrointestinal distress. Pistachios are rich in fat and can cause an upset stomach and pancreatitis. Walnuts contain tremorgenic mycotoxins that can cause seizures. Macadamia nuts are very rich in fat and can cause gastrointestinal distress and pancreatitis. They belong to the grape family and contain an as yet unknown toxin that may cause neurological deficits. Pecans and hickory nuts contain the toxin juglone that causes gastric intestinal upset.
These are just a few common examples of foods that can kill your dog. Err on the safe side and leave the human food to humans. If in any doubt about what your dog has eaten, call the Veterinary Poisons Unit helpline and consult your vet immediately.