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When feeding your dog, it might be best to avoid canned food

A dog eats its meal from a bowl.
Seth McCann
Kohda the mutt chows down on his meal, which came from a bag.

Pet owners should take caution when purchasing canned food for their animals, a study from the University of Missouri-Columbia warns. 

Most canned foods are lined with a resin that contains BPA, or Bisphenol-A, an industrial chemical that can seep into the food contents. Research in recent years has suggested it could interfere with brain development, particularly for infants and children. However, there are few studies on pets' exposure to BPA.

Scientists at Mizzou led an experimentwhere they fed canned food to two groups of dogs that normally eat dry food from a bag. One group was fed canned food advertised as being BPA-free and another group received canned food without that label. Blood and fecal samples revealed that after two weeks, BPA concentrations rose threefold for both groups.

This concerned Mizzou veterinarian Cheryl Rosenfeld, who co-authored the study. 

"What if a dog is on canned food for some time, its lifetime essentially?" Rosenfeld said. "That could mean it could have really high concentrations of [BPA] and they could be at greater risk of getting other diseases." 

Cheryl Rosenfeld, co-author of the paper, is an associate professor of biomedical sciences in the MU College of Veterinary Medicine.
Credit University of Missouri-Columbia
Cheryl Rosenfeld, co-author of the paper, is an associate professor of biomedical sciences in the MU College of Veterinary Medicine.

Rosenfeld and her colleagues also analyzed the participants' gut bacteria. They found that as the dogs continued to eat canned food, levels of a bacteria that metabolizes BPA decreased. In other words, the dogs' bodies became less able to reduce the consumed BPA.

Rosenfeld said she wasn't sure why that happened, but it's one of several directions they're hoping to take this research. 

Some of the next steps could also include seeing how BPA concentrations change when the dogs are switched back to bagged food, or observing dogs that have eaten only canned food for their entire lifetime. Rosenfeld mentioned interest in using MRI scans to see if the chemical has any affect on the pets' brains. 

"One thing we could certainly do is see how does it affect their behavior," she said. "We could see if there are changes in the brain that correspond with greater levels of BPA." 

Nonetheless, she stressed that pet owners take her findings seriously when purchasing food for their animals. 

"If at all possible, feed them dry food that's contained within a bag," Rosenfeld said. "If you can get it fresh, that's even better yet."

Follow Eli Chen on Twitter: @StoriesByEli

Eli is the science and environment reporter at St. Louis Public Radio.