Friday, July 3, 2009

Faith based feeding and the defense of science

I’m a clinician, not a scientist. But I’ve known quite a few scientists, starting in college when I worked in a physiology lab, through 4 years of veterinary school, 3 years of post doctoral immunology research, and 2 years of a residency. And one very common characteristic of scientists is that they are very aware of what they don’t know. In fact, one DVM, PhD nutritionist told me that studying for the board examination should be done with an eye to the limits of our knowledge – what we don’t know about nutrition rather than what we do.

I’ve been following a very interesting email dialogue between, on the one hand, a person who is feeding a prey-model raw diet to her dog with kidney disease, and on the other, people who have studied nutrition and are trying to convey what is and is not known about feeding renal patients based on existing science.

What’s interesting to me is that the raw feeder has developed a feeding regime that she thinks is working, and states that she is a die hard raw feeder who is not likely to change her mind about that aspect of feeding her dog. That’s consistent with every die-hard raw feeder I’ve ever met – they know what they know and really don’t want to be confused by facts.

One theme that needs to be explored is why they’re so sure of their facts. This is clearly based on first hand experience and the remarkable improvements we often observe in dogs who are switched to raw. But that certainty, when based on an n of 2 (the two dogs that live in the house) or even 200 rescue dogs, is suspect. Because there are usually other factors at work, such as whether a diagnosis is accurate in the first place, changes in environmental stressors, drugs stopped or started, supplements started, etc. And in the case of rescue dogs, there is inadequate follow-up to know whether improvements were sustained and whether the dogs lived normal (or shorter or longer than normal) lifespans. Veterinarians and other scientists require more information about cases to be convinced by new information, rightfully addressing all other mitigating factors as is done in properly written, peer reviewed case reports.

The other theme here is the raw feeders’ attitudes towards science. What we do know about nutrition of the renal failure patient is that restriction of phosphorus slows progression of the disease, and that in the later stages of kidney disease, restriction of protein reduces the number of uremic episodes that require hospitalization. Prey model diets by definition cannot be restricted in either, and reducing the phosphorus in other ingredients like carbs and veggies (if being used at all) will have minimal impact compared to reducing meat levels.

When confronted with this science, the information is brushed off, but other science is presented to support the contention that the way they feed high protein diets is just fine for these patients.

You see, some die-hard raw feeders are using faith-based care for their animals. They pick and choose the science that fits their faith, but wrap themselves in a pseudoscientific exterior to try and persuade others that they are knowledgeable about the science of feeding. A good scientist remains open to conflicting information and incorporates it into the existing knowledge base going forward. Are die-hard raw feeders the Christian Scientists of the pet owning world?


  1. You raise several very interesting points, Dr. Wynn. Your comment about the attitude of die-hard raw feeders towards science was particularly insightful. Over the years, I've observed that many pet owners who adhere to the various philosophies of raw feeding (e.g., BARF, prey model, etc.), also embrace alternative practices and treatments that are often based upon faith, not science.

    In his book, "Why People Believe Weird Things" (Holt Paperbacks, 2002; Chapter 18, page 283), Michael Shermer states that "smart people believe weird things because they are skilled at defending beliefs they arrived at for non-smart reasons." Perhaps this explains why some die-hard raw feeders excel at promulgating myths about dogs, wolves, animal physiology and nutrition. ;-)

    Also see:

    Kind regards,
    Heidi Schmeck

  2. Thank you for your view point on raw feeding, Dr. Wynn.

  3. Fantastic post Dr. Wynn. As Mark Twain said, "It ain't what you don't know that gets you in trouble. It's what you know for sure that just ain't so."

    I think most of us clinicians are wary of ANY claims, be they from fad-diet zealots, pharmaceutical companies, or other clinicians, because we have seen so many different claims disproven given time and appropriate research.

    There is a particular personality type that seems to be attracted to the raw food diet. I'm not smart enough to figure it out or put it into words, but I think it has to do more with the owner's psychological needs than the pet's nutritional needs.

  4. I agree that many- probably a majority- of raw feeders start feeding because they are attracted to the philosophies behind raw feeding. The problem is that many pets respond very beautifully to these diets, so they rightfully become believers.

    I have patients who have been fed raw diets, properly supplemented and reasonably balanced, for many years, living well beyond expected life spans. And I have clients who can take a hard look at their feeding plans if I suggest an illness may be related to the diet, and are willing to test the theory.

    It's the others - the majority of raw feeders - I worry about. Those who can't see the role of the diet if their animal develops a chronic illness after having been on the diet for awhile are just blind, and I cry for the pets who belong to these people.

    1. None of the supposed benefits have been proven to be attributed to the meat being raw. For example, the shinier coats are due to a high fat composition of the diet. You could supplement more fat to a cooked diet and get the same result.

      You're probably already aware of this article but I'll reference it:

  5. Susan Wynn said:
    Veterinarians and other scientists require more information about cases to be convinced by new information, rightfully addressing all other mitigating factors as is done in properly written, peer reviewed case reports.

    Ya know, I wish vets took this attitude WRT commercial food. Seems to me it's just as "faith-based" when flogging that Hills in the waiting room.

    And no vet makes all decisions based solely on properly written, peer reviewed case reports. I've seen case notes in journals. Sample of 2, written up, hardly any background info collected. What is that? Anecdotal.

  6. CathyA, I do not disagree with you.

    However, commercial foods have *not* shortened the lifespans of pets - dogs and cats are living longer now than they ever have, and for veterinarians using that as a primary measure of health, commercial foods appear to be a contributing factor. These foods are supported by science that describes at least minimum nutritional requirements, as well, so there is the perception (real or imagined) that science proves these foods to be the best hope for supporting health and longevity.

    Raw diets, in that context, are new. They will simply not be accepted until there is a longer tradition of safe use, or there is some supporting science. So while faith may play a part in recommending commercial diets instead of homemade or raw diets, there is more to it than that. Raw diets could catch up, but my point here was to illustrate the reasons for resistance by the veterinary community.

    And the above applies to maintenance diets only. There is good support for feeding low phosphorus diets in renal disease. Anyone who feeds high protein diets to kidney patients (which are high in phosphorus) need to supply some pretty strong scientific proof before I would abandon a proven strategy to increase quality of life and longevity for a kidney patient.

    1. How, or why, would raw diets catch up when we know food borne pathogens and parasites to be a very real concern? Especially when nothing has shown that there are any proven benefits worth the risk of infection and resulting illness? Would like to hear your opinion on this, thanks.

    2. First, raw feeders will tell you that the risk of food borne pathogens is no different between feeding your dog raw chicken and preparing raw chicken for your own cooking purposes. You clean your knives, utensils, and counters and you have dealt with that risk. What they don't take into account is the fact that the raw fed pet is passing these same pathogens into the environment, so I find myself reminding people of this if they have toddlers/babies, very old people or immunesuppressed people in the house.

      But there is one company that is producing raw meat diets that are high-pressure pasteurized, reducing the the bacteria to very, very low levels. To me, that is the future of raw feeding if you want to reduce the risk of enteropathogen transmission. And for raw feeders who want to claim that pressure pasteurized food isn't raw, well, don't bother. I just don't agree with you.

      Whether veterinarians like it or not, raw diets are being fed by a very significant percentage of pet owners - the studies I've seen say something like 8% of dog owners. So deal with it. There are ways to safely feed raw that can satisfy us, even if they don't satisfy the most rabid of the raw feeders.

  7. Hi Dr. Wynn,

    I'm a raw feeder and had a pup with congenital kidney disease. She had polyuria and polydipsia at just six weeks of age but wasn't diagnosed until 13 months when I took her in to be spayed. I DID mention the excess volume of urine but was told "puppies urinate more". Hers was more than "more" though. I got her at nine weeks of age and at that time overnight she would completely FILL a high end potty pad to the point that I'd have to line the bottom with newspapers to catch the overflow.

    Anywho, she ate balanced raw from 9 weeks to 13 months when diagnosed. I fiddled with her diet and then blood work done every three months for the next year. At the end of that year I put her back on the high protein (and yes, high phosphorus) diet she ate her first year of life. I also ended up using acacia fiber and probiotics for enteric dialysis as well as MULTIPLE supplements.

    Audrey lived to eight years and seven months and passed away from an oral infection (bad tooth) that went systemic. I thought it was the progression of KD so I did at that point start her on SD canned KD but because it was an infection the diet did not help. She was diagnosed with the infection but the damage had been done.

    I would NEVER recommend the exact diet I fed Audrey to others but she did marvelously on raw, high protein and phosphorus for many many healthy years.


  8. Hi Shawna:

    Yes, she did well for 8 years and seven months. But you give no information on the progression of the kidney disease, such as what stage she was when the oral infection occurred, or any other confounding issues such as treatments, other conditions, monitoring labwork, etc. If the kidney disease was late stage 2 or greater, it's certainly possible that it impacted her immune function and helped the infection go systemic.

    But the real point here is that we have an n-of-1. How do we know that she wouldn't have lived even longer with proper dietary treatment? This is why we do prospective studies - and the studies show that dietary manipulation are the most important way to increase longevity and quality of life for kidney patients.

    Please be aware that I said dietary manipulation - not protein and phosphorus restriction across the board. There definitely comes a time when protein restriction is inappropriate, and what I'm advocating is customizing the diet to the stage of the disease. I think a one-size-fits all approach to kidney disease makes these patients as sick as feeding a high protein diet inappropriately!