As pet food health benefit claims go, these are relatively modest. Dozens of companies advertise specialty “skin and coat” or “healthy joint” offerings that suggest they will help prevent or treat itchy skin or arthritis — common, painful issues for many dogs. PetSmart, a major retailer, has an entire sales category for “skin and coat” dog foods.
There is typically very little scientific evidence to back up these alleged health benefits.
“You don’t have to have any real evidence for that,” said Dr. Kathy Michel, professor of nutrition at the University of Pennsylvania’s School of Veterinary Medicine. “A lot of it’s marketing.”