New Studies Confirm – Kitty Is A Predator Who Is On A Lifetime Atkins Diet

Written by:  Heather Clemenceau

Cats have evolved into a highly specialized hunter, who has been more lightly impacted by domestication relative to dogs.  As an obligate carnivore, they rely on their prey to supply most of their nutritional needs as they lack sufficient enzymes to synthesize their metabolic requirements. Cats are designed to extract their nutrients from meat, not from plants, and any nutritional deficiencies that may result from an inadequate diet often take months or years to manifest themselves, by which time a disease condition may be irreversible. This is why it’s important for cat owners to mimic the high-protein, low-carb diet cats would source for themselves (rather like the high protein,low-carb diet developed by cardiologist Dr. Atkins).

Cats – Evolutionarily Positioned To Eat Meat

What evidence do we have that cats are strictly meat eaters?  Cats are obvious hunters – they have high visual acuity and an acute sense of hearing.  Like all predator species, their ears and eyes face forward to detect prey.  Their claws are normally retracted while stalking, to mask their movements as much as possible. Cats teeth are ideal for immobilizing the spinal column of the small prey animals they would typically hunt in the wild, and their small stomachs are adapted for smaller meals, approximately the size of mice. They also prefer their food at roughly the same temperature as that of freshly killed prey.  Feeding behaviours evolved in cats include searching for food during both day and night, which corresponds with the activity of their traditional prey animals.

A wild or feral cat WILL eat some plant matter in the G.I. tract of smaller animals they kill and swallow mostly intact.  If they catch larger prey, like baby rabbits, they would likely not eat the grassy stomach contents.  The plant material in the guts of prey animals is a very small amount of their food intake and in any case, these plant materials are very different from the metabolically high-glycemic carbs offered in vegan cat food.

What It Means To Be An “Obligate Carnivore”

All protein is made from only 21 different amino acids. Cats are able to synthesize only 12 amino acids, so there are 9 amino acids that must be obtained directly directly from their diet. In the case of vegetarian and vegan diets, the amino acids, vitamins and minerals must be heavily supplemented, and thus come from synthetic or lab-created sources (because otherwise most would not be vegan). This is not ideal, since the food must be more highly processed than foods that naturally contain these amino acid requirements.  While dogs have evolved (thanks to living closely with humans for 10,000+ years) the ability to eat a more starchy diet comprised of about 30% from protein, cats require that their diet consist of about 52% from protein.  This requirement is similar to that of wild exotic cats.

A meat-based diet supplies abundant taurine; cereals and grains supply only marginal or inadequate levels of taurine for cats. Therefore, diets based on these types of protein sources will need supplementation. Three disease states have been identified related strictly to taurine deficiency; feline central retinal degeneration, reproductive failure and impaired fetal development and feline dilated cardiomyopathy. Clinical signs of taurine deficiency occur only after prolonged periods of depletion (from 5 months to 2 years).

Cats do not possess salivary amylase, which begins digestion of carbohydrates and starches in the mouth while chewing.  If they are forced to consume carbohydrates this places the burden on their pancreas, which can only produce amylase comparable to about 5% of that of dogs. Cats have very low liver glucokinase activity and therefore limited ability to metabolize carbs by this route either.

The cat is unable to convert beta-carotene to vitamin A due to a lack of intestinal enzymes necessary for the conversion, and therefore cats requires a dietary source of vitamin A. Because vitamin A is a fat-soluble vitamin and is stored in the liver, any deficiencies are slow to develop, and are only seen in cats with severe liver failure. Cats also lack sufficient enzymes to meet the metabolic requirements for vitamin D photosynthesis in the skin; therefore they require a dietary source of vitamin D. Cats need increased amounts of many dietary water-soluble B vitamins, including thiamin, niacin, and other B vitamins.  The requirement for niacin and pyridoxine is four times higher than that for dogs.

Sweet Taste Receptors

Taste receptors reflect a species’ food choices.  Cats are missing the genes that code for part of the “sweet” taste receptors that recognize carbohydrates. This explains the indifference that domestic cats and their wild relatives lions and tigers, etc. show towards sweet foods. And it may also explain why they have evolved into such accomplished hunters. It makes sense that their taste preferences evolved to ensure they consume an appropriate source of the right calories and that they avoid unsuitable foods.

Nutritional Inadequacies in Vegan Cat Foods

When I first began blogging about vegan cat diets, there was a dearth of information about the long-term effects of carb diets for cats. But now, studies are being carried out as vegan diets increase in popularity. A study published in January 2020 tested several vegan pet foods for dogs and cats available in the Brazilian marketplace, for the purposes of evaluating the macronutrient composition, fatty acid and amino acid profiles, and essential mineral content. The results were then compared with FEDIAF (2019) and AAFCO (2019) recommendations.

“The cat food presented potassium content lower than recommended. The Ca:P ratio did not meet the minimum recommendation of FEDIAF (2019) and AAFCO (2019) in any of the dog’s foods analyzed, and the cat food also did not present the minimum recommendation based on FEDIAF (2019). Copper concentrations exceeded the legal limit in all foods. Zinc concentrations exceeded this limit in two foods (one for dogs and one for cats). the cat food did not meet the minimum recommendation for arginine. In addition, when the amount of nutrients consumed by animals with low energy requirements was simulated, in addition to the same non-conformities described above, it was observed that the cat food does not meet the minimum recommended of protein and taurine in unit/Kg0.67. therefore, these foods should not be recommended for dogs and cats, because dietary deficiencies found may lead to health risks for dogs and cats. Furthermore, manufacturers should review their formulations to ensure the nutritional adequacy of these foods.”

And Some Vegan Cat Foods Are Not Truly Vegan At All….

This 2016 study found that half of the vegan dog and cat foods tested (7/14) were positive for the undeclared DNA of cows, pigs,  and sheep.  Not only should this raise concern for vegans who believe they are feeding an entirely vegan diet, it tells us that food manufacturers have issues with quality control and adherence to diet profiles.  And this was not a one-off occurrence either – the tests were repeated some months apart and the same observations about unintentional adulteration were found.

So the lessons learned here are that vegan or supposedly vegan cat foods are a somewhat of a wildcard – food processing lacks control and food manufacturers evidently do not review their own products for compliance with recommendations for nutrition/protein.  Maybe cats are getting a subsistence level of nutrients from these not-vegan foods which is why more cats do not appear to be unhealthier, at least not initially.  But even so, it’s very doubtful that the cats can truly appreciate the carbohydrate-derived foods because they don’t have taste receptors for it.  To them, it might taste only marginally better than eating flavourless cardboard, which might be why Evolution Pet Food’s founder Eris Weisman advises that cats may need to be “starved” for a few days in order to appreciate his company’s food.  I hope that if you were considering giving your cat vegan foods that you at least read that statement and give it some serious reconsideration.

As a vegan, I can completely relate to the desire to minimize the environmental impacts of dog and cat food diets. While feeding a vegan diet to a carnivore is ethically consistent with animal rights philosophy, the specific physiological and behavioural requirements of cats mean that such long-term diets are really an uncontrolled experiment, with our cats as the test subjects.   Despite the dramatic anecdotal claims made by some proponents of these diets, there is STILL insufficient evidence showing a benefit (or lack of harm) in feeding vegan diets.

Vegan Cats – Still Tragic!

Written by;  Heather Clemenceau

Humans have teeth ideally suited for grinding. Plant-based eaters often tell meat-eaters that “if we were meant to eat meat, we would have canine teeth.” Well of course that’s true, but look at the cat’s dentition. We sometimes claim that humans are plant-eaters based on our dentition, while hypocritically asserting that, despite having canines, we shouldn’t have to feed cats meat if it interferes with our belief system.

Since I wrote my first and only blog post on vegan cats and dogs, not much has changed. Cats are still strict carnivores that rely on nutrients in animal tissues to meet their specific nutritional requirements. To the best of my knowledge there are no long-term clinical studies of cats (or dogs) eating vegetarian or vegan diets, with or without non-vegan control groups.

Despite rather scant literature on the subject matter, the limitations of substituting animal-origin protein with plant-origin protein in food formulated for cats is being increasingly recognised. Simply looking at the overall protein content of a food is not enough to determine whether the food is a good choice for cats. We must consider then when feeding – what is the biological value of that protein to the cat? The natural diet of cats in the wild is a meat-based diet of rodents and birds. Cats are metabolically adapted to preferentially use protein and fat as an energy source, not carbohydrates. Not all proteins are equal either – proteins are made up of amino acid chains and there are a myriad of different combinations that serve many functions in the body. Since meat is a natural food source for cats, it is easy to conclude that meat proteins will have a higher digestibility for cats than plant proteins.

I do understand the motivation by some plant eaters to reduce their cat’s ecological pawprint in any way possible. But as

“Cats have a limited ability to adjust protein utilization to the amount of protein in their diets. In other words, they need to burn protein for energy even if they aren’t getting enough in their diet. Cats have lost a number of metabolic pathways that omnivores still utilise to metabolize plant-based foods. They have lost these pathways because in their natural habitat they hunt prey species that are high in meat-based protein, so they no longer needed the ability to efficiently metabolize plant material.”
Source: http://feline-nutrition.org/answers/answers-plant-vs-meat-the-protein-feud
Lyn Thomson, BVSc DipHom

mentioned in my previous blog post on the subject, the vast majority of cat and dog food is derived from the meat industry, so additional animals are not killed to feed dogs, cats, or ferrets. Nevertheless, the feeding of vegan diets to cats, dogs, or ferrets does problematize the definition of “vegan” for many people. They quite understandably feel that if they buy any meat-based pet foods, they are supporting the meat industry and not carrying out the  “noble vegan boycott” of those industries. Over time I’ve found that some vegans/vegetarians invariably equate non-animal food sources as some sort of penultimate launching pad towards spiritual purity. But when we insist that cats, who are obligate carnivores, actively participate in that effort, we’re anthropomorphizing them.  We don’t ask that cats share our religion,  so why must they share our diets?

Moreover, sometimes we steadfastly refuse to consider the implications of the few studies that are available that cast doubt on the long-term health effects of vegan diets, relying instead on anecdotal evidence. But consensus via anecdote is not empirical evidence. Anytime the main “evidence” for a product’s efficacy is testimonials or other anecdotes, everybody’s woo detector should light up.  And even though you may have consistently observed a phenomenon again and again (cats eating a vegan diet and thriving), there is no guarantee that your next observation will agree with the previous one. For example, even if you’ve only ever seen white swans, it is still incorrect to assume that all swans are white. So, if you require that all knowledge must be based on your personal observation alone, you can never be sure you know anything.

If the studies mentioned in the previous blog post weren’t sufficiently convincing that vegan foods for cats are, at the very least, completely experimental, perhaps the following study and interview will make a skeptic of some readers. As it turns out,  there is more literature available on vegan cats,  but we were just looking for it in English! Both the study and interview have been translated from their original German, and should you wish to read them or translate them yourself, the original links are included.

“There is a substantial difference in protein requirements between our cats as obligate carnivores and other carnivorous species, such as the dog. Adult cats require two to three times more protein than adults of any omnivorous species, such as humans.”
Source: http://feline-nutrition.org/answers/answers-plant-vs-meat-the-protein-feud
Lyn Thomson, BVSc DipHom

The Interview – Dr. Kienzle and Spiegel Online

The following translation is ©Anke Hagen. Translated from the German original and supplemented with additional information on Prof. Kienzle by Anke Hagen. Should you share this, kindly make no alterations whatsoever – thank you.

Prof. Dr. Ellen Kienzle is the head of the Department of Animal Nutrition and Dietetics at the Ludwig-Maximilian University of Munich in Oberschleißheim.

She in on the Livestock Commission and has obtained credentials at the ECVCN committee. In addition to student counselling her research field includes the veterinary nutrition of dogs, cats and horses

The European College of Veterinary and Comparative Nutrition (ECVCN) is recognized throughout the veterinary profession for its progressive leadership, for the high standard of professional excellence of its members, the Diplomates.

In order to become a Diplomate, veterinary surgeons, known as Residents, must undergo a rigorous training programme in either Large or Small animal nutrition, supervised by recognized veterinary specialists e.g. other Diplomates or Professors of Nutrition at a number of Universities

What does ‘ECVCN Diplomate mean? A specialist?

A ECVCN Diplomate is someone who has founded the ECVCN, or has successfully passed the examination of the European College of Veterinary and Comparative Nutrition, a EBVS-recognised College.

The objective of the European College of Veterinary and Comparative Nutrition (ECVCN) is to advance the quality of animal health care in Europe by increasing the competency of those who are active in the field of veterinary nutrition.

The ECVCN was founded in 1998 from the European Society of Veterinary and Comparative Nutrition.

The college obtained full recognition by the European Board of Veterinary Specialisation (EBVS) and currently counts 39 Diplomates.

Prof. Kienzle does not recommend a vegan diet for dogs! She said an ‘ovo-lacto vegetarian diet’ (as opposed to a vegan diet) is POSSIBLE (but not optimal) for dogs, but then only under the strict supervision of an expert veterinary dietician. It is very rare to find persons with a qualification like hers. She says that whether or not one adds raw meat or not or feeds dogs an ovo-lacto vegetarian diet, people generally tend to underestimate the canine calcium requirement, because their ability to metabolize calcium (their uptake efficiency) is far worse than ours.

When asked by Spiegel Online how a calcium deficiency manifests in dogs, Prof. Dr. Kienzle replied:

“Kienzle : dogs develop skeletal diseases such as brittle bones, which can manifest themselves within two years. With puppies this can happen within a few weeks. Unfortunately, you can not tell that a dog has a calcium deficiency on the basis of a haemogram in time! One only notices the lack when it is already too late clinically speaking. Pregnant bitches (female dogs) have a particulary high calcium requirement A particularly high calcium needs are pregnant bitches and especially puppies who pick up weight particularly fast. In such cases, I strongly advise heeding *specialist* veterinary nutritional advice.

SPIEGEL ONLINE: Is not it enough then to simply feed them more eggs and dairy products?

Kienzle: No, that’s not enough. You have to supplement with calcium. Calcium tablets used in human medicine are not suitable for this incidentally, the doses are far too low.

SPIEGEL ONLINE: Can’t dog owners simply rely on ready-made vegetarian feed mixtures to ensure that the dog has no deficiencies?

Kienzle: I would not rely on that. The vegetarian dog mixtures that exist on the market, usually come from vendors who lack the necessary expertise. Incidentally, the Stiftung Warentest recently tested ‘vegan’ cat food and found chicken components in a vegan food mixture intended for cats and dogs.

SPIEGEL ONLINE: So it is possible to feed dogs vegetarian food. What about vegan nutrition?

Kienzle: At a stretch, and if you are absolutely desperate to do that, you can do that with an adult dog, but only in keeping with the aforementioned reservations and recommendations. But in pregnant or lactating bitches and in puppies a vegan diet is not acceptable.

SPIEGEL ONLINE: Do dogs accept the transition to a vegetarian diet that simply?

Kienzle: Dogs might not accept the new food at first. But usually you can get them to accept it by letting them starve for a while. I would not recommend that. Whether a vegan regards that as being ethical or not is something he will have to to reconcile with his own conscience.

SPIEGEL ONLINE: I’ve heard that it is essential to supplement two substances on a vegan diet: L-carnitine and taurine. Is that correct?

Kienzle: That statement cannot be validated in such a generalized sense – it depends on the one hand on the breed of the dog, on the other hand, on the individual nutritional requirements. But on a vegan diet, it would not be harmful to supplement with both substances, because a shortage of either of them would mean that the animal is in danger of suffering from heart muscle disease.

SPIEGEL ONLINE: People who feed their dogs vegan food, always claim that their dogs benefit health-wise. Can you confirm that?

Kienzle: I regard a generalization like that as being highly problematic and questionable. Those who feed their dogs raw meat also claim the same things. We know that both dogs and horses display very strong placebo effects, simply because the animal gets more attention from its guardian/keeper. But of course, you will always find individual cases where a dog with an allergy or skin disease, for example, will benefit from a change of diet.

SPIEGEL ONLINE: Can you feed a vegan diet to cats?

Kienzle: Dogs have been domesticated for about 20,000 years and have adapted their diet and their metabolism to humans. Dogs are much more flexible in their diet than cats who have indeed continued to feed on mice during their domestication – which is precisely why they were kept by humans in the first place. Feline metabolism has also not been researched in as much detail as that of the dog. I therefore reject the nutrition of vegan food to cats, and an ovo-lacto-vegetarian diet for cats is also to be regarded in a far more critical light than one for dogs. In addition it is also difficult to change a cat’s nutrition because they are subject to stringent nutritional conditioning. It would not function to allow a cat to starve. The cat would die.

SPIEGEL ONLINE: What is your view of carnivorous companion animals in general?

Kienzle: I find it questionable that vegans even keep predators as companion animals at all. The animal serves the purpose of entertaining them, which alone is selfish enough. Then in that case, the least you should do is to respect the needs of the animals. You don’t necessarily have to keep a carnivorous companion animal. One could also keep a rabbit or a small guinea pig. They are very amusing and loving companions too.”

Interview conducted by Jens Lubbadeh.

“Not all proteins are equal. Proteins are made up of amino acid chains and there are a myriad of different combinations that serve many functions in the body. Proteins are structural and tissue components in the body, enzymes and antibodies and serve messenger and transport functions. Ingested proteins will vary considerably in how well they are utilised by the body. Plant-based proteins do not have the same amino acid profile as meat-based proteins and these differences are crucial to cats.”
Source: http://feline-nutrition.org/answers/answers-plant-vs-meat-the-protein-feud
Lyn Thomson, BVSc DipHom

The Study – Dr. Radka Engelhard, DVM – Field Study of Vegetarian Food for Dogs and Cats

The following translation is joint collaboration between Tamara Goertz,  Dr. Werner Liesack and Birgit Liesack. ©Tamara Goertz et al. Translated from the German original published on http://www.vetmed.uni-muenchen.de

“In this study interviews were conducted with 54 owners of dogs and five owners of cats, for a total of 86 dogs and eight cats. These owners were feeding their dogs and cats a vegetarian diet and for this reason they were picked for the interviews.

The questions in the interviews included, what type of vegetarian dishes were fed and what feeding techniques were used, and what portions were dispensed. These questions were asked on a standard questionnaire.

The results of these questions were:

66 adult dogs received 11 per cent ovo-lacto vegetarian diet (which includes eggs and dairy), 47 per cent lacto-vegetarian diet (dairy), 29 per cent vegan, 13 per cent semi-vegetarian (with not pure vegetarian supplementary food), for eight vegan pups and eight vegan cats.

As well, the results of all details of illnesses were recorded and clinical checkups were undertaken, and in some cases blood work and urine samples were taken.

And finally, commercial pure vegetarian animal food was tested for its suitability.

1. The main reason for the participants’ involvement (in the study) was to present the ethical-religious aspects, that man has no right to kill animals for their meat. As well, that the current meat standards entail many health risks.

2. The supply of protein was insufficient by more than half of the adult dogs. Also, results often showed that the intake of S-containing amino acids, such as cysteine, were too low. Nonetheless, all plasma parameters were tested for protein intake (total protein, albumen, urea) inside the reference area.

3. The typical mistake made in the homemade ratios of mineral elements were also found in vegetarian dogs. Sixty-two per cent of the dogs were lacking the minimum calcium requirement, and about half the dogs were lacking the minimum phosphorus requirement. An unbalanced Ca/P ratio was glaringly apparent. Also, 73 per cent of the dogs lacked sodium.

4. In the trace elements the supply of iron, copper, zinc and iodine were often insufficient.  The content of iron, copper and zinc in plasma was mostly below the reference value, but there was no clear relation between their intake and plasma content.

5. It was discovered that vitamin D in the vegan rations were often insufficient. Also here were reduced plasma content of 25-OH-vitamin D; however, no firm relationship to vitamin D intake was recognized. A total of 56 per cent of dogs received insufficient supply with vitamin B12. Supply with panthotenic acid was frequently marginal.

6. The adult dogs displayed no clinical deficiency from the insufficient vitamin intake.

7. The vegan puppies at eight weeks of age were only about half of the expected body weight.”

 

Biological value (BV) is a number from 100 down to 0, that describes how well a protein is absorbed by the organism’s body.  More precisely,  it is the measure of the percentage of the protein that is actually incorporated into the proteins of the body.
When one or more of the essential amino acids are missing or present in low numbers, the protein has a low biological value.

Unfortunately, the vegan lifestyle can never be unassailably consistent, or free of contradiction. In fact, one could say that most vegans already support the meat industry if they eat in any restaurants that serve meat, so just like my non-vegan cats, we’re both supporting agribusiness. And depending on where you live and what vegan cat food you buy,  it may not even be vegan anyway,  since Dr. Kienzle’s research has shown that chicken has been determined to be an ingredient in some foods.  Perhaps this explains the relative good health of some vegan cats in studies – they’re actually getting biologically valuable proteins from ingredients that weren’t intended to be added to the food!

Even by purchasing only vegetarian or vegan special product lines exclusively,  we might still be unknowingly supporting the meat industry.  This is because so many of the cruelty-free foodstuffs and other products we love to eat are owned by big food conglomerates (Conagra used to own Lightlife, the maker of “Smart Bacon;” Dean Foods purchased Whitewave, makers of “Silk;” Kellogg owns Morning star Farms who make meatless sausages and burgers, and Kraft owns vegetarian burger company Boca). As if none of that were bad enough, Big Tobacco company Philip Morris owns Kraft. As unhealthy as Velveeta is, probably Marlboros are worse….

But even without all this skepticism of vegan diets by veterinarians and veterinary nutritionists, is the presence of canine teeth not suitably convincing? Some people already remove a cat’s claws, and aside from this being extremely painful to the cat,  it also greatly infringes upon a cat’s ability to partake of its natural behaviours.  Must we inflict extruded vegetable pellets or vegetable mush on them as well?

It is both ethical and humane to permit cats to scratch and eat meat.  These are both undeniably inherent feline attributes. If we can’t accept a cat’s natural ways of being then perhaps a different companion animal would be in order?

I do love this tweet, and appreciate Ricky Gervais advocating for the true nature of cats everywhere.

Vegan Pets: An Unscientific Dogma?

Written by:  Heather Clemenceau

When meat-eaters ask vegetarians or vegans how we get our protein or nourish ourselves without meat, we can confidently refer them to the Position of the American Dietetic Association and Dietitians of Canada on Vegetarian Diets: “Well-planned vegan and other types of vegetarian diets are appropriate for all stages of the life-cycle including during pregnancy, lactation, infancy, childhood, and adolescence.”

But pet cats and dogs share a common ancestry and belong to the order Carnivora. The very definition of a carnivore is an animal that consumes a diet consisting wholly or almost exclusively of meat. Carnivora includes domestic cats and dogs, ferrets, lions, raccoons and even the giant panda, which is herbivorous. Carnivores are well-suited to a hunting lifestyle. Most members of Carnivora are superb hunters possessing sharp teeth and eyesight, a well-developed sense of smell, and sharp claws. Dogs differ from cats in that they are not strict (obligate) carnivores but are more omnivorous. One of the most complete studies of the daily nutrient requirements for dogs and cats currently available is the 424-page Nutrient Requirements of Dogs and Cats. When considering whether to feed a cat or dog a vegan diet, that reference is especially useful. It acknowledges that there is far greater latitude in ingredient selection for dog foods and quite feasible that they contain no animal products. However, the same is not true for cats, since strict vegan diets, when fed alone, are not nutritionally adequate even though it’s possible that cats will find them palatable. All commercial dog and cat foods should also adhere to the AFFCO nutrient profiles for cats and dogs.

Vegans and vegetarians naturally want to refrain from contributing to animal cruelty by feeding pets meat-based diets. But the pet food industry exists as a by-product of the meat industry itself, and that industry shows no signs of discontinuation. Some people feel that the term “by-product” used as an ingredient in pet foods means that it is of low value or garbage that is not fit for human consumption. It is true that much of the content of pet foods comes from the “4-D Animals” – downers, the dead, the diseased, and dying animals. Pet foods also contain less palatable parts of animals that people do not want to eat. This includes some organ meats, intestines, lungs stomachs, legs, limbs, and sinewy parts etc. What makes “human grade meat” is in large part a culturally based aesthetic rather than anything practical. In other words, we choose not to eat many perfectly edible organ meats or other body parts simply because they gross us out.

As repugnant as we may find all these things, the reality is that cats, dogs, and ferrets can handle greater microbe burdens in their food, most of which is killed by the cooking process. In any case, carnivores or scavenging carnivores (like dogs) would all eat these same body parts in the wild, but probably in less hygienic conditions than those found in a cooked food.

So the question to feed vegan diets to cats, dogs, and ferrets really becomes an ethical concern. We want to have carnivores as pets, so should those carnivores be compelled to eat a diet without animal products even though making one that is nutritionally appropriate is difficult, and some of them may have to subsist on an inadequate diet? We domesticated them, invited them into our homes, and are now faced with the decision – are we trading one kind of animal welfare for another?

Observations About Dogs, Cats, and Other Carnivores In General

Domestic dogs (canis lupus familiaris) diverged from wolves (canus lupus)about 100,000 years ago. Their diets are predominantly meat, but they will eat non-meat foods such as vegetables and fruits. They do however, have some issues breaking down carbohydrates and cellulose in their guts.

Neither dogs, cats, nor ferrets produce amylase in their saliva, which starts the break-down process for carbohydrates and starches. Amylase is something that omnivores and herbivores produce, but not carnivorous animals. This places the burden entirely on the pancreas, forcing it to produce large amounts of amylase to cope with the cellulose and carbs in the plant material. The carnivore’s pancreas does not secrete cellulase to split the cellulose into glucose molecules, nor have dogs become efficient at digesting, assimilating and utilizing plant material as a source of high quality protein. Herbivores do those sorts of things.

Dogs, cats, and ferrets have the internal anatomy and physiology of a carnivore.   They have impressive, sharp teeth designed for grabbing, ripping, tearing or shearing meat – all adaptations for a prey-based diet. They do not have large flat molars for grinding up plant material. They have a short gut and smooth colon, which means that food passes through quickly. Plant matter though, needs time to sit and ferment, which translates to having a longer colon, as humans possess.

The carnivorous nature of the cats’ (felus catus) diet has lead to very specific metabolic differences that show up in their nutrient requirements. These differences make cats (and ferrets) “obligate” carnivores, meaning that they rely on nutrients in animal tissues to meet their specific and unique nutritional requirements and that some level of animal meat is required in their diet for survival. Specific nutritional idiosyncrasies of the cat includes increased protein requirements, as well as the inclusion of arginine, B12, vitamin A, methionine, lysine, taurine, carnitine, choline, and arachidonic acid. Taurine, arginine, arachidonic acid, along with vitamin A and other nutrients, are all found in animal meat and are either completely absent or found at much lower levels in plant material. The reality is that while dogs can utilize plant material and eat vegan diets, neither dogs,  cats,  nor ferrets bodies are designed to eat only plants as are herbivores.

Studies and Articles on Vegan Pet Foods

There aren’t a lot of studies on the long term health effects or appropriateness of vegan foods for pets. There are no long term studies that I could find (10+ years or the life of the pet). Therefore, feeding pets vegan diets amounts to in-home animal testing.  There are however,  shorter term studies and articles available,  authored by veterinarians and veterinary nutritionists:

• Veterinarian Lorelei Wakefield’s peer-reviewed study, published in the Journal of the American Veterinary Medical Association – “Evaluation of cats fed vegetarian diets and attitudes of their caregivers,” found that taurine levels were low in all the cats, but not critcally so. Dr. Wakefield is a vegan who owns a cat who eats meat-based prescription food.
• The American Society for the Prevention of Cruelty to Animals says: “The nutritional needs of dogs and cats are very different. Dogs are omnivores and can do well on either meat-containing or vegetarian diets, while cats are strict carnivores with very precise nutritional needs.”
• The US National Research Council released dietary guidelines for Cats and Dogs in 2003 “Cats are descended from carnivores, and their gastrointestinal system is well-suited to digesting and absorbing nutrients from animal-based proteins and fats. They should not be fed a vegetarian diet because it could result in harmful deficiencies of certain amino acids, fatty acids, and vitamins.. Although dogs may prefer animal-based food, they can survive on a vegetarian diet as long as it contains sufficient protein and other nutrients..”
• Vegan vet Armaiti May advises having a vet monitor your cat’s urine pH, rather than doing it yourself.
  Animal Voices (Toronto) covered this topic in 2006 with a round table discussion, involving two local activists whose cats fell seriously ill on a vegan diet
• Gray, et. al., published in JAVMA (Journal of American Veterinary Medical Association) – Nutritional Adequacy of Two Vegan Diets for Cats. The study showed two commercially available vegetarian cat foods (Vegecat KibbleMix and Evolution canned diet for adult cats) to be deficient in several key nutrients.
• Veterinary nutritionist Dr. Julie Churchill says a vegan diet can eventually cause eye lesions and heart valve problems in cats.
• One survey conducted by PETA found that 82 percent of dogs that had been vegan for five years or more were in good to excellent health and that the longer a dog remained on a vegetarian or vegan diet, the greater the likelihood that the dog would have overall good to excellent health. The study, however, also found that vegetarian dogs may be more prone to urinary tract infections as well as a form of heart disease known as dilated cardiomyopathy, which can be caused by a deficiency of the amino acids L-carnitine or taurine.
• Cats tend to form struvite crystals and stones if their urine pH is too low as a result of lower than required protein.  Urinary blockage risk is increased.  Male cats are especially at risk due to having a narrow urethra.

From these studies I can see that vegan food for pets must be supplemented, which begs the question – how natural can it possibly be? The logic behind claiming that an obligate carnivore like a cat or ferret is healthiest if fed a vegan diet seems rather indefensible to me. And it’s certainly not without some degree or risk for dogs either. While a manufacturer’s statement that thousands of healthy and long-living animals are on their diets is interesting, additional information is needed to support the diets’ nutritional adequacy.

Highly Questionable Claims by Vegan Pet Food Manufacturers

Unfortunately, some pet owners seem to be endorsing what former chiropractor and Evolution Diet pet food CEO Eric Weisman regurgitates about vegan cats. He is often touted as an expert in nutrition even though he was not, as far as I could determine, a medical doctor or veterinarian of any sort. Some of his more outrageous claims about vegan foods and pets are found variously on the internet, where he is prone to making many unsubstantiated claims, including the following (in reference to the Evolution diet):

• “Dogs Live to be 21”
• “Cars live to be 22”
• “Ferrets live to be 13 ½”
• “Evolution Pet Food reverses late stage cancer in dogs and cats, even in those near death.”
• “Vegan diets reverse organ failure”
• “We are observing up to a 40% increase in life expectancy with Dogs and Cats in Human Family Homes.”
• “Wild animals are ground up in pet food”
• “…treats joint, vascular, autoimmune diseases, liver – kidney disorders, cancers, and other internal diseases in sick animals”
• “Meat, poultry, and fish contain radioactive ingredients”
• “Evolution pet food will clear any opacities from a cat’s corneas”
• “Cats are kinder and more loving on a vegan diet” (I suspect that a cat with a conscience would probably not be a cat)

Weisman’s biography describes him as a “former human physician” and a physician in private practice. Instead, he appears to have been a Dr. of Chiropractic, which is not a medical doctor. Along with his education at Ryerson, University of Toronto, and McMaster, he cites 2 Diplomas including a “Doctorate in post-graduate Health Sciences” at what is now Northwestern Health Sciences University in Minnesota. I have no idea how a diploma is also a doctorate. Northwestern Health Sciences U is a chiropractic and massage therapy school. According to news reports, he faced 58 charges, including practicing human and veterinary medicine without a license and animal cruelty and plead out to some of those charges.

Weisman has made this food for approximately 2 decades but hasn’t yet published any proof of his claims. By Weisman’s account, there is no “national test data” either.  I could not locate any veterinarian testimonials on any of his sites. Of course, any “studies” Mr. Weisman refers to don’t actually exist, or are simply anecdotal comments from purchasers of his pet food. Where he ran in to trouble with the chiropractic board is when he started reviewing his client’s pets blood chemistries, analysis upon which he’s not qualified to render any opinion. The chiropractic board was hearing complaints that Weisman was keeping his pets in the office, and sometimes did his chiropractic treatments covered in animal hair and without washing his hands. Further compounding his problems with the board, Weisman’s website began offering $50 packages to treat cancer, kidney failure, and dementia, not including the price of up to $275 worth of vitamins and supplements. For $100, pet owners could buy a “Heart Disease Emergency Treatment Plan” that included a 24-hour emergency pager number for Weisman. For one client, Weisman recommended a dog receive caffeine enemas for lymphoma.

Listening to the various podcasts he appears in, he does give a lot of veterinary advice even after being reprimanded for doing exactly that. His soundbites are filed with “woo” from start to finish. On his own site – www.weismannutrition.com, he claims he is a scientist. He cites such terminology as “The World’s Most Advanced Nutrient-Metabolite Procedures for Cancers, Organ Failure, and Systemic Infectious Diseases.” Seriously? What’s a “nutrient-metabolite procedure” and how does it cure or treat infectious diseases?  Weisman can’t seem to stop practicing medicine without a license.

In a very revealing and highly entertaining exchange, Eric Weisman runs up against a vegan interviewer with a PhD in Biochemistry, who also isn’t sure what a “nutrient-metabolite procedure” is either,  and isn’t afraid to ask him hard questions about his convictions or his claims about his pet food. Weisman doesn’t respond to the really difficult questions, and sends the interviewer, Ian McDonald,  a vegan himself,  a nastygram after claiming that he is merely a misunderstood visionary, which is an oft-repeated claim by people selling quackery.

In addition to all the above, in 2003 a recall of Go! Natural pet food was conducted due to a number of cases of acute liver failure associated with the food. The underlying cause was never found, but the company manufacturing the food continues to tout it as healthier based on claims about “good” and “bad” ingredients very similar to those made on the Evolution Diet site. Simply claiming something is healthy and natural provides no assurance that it is safe or healthy.

Vegan pet food promoters often sell their food with fear, vague or even fantastical claims. It is the most egregious kind of unfounded fear mongering with no evidence provided to support it.

Even without the unsupportable claims, it’s hard to justify feeding vegan foods to these animals as a mainstay diet. Since I eat mostly vegan, it’s an understatement for me to say that I don’t care for industrial meat production. However, I find it almost as offensive when any food is marketed by misrepresentation. Since Weisman has made a career out of embellishing the benefits of his food and violating the law, I can’t imagine why anyone would think that a properly balanced commercial meat-based food is a worse alternative than what is being promoted.

In one of the MP3s featuring Weisman, he suggests with-holding food from cats if they don’t want to go vegan. Refraining from feeding cats anything else to eat other than their products in order to force them to eat vegan is cruel, IMO. I can’t personally comprehend how we can stop animal cruelty by feeding a carnivore plant matter – we’re really only substituting one form of cruelty for another by imposing our own ethical principles on a species dependent upon us for their welfare.

Even if we can justify feeding dogs an entirely vegan diet, why would we necessarily want to since it cannot be said that vegetable matter is natural for them. And it isn’t clear yet whether a nutritionally adequate vegan food can be made for cats. It may be possible, but there are reasons to doubt it and there is no evidence that cats can be healthy for long periods of time on such a diet. It amounts to deciding which of your conflicting ethical principles take precedence. Do you do more harm supporting the meat industry or take a chance with an animal companion’s health? It seems to me the most ethically straightforward option for vegans is to choose herbivorous or omnivorous pets.

Half-Baked – BARF Diets For Dogs And Cats

Written by Heather Clemenceau

The provision of food to our pets is an expression of affection and a symbol of the duty of care we owe to them. One thing I’ve learned from interactions on forums and Facebook groups is that you cannot ever underestimate the relationship between pets and their people. Kids, sure. But pets? Just don’t go down that path. People often react fiercely (and illogically) when it comes to discussing food for their pets. At one time, the majority of dogs and cats were fed commercially prepared foods without question. However, some pet owners have moved away from feeding commercial pet food products exclusively and more are asking questions and looking for alternatives. The 2007 pet food recall due to melamine contamination brought the issue of pet food safety to the forefront. As in any market-driven economy, there are many more alternative diets and food products available, but the dietary appropriateness, adequacy, and safety may be in question with alternative diets, especially those consisting primarily of raw meat.

BARF stands for Bones and Raw Food or Biologically Appropriate Raw Food diet. It’s also occasionally referred to as RMBD (raw meat based diet). These diets usually include uncooked ingredients derived from domesticated or wild-caught food animal species and that are fed to dogs or cats. These ingredients can include skeletal muscles, internal organs, and bones from mammals, fish, or poultry as well as uncooked eggs. The vast majority of pet foods are by-products of the human food industry.

Dogs Are Not Wolves

Adherents of BARF tell us that raw meat is an appropriate diet to feed our dogs because dogs are essentially wolves. Raw meat and bones are the major part of a wolf’s diet, along with offal such as organs, eggs, decaying material, birds with feathers – whatever they eat is obviously going to be raw. They may eat vegetables or foods left behind by humans if they are particularly hungry, but for the most part, the vegetables they consume come from the guts of the prey animals they eat. Taxonomically and phylogenetically, dogs, like wolves, are carnivores and they all belong to the order Carnivora, aptly named since most members are primarily meat consumers. Functionally however, dogs are scavenging carnivores, not obligate carnivores, and they can usually adapt quite easily to an omnivorous diet regardless of their taxonomic classification. Therefore, we could say that the concept of “evolutionary nutrition” ignores the simple fact that taxonomy and phylogeny are not necessarily destiny, nor do they predict the precise details of a species’ nutritional needs. A good example of this exception is with the giant panda, who, while possessing the same digestive system of a carnivore, is almost completely herbivorous.

The domestic dog is the most phenotypically diverse mammal on earth. Domestic dogs branched off from their wolf ancestor approximately 100,000 years ago, and artificial selection has shaped modern breeds and has been an important source of the extreme phenotypic variation present in modern-day dogs. Since then numerous anatomic and behavioural changes that have occurred as a result of dogs living with humans and sharing our food. In contrast, the modern wolf has not been exposed to 100,000 years of eating alongside humans, and therefore its nutritional needs were not altered in the same manner as dogs. To expect these different species to have the same nutritional needs is simply not substantiated via biology.

Domestic dogs exhibit many features of neoteny, which has occurred as a result of humans selecting dogs for “cute” characteristics such as large eyes, soft hair, rounder heads, smaller teeth, and floppy rather than upright ears. So their refined anatomical structures are significantly different from wolves. Of course, even if BARF advocates could demonstrate that dogs were the modern day equivalent to wolves in terms of diet, the evolutionary nutrition argument would still fail because at its heart it is nothing but a form of the naturalistic fallacy. It’s a fallacy that just because wolves get their nutrition from carcasses that raw meat is the appropriate source of food for domesticated dogs – “natural” cannot necessarily be equated with “optimal.”

Unsubstantiated Claims….

BARF advocates claim that dogs have better health and less disease on these diets. Claims are even made that bones boost the immune system. Proponents of raw meat diets also claim that other benefits consist of improvement in coat and skin; elimination of breath and fecal odour; improvement in energy, behaviour, and a reduction in medical conditions including allergies, arthritis, pancreatitis, dental disease, and oddly enough, parasitism. Once again, anecdotes are not evidence, and these claimed health benefits have not undergone scientific evaluation. Dr. Mark Crislip, an infectious disease specialist with a very listenable podcast on iTunes, repeatedly reminds his listeners that the phrase “in my experience” is a dangerous expression!

Sometimes the commercial pet food industry is demonized in the same way that the Complementary Alternative Medicine industry (CAM) attacks Big Pharma. CAM veterinarians frequently attack traditional veterinary medicine with often irrational and unfounded criticisms. In addition to suggesting that conventional medicine is misguided and ineffective, CAM practitioners frequently assert that it is actively harmful, particularly vaccines and medicines. The same arguments and logical fallacies are often used to promote alternative feeding methods. For instance, homeopathic veterinarian Dr. Richard Pitcairn, who claims medicine is “unscientific,” and is obsessed with “toxins,” describes a mystical “life energy” that dogs cannot, in his opinion, get from processed food. Why is it that so many followers of homeopathy claim to be able to detect “life energy” that other people cannot? And I wonder if Pitcairn eats all his food raw as well? Dr. Pitcairn also claims that euthanized cats and dogs are routinely disposed of by veterinary hospitals to be recycled into pet food. This simply isn’t true. Veterinarian Dr. Dan Scott claims that commercial pet foods are responsible for the majority of pet diseases. So where is the proof? Where is the evidence of widespread disease that can be attributed to commercial pet food? Scott doesn’t seem to provide any but his followers are expected to take him at his word. There is no evidence that manufactured pet foods cause disease (obviously this precludes foods made in China, which have caused the death of thousands of pets). Dr. Tom Lonsdale (who was kicked out of the Australian Veterinary Association) claims that fake animal rights activists conspire with veterinarians and the commercial food industry to keep pet owners in the dark about “junk food” for pets.

Benefits Vs. Risks

There is some evidence that raw diets afforded higher levels of protein for certain species of exotic and domesticated animals, but that this is offset by other specific risks. Furthermore, nutrients that are lost during the cooking process for manufactured pet foods are supplemented to account for this.

The FDA has warned against feeding bones to dogs, as they can cause fractured teeth, intestinal perforations leading to peritonitis, and obstipation/impactions in the GI tract. Dogs can die without veterinary intervention if they cannot pass an obstruction without help. And if a dog fractures a tooth, it is likely to be a “chewing tooth” such as a large molar and not a small pre-molar. Softer bones are also great for lodging themselves in the narrow spaces between teeth and becoming food for anaerobic bacteria, thus generating periodontal disease. Cats can also choke on bones,  particularly chicken bones.

There is mounting evidence of other potential harm as a result of BARF feeding. Renal failure is a common cause of death in older dogs and cats – protein is poorly metabolized by dogs with kidney failure. Most veterinary hospitals are unable to detect kidney failure until it is quite advanced, and in any case it is irreversible. Proponents of raw diets seem to ignore this common cause of death in older pets. Commercial pet foods are available for animals with renal failure or allergies to certain proteins.

We cook meat for a reason and most of us know that we have to take precautions when handling it. While dogs and cats can usually handle a larger burden of microbes in their food than humans, BARF feeders have no way of knowing whether their pets are acquiring parasites or infectious disease. The digestive systems of dogs and cats are short, acidic, and handle bacteria well. This is why they are not susceptible to Salmonella, parasites, or E.coli from tainted meat as humans are. Humans have very long digestive tracks which allow food to linger for 24 hours or more, thus allowing more time for parasites to get into their bloodstreams. The majority of dogs and cats with E.coli or Salmonella organisms may not even exhibit symptoms.

Dogs and cats will periodically shed parasites and this is a risk to children and owners who have compromised immune systems. In one study, approximately half the dogs fed a single meal of contaminated raw food shed Salmonella in their feces for up to 7 days  Other bacteria that have been found in raw meat diets include E. coli and Clostridium. Dogs also shed Salmonella in their saliva, so if your dog eats raw foods with Salmonella bacteria and then licks your hands or face, the dog may be transferring bacteria to you.

In a large study conducted on 200 hundred healthy therapy dogs from Ontario and Alberta, some of whom were fed raw meat during the year, it was observed that the incidence rate of Salmonella shedding in the raw meat-fed dogs was 0.61 cases/dog-year, compared with 0.08 cases/dog-year in dogs that were not fed raw meat. Raw meat consumption was also significantly associated with shedding E. coli. One of the conclusions of the study was that dogs fed raw meat may be a risk to humans whose immune systems are not fully functioning, and should be excluded from AAI (animal assisted intervention) programmes, particularly when the programmes involve interaction with humans at high risk of infection.

An article from Phys.org entitled “Raw Meat May Not Be Enough for Cats or Tigers” found that:

“… raw meat diets met many nutrient requirements for (captive wild) cats, but there were some gaps. None of the diets contained the recommended levels of linoleic acid, the horsemeat did not provide the levels of arachidonic acid recommended for kittens, gestating females and lactating females.”

These same researchers were:

“…a bit wary” of pet owners feeding homemade raw diets. … pet owners risk exposing (domestic) cats to increased pathogens and nutrient imbalances. Pet owners often feed trimmed cuts of meat. These cuts lack fat, which is crucial in feline diets. According to the researchers, if pet owners feed raw meat diets, they will likely have to supplement it with other nutrients, including appropriate sources of fat and essential fatty acids. A high-protein diet can also change the types of microbes in the gut. The researchers write that increased protein fermentation in the bowel may lead to more “odiferous” feces, depending on the digestibility of the protein.”

Another study found that dogs fed raw chicken may be a source of contamination.

There don’t appear to be any measurable demonstrated benefits from a BARF diet, only theoretical benefits that are often based on erroneous assumptions or anecdotal observations, while there are documented risks, potential nutritional inadequacy and possible injury from raw bones. On the other hand, cooking food comes with advantages. Basically, cooking is just a method of doing some of the digesting beforehand. Ruminants ferment their food in their stomachs, and we cook ours. Do people eat raw eggs and raw meat? Yes, we do, but just because we occasionally eat raw meat doesn’t mean that it’s a particularly good idea.

The most common forms of commercial BARF diets consist of are fresh, frozen, and freeze-dried meats intended to be nutritionally complete and balanced. These diets are often formulated to meet values listed in the AAFCO Dog or Cat Food Nutrient Profiles. However, some of these foods may be labelled as intended for intermittent or supplemental feeding only, which means that they are not nutritionally complete and balanced. Traditional pet food manufacturers are regulated in that they must use ingredients that are “Generally Recognized As Safe” or GRAS. At the very minimum, canned food must contain minimum percentages of crude fat and crude protein. Commercial feeds often provide ingredients that BARF diets cannot possibly provide, such as foods for dogs or cats with renal failure and allergies. If you feed dry food it is very easily measured for consistent feeding and dogs and cats usually have solid poops that are easy to pick up. Dry food cleans teeth better than either soft or BARF food too. I wouldn’t give a dog rawhide either, because I have never been able to verify the country of origin for these products – for all I know they may originate in China as well.

The key factor is risk reduction and BARF is not exactly a low risk diet given the potential for contamination for both pets and humans. Given that dogs and cats do get foodborne illnesses there is all the more reason to cook their food beforehand. When I do give my dog and cat meat instead of commercial food, it is always pre-cooked.