Research Review: Raw Dog Food, Raw Cat Food
June 28th, 2011
In the past, Dog Food Dish has covered The Case for Feeding Raw, The Case Against Feeding Raw, Raw Feeding Logistics as well as a bunch of Q&As with K9Cuisine.com community members who feed homemade, raw food to their dogs and cats. Today, I’m happy to share with you a few details from a recently published veterinary medical journal article that reviews and assesses the existing research into raw food diets in companion animals.
Published in January 2011 by the Canadian Veterinary Journal (vol 52, pages 50-54), the review article abstract begins:
“Feeding of raw meat-based diets to pets has become an increasingly popular trend amongst pet owners. Owners, who desire to provide the best for their pets, seek veterinary opinions about food options. This paper reviews and applies standards of evidence-based medicine to grade the available scientific literature that addresses the nutritional benefits or risks, infectious disease risks, and public health implications of raw, meat-based pet diets. Although there is a lack of large cohort studies to evaluate the risk or benefit of raw meat based diets fed to pets, there is enough evidence to compel veterinarians to discuss human health implications of those diets with owners.”
Broad Recap of Raw Pet Food Studies Noted
After explaining the various kinds of research out there and its relative level of evidence, the review article goes on to recap studies the authors found and considered. On this scale (1-5), those with lower level numbers carry more scientific weight based on a variety of factors. This graphic and page from Dartmouth University explains what evidence-based medicine means.
Evidence of Nutritional Benefit
Level 4 evidence of nutritional benefit ( ~98% of pet owners reporting “healthy” dogs and cats)
Level 5 evidence of nutritional benefit (the Prochaska and Piekutowski paper noting increased bioavailablity of raw food) … except another study in people showed cardiovascular risks of raw (non-meat) diets due to Vitamin B12 deficiency
Evidence of Nutritional Risks
Level 4 evidence of nutritional risks, including:
- Too much Vitamin A in cats fed raw pork liver
- Feline pancreatitis in cats (usually related to too much fat in the diet) fed cooked pig brain or raw or cooked oily fish
- Poor bone development in two litters of 6-week-old, large-breed puppies (fed raw since week 3)
- Excessive thyroid hormone production in a some members (not all) of litter of German shepherd puppies (eating 80% rice with 20% raw meat, with excessive phosphorus)
- Commercial and homemade diet analysis showing low calcium and phosophorus in three of five diets measures
- Commercial and homemade diet analysis showing two of the five deficient in potassium, magnesium, and zinc
Evidence of Infectious Disease Risks
Level 2 and 3 evidence of infectious disease “risks” to pet or humans sharing their environment, including:
- 6% of raw pet foods testing positive for Salmonella
- 50% of raw pet foods testing positive for Escherichia coli
- 80% of raw chicken diets testing positive for Salmonella (some pets on this diet shedding Salmonella in stools up to 1-7 days after consumption)
While the authors note some antimicrobial resistance and some cases of animal and human illness, they go on to say, “Few studies document that Salmonella shedding by dogs or cats can result in illness in humans.”
Yet, there is more Level 4 evidence that Salmonella, in particular, is indeed found in many raw pet diets, so they say, “As there appears to e strong evidence that raw food can contain Salmonella, it is vitally important, if feeding a raw meat diet to a pet, that hygiene of the food preparations area and the feeding bowls be diligently maintained. This may, however, be difficult to achieve. A recent study found that standard methods of cleaning and disinfecting food bowls were minimally effective at eliminating Salmonella. This included soaking with bleach and cleaning in the dishwasher.”
Study Conclusion
The authors ultimately conclude that at this point, looking at the research that currently exists, “Clearly, there is some compelling evidence suggesting that raw food diets may be a theoretical risk nutritionally. In addition, raw food poses a substantial risk of infectious disease to the pet, the pet’s environment, and the humans in the household. What is lacking, however, is level 1 evidence from randomized controlled trials or strong level 2 evidence from large cohort studies to evaluate risks or benefits of raw meat diets in pets.”
***
I know this post is much more technical than usual, so holler if you have questions, and I’ll do my best to answer. I have not read all 42 references cited in the footnotes. It’s actually quite hard (an expensive) at times to get copies of scientific journal articles.
I had the chance to attend the American College of Veterinary Internal Medicine Forum in Denver a couple weeks ago, and I planned to attend a session called “Raw Food Diets: A Research Review,” but the presenter ended up super sick and could not do the session, so it got cancelled.
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Tags: raw cat food, raw dog food, raw pet food, raw pet food research
Posted in Dog Food Basics, Dog Food Debates, Dog Health, K9 Nutrition | 5 Comments »
5 Responses to “Research Review: Raw Dog Food, Raw Cat Food”
A professional writer based in Colorado, Roxanne Hawn doesn't just love dogs. She deep-down requires them in life. Something inside her genes, perhaps? That's why it's such a joy to write about all things canine. Roxanne began writing about pets in 1995, when she worked for the American Animal Hospital Association and later for the American Humane Association. During this period in her career, Roxanne served on the board of directors for the National Council on Pet Population Study and Policy (a coalition of animal welfare groups). Roxanne also volunteered for many years at an animal shelter, where she witnessed firsthand what happens when the human-animal bond breaks or never forms.
Hi! I am a biological scientist so I loved the technicality of this post. I was wondering if the Honest Kitchen dehydrated food would fall into the category of raw food that this paper evaluated. I have always been apprehensive about raw food and I just started feeding Honest Kitchen to my Great Dane 2 months ago after much deliberation and research. Thanks for sharing this information.
Hey, Caroline … I read back through the paper, and it sure looks to me like we’re talking about frozen / fresh raw meat diets (not freeze dried ones). I’m sure you could ask The Honest Kitchen folks if any of their foods have been studied by veterinary nutritionists.
Well, some of this evidence seems based on wrong premise to start out with, to me.
e.g. Too much Vitamin A in cats fed raw pork liver
There would be too much vitamin A in any diet that consists solely or primarily from liver, whether it’s raw, cooked or processed, simply because liver has a huge amounts of Vitamin A. Liver needs to be fed in small amounts, whether it is raw or not. To me this is evidence of a bad recipe and has nothing to do with the fact that the diet is raw … ???
e.g. Pancreatitis is also likely to happen with ANY food that is too high in fats, regardless of whether it’s raw, cooked or processed.
Similar applies to the other arguments also. It is showing that there is a lack of nutritional balance. This can happen with raw, cooked or processed, it is question of balancing nutrients regardless whether the diet is raw or not … ???
The recipe book that comes with the Canadian supplement for balancing home-made meals includes raw recipes. These are calculated for nutritional balance (when used WITH the supplement).
These recipes (and the supplement, similar to BalanceIT in US) were developed by a nutritionist, using software identical to the one used by commercial dog food companies.
I think there are two arguments mixed in the subject. One argument being whether raw ingredients are better than cooked or processed, and completely different argument being the need for nutritional balance.
I think that mixing these two arguments into one skews the discussion.
Sorry for the rant.
Feel free to rant away. Remember, though, that this study looks at ALL the past raw studies and summarizes the results in one place. In some cases, like the one with liver, the researchers were looking at real diets that real people feed real dogs. So, there must be people who feed too much liver … if that makes sense.
Oh yes, I bet there are people who feed too much liver. I just do feel that same thing happens with home-cooked as well (I know at least one person who’s doing that; unfortunately there is no talking to her. She’s feeding liver fried with onions and pasta and won’t hear reason).
I do feel that these ARE separate issues and should likely be addressed separately.
1) pros and cons of raw ingredients
2) imbalanced formulas