Veterinarians at the ASPCA Poison Control Center (APCC) have recently cracked a 20-year-old puzzle: why grapes, raisins, and sultanas are poisonous to dogs. The surprising answer points to tartaric acid as the toxic culprit found in these fruits. This groundbreaking discovery sheds light on why these seemingly harmless snacks can cause serious health issues in our canine companions.
Mystery Solved: Veterinarians discover tartaric acid is the cause of grape toxicity in dogs, showing a dog looking questioningly at grapes.
The symptoms of grape toxicity in dogs are now understood to be directly linked to tartaric acid. These symptoms include:
- Vomiting
- Diarrhea
- Excessive thirst
- Kidney damage or even kidney failure
Previously, the level of grape toxicity in dogs was unpredictable. Some dogs would only experience mild symptoms after eating grapes, while others tragically suffered acute renal failure. The variability in reactions is now better understood with the knowledge that grapes, raisins, and sultanas contain varying concentrations of tartaric acid. These levels differ based on factors like the type of grape, where it was grown, and its ripeness.
The Unexpected Clue: Playdough
The breakthrough in understanding grape toxicity came from an unexpected source: playdough. Dr. Colette Wegenast, a senior consulting veterinarian in clinical toxicology at the APCC, shared in an interview with AAHA’s NEWstat how a case of homemade playdough toxicity led to this discovery.
While investigating a dog’s reaction to homemade playdough, Dr. Wegenast noticed the symptoms were atypical. She explained, “Most homemade playdough contains significant salt, causing dogs to develop severe hypernatremia (high sodium levels in the blood) upon ingestion, often requiring aggressive fluid therapy. However, in this particular case, the playdough had less salt, so hypernatremia didn’t develop. Instead, the dog suffered severe azotemia (high nitrogen levels in the blood), preceded by significant vomiting.”
Upon examining the playdough recipe, Dr. Wegenast found a key ingredient different from standard recipes: cream of tartar. Cream of tartar is a source of tartaric acid. This realization sparked an investigation by Dr. Wegenast and her colleagues.
“The ‘lightbulb moment’ occurred when we recognized that tartaric acid and potassium bitartrate are uniquely and highly concentrated in grapes. Furthermore, dogs are known to be a species sensitive to tartaric acid, as indicated by older studies reporting acute renal failure. Further research revealed that tartaric acid and potassium bitartrate consistently aligned with the characteristics expected of the toxic agents in grapes and raisins.”
Implications for Treatment and Prevention
This exciting discovery offers hope for improved understanding, testing, treatment, and prevention of grape and raisin poisoning in dogs. Knowing that tartaric acid is the toxic component opens new avenues for research and potential therapeutic interventions.
For dog owners, the message remains clear and crucial: never feed your dog grapes, raisins, or sultanas. Even a small amount can be dangerous due to the unpredictable levels of tartaric acid in these fruits. Protecting your beloved canine companion means keeping these potentially toxic treats out of their reach.
