Preliminary study suggests mercury is not a risk in dog food

Researchers at the University of California at Davis recently studied methylmercury levels in a small sample of commercial dog foods and found some good news for dog owners. Of the 24 diets tested, only three were positive for low levels of total mercury and only one of them contained detectable methylmercury. The study was published in Topics in pet medicine.

"Detected concentrations are unlikely to pose a risk to healthy adult dogs," said lead author, Rae Sires, a resident in nutrition at the UC Davis University Veterinary Hospital. "These results should rebadure dog owners."

Excessive exposure to mercury poses a risk to the health of people and animals. Depending on the method of exposure – skin contact, ingestion or inhalation – it can lead to respiratory and gastrointestinal diseases, kidney damage, fetal development and neurological problems. Although previous studies have measured total mercury in pet foods, no additional testing has been done for methylmercury.

"This is the form in which we worry about bioaccumulation or the possibility of becoming more concentrated in animal tissues during its course in the food chain," said Sires. "We know that there is some level of total mercury in commercial dog foods based on recent studies, but we did not know yet if that was a concern."

As methylmercury is known for its presence in aquatic species, Sires explained that researchers have evaluated diets containing fish – mainly salmon – and control samples that do not contain fish-based ingredients. Of the 24 diets tested, only three were positive for low levels of total mercury and only one of them contained detectable methylmercury. Surprisingly, Sires said he found two of the three positive samples from diets other than those based on fish, suggesting that common sources of mercury in pet foods might not come from seafood.

The bulls acknowledged that this study included a relatively small sample. She added that this should be considered as a starting point for further research, which could be expanded to cover more samples and be completed over a longer period and seasons.

"We need more data to determine where the total mercury detected in dog food comes from, but our study does not help avoid diets based on fish or salmon," he said. Sires.

###

Sires completed the project as part of his residency training and presented his findings at the recent Research Symposium on Residents and Interns in Veterinary Medicine.

The study was funded by donors from the Center for Companion Animal Health at the UC Davis School of Veterinary Medicine. Co-authors include Jennifer Larsen and Andrea Fascetti with UC Davis.

Warning: AAAS and EurekAlert! are not responsible for the accuracy of the news releases published on EurekAlert! contributing institutions or for the use of any information via the EurekAlert system.