Fact #1: Animals need nutrients not ingredients.
This is one fact that is guaranteed to stir the home-prepared meal crusaders into a rapid froth. Proponents of preparing your own food for Maggie or Mittens claim that dogs and cats need fresh whole ingredients and anything less is tantamount to negligence. Yes, feeding (and eating) a less processed diet is what our companion animals’ (and our) digestive systems have adapted to handle over tens of thousands (actually millions) of years, but that doesn’t mean that if we take a few digestive short-cuts by feeding a diet containing purified essential nutrients (meaning the nutrients are being provided in their basic structure as opposed to bound in a food) that the dog or cat can’t do well long term. There are dogs and cats (and people, too) living with severe forms of gastrointestinal disease that prevent them from eating foods in any solid form, but they survive and thrive when fed “elemental” (i.e., purified) diets as an oral liquid or even as intravenous nutritional support. Nature has gifted us quite a bit of flexibility when it comes to the types of foods and nutrients our companion animals (and people) can handle.
The true fate of the diet, irrespective of form, is that the ingredients will be broken down into their chemical composition for absorption in the body. Proteins are enzymatically degraded into their single amino acid building blocks and absorbed by specific amino acid transports; fats are broken down into their individual fatty acids and repackaged in gut before absorption across the cell membrane; and carbohydrates are enzymatically broken into their individual sugar subunits and absorbed by specific single sugar transports. Simple compounds are easy to digest and complex compounds require more digestive action, whether that “digestion” is happening in the animal or in a laboratory. The best diet will dependent on the needs of the individual.
Fact #2: Not all supplements are created equally.
One of my two biggest concerns with pop-culture recipes for dogs and cats is the complete disregard for essential vitamins and mineral. I’ve seen recommendations to use children’s chewable multivitamins in recipes for dogs and cats (which you should not do as most of them contain xylitol, a known toxin for dogs and cats) or to use any general purpose adult multivitamin/multimineral, if one is recommended at all. When I develop a home-prepared diet formulation, I am very specific with the type and sometimes the brand of supplements that I include. Not because I am getting any financial benefit from these human over-the-counter supplements, but because they are made by reputable manufacturers, are widely available for purchase, use forms of essential nutrients that are well absorbed by animals, and are free from harmful ingredients or toxic levels of certain nutrients. Human supplements are developed to fill common human nutrient deficiencies and some of these nutrients, like vitamin D, can be provided at toxic levels to dogs and cats. Potentially toxic ingredients aside, there is a huge variation in what and how much of each nutrient is included in supplements intended for human consumption and they won’t all work in home-prepared diets for dogs and cats.
Don’t even get me started on veterinary supplements. There are only three that I have found that will work marginally well to balance home-prepared diets, and none of them are available at your local health food or pet supply store. The vast majority of canine or feline multivitamin/multimineral supplements that you will find available over-the-counter or through your veterinarian are actually intended to be added to already complete and balanced commercial foods, not to fill deficiencies in home-prepared ones.
Fact #3: Not all proteins (or oil or carbohydrates) provide the same nutrients.
The second big concern I have with pop-culture recipes is that they often make big sweeping ingredient recommendations without any consideration for the nutrient variation in those ingredients or the nutrient requirements of dogs and cats. I can’t tell you how many recipes I’ve seen that advocate substituting protein sources with dramatically different fat (and calorie) contents or call for adding one of a list of different oils, none of which provide enough essential fatty acids. An ounce of cooked chicken thigh and an ounce of cooked salmon may be comparable in calories (about 50 Calories each), but an ounce of browned and fat drained 80% lean ground beef has 50% more (77 Calorie) while an ounce of low-fat cottage cheese has 50% less (25 Calories). Olive oil is high in the non-essential omega-9 fatty acid oleic acid (80% by weight), with a very low concentration of the essential omega-6 fatty acid, linoleic acid (9% by weight); coconut oil is a medium-chain triglyceride with almost no linoleic acid content (1% by weight). Olive or coconut oil (or borage, hemp or chia seed oils for that matter) do not meet the canine or feline essential fatty acid requirements and should not be relied on as the sole source of fatty acids in the diet.
You can absolutely use different protein sources on a rotational basis for a healthy dog or cat and, assuming that the overall essential fatty acid intake for the week remains adequate, you can alternate oil sources, too. But unless you understand the requirements of the individual dog or cat AND the nutritional properties of what is being fed, inadvertent over or under feeding or feeding of an unbalanced diet can occur.
I want to help you keep your companion dogs and cats happy and healthy for years to come.
Lisa Weeth, DVM, MRCVS, DACVN