Evidence Update-Review of Risks and Benefits of Raw Meat Diets for Dogs and Cats

A nice new review of the evidence concerning raw meat-based diets appears in the most recent issue of the Journal of the American Veterinary Medical Association.

Freeman LM, Chandler ML, Hamper BA, Weeth LP. Current knowledge about the risks and benefits of raw meat-based diets for dogs and cats. J Am Vet Med Assoc. 2013 Dec 1;243(11):1549-58.  

The article reviews many of the studies looking at basic issues such as the effects of cooking on digestibility and the risks of nutritional inadequacy and infectious organisms in raw diets. I have previously written about a number of these studies. The bottom line, which is consistent with my own understanding, is that there are no proven benefits of feeding raw diets, a few small but well-established risks, and little direct research evidence involving comparisons of pets fed different kinds of diets. Here are some of the conclusions of this review:

Proponents of RMBDs claim that they are a safe and natural way to promote animal wellness; these claims are made without long-term supportive evidence and largely ignore the potential life-threatening consequences to pets and their human caregivers when contaminated RMBDs are fed.

Pets often consume RMBDs without developing any health problems, but sometimes even healthy adult dogs and cats can develop adverse effects, ranging from relatively benign effects (eg, increased colonic fermentation and gas production with higher protein intakes) to more overtly life-threatening concerns (eg, higher fat diet fed to an animal with a history of pancreatitis), as a result of consumption of these diets. Additionally, raw meat has an inherent risk of bacterial and parasitic contamination, and animals that consume RMBDs may pose a risk to other pets and people in the household and surrounding community, including veterinarians and veterinary support staff.

If a commercial RMBD is formulated to meet AAFCO nutrient guidelines…there should be minimal risk of nutritional inadequacy. However, few manufacturers of raw diets conduct AAFCO feeding trials or digestibility…Thus, the assumption that these diets are truly complete and balanced for long-term feeding relies heavily on the expertise of the individual formulating the original recipe…

If these diets are manufactured in accordance with current FDA regulations for handling of foods and requirements for microbial testing during food manufacturing and storage, there should be minimal risk of exposure to foodborne pathogens. However, variation in quality-control testing practices or inadequate testing conducted by a manufacturer of a raw food may allow for introduction of pathogens into pet-owning households.

On the basis of published diet reviews, most home-prepared diets (both raw and cooked) are deficient in 1 or more essential fatty acids, vitamins, or minerals or a combination thereof. Although the perceived benefits of home-prepared diets may be reinforced daily to owners through a pet’s appetite or coat quality, nutrient deficiencies and excesses in adult animals are insidious and can lead to long-term complications if not detected and corrected.

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10 Responses to Evidence Update-Review of Risks and Benefits of Raw Meat Diets for Dogs and Cats

  1. Amelia says:

    The most I like parts about this information is “Pets often consume RMBDs without developing any health problems, but sometimes even healthy adult dogs and cats can develop adverse effects, ranging from relatively benign effects (eg, increased colonic fermentation and gas production with higher protein intakes) to more overtly life-threatening concerns (eg, higher fat diet fed to an animal with a history of pancreatitis), as a result of consumption of these diets. Additionally, raw meat has an inherent risk of bacterial and parasitic contamination, and animals that consume RMBDs may pose a risk to other pets and people in the household and surrounding community, including veterinarians and veterinary support staff.” Thanks for sharing such a wonderful article.

  2. Serge says:

    I might have been convinced about the risks of a raw diet, but I don’t buy that cooked or semicooked diet cannot at least complement commercial diets. I believe the dog’s body is perfectly capable to extract the nutrients it needs as long as a variety of foods are offered. As well as eliminate excess nutrients, just as humans’ body can. Feeding a dog just dog kibbles, is like feeding a kid just breakfast cereal. It may contain all the known nutrients, but the lack of variety may omit unknown nutrients. Not to mention the decreased palatability.

  3. Diana Larson says:

    You are on the right track to warn people to be very careful with the raw diet. I decided to feed my 9 1/2 yr old pit bull and my 4 yr old pit bull Honest Kitchen organic dog food mixed with either raw chicken or raw hamburger based on friends who have fed this diet for years, and a small amount of research. Most research I saw was positive. Few people had negative things to say. I started the diet on Dec. 1 2013 and my 9 1/2 yr old dog died Feb 8th 2014 of complications associated with e-coli poison.
    I had taken her to the vet on the 1/27 and informed him of the diet change. He said he did not recommend it but did not seem to associate her lethargy and lack of appetite to that. I said I was no longer going to feed raw. I requested blood work, thinking it would show anything that the food may have caused. It came back normal. I did not know it would not show e-coli.
    Two days later I came home from work and found her again lethargic, having stomach spasms and cold to the touch . The same vet (unfortunately) took an x-ray, said “I can’t find anything wrong with your dog. She is constipated. You should just take her home and leave her in the yard for a while. She is healthy and should live several more years.” I got one more week. I was uncomfortable with his diagnosis and asked several more questions about the stomach spasms. When the vet tech took her temp he commented on her coldness, but no further mention was ever made of this critical symptom. After she died I found out her temperature that day was 100 degrees. Symptoms of hypothermia which is related to e-coli.
    I went home and kept an eye on her. She went to the bathroom so I thought we were good. She seemed ok for 9 days. Then on Feb 8th she was having the same symptoms. It was a Saturday. The vet said “keep an eye on her and bring her in Monday if she seems worse”. By 2 pm she was much worse. All this time I was googling her symptoms, mainly focused on the stomach spasms. I couldn’t find anything about coldness at that time. Later I did. To make this long story shorter, at 2 pm she was unable to walk and I could see she was in shock. We rushed her to the ER vet who did many tests and came back to say there was fluid in her stomach and the prognosis was bad. They suspected it was septic. She died at 5 in my arms. Their diagnosis: septic peritonitis with possible GI perforation.

    Needless to say, I am on a crusade to warn people. Just cook the chicken a little bit, even run boiling water over it. Something. Don’t just blindly jump into something like this that is much more dangerous than the raw foodies out there make it out to be. I would give anything to have my baby back, but it’s too late. Hopefully I can save someone else’s baby.

  4. Greta Wallace says:

    Diane, I am so sorry for your horrible experience. Unfortunately, these unusual experiences have lead the Vets to practically ban raw food diets, and promote a very unhealthy processed food diet that will take its toll in the long run. I find it frustrating that more Vets are not pro raw food diet. It was unfortunate that your Vet was not on top of things, which is often the case. That was why I began using BARF raw food diet for my pets almost 15 years ago. My Akita almost died from Bloat and a compromised liver, from the commercial diet they suggested and all the meds prescribed. I promote the Barf diet, every chance I can. I do not believe that most humans understand what their dogs need nutritionally. Dogs know what they need to eat, in the wild, and it is not cooked, dried or processed for “safety.” The BARF diet is frozen and absolutely fabulous for changing a dogs life, if you have a dog with allergies, etc. I recently rehabilitated a dog who was aggressive since birth. Only one Vet could handle her. She bit me the day I arrived to pick her up. After 3 months on the BARF diet, with E Barf supplements and salmon oil, she is a miracle dog says everyone who met her before the diet change. She adores everyone…No more biting, no more chewing her skin, no more flaky skin and no more periodontal disease. The secret, even in feeding chicken wings (which is not necessary if you are using BARF products) is to find a reliable source for the meat. I don’t allow my pets to eat anything but organic meat and the meat must be fresh. We humans let meat sit in the frig for days and then cook the bacteria out of it. Dogs would not naturally eat a dead carcass that is sitting in the road, unless they are starving. They kill their prey and eat it immediately. They don’t cook their meat first. Dogs were meant to eat fresh raw meat and other things that we don’t think about, such as the stomach contents that contains the predigested vegetables. Commercial food is a relatively new thing and I have seen my share of health issues, from allergies to cancer, that could have been avoided on a high quality raw food diet. All of this said, a dog with a healthy immune system can eat rotten garbage with little trouble. I am guessing that your dog had some other issues that prevented her from handling the bacteria. Don’t beat yourself up about this diet change. Had I not learned about the raw food diet, my Akita would have died in my arms. The Vets sent him home to die after his bloat surgery. It was a very special doctor who pointed me in the right direction, and my Akita had the healthiest years of his life from that point on. No dentals needed and no health issues again.

  5. skeptvet says:

    Surely you see the inconsistency of dismissing Diane’s anecdote as not proving raw diets are unsafe and then using your own necdotal experience to claim they are miraculously beneficial? Anecdotes, good or bad, simply don’t settle anything in medicine. Positive stories can suggest a benefit, but often research turns out to find that it isn’t real. Similarly, negative stories can warn us of potential problems, but they don’t prove something is unsafe. Raw diets are promoted entirely on the basis of “common sense” and the notion that somehow dogs=wolves and natural=healthy, neither of whihc is true. Infections and illness from raw diets are not rampant by any measn, but they do occur and they do hurt and even kill some pets. This risk, however small, is not worth taking until all the benefits you and other raw advocates calim are proven true. Only decent scientific research can do that. And the burden of making that case falls on the folks promoting these diets. In the meantime, anecdotes don’t settle the issue.

  6. v.t. says:

    Nothing like Greta Wallace adding insult to injury upon Diana’s heart-wrenching post.

  7. joemuggs says:

    I know I’m quite late to the discussion, but I just find it quite annoying how raw diet proponents constantly say what they’re saying as though it is established fact. Every time I hear something good about raw foods the only evidence provided are anecdotes. Common sense is promoted yet is routinely ignored. Most dogs are fed kibble and are perfectly healthy, yet it has been claimed that kibble is the unhealthiest thing for dogs. It’s also claimed that chicken bones don’t splinter if they’re raw, yet there have been cases where raw chicken bone splinters had to be surgically removed from a dogs digestive tract. I’ll stop… I can feel myself about to type up a rant..

  8. dogowner says:

    “Dogs would not naturally eat a dead carcass that is sitting in the road, unless they are starving. They kill their prey and eat it immediately.”

    Wait, what? Is there any canid species that behaves this way?
    Dogs LOVE rotting meat, and some of them bury their food ’til it gets that way. Watch a dog’s reaction to a freshly-killed chicken (feathers and all) versus a chicken that has maggots going through it and there’s no comparison.

  9. Raveller says:

    If you are in an online community, and have an IBD cat, someone will direct you to Dr. Pierson’s site as the definitive source of information on feeding cats.

    The anti-science people will dismiss the evidence on principle. The trend followers will listen to their friends instead of research. But where can people trying to help a chronically ill pet find good information? After a cat has been through all of the prescription diets, and is taking the recommended drugs, and still has problems, the confident tone of the raw diet proponent is attractive.

    I had such a cat, and he developed a severe infection on raw food. One vet in the practice gave me hell for being irresponsible, and the other vet said to continue feeding it, because the cat had to eat and we had exhausted options. I have another cat withIBd, and he’s doing well on a mix of commercial canned and dry foods, with 2 drugs and monthly weigh-ins at the vet. If I could’t afford that, the raw diet might be tempting to try again.

    The new thing is that some vets are offering fecal transplants for IBD. The science isn’t there, but I can see being desperate enough to try it. I believe in evidence based medicine, but there’s not enough research in some areas to have it, and emotions take over.

  10. skeptvet says:

    where can people trying to help a chronically ill pet find good information

    As always, I would recommend a board-certified veterinary nutritionist, ideally in communication with the internist or other vet managing the chronic illness.

    You are, of course, correct that desperation drives people to try implausible things. This is both understandable and deeply unfortunate, since such things are as likely to make the situation worse as better, and we always seem to forget this possibility. From a strictly rational point of view, of course, there may very well be times when rolling the dice on the unknown is perfectly reasonable and appropriate. I often discuss the pros and cons of using therapies for which there is little controlled evidence when the urgency to intervene is high. However, the very fact that we want to do something to help doesn’t mean that anything we do is likely to be helpful, or even safe. It is hard to remember this when we are desperate, but for the sake of our animal companions we should try.

    Thanks for the comment.

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