- vr 21 sep 2012, 10:33
#2464120
Onderstaand is een posting onder het door jou gestuurde artikel:
Ik denk dat jij hierin alle antwoorden kunt vinden.
JMon 20 Jul 2010 at 6:42 pm
I was approached at TAM 8 by a friend who knows that I am a vet student with a keen interest in nutrition and asked how I felt about raw diets. I said that I was cautiously in favor of them, as I felt that there was a strong physiological argument in their favor and having had several clients who fed raw successfully, however that without any actual data in favor or against raw diets I could not fully throw my support behind them. Then my friend told me about this article opposed to raw diets and I was a bit taken aback. I was surprised that a blog bearing the name Science Based Medicine would come out strongly opposed to something that we have no controlled studies for and no data to recommend or dissuade against its implementation. I had to see this for myself.
Let me begin by saying that I am not a woo. In fact, I was fired from my very first position as a veterinary assistant because I expressed skepticism about the applied kinesiology and acupuncture treatments that I was asked to assist with. However, I believe that in our circle of skeptics and science afficianados there is a knee jerk reaction against anything even remotely associated with woo that needs to stop. Yes, if it smells funny we should investigate and hold claims accountable to an equal standard of evidence and plausibility. We should not immediately dismiss them because of their associations, and instead evaluate them based on their own merit. I feel that the tone of this article started off dismissive from the beginning and used quite a bit of fallacious reasoning to make the claims about raw *appear* foolish instead of addressing them head on. Particularly the bit where you said, paraphrasing: “Imagine a pack of chihuahuas taking down an elk. That’s just silly! Clearly they shouldn’t eat what wolves eat.” Non sequiturs such as this are lazy, intellectually dishonest and disappointing to see on a blog such as Science Based Medicine. I expected better.
The physiological claim that dogs are carnivores and thus should eat meat is, in my opinion, at the very least plausible. Their lack of salivary amylase, their inability to move their jaw laterally which is needed for the grinding of fibrous plant material, their short, smooth GI tract, all point to an animal that is anatomically adapted to a prey-based diet. To me, this should serve as a jumping off point for further study for anyone curious to know the best way to feed our domestic companions. Instead, here you have superficially acknowledged that a physiological basis exists and then completely dismissed it as irrelevant. It is interesting that you provided the example of Great Pandas to demonstrate that physiology doesn’t determine what an animal should eat. I recently took on an independent reasearch study last semester working with several other vet students, grad students and professors to compile natural history information on over 3,000 species to serve as a reference guide for zoos and other captive management programs. Pandas were one of my species of interest and I was immediately deeply curious as to why an animal categorized as a carnivore would consume a diet that is almost entirely comprised of plant material. I read through dozens of journal articles and eventually found that this diet is extremely energetically unfavorable for pandas. They must consume massive amounts of bamboo and spend a much greater amount of their time foraging simply to sustain their basal metabolic rate due to the extremely poor digestibility of their diet. Likely this behavior developed due to the relative abundance of bamboo compared to prey in their environment, however it has had no impact whatsoever on their physiology. They have not developed an enlarged cecum or the microbial ability to handle their high cellulose diet. Thus I believe that pandas are less an example of a carnivore that is misclassified as an example that physiology is the best predictor for what diet an animal is *best* suited for rather that simply what an animal can or will eat. And in fact, zoos often provide meat-based diets for both Red and Great Pandas with bamboo as a supplement for natural foraging behavior, but not as a major component of their diet.
I was very interested to see your claim that: “Captive wolves live longest and are healthiest when fed — guess what? — commercial dog food!” I was unaware of any studies that have yielded data comparing the relative health and longevity benefits between raw and commercial diets, either on domestic dogs or captive wolves, and so I was excited by the implication that such data exists and quickly scrolled down to obtain and read through references 9-12. Unfortunately I could not find a single reference to a study comparing longevity between wolves fed a commercial dog food vs. a prey model diet. I certainly found the recommendations you mentioned, but nowhere were these recommendations based on any cited, controlled study yielding statistically significant differences in longevity or overall health. Also, at least one of these (the Red Wolf Waddell manual) recommends commercial dry food largely due to the relative difficulty and expense of obtaining whole prey items between facilities in order to establish a uniform diet regimen, not due to any specific health differences between the two. Another of your citations prefaces itself with the following: “Nutritional requirements for Mexican wolves have not been thoroughly studied but are assumed to be similar to those of the domestic dog.” Another uses Maned wolves as the model species, which have a higher capacity for plant material digestibility that is “peculiar to carnivorous animals” (Fowler and Cubas, 2001).
Recommendations are all well and good, but the problem is that wolf experts vary considerably in their recommendations and base them on personal biases and anecdotes. For every captive wolf expert that recommends a commercial dry dog food diet, there is another who recommends as close to a prey model diet as a facility can provide. Take for example, David Mech, who is considered one of the world’s leading experts in wolf behavior and a supporter of raw diets. I myself have worked with a captive wolf facility, two large feline facilities and a zoo, and all of our carnivores were fed whole carcasses donated by local farms and hunters or commercial, processed raw carnivore diets. Until we have actual data suggesting that one diet is better than another, we can only take recommendations with a grain of salt and regard them as largely anecdotal.
I have a lot to say on the subject of the level of regulation and testing of the pet food industry. In the interest of brevity in an already too-long comment, however, I will just quote from the FDA’s Pet Food webpage: “There is no requirement that pet food products have pre-market approval by the FDA. Many ingredients such as meat, poultry and grains are considered safe and do not require pre-market approval. Other substances such as minerals, vitamins and other nutrients, flavorings and preservatives, or processing aids may be generally recognized as safe and do not require pre-market approval.” So the level of testing of both ingredients that go into pet food and the foods themselves post-production is extremely questionable to nonexistent. Also, there is some evidence that even with FDA and AAFCO regulations, guidelines and feeding trials, that simply meeting the nutritional requirements is not always enough. You already mentioned the studies on diabetes remission, which has been linked to a simple switch from a high-carbohydrate kibble to a lower carb wet food. Similar results have been found linking chronic renal disease to dry food diets (Jones et al, 1997; Sturgess et al, 2002).
I would also like to address this claim: “commercial raw diets are seldom tested for nutritional adequacy, and when they have been tested they have usually failed to meet known nutrient requirements.” Both Bravo! And Nature’s Variety, the two most commonly available commercial raw pet food diets sold in stores, process their food following AAFCO guidelines. Nature’s Variety also is the first raw commercial diet to submit its product for an AAFCO feeding trial and passed.
I apologize for such a long comment, however I felt it necessary to provide a devil’s advocate that also approaches the issue of raw diets from a skeptical and science-based position, but who has arrived at a different conclusion. My own anecdotal experience has done nothing to convince me that raw diets are harmful. I have never witnessed a broken tooth or salmonella infection, nor any perforated bowels by bone shards. In fact, on the contrary I have helped to pull several commercially available, “safe” products such as rawhide, Greenies and the supposedly indestructible Kong toys out of dog intestines. I feel that the physiological argument for raw provides a plausible basis for further study and that such an argument might yield positive results if ever subjected to a properly controlled and blinded study, but without proper data I will continue to be cautiously optimistic about the potential benefits of a properly-fed raw diet, and won’t dissuade clients who approach me about the possibility of starting a raw diet and will try to steer them toward one of the AAFCO-tested commercially raw diets whenever possible.
