Not All Protein is Created Equal
Protein quality is extremely variable. There are highly assimilable and digestible proteins (proteins your pet’s body can easily absorb and make use of), and there are proteins that are wholly indigestible. For example beaks, feet, hides, tails and snouts are 100 percent protein, but all 100 percent is indigestible.
All protein has a biologic value, which is its usable amino acid content. Eggs have the highest biologic value at 100 percent. Fish is a close second at 92 percent. Feathers, as you might guess, have zero biologic value. They are all protein, but they are neither digestible nor assimilable.
Now there are some foods high in protein that are not species-appropriate for dogs and cats. Soy is a good example, with a biologic value of 67 percent. Many popular pet foods contain soy as a protein source, as well as corn. This is an inexpensive way for pet food manufacturers to increase protein content on the guaranteed analysis printed on the label.
But because soy and corn are not species-appropriate, I don’t recommend you feed pet foods that contain it.
Unfortunately, digestion and assimilation are not measured for dog and cat foods, so manufacturers can include other types of protein that have no biologic value for the species of animal eating it (this is also why melamine was added to pet foods that killed thousands of animals). You can be fooled into thinking you’re feeding a higher-protein food, when the reality is the protein isn’t biologically appropriate for your pet.
Rendered Pet Food – The Worst of the Worst
Asking a dog’s or cat’s liver and kidneys to process low-quality, indigestible protein over a long period of time is exactly how protein in pet food got a bad rap.
In the 1940s and 1950s, there were really no high quality commercial pet foods on the market. Formulas at that time contained 100 percent run-off or rendered byproducts from the human food industry.
Pet food companies took all the pieces and parts left over at slaughterhouses, mixed them with discarded vegetables and grains not fit for human consumption, added a synthetic vitamin-mineral supplement, and called it pet food.
While there was a fair amount of protein in pet food back then, the quality was just terrible. Because the protein was so difficult for dogs and cats to digest, kidney and liver function suffered.
That’s why veterinarians around the mid-century mark started recommending lower protein senior pet foods. Senior formulas came into being because of the terrible quality of dog and cat foods on the market.
That’s why I strongly recommend if you’re feeding a rendered pet food formula – food that contains protein that is not digestible or assimilable – that you reduce the amount of protein you’re feeding. Your pet’s organs can’t process a steady diet of terrible quality protein.
Your Pet’s Protein Requirement Increases with Age
The good news is the quality of pet food has increased dramatically in the last 30 to 40 years.
And in 1992 Dr. Delmar Finco, a veterinary nutritionist, discovered protein requirements actually increase as pets age. Even in animals with kidney failure, restricting protein didn’t improve their health or longevity.
In fact, Dr. Finco’s research proved cats on low protein diets developed hypoproteinemia. They had muscle wasting, became catabolic, and lost weight. The more protein was restricted, the more ill these kitties became. Fortunately, Dr. Finco discovered it was the level of phosphorus in foods, not necessarily the amount of protein that exacerbated kidney disease.
Since that research was published, veterinary recommendations have changed. What we’re recommending for animals struggling with under-functioning kidneys and livers is that you feed really good quality protein that is highly digestible and assimilable.
We also recommend you restrict phosphorus in the diet, but not necessarily protein.
We know that cats and dogs, as carnivores, require lots of high quality protein not only to maintain good organ and immune function, but also to maintain healthy muscle mass as they go through life and the aging process.
Whole, Raw, Natural Foods Are Best
Some foods are metabolically stressful and some create low metabolic stress on your dog or cat.
Foods that generate the least amount of metabolic stress are whole, raw, unprocessed, and in their natural form. Foods that have not been dehydrated or processed are the most assimilable for your pet’s body.
These foods are biologically appropriate. All the moisture in the food remains in the food.
Foods that have been dehydrated, extruded or processed can have drastically depleted moisture content. It can drop from 70 percent down to as low as 12 percent, in fact. Your pet’s kidneys and liver become stressed due to chronic low-grade dehydration.
Dogs and especially kitties must drink lots of water to rehydrate their bodies after eating dehydrated food. This situation can stress organs that are congenitally defective or are experiencing age-related changes.
I recommend serving your pet food in its natural state to provide needed moisture, and to insure the highest level of biologic assimilation and digestion.
Appropriate Food for the Species
‘Species-appropriate’ for your dog or cat means a food that is high in protein in its natural form, and low in grain content. Your pet is a carnivore – dogs are scavenging carnivores and cats are obligate carnivores. Carnivores need to eat animal protein and fat in order to be healthy.
Foods that cause metabolic stress – those that are highly processed and/or dehydrated – are not species-appropriate. Take high-protein kibble, for example.
In recognition that dogs and cats do better on higher protein, low-grain diets, over the last 15 years there’s been movement by veterinarians and pet food companies toward formulas containing more protein and fewer carbohydrates.
I can certainly agree with that, except in situations where the food is not biologically, species-appropriate.
Pets eating a protein-based diet do just fine as long as it contains 70 to 80 percent moisture. But when you take moisture out of high protein foods, they become difficult for your pet’s body to process because of the dehydration factor. That’s why I prefer foods that are unprocessed and therefore not dehydrated.
Feed Your Pet Exactly What His Body Needs
When you’re contemplating the issue of protein for your dog or cat, it’s important to recognize you can’t save kidney function with a low protein diet.
Your carnivorous companion needs protein to be healthy throughout life, and especially as she deals with the muscle wasting that comes with the aging process.
I recommend you feed your pet food in its natural form, full of moisture and unprocessed. This will provide the best species-appropriate nourishment for your dog or cat, with an optimum level of digestion and assimilation.