Raw Food Diets

You can find site after site on the Internet—as well as brochures and other print media—with exhortations to feed your dog a raw food diet, or at least a diet with raw food as its centerpiece. This includes whole raw chicken and other types of meat, often still on the bone. Claims for the benefits of raw food abound everything from an improvement in your pet’s energy and deportment to a stronger immune system, fewer allergies, less arthritis, and a lower risk for cancer.

People who argue in favor of raw food diets often say that dogs are carnivores who evolved in the wild eating raw meat and nothing else, and that the heat processing involved to make most commercial foods destroys nutrients and enzymes essential to a dog’s health.

Not true. First, dogs are not carnivores. Like humans, they are omnivores whose systems thrive best on a mixed diet of animal food and plant foods. Furthermore, while heat does degrade certain nutrients, such as the B vitamin thiamin, nutrient deficiencies do not abound. Pet food manufacturers compensate so that the product that reaches your dog’s bowl still has sufficient levels of vitamins and minerals.

It’s true that the ancestors of today’s pet dogs, wolves, did eat raw meat. But we should not take our feeding cues from them. Wolves in the wild, as opposed to dogs who live in human homes, survive for only a few years.

If raw food does provide any benefits, it has nothing to do with its lack of cooking. For instance, raw food diets are said to give dogs a better-looking coat. But that’s because raw food regimens are typically very high in fat—which can be true for a food whether or not it has been heated. Similarly, raw food diets may reduce symptoms in dogs with urinary problems. But that’s a result of raw food’s high moisture content, which, like a high fat content, is easily achievable with commercial diets.

What does stand out about raw food diets are their many downsides. Eating bones often left in raw meat, for instance, can result in obstructions of the gastrointestinal tract, broken teeth, and an inflammation of the GI tract called gastroenteritis. Plenty of dogs have appeared in our emergency room because they needed costly surgery to have bones removed from their throat or esophagus, fractured their teeth on raw food, or needed to be admitted as an inpatient in our intensive care unit because their GI tract was damaged.

In addition, there is a very real risk for bacterial contamination, just as there is for humans who eat meat uncooked and therefore don’t kill harmful bacteria in the food by heating it first. Sometimes, a foodborne illness arising from bacterial infection of meat causes vomiting, diarrhea, and dehydration, and owners are chagrined to learn that their dog is sick as a result of being fed a raw food regimen. But sometimes the complications are much more serious. There have been published reports of death resulting from blood infections caused by bacteria in raw food diets.

The risks are significantly greater for an older dog than a middle-aged dog. They may not have the immune systems of a younger adult dog to fight the offending bacteria, and they are less able to withstand the sometimes severe effects of dehydration and other effects of contamination.

The dogs aren’t the only ones at risk. So are the people in the home. Harmful bacteria may not be cleaned thoroughly enough from utensils, dishes, counters, hands—anything used to feed the dog. The very young, the elderly, and anyone dealing with an illness (even a cold) are especially vulnerable, because the immune systems in those groups do not work as well as in other people to fight bacteria.

The bacterial culprits that affect dogs are the same ones you hear about when you hear of bacterial contamination of human foods. Researchers at Tufts and the University of Pennsylvania analyzed five different raw food diets (two of them were actually commercially prepared rather than made in home kitchens) and found that one of them tested positive for E. coli 0157:H7, a particularly harmful form of E. coli that is the leading cause of kidney failure in children (and has even caused deaths).

Several other recent research projects found widespread contamination of commercially available raw meat diets with various forms of E. coli, salmonella, Campylobacter, and clostridium bacteria. All can make a susceptible person, as well as a susceptible older dog, quite sick.
Freezing, incidentally, will not kill the bacteria—it will just slow their growth. But bacterial growth isn’t the end of the problem. Raw food diets might also very well be nutritionally inadequate.

When the Tufts and Pennsylvania scientists examined the nutrients in the five raw food diets (including the two that were commercially prepared), they found shortfalls in a wide variety of minerals, including iron, zinc, potassium, manganese, calcium, and phosphorus, as well as vitamin E. Furthermore, some of them contained too much vitamin D and the mineral magnesium, in addition to other nutrients.

Such nutrient imbalances can result in a large number of health problems, including (but not limited to) skin conditions, anemia, and orthopedic complications. Again, old dogs are going to be more vulnerable than middle-aged dogs.