Toxic Foods – Dr. Ingrid Judge
Our animal friends love food and they are attracted to what they see us eating. Not all of the foods we eat are safe for animals to eat. In some cases, even a small tidbit is enough to cause a serious medical problem. One of the most common hazardous foods is chocolate. Halloween is just around the corner and chocolate candies are still a trick or treat favorite. The compounds in the chocolate that are toxic are caffeine and theobromine which belong to a group of chemicals known as methylxanthines. The rule of thumb with chocolate is “the darker it is, the more toxic it is.” White chocolate contains very few methylxanthines, dark baker’s chocolate has high levels of methylxanthines and plain, dry unsweetened cocoa powder contains the most concentrated levels of methylxanthines. Depending on the type and amount ingested, the signs can range from vomiting, increased thirst, abdominal discomfort, restless behavior, muscle tremors, irregular heart rhythm, high body temperature, seizures and death. Another party time hazard is ethanol or drinking alcohol. Dogs are far more sensitive than humans to the effects of ethanol and even a small amount can result in significant intoxication. Mixed drinks with milk such as egg nog and White Russians are especially appealing to dogs. Dogs can also be exposed through alcohol containing elixirs and syrups as well as the more common beers and wines. Symptoms of intoxication include loss of coordination, disorientation, stupor, vomiting, coma, seizures and death. In addition, for the beer brewing enthusiast, caution with the hops! Cultivated hops both fresh and spent (cooked) are hazardous. Signs with ingestion include restless behavior, excessive panting, muscle tremors, seizures and in some cases uncontrollably high body temperatures causing secondary organ compromise.
What else is toxic in the kitchen? Grapes and raisins are toxic and have been associated with kidney failure in dogs. The exact mechanism of action is not yet known, nor is it understood why some dogs can eat these toxic fruits without harm, while others develop life-threatening kidney failure with just a few grapes. Still other dogs can eat these fruits with no side effects and then later on ingest them and become very ill. Symptoms include vomiting, diarrhea, lethargy, inappetence and decreased or absent urination. Death can occur in three to four days and long-term kidney disease can result in dogs that survive. Another toxic food product is bread dough made with yeast. The warm moist environment of the stomach provides an ideal environment for the yeast to multiply causing an expanding mass effect compromising blood flow to the stomach as well as pressing on the diaphragm and resulting in difficulty breathing. The multiplying yeast also produce alcohols that can result in alcohol intoxication. Symptoms with ingestion include abdominal distension, vomiting, lack of coordination, disorientation, coma and seizures. Finally, in the toxic vegetable group we have avocados, onions and garlic. Avocado leaves, fruit, seeds and bark contain persin that can cause respiratory distress, pulmonary congestion and fluid accumulation around the heart. Birds, rabbits and some large animals like horses are especially sensitive to the persins. In dogs and cats, only mild stomach upset is typically noted if the animal eats a significant amount. Avocado is sometimes included in dog and cat foods for nutritional benefit and it is not considered a hazard. All close members of the onion family (shallots, onions, garlic, scallions, etc.) are considered toxic. The toxic compound in this family of vegetables causes damage to the red blood cells and a resultant anemia. The rule of thumb is “the stronger it is, the more toxic it is.” It is uncommon for dogs to eat enough raw onion and garlic to cause a serious problem, however, exposure to concentrated forms in soup mixes or garlic/onion powder can cause toxicosis. Symptoms include weakness, exercise intolerance and orange-tinged or dark red urine.
Finally, don’t forget those toxic foods we commonly carry as snacks in our purses and backpacks. Xylitol and macadamia nuts fall into this category. Xylitol is a non-caloric sweetener found in sugar-free chewing gum and baked products. Xylitol can cause a rapid and severe drop in blood sugar levels. Symptoms include disorientation, seizures and in some cases liver failure. Macadamia nuts are not likely to cause a fatal toxicity, however, affected dogs may develop pelvic limb weakness, pain, muscle tremors and a low grade fever.
In conclusion, as temping as it may be to give our four legged friends a tiny treat, the safest course of action is to avoid feeding table food all together. In the event that your animal ingests a food material or other substance that you suspect might be toxic, contact poison control immediately (ASPCA Poison Control 888-426-4435). Sometimes a poison’s toxic effects may not be immediately evident but decontaminating the animal as quickly as possible can be life-saving.