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Raw food diets for pets chock-full of controversy, complexity

Veterinarians' views run gamut as movement gains steam


November 22, 2010
By: Carrie Peyton Dahlberg
For The VIN News Service


Raw food and boarding don't mix for Dr. Richard McAroy. In the face of a surge in the number of his clients feeding their pets uncooked meat, the New Hampshire clinic owner has instituted a rule for boarders: no raw diets.

He believes the diets bring too high a risk of spreading pathogens in the environment. "If one of my staff members gets signs of something like Salmonella or E. coli, that would hit my workers compensation (insurance)," McAroy says. "I can't guarantee the sterility of the food as delivered to me by the owner."

His concern is not unique. Earlier this year, the Delta Society, a nonprofit group that promotes the use of therapy and service animals to improve human health, banned raw-fed animals from its "Pet Partners" program, saying the animals may shed pathogens that could infect vulnerable people.

The bans represent a sharpening in the division between proponents and opponents of raw protein pet diets, with veterinarians falling on both sides of the line and sometimes straddling the middle.

The need for veterinarians to grapple with the issue is rising as a small but devoted contingent of pet owners gives momentum to the dietary movement. Practitioners must answer questions about raw food knowledgeably, present their medical opinions along with research findings and find reasonable ways to work with clients who have embraced the alternative feeding practice.

Proponents of raw-food diets have been around for decades. Dr. Jennifer Larsen, an assistant professor of clinical nutrition at the University of California, Davis, School of Veterinary Medicine, reports that some dog breeders and trainers have sworn by raw meat for 30 or 40 years.

Anecdotes suggest the practice may be gaining popularity, although hard data is scant.

The American Pet Products Association (APPA), which surveys pet owners every two years, asked about raw foods for the first time in 2008. Among the 587 dog owners and 463 cat owners who responded, 1 percent reported buying commercial raw diets for their pets more often than anything else. Another 3 percent of dog owners said they occasionally fed their pets commercial raw foods. And more than 20 percent of dog owners and 15 percent of cat owners occasionally feed their pets "human food," whether cooked or raw. Because the APPA does several rounds of surveys, those 2008 responses are included in its 2009-10 survey. Pet owners' 2010 responses should be available in spring, according to an APPA spokeswoman.

Although the popularity of raw diets is not well quantified, no one doubts that many pet owners have high interest in alternative diets for their animals, an interest propelled by recent recalls of commercial diets, especially the massive pet food debacle of 2007 in which melamine-laced products sickened pets by the tens of thousands, many fatally.

"There are a number of people who are skeptical about commercial diets and for good reason," says Dr. Bree Montana, a practitioner in California.

People who give their dogs and cats raw meat regularly report that the animals have fewer allergies, better coats and healthier teeth and are less likely to fall prey to a wide range of diseases.

For the most part, the claims are supported by anecdotal reports and testimonials. By contrast, potential nutritional and bacterial risks of raw diets have been documented in published, peer-reviewed studies.

That doesn’t mean potential benefits are non-existent. In human nutrition, high-protein diets were scorned for years until rigorous, side-by-side comparisons showed greater weight loss and fewer medical complications than detractors had predicted.

For now, though, the animal health arena lacks data to confirm the purported benefits of raw protein diets.

Current research makes it clear that while some dogs and cats can tolerate the bacterial load in raw meat and stay healthy, they may shed Salmonella or other pathogens at higher levels than animals that eat cooked food.

Instances of dogs and cats passing infections to humans have been documented in published studies as well as instances of animals becoming seriously ill or dying from illnesses linked to pathogens contracted by ingesting raw meat. [*Lefebvre SL, Reid-Smith R, Boerlin P, Weese JS. Zoonoses Public Health. 2008 Oct;55(8-10):470-80, **Cherry B, Burns A, Johnson GS, et al; Emerg Infect Dis. December 2004;10(12):2249-51]

On top of that, clients who feed their pets significant amounts of raw meat must ensure the diets are properly balanced, or the animals could be at risk of nutritional deficiencies, experts say.

Larsen says it’s important for veterinarians to understand why raw feeding may appeal to some clients. “Talk to the owners about what exactly their goals are,” Larsen says.

Often, whether owners prefer an organic food supply, fewer additives or better control of what their pets are eating, they can accomplish the same thing by feeding cooked food, either home-prepared or commercial, she says.

If a client is set on raw, working with a veterinary nutritionist can help balance the pet’s diet, avoiding the risk of nutritional deficiencies.

As for the pathogenic risk of serving raw meat, that one is tougher to address.

High-pressure pasteurization might hold some promise, but more study is needed, Larsen says. More research is also critical to determining whether any of the benefits claimed for raw diets outweigh the potential risks.

“We really need studies that compare home-prepared diets that are raw with the exact same diets, cooked,” she says.

One effort to begin filling the data gap is under way at the University of Tennessee (UT), led by Dr. Beth Hamper, who has completed her residency in veterinary nutrition and is working on a doctoral thesis that combines aspects of nutrition and immunology.

“There are all kinds of claims made about raw diets, but none of it has been substantiated,” Hamper says. “I’m looking to see if the claims are true.”

Her research is funded partly by the Winn Feline Foundation, which awarded $14,878 in 2009 to a UT team that includes Hamper to examine raw diets of kittens.

The goal of the research is to “determine whether a commercially produced raw food diet and a homemade raw diet are nutritionally adequate for (feeding) kittens and whether these diets enhance immune function and improve digestibility,” according to the foundation.

Hamper says she hopes to complete her thesis in June.

Until research comes up with more definitive answers, veterinarians have their own experiences with the effects of raw food diets to consider.

Dr. Cynthia Easton, a holistic and conventional veterinary medicine practitioner in the San Francisco Bay area, has happy and horror stories alike.

In one case, a family opted to give their golden retriever raw meat without discussing it with her. This family had an infant, and the baby spent a week in intensive care fighting an E. coli infection that was traced to the dog’s raw food, Easton says.

“It just never occurred to them that the dog would be licking their baby,” she says.

Easton is not against raw diets. She occasionally recommends them for certain conditions but always asks first if anyone in the household is very young, elderly, on chemotherapy treatment or otherwise immune suppressed.

In a case for which Easton suggested raw food, the patient was a black Lab that was so miserably itchy, he had to wear a cone for five years. Following the diet change, his skin improved significantly, and the cone came off.

It’s possible, says Easton, that raw food contains beneficial enzymes or other nutrients that are destroyed by cooking. Clearly, it doesn’t contain as many additives or preservatives as many commercially prepared foods.

“I understand the convenience of grabbing something out of a bag and having it last forever on a shelf,” she says, “but it’s not the way I eat myself. Why would animals be any different?”

Easton is eager to see more research done. “You can either pooh-pooh (the diet), and then your client is going to go off and find someone who won’t make them feel like a weirdo, or there are going to have to be some studies so regular vets can have some information about it,” she says.

The pros and cons of raw foods have been the subject of recent discussion and debate on the Veterinary Information Network (VIN), an online community for the profession.

(VIN also provides a brief overview about raw feeding in a “frequently asked questions” format.)

Many discussion participants share McAroy’s concerns about the risk of illness and legal liability; others express more acceptance of owners’ unconventional decisions about diet.

Montana, the veterinarian from California, is among those advocating tolerance. Although she tries to discourage the practice, she says, 20 percent of her clients serve raw meats to their pets. When it comes to allowing animals fed raw diets into boarding facilities, she considers the argument that staffers might pick up pathogens to be "silly” when simple hand-washing can mitigate the dangers.

"In reality, all of our food is potentially dirty," she says, referring to a recent rash of recalls of commercial diets, some suspected of harboring Salmonella contamination. The latest incident occurred in September when The Hartz Mountain Corp recalled 74,000 bags of canine beef treats due to the possibility that they could be tainted by Salmonella, which can cause diarrheal illness in humans and pets.

UC Davis’s Larsen agrees. “You should wash your hands after handling kibble,” she says, noting that Salmonella from tainted dry pet food has been passed to people.

Similarly, Larsen says that she’s treated animals that developed nutritional problems on raw diets, on home-cooked diets and on commercial diets alike.

But the legal risk is compelling, in the opinion of Dr. Sherry Sanderson, an associate professor at the University of Georgia’s College of Veterinary Medicine, where she specializes in small animal clinical nutrition and internal medicine. If a raw-fed animal passes an infection to a person who becomes seriously ill or dies, “it’s just a matter of time before we start seeing lawsuits,” Sanderson predicts.

The potential for lawsuits doesn’t worry Dr. Adam Behrens, who runs a house-call practice in the San Francisco Bay area. He sometimes recommends raw meat for pets with skin problems or food intolerance, first making sure that clients know the diets are controversial and that the U.S. Centers for Disease Control and Prevention and other health authorities caution against them.

“I treat raw food as if it’s an off-label drug,” Behrens says.

Perhaps the most difficult aspect of the raw-foods debate is the underlying animosity between avid proponents and opponents. McAroy, the practitioner in New Hampshire, says vitriol on the Internet inflames matters.

"You can type in a lot of stuff about diets, and you find websites that actively attack the pet food industry,” he says. "When clients announce that they feed their pets raw foods, they are looking for a fight. They’re on the defensive.”

Sometimes those passionate about the virtues of raw meat also suspect the motives of veterinarians who caution against it, believing the naysayers have been co-opted by vast food conglomerates that fund research or produce hefty profits for clinics that sell their food.

Larsen has heard the criticism, and it frustrates her.

“People overstate the role of the pet food industry in veterinarians' behavior,” she says. “Most vets don’t have a vested interest if you want to feed your pet a raw diet.”

Behrens is concerned that if pet owners fear their veterinarians’ disapproval, they may keep their feeding habits a secret, creating distance between client and practitioner. Such a gulf can undermine relationships and even interfere with diagnoses, he says. To bridge the gap, he urges frank, respectful conversations.

In fact, veterinarians should be having regular conversations with clients about food no matter what a pet eats, Larsen advises.

“A diet history is so important, regardless of whether you’re feeding raw,” she says.


*Evaluation of the risks of shedding Salmonellae and other potential pathogens by therapy dogs fed raw diets in Ontario and Alberta.

Lefebvre SL, Reid-Smith R, Boerlin P, Weese JS. Zoonoses Public Health. 2008 Oct;55(8-10):470-80.

**Salmonella Typhimurium outbreak associated with veterinary clinic

Cherry1 B, Burns A, Johnson GS, et al. Emerg Infect Dis. December 2004;10(12):2249-51.









VIN News Service commentaries are opinion pieces presenting insights, personal experiences and/or perspectives on topical issues by members of the veterinary community. To submit a commentary for consideration, email news@vin.com.



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