Raw Diets – Good or Just Gross?
When we first decided to write this blog, I asked for topics of interest, and several people requested information on raw diets. Now, I will be honest that I have a really strong opinion on this subject, but I want to present you with data to let you draw your own conclusion before sharing my opinion.
First, let me tell you that there are two categories of raw meat-based diets (RMBDs). The categories are commercial and home-prepared. Of the commercial diets, there are four types – fresh, frozen, freeze-dried, and carbohydrate pre-mixes to which a raw meat protein source is added. There are several highly publicized home-prepared RMBDs, including BARF (originally defined as bones and raw food, but currently referred to as biologically appropriate raw food), the Ultimate Diet, and the Volhard Diet. These diets are often formulated using a rotation of ingredients with the assumption that rotating will ultimately provide all essential amino acids, fatty acids, vitamins, and minerals.
Another variety of raw or freeze-dried pet treats should also be briefly mentioned in this discussion. These products include rawhides, pig ears, cattle hooves, bully and pizzle sticks, along with freeze-dried liver and lung.
Proponents of RMBDs report numerous health benefits, including healthy teeth and gums, healthy skin and coat, improved immune system, improved digestion, improved mobility, decreased allergies, and improved behavior. They claim that these benefits are proven, but unfortunately, there are no scientific studies showing these benefits.
An owner motivation for feeding RMBDs is that dogs and cats in the wild eat a raw diet. Although
cats have remained obligate carnivores during domestication, dogs have adapted to a more omnivorous diet, and both dogs and cats are able to digest many nutrients from plant-based ingredients. Through natural selection, dogs and wolves have 36 regions of their genomes that differ, and 10 of these regions play a role in starch digestion and fat metabolism. These differences constituted a critical step in the domestication of the dog. So, even if the diet eaten by a wild dog or cat, whose lifespan was short, was optimal for their survival and reproduction, the same diet may not be optimal for a domesticated dog or cat, whose lifespan is expected to be long.
As mentioned previously, one of the reported benefits of RMBDs is improved digestion. One of the arguments for improved digestion in RMBDs is that cooking destroys enzymes necessary for digestion. However, most dogs and cats do not require the addition of enzymes to their diets. Another argument for improved digestion is decreased fecal matter, and RMBDs have been found to result in decreased fecal output.
Improved immune function is a reported benefit. In one study, cats fed an RMBD for 10 weeks had an increase in their lymphocyte count and immunoglobulin production, but they were also found to shed Salmonella spp. in their feces. In fact, fecal shedding can be seen for 7 days following ingestion of one contaminated RMBD.
Now, we will look at some of the risks of feeding raw diets. Many of the raw diets, including commercially available and home-prepared RMBDs, are not nutritionally balanced. Some nutrients are deficient, and others are present in excess. These imbalances have led to serious medical conditions such as rickets and hyperthyroidism. Even if the diet is formulated to meet AAFCO (Association of American Feed Control Officials) guidelines for a particular life stage such as growth, reproduction, or maintenance, the diet is not necessarily appropriate for all life stages.
Bacterial contamination of RMBDs is a huge safety risk, and contamination with Salmonella has received the most attention. The prevalence rate for contamination of commercial RMBDs ranges from 20-48%, and rates of contamination for home-prepared diets ranges from 21-44%. Other organisms that have been found as contaminants of RMBDs include E. coli, Clostridium, Campylobacter, and Listeria. Although listeriosis is rare, it causes serious disease with a mortality rate of 20-30%. Parasites, in particular Toxoplasma gondii, can be acquired from raw or undercooked meat, and this organism poses the biggest health risks to immunocompromised individuals, pregnant women and their unborn babies.
Some RMBD manufacturers use high-pressure pasteurization, freezing, or freeze-drying to kill bacteria. These processes can reduce the number of many pathogens, but many bacteria can easily survive.
Dogs and cats can shed organisms even if they are not showing any clinical signs of illness, and this can contaminate the environment. This poses the greatest health risk to children, elderly, pregnant, and immunocompromised individuals.
Bones pose a particular health risk to pets eating RMBDs. Raw bones carry the same pathogens as cooked bones. Bone chewing can fracture teeth. Small or splintered bones can obstruct the esophagus, stomach, or intestine, and this can lead to perforation of the gut, which causes severe infection.
To wrap this up, RMBDs are generally palatable diets. They carry a risk of bacterial and parasitic contamination, which can affect pets and humans who come in contact with them. There can be potential legal implications because of environmental contamination. The commercially available RMBDs should be nutritionally adequate for certain life stages if formulated according to AAFCO guidelines, but not all life stage formulations are appropriate for all pets. Home-prepared RMBDs are much more likely to have nutritional deficiencies or excesses. Pig ears, rawhides, bully sticks, and human food used as a treat or as a means of administering medication, may carry the same risks as other RMBDs even though they are not the primary diet fed.
NOW IT IS TIME FOR MY VERY STRONG OPINION - cooked commercially prepared foods are the most appropriate and safest diets to feed our pets! The American Veterinary Medical Association, American Animal Hospital Association, and Canadian Veterinary Medical Association have adopted position statements discouraging the feeding of raw or undercooked animal-source proteins in dog and cat diets. The Delta Society’s Pet Partner Program even adopted a policy that precludes animals eating RMBDs from participating in their therapy programs.
If owners wish to feed a home-prepared diet, a board-certified veterinary nutritionist can be consulted to formulate a safe, nutritionally balanced diet. When choosing the cooked, commercially prepared diet, several important things should be considered. The company making the diet should employ at least one qualified nutritionist. The manufacturer should test the diets in AAFCO feeding trials. The manufacturer should own the plants where the diet is manufactured, and they should practice strict quality control. They should be able to provide a complete nutrient analysis and number of calories on a weight basis. The manufacturer should conduct and publish research in peer-reviewed journals.
Good eats!
References:
1) American Animal Hospital Association website. Raw protein diet position statement. Available at www.aahanet.org/Library/Raw_Rood_Diet.aspx.
2) AVMA website. Raw or undercooked animal-source protein in cat and dog diets. Available at:
3) Canadian Veterinary Medical Association website: CVMA policy on raw or undercooked animal- source protein in cat and dog diets. Available at: www.cvma.net/doc.asp?id=21753
4) Pet Partners website. Raw protein diet policy. Available at: www.petpartners.org/rawdiet.
