Yet Another Study Shows the Real Dangers of Raw Diets for Dogs

I have covered the raw diet issues since the very start of this blog, which is about nine years now. My articles on the subject are collected here. Very little has changed in my assessment of the evidence over this time. The bottom line is clear:

There is evidence of risk in feeding raw, including infectious disease, parasites, and injury from raw bones. There is no scientific evidence, only anecdote and dubious theories, to demonstrate any benefits from feeding raw.

A new study has recently been published which adds to the already considerable evidence of risk from infectious disease.

Martinez-Anton, L., Marenda, M., Firestone, S.M., Bushell, R.N., Child, G., Hamilton, A.I., Long, S.N. and Le Chevoir, M.A.R. (2018), Investigation of the Role of Campylobacter Infection in Suspected Acute Polyradiculoneuritis in Dogs. J Vet Intern Med, 32: 352–360.

This was a case control study conducted in Australia and designed to look for associations between the occurrence of a serious neurologic disease, Acute Polyradiculoneuritis (APN) and infection with the bacterium Campylobacter sp. This bacterium has been identified as a common trigger for the analogous disease in humans, Guillain-Barré Syndrome. Because exposure to raw chicken is a common source of Campylobacter infection in humans, the feeding of raw chicken, and other raw meats, was one of the variables evaluated in this study.

The results were quite clear. Dogs with APN were far more likely to be have Campylobacter than healthy dogs, and dogs with APN were also much more likely to have been fed raw chicken and other raw foods.

This type of study only shows an association, not a definitive cause-effect relationship. A prospective randomized controlled trial would be needed to prove feeding raw chicken can cause Campylobacter infection which can then cause APN. However, such studies are not always necessary or appropriate to guide us in reducing our risk of disease. Case-control studies are the main source of evidence showing smoking increases the risk of lung cancer, and certainly a randomized trial in which some people are made to smoke for years and others are not to definitively prove this relationship would be unnecessary and unethical.

We are more often willing to inflict harm on animals in order to investigate the causes of disease, so it is possible someone will do such a study in dogs even though we would not do it in humans. However, it is clear that this study, in the context of the existing evidence in veterinary and human medicine, supports the clear health risks eating raw meat.

Proponents of raw diets will certainly argue that the risk is small compared to the benefits. Unfortunately, no scientific evidence yet exists to show any benefits, and personal anecdotes or theories about the natural history of dogs are not sufficient reason to ignore the robust scientific evidence of the harm that raw diets can cause. Unless some reliable research evidence emerges to show meaningful health benefits from raw feeding, there is no good reason for pet owners to participate in this dangerous fad.


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75 Responses to Yet Another Study Shows the Real Dangers of Raw Diets for Dogs

  1. Cathy Whitney says:

    Hi, I find your ideas about raw feeding interesting. I am not a scholar, nor a vet, nor a nutritionist. I am a dog owner who has been feeding my dogs raw for over 20 years. I grind the bones on the proteins I can(duck and turkey) and if I can’t I supplement with high quality bone meal. I have always worked with veterinarians for my dogs diet. They are licensed the same as you, with additional training. My most current vet went to UC Davis. She told me she got into alternative/complimentary medicine after she graduated from Davis. She had a dog that wasn’t getting better from traditional medicine, and decided to look into the holistic medicine field. She embraces/endorses raw feeding. This is not thrown together. There are supplements added to make it nutritionally complete, they also get a small amount of a vegetable mix along with mostly organic meat. My dogs have thrived over these 20 years with long lives, improved health,skin and coats. Not one in 20 years have become ill do to raw feeding, and neither has my husband or I. As far as nutritionally being balanced, may I ask do you eat a “completely nutritionally balanced” diet 2-3 times a day? Something out of a box or bag? I would hazard the answer is no. I cook from scratch for my husband and myself. I try to maintain a good balance of food for us. Just like my dogs. I understand you are coming from a place where studies prove everything. Maybe you should study those of us who have had glowing success from feeding our dogs raw, and especially the homemade diets. Maybe you would change your mind a wee bit…maybe?

  2. v.t. says:

    Cathy Whitney, skeptvet doesn’t have to prove to you or anyone that raw food is any healthier than commercial brand food. He certainly is not obliged to study anecdotes, which is really what you are suggesting. Maybe you should question that in the 20 years you’ve “successfully” been feeding raw, why no one has stepped up to do a proper long-term study comparing any so-called health benefits of raw vs commercial. Anecdotes don’t count.

  3. skeptvet says:

    You won’t be surprised to learn that I have heard all of these arguments before, and if they were convincing I would certainly have changed my mind by now. In terms of specifics:

    1) I’ve fed raw for 20 years and my dogs do great>
    This is just an anecdote. I’ve fed commercial kibble for as long, and my dogs do great too. Some people smoke all their life and live to 110, others never smoke and get cancer while still young. Anecdotes and personal experience doesn’t tell us what works and what doesn’t in medicine, which is why we have science and why, using science, we have dramatically improved our life expectancy and health more in the last 200 years than in the entire prior history of our species.

    2) Other vets believe in raw feeding.
    Again, this doesn’t matter. The overwhelming majority of vets consider the risks of raw to be greater than the claimed but unproven benefits. Almost none of the real specialists, board-certified veterinary nutritionists, endorse raw feeding., Some vets probably belief in UFOs or demonic possession too, but that fact has nothing to do with whether or not their beliefs are true.

    3) People don’t eat commercial balanced diets so dogs shouldn’t either.
    Many of the most important diseases in humans, obesity, diabetes, cardiovascular disease, and cancer, are related to dietary risk factors, so our diets are generally not optimal and certainly not an example of how we should feed our pets.

    4) Personal experience is better than studies.

  4. Cathy Whitney says:

    Okay, so personal stories/experiences/anecdotes don’t count. I will politely disagree with you. However, I will give you a story/anecdote that I would love to hear your response. First, I will tell you I do not make up stories. You don’t know me, so maybe you won’t believe what I’m about to tell you, and that’s ok.
    Many years ago, when embarking on my new way of feeding, recommended by my then vet, I stopped into a natural food grocery store called Mollie Stones in San Mateo, California. I asked the butcher(whom I did not know) for a case of chicken wings. He looked at me funny, and asked what I was doing with them. I told him I was raw feeding my dog the wings. He, without any, as in zero prompting from me responded I was doing the best for my dogs. He then told me he came from the Petrini family. There used to be a couple of their grocery stores here in San Mateo county but closed a number of years ago. He then told me besides the grocery stores his family owned, they also owned a rendering plant. They got the animals(dogs,cat,rat,rabbits etc..) from the local shelters that were euthanized, including the peninsula humane society in San Mateo, Calif. They rendered the euthanized animals, and their biggest client for purchase of this was Purina. That alone cemented what I was doing. Can you explained how the nutrition experts(vets, nutritionists, etc…) that work for Purina would EVER think this was an acceptable form of protein, or “meat meal”(what the heck is this?), for our beloved pets? These are the people you say are your scientific evidence. So, give my dogs rendered euthanized dogs/cats and whatever, filled with pentobarbital sodium, hydrochloride acid etc..vs fresh organic meats and homegrown vegetables…..ummm no brainer for me. Maybe some people trust purina to give their beloved dogs and cats real clean meats in their kibble. I believe the gentleman I dealt with that day, and have read that purina is the not the only one to use this disgusting meat source. Maybe you can convince me that in the boiling and sterilization of this crap it cleans it and becomes acceptable to feed dogs and cats…I will say…as you did..nope!

  5. L says:

    “I believe the gentleman I dealt with that day, and have read that purina is the not the only one to use this disgusting meat source”.

    Your comments borders on slander/libel.
    Spreading false rumors like this is disgusting and causes harm to pet owners who cannot afford anything other than supermarket pet foods, some of which are perfectly fine.

  6. Cathy Whitney says:

    L…this was years ago. But even today these drugs are being found in bags of pet food. Do they come today from shelter animals? Perhaps, or not, or from horses? I own horses and a boarding stable. When they are put down, it’s with euthanasia drugs. Cattle, pigs, chickens and other farm animals unless pets, are not put down using drugs. Where does this stuff come from?. Look around my dear. There has been recalls for this unacceptable stuff, as well as radiator fluid(propylene glycol) as a preservative.
    I’m not making this up, it was told to me, unsolicited about 20 years ago(yup..anecdotally) No excuse for disgusting unacceptable cheap meat/protein source. It’s also what has happened in “grain free” kibble. Legumes seem to be what is causing the heart issues. Dogs don’t need legumes. It is cheap protein, soy being the worst. All of this is why I make my dogs their food, I know exactly what is put into the bodies. I am not against cooking. I would cook everything if my dogs were not doing great on raw. I get full blood panels done on a continuous basis, and those tests confirm their good health. Maybe not scientific enough here, but good enough for me, along with the results I see.

  7. Cathy whitney says:

    Of course there is snopes…
    The video is quite interesting

  8. v.t. says:

    Most of us here, and especially skeptvet, will not respond to fear-mongering websites such as the link you posted.

    As for Snopes, or the information that has been propagated for 2 decades, there has yet to be proof that domestic pets who were euthanized were ever in pet foods. DNA has determined that somehow through the food rendering chain, cattle or horse DNA (when testing for pentobarbital), was the culprit.

    Oh, and here’s the FDA link that your fear-mongering website failed to include in it’s entirety:

    Follow the links at the end of each article above for more information about the testing, results, etc.

  9. L says:

    I don’t think sabotage has ever been ruled out. Such as a disgruntled employee or ex-employee dumping meds into the food supply.
    Anything is possible. I respect your opinion but I don’t buy your theory.

  10. skeptvet says:

    Sorry, but all of that amounts to is you saying “I believe X and so does this other guy” and there is no reason anyone needs to take that as meaningful. There is a whole collection of myths and misconceptions and unfounded assumptions and a complete lack of evidence or science in your statement, so it stands as just your opinion. And as the saying goes, everyone is entitled to their own opinion, but not their own facts.

  11. skeptvet says:

    Grain-free kibble was pushed y exactly the same kind of opinion-based, evidence-free reasoning you are using, along with testimonials from plenty of people who said “My dogs do great on grain-free!” The problem with anecdotes is that for every subject you can pile up plenty on both sides, and they are all equally unreliable. Someone says raw food cured their dog’s cancer, someone else says raw food caused their dog’s cancer, someone else says they were kidnapped by alines, and there is no difference in the honesty or sincerity of any of these stories.

  12. skeptvet says:

    Meaningless for several reasons:

    1) the presence of pentobarbital in some foods is not evidence for the presence of euthanized pets, and the only test ever done to look for this (looking for dog and cat DNA in these foods) didn’t show any. Of course this contamination is a bad thing, but it doesn’t support your claim.
    2) The contamination of a few foods doesn’t demonstrate that the entire commercial pet food industry is unsafe. Tens of thousands of dogs and cats live long, healthy lives on commercial diets and have for decades, so you are simply identifying the rare exception and calling it representative.
    3) I notice you choose not to mention the recalls or illnesses and deaths that have been proven to be caused by raw diets. Seems like you are only interested in facts that support your unwavering beliefs.
    4) None of this has anything to do with the point of the original post- there are no proven benefits and significant proven risks to raw diets.

  13. Cathy Whitney says:

    I don’t buy any food for my dogs (raw or otherwise)that are pre made because of the potential for junk being put into it. I don’t buy pre packaged food for my husband and myself either. I grind my flour for bread most of the time, grind meat for hamburgers and sausage I make,grow our vegetables, have chickens for eggs, etc..I don’t trust Most pre made food out there. I make my dogs their food because I don’t trust anyone else to do it. I know exactly what is in it their food bowl. I know what supplements are in it. I know that they are getting organic real food. Silly me..cause science doesn’t back it must be wrong. That’s ok…my food will never be recalled. My food will never have some off the wall preservative in it, or oops..crap from China, or some unknown meat that was rendered into “meat meal’…my bad?

  14. Massimo D'accordi says:

    And what about cats?

    Read this news release from Edinburgh University

    Do you feed your cat a raw food diet?

    Latest studies have shown that TB in cats may be linked to raw pet food – please read the Press Release below from Edinburgh University for more information.
    Cases of tuberculosis in indoor cats may have been linked to a particular type of raw pet food, research suggests. Some 13 cats from across the UK are thought to have been affected so far. Experts stress that the risk to people is very low, however.

    The issue came to light when six cats were taken to separate vet practices across England with clinical signs of TB. Tests confirmed the animals were infected with bacteria that usually cause TB in cattle, called Mycobacterium bovis. This bacteria can also infect other animals including rodents and deer.

    An additional seven cats living in the same households were also found to be infected but did not have symptoms of disease. All of the affected animals were exclusively indoor pets and had no contact with any wildlife that could have passed on the disease.

    Vets at the University of Edinburgh’s Royal (Dick) School of Veterinary Studies carried out an investigation to identify the source of infection. They found the only common factor was that they had all eaten the Wild Venison variety of a commercial brand of pet food, called Natural Instinct. The team did not test food samples so they cannot confirm that it was the source of the infections. The company voluntarily recalled the product in December 2018 and has advised people who may still have stocks to return unused items for a full refund.

    Symptoms of TB in cats include swollen belly, persistent cough and enlarged lymph nodes. There have been rare cases of people catching TB from their cats, though experts say the risk is very low. A report on the first six cases is published in the Journal of Feline Medicine and Surgery. The study was funded by the Biotechnology and Biological Sciences Research Council. Professor Danièlle Gunn-Moore, of the University of Edinburgh’s Royal (Dick) School of Veterinary Studies, said: “We found circumstantial evidence that these cases of TB in cats were linked to a particular brand of raw food diet. Not all animals that are infected with the bacteria will develop disease but we would encourage owners with concerns about their pets to get them checked by their local vet.”

    A spokesperson from Natural Instinct said: “Everything we do at Natural Instinct is done so with the best interests of our customers and their pets in mind. We can assure our customers that Natural Instinct followed, and continues to follow, every food standard, hygiene regulation and best practice required to produce raw pet food in the commercial market place. As a responsible manufacturer, we are regularly inspected by the Animal and Plant Health Authority (APHA). We have complied with all of the necessary requirements, and consequently APHA have confirmed they are satisfied all standards have been met by us. Even though we no longer manufacture and sell the Venison cat product, we are continuing to work with Food Standards Agency as part of the investigation into the Venison cat food product.”
    To find our more about TB in cats, please click here
    QUESTIONS AND ANSWERS, relating to raw food and TB:
    Were these infections definitely caused by food?
    We did not test the food itself so we cannot say with certainty that the food was the source of the infection. We were not able to identify any other source of infection.

    I have bought this food, can I still feed it to my cat?
    Natural Instinct voluntarily recalled their Wild Venison product from the market on 11 December 2018. The company has advised owners not to feed Wild Venison products sold before this date to their cats. Anyone with unused product can return it to the store they purchased it from for a full refund. No other products from this company are affected. For further information, please visit the Natural Instinct website –

    I have fed this food to my cat – what should I do?
    The link between the recalled food and the disease has not been proven. Even if the link is confirmed, not all cats fed this food will be infected and not all cats that are infected will develop disease. If your cat shows signs of ill health, you should take it to your local vet immediately. TB infections can lie dormant for many years so if you have fed this recalled product to your cat you should remain vigilant throughout its life. If your cat becomes ill at any stage, you should mention to your vet that they have eaten this food so that appropriate tests can be arranged.
    For more information please contact: Jen Middleton, Press & PR Office, Tel.: 0131 650 6514, 07795 640662, or email:
    Vet Professionals Limited
    Midlothian Innovation Centre
    Pentlandfield, Roslin
    Edinburgh, EH25 9RE

  15. Debbie Austin says:

    Cathy Whitney, I agree with you. I switched to raw after 2008 when commercial dog food brands were pulled and so many pets died from them. My dogs have thrived on raw and last week after their annual physicals my vet said both are “remarkably healthy” for their ages. I have never heard of a outbreak of disease from raw. Just last week saw another notice of commercial pulled from shelves because of plastic in the food. I also saw the notice about Purina and Old Roy containing meat from euthanized animals. I’ll stick with species appropriate diet for my canines.

  16. skeptvet says:

    If you’ve never heard of a disease outbreak from raw diets, there are plenty of examples listed right here on this blog (e.g. 1 =, 2, 3). There is also a post addressing the claim that euthanized pets are routinely included in commercial diets. If you are making your feeding selections based on misinformation, it is easy to be misled.

  17. Pingback: Help! My Dog Ate Raw Chicken: Should I worry?

  18. Amber Behm says:

    #2 – Existence of a healthy life is proof.

  19. skeptvet says:

    OK, so every dog that is healthy proves that whatever they fed is a healthy diet? So my healthy, long-lived dogs eat commercial dry food, so that is the perfect diet then.

  20. Pingback: Raw Diets for Pets |

  21. Lisa says:

    A review of online listserv postings in 2006 shows that the number of cases of illness or death associated with homemade raw diets has grown substantially. The increasingly common problems include osteochondrosis (a type of arthritis), enteritis, obesity, and vitamin A toxicity – all health conditions best avoided by feeding a balanced, species-appropriate diet to your dog.

    Three of the most respected veterinary nutritionists worldwide are concerned that raw feeding advocates are encouraging pet owners to make inappropriate diet choices, setting themselves and their pets up for disaster. These experts are Ian Billinghurst, DVM; Patricia Schenck, DVM, Ph.D., and Marilyn Blankenship, DVM. Billinghurst has been studying canine nutrition for 30 years – he co-wrote “Practical Feeding & Nutrition” with Drs. Foster & Smith’s founder Bernadette Friesen. Marilyn Blankenship wrote two books on canine nutrition; she also sat on the AAFCO Dog Food Nutrient Profiles Committee for over 15 years (the committee responsible for determining nutrient profiles). Schenck was one of the first veterinarians in the US to become board certified as a Diplomat of the American College of Veterinary Nutrition.

    These three experts have each raised serious concerns about the dangers associated with feeding a raw food diet. The concerns are backed by scientific evidence – from both real-world cases and controlled studies on dogs fed different diets, including commercial foods, balanced home-cooked diets, live prey, processed diets, and RMBDs.

  22. mn34 says:

    Ive seen this video in facebook:

    in this video this certified nutritionist

    prepare a raw diet and add spiruline to “reduce the risk of cancer”
    Spiruline really works to prevent cancer?

  23. skeptvet says:

    1. There is no such thing as a “certified nutritionist” in veterinary medicine other than board-certified veterinary nutritionists. This woman is not a veterinarian, much less a board-certified nutritionists, so her “credentials” are completely meaningless. She is listed elsewhere as “a healthcare administration student at Grand Canyon University,” which is not the background of someone who should be taken seriously as an “expert” in animal nutrition.

    2. She makes numerous claims about raw diets which are either unproven or completely false, and her advice is completely unscientific and unreliable.

    3. There are test tube studies showing Spirulina and compounds extracted from it can have effects on cancer cells. This is far from meaningful evidence for a reduction of cancer risk when it is fed to a living animal. Bleach kills cancer cells in the test tube as well, but I wouldn’t add it to your dog’s food!

  24. Lisa says:

    I also feed my dog raw meat with nutro kibble once a day and kibble later in the day with veggies. He had frequent Bouts of gastritis leading to blood in stool and general malaise with low energy. He also had yeast infections in his ears often. Adding the raw meat and giving half the kibble amt he normally got cured all of this. I am grateful.

  25. Tyler says:

    BTW that Kayla Kowalski person’s entire list of qualifications is a course she took from “Dogs Naturally Magazine” which she refers to as a “certification from DNM”. hahahaha these people are NUTS and it’s amazing how few people question them! Their qualifications fall apart under the smallest scrutiny.

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