It’s understandable that people would like there to be a dietary component to treating and even curing cancer. We love our dogs and want to be able to do something for them in their time of need. But the incontrovertible fact is that cancer is the leading cause of death in dogs over the age of two. And in some breeds, such as golden retrievers, the rate of death attributable to cancer is greater than 50 percent (albeit generally late in life). “We don’t want pet owners to lose hope,” says Cailin Heinze, VMD, DACVN, a board-certified veterinary nutritionist at Tufts. But food is not medicine. It’s food. “There’s no evidence right now that we’re going to fix anything with diet. It’s so hard when people whose dogs have cancer come to us and feel like the Nutrition Clinic is going to be able to make the difference in how long their pet lives. However, we can help make sure that pet owners are feeding a diet that is as optimized as possible using the knowledge that we do have, whether this be a commercial diet, a home-cooked diet, or a combination.” Veterinary nutrition researchers are always looking for the ways in which dietary patterns impact disease, but they simply haven’t uncovered anything yet that will change the course of cancer’s impact.
That said, there is some preliminary evidence — with the emphasis on preliminary — that altering the fatty acid balance of the diet might be beneficial. “While we don’t have stellar information,” says Dr. Heinze, “there’s a good bit of early data that long-chain omega-3 fatty acids may help animals with cancer. Omega-3s have a lot of functions: an anti-inflammatory function and also effects on blood flow along with the immune system. I don’t think we really know why omega-3s might help,” she adds. “The signaling mechanisms for cancer development and progression are complicated. But in a study or two in dogs there certainly have been some data to suggest that omega-3s are likely to be beneficial.
“The challenge is that we don’t know an ideal dose. But the safety of fish oil has been pretty well worked out. So feeding a diet that’s naturally high in fish oil or supplementing a dog’s diet with fish oil is reasonable to consider.
“You need to talk to your vet about doses and brands. There isn’t really a paper that says, ‘this is how much dogs with cancer need.’ A veterinarian, particularly a veterinary nutritionist or a veterinary oncologist treating your dog for cancer, can work with you to make sure all your dog’s other nutrient needs are being met, with the right number of calories, while you add calories in the form of omega-3s.” The doctor might suggest supplements or even adding small pieces of certain types of fish to your dog’s diet. Once again, it’s important to keep in mind that more isn’t always better.