Pet Nutrition & Raw Food Diets
Undoubtedly, if you are a pet owner you have encountered information about raw food diets. Advocates of these diets tend to be very passionate about this practice of feeding raw foods. If questioned as to why they choose to feed a raw diet, they often quote information from the internet and believe that it is scientifically sound.
The internet is filled with web sites that discredit commercial pet foods and often do so in an unethical and tabloid fashion. Many of these web sites seem to be very convincing, and it is understandable how some pet owners could be influenced by them. There are also numerous anecdotal testimonials of pets whose lives were saved by feeding a raw diet. Unfortunately, these same sites fail to include patients who were harmed by raw diets. Efforts to educate clients on the risks of feeding raw diets are sometimes met with resistance.
This article will discuss some of the common myths that people have about raw diets and commercial pet foods and will present information to help educate clients about these diets.
Claim: Raw diets are the evolutionary diet of dogs and cats
Raw diets are the evolutionary diet of all creatures, including humans. Archeological evidence of fire and cooking dates back only ~800,000 years, although some argue biological evidence shows that fire dates back to ~1.8 million years. Nonetheless, humans did not always cook their food, yet few, if any of us, would want to go back to eating only raw food, especially meat.
Claim: Cooking destroys the nutritional value of food
There are as many truths as there are exceptions to this statement. It is true that overheating protein can lead to reduced protein digestibility, as well as amino acid destruction. However, these are not the kinds of temperatures that are used to manufacture pet foods. The temperatures that most pet foods are cooked at are similar to the temperatures we use to cook our own food. If cooking completely destroyed the nutritional value of protein, then why isn't there widespread protein malnutrition in humans in this country since most of us cook our meat? In a study by Claudia Kirk, cats were fed identical diets, except one was heat processed and one was a frozen (raw) diet. Protein digestibility decreased by ~5-7% in the cooked food compared to the raw diet, but carbohydrate and fat digestibility improved with the cooked diet. It is well known that antioxidants are more available in cooked foods, such as tomatoes or carrots, compared to the same foods that are uncooked.
Although there are numerous health claims for these diets, there is no scientifically proven information, only testimonials. There are several serious potential drawbacks to these diets:
- Nutritional imbalances In a recent study, raw food diets were found to have one or more of the following: an unbalanced calcium-to-phosphorous ratio, increased vitamin D levels, decreased potassium content, decreased manganese content, decreased or increased zinc content, decreased iron content, and increased vitamin E content.
- Intestinal foreign bodies There are reports of esophageal foreign body and obstruction due to ingestion of bones.
- Infectious agents Raw foods, especially meat, may contain infectious agents, many of which are zoonotic and can affect humans. Escherichia coli O147:H7, Yersinia enterocolitica, Listeria monocytogenes, Salmonella spp, Proteus spp, and Pseudomonas spp. All of these have been cultured from homemade diets or isolate in the feces of the pets that ate them. Clostridium difficile has been isolated from feces was cultured from one homemade raw food diet. In addition to bacteria, raw foods may contain Toxoplasmosis, trichinella, and other parasites including Echinococcus. These may pose health hazards to animals as well as to the humans who are preparing the food. One argument given by raw food proponents is that the bacteria do not cause disease in dogs or cats. One concern that is often overlooked is the role of dogs and cats to be carriers of zoonotic infectious agents and that while the pet may not show symptoms, they can spread the disease through their feces to other pets and people.
What Should I feed My Pet?
Good diets include the Purina Veterinary and Pro Plan diets, Royal Canin diets, and Hills brand diets. Pet foods have come a long way in recent years, and many are great, but we recommend staying away from the “grocery store” or “warehouse” diets and raw food diets. Unfortunately "cheap" pet food equals cheap ingredients and many of these diets are more like junk food and just do not include quality ingredients which are vital to nutrition. Meat and grains from these cheaply made foods can also come from overseas and have the potential to contain harmful things.
Raw food diets are available commercially or as recipes you prepare at home. Commercially prepared raw food diets have been thought to be nutritionally complete and safe as they use methods of killing bacteria in the dairy and meat products included in these diets, however a recent study by the FDA's Center for Veterinary Medicine has shown otherwise. 30% of the 197 commercially available raw food diets tested were positive for Salmonella or Listeria. Homemade raw diets are typically not nutritionally sound and tend to be protein heavy, causing problems with bone growth, and organ function later in life. Other concerns, as previously discussed, include health risks from bones such as tooth fracture, tooth loss and overall wear, and esophageal/intestinal blockage or rupture.
Foodborne illness from raw meats is perhaps the greatest concern due to the zoonotic potential of bacteria such as salmonella, E-coli, and listeria. The safe handling of these foods is critical but do not ignore the risk to your pet that consumes them.
Regardless of your choice, be sure to use a diet formulated for your dog's needs or as recommended by your veterinarian.
Resources: The ACVN (http://www.acvn.org/) Angell Memorial Michigan State Ohio State Tufts University UC Davis http://www.ucvmc-sd.vetmed.ucdavis.edu/nutrition.cfm University of Missouri: University of Tennessee firstname.lastname@example.org