Sunday, May 16, 2010

False Assumptions, Bad Advice About Pet Food

Marion Nestle is a human nutritionist, who endorses fresh, whole foods for people and criticizes processed junk foods.  Her advice to people is to eat less and to eat a wide variety of minimally processed foods.
Her advice to pet owners is much less healthy and helpful.   For this book, Nestle teamed up with Malden Nesheim, a veterinary nutritionist by training.  He seems to have lead Nestle woefully astray.  They endorse starchy kibbles and canned mush as pet food – the commercial pet foods that cause rampant periodontal disease, stress pets’ immune systems, and leave them victims of myriad chronic diseases.   It is puzzling that an advocate of fresh whole foods for people would not make similar, species-appropriate recommendations for their pets.
The vast misinformation in this book is based on a false assumption: That dogs, like humans, are omnivores.  No references are provided to support this erroneous belief, because there aren’t any.  All the scholarship of the last 10 years shows that dogs are carnivores. 
To back up their false assumption, they assert that dogs’ intestinal track is long like human omnivores.  This is factually incorrect.  Both dogs’ and cats’ small intestines are 2.5 times as long as their bodies.  Humans’ small intestines are 10 times as long as their height.  Long intestines digest vegetables and cereals slowly and well.  Carnivores’ short and highly acidic intestinal tracks digest meats and bones fast and pass remaining matter out as poop – great piles of malodorous poop from grain-fed dogs and cats.
The authors assert that dogs “descended” recently (in evolutionary time) from wolves.  They fail to acknowledge that dogs are currently classified as a sub-species of wolf.  Dogs are wolves, not a separate species.  They fail to cite the last decade of genetic research that demonstrates the wolf-identity of domestic dogs.  Despite the many human-designed changes in dogs’ sizes and shapes, their digestive and immune systems are species wolf. 
As we all know, wolves are carnivores, whose natural diet consists of whole prey.  Dogs’/wolves’ natural diet is whole prey, as demonstrated repeatedly in studies of feral dogs  Domestic canines, that are abandoned and live in wild packs all over the world, prey on small animals.  Feral dogs never graze in fields of corn or eat vegetables or garbage, unless no animal prey is available.  Dogs and wolves evolved to eat raw meats and bones, not grains and vegetables.   Wolves/dogs do not cook their meat and meaty bones.  Cooking alters the nutritional value of foods and causes bones to splinter.  Raw bones do not splinter.   Dogs and wolves evolved to eat whole prey -- or its convenient form, raw-meaty-bones.
In times of famine, wolves and dogs can subsist briefly on carbohydrates, a convenient fact the authors use to endorse cooked grains and vegetable diets for domestic carnivores.  Most pet owners do not aim to feed their beloved pets a starvation diet.  If pet owners were told the truth about carnivorous pets, many would choose to feed their pets raw meats and meaty bones.  The authors’ false assumption about the very nature of dogs renders their dietary advice misleading at best. 
Cats do not fare much better than dogs in this book.  Although the authors realize that cats are carnivores, that in the wild feed entirely on whole prey, they accept the pet-food industry line that cats can be fed on grains and artificial nutrients.  That carnivorous cats can subsist on a totally inappropriate diet of cooked grains and vegetables is a view endorsed by veterinarians, whose livelihood depends materially on pet-food sales.  Cats fed high-carbohydrate diets often develop urinary tract stones, irritable bowel syndrome, diabetes, and other chronic disorders from stressed digestive and immune systems. 
One interesting chapter is an attack on corruption in veterinary training, nutritional research, and practice.   Global pet-food companies, notably Mars, Nestle-Purina, Proctor & Gamble, Colgate-Palmolive, and Del Monte, fund and control small animal nutrition in the veterinary profession.  By supporting student training, providing employees to teach nutrition courses, funding “nutrition research”, and contributing substantial income to practicing vets, these giant food companies buy veterinary endorsement of their junk foods that do irreparable harm to pets’ health. 
Nestle and Nesheim call for reform of the veterinary profession and establishment of independent teaching, research, and practice.  Unlike medicine, there seems to be little concern among veterinary schools or professional associations about undue commercial influence on their profession.  Whereas revelations of drug-company influence on medical education, research, and practice provoked some reforms in medicine, little unrest is evidenced among vets, who know how dependent they are on pet-food company largesse.

The authors' recognition that nutritional information about pets is tightly controlled by pet-food companies, to their enormous profit, does not jar them sufficiently to reject the lies they were fed about appropriate diets for dogs and cats.  For scholars, who cite many references to trivial details, their blindness to their most basic (and false) assumption about pets' digestive systems is startling.  
Although the authors conclude that home-cooked and raw diets can be safe and nutritionally appropriate, they do not favor species-appropriate diets over commercial junk foods.   Neither dogs nor cats can safely eat cooked starches daily year in and year out.  The authors express faith in AAFCO’s brief feeding trials on a few animals to endorse feeding a monotonous, commercial diet for pets’ lifetimes.  Six months of feeding a concocted diet to 8 animals, 2 of which may die during the feeding trial, support an AAFCO recommendation of “complete and balanced” food for pets’ lifetimes.  How illogical and unscientific is that?
 In a few chapters, Nestle’s familiar theme of diet variety is voiced.  Variety of foods assures people’s nutritional needs are met.  Variety of meats and meaty bones, and occasional leftovers, also assures that pets’ nutritional needs are met.    I agree that variety of foods is both healthy and pleasant for both people and pets, with one major caveat:  Dogs and cats are not omnivores.  They do not need a variety of grains and vegetables in their diet, as humans do.
Two other Nestle themes are safety and the interconnectedness of human and animal food supplies.   On these topics, Nestle is an expert with valuable and disturbing information.  Her earlier book on pet food safety reviewed the massive 2007 pet food recall for deliberate melamine adulteration.  The same contaminated wheat gluten was fed to farmed fish and poultry intended for US human consumption and put into baby formula in China, with disastrous results.  She points to frequent recalls of both human and pet foods for dangerous contamination and the FDA’s inability to prevent or respond effectively to safety issues in the food supply. 
Most of the later book deals with pet diets, however.  This is a deeply disappointing book.  I admire Marion Nestle’s approach to human food.  She was badly misled about the diet carnivorous pets need to thrive. One wonders if the authors are otherwise motivated to keep the peace with food-industry giants, the same global companies that make pet foods from human food wastes?  Both authors are professors of nutrition at universities.  Their careers are based on food.  Global food production, processing, and distribution are controlled by the same companies that make pet foods.  Getting on the wrong side of Mars and Nestle (the company) by rejecting their junk pet foods is probably not a wise career move.  Truth is another matter.

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