Protein is arguably the most important component of your dog’s or cat’s diet, and
it is often the most hotly debated aspect of pet foods. What is the best source
of protein for dogs? For cats? How much protein should be in the diet and can you
feed too much of it? How can you tell which foods have better protein sources? What
about pets with food allergies? It’s a lot to ponder and leaves many guardians frustrated
and confused about which of the seemingly endless variety of pet foods they should
feed their companion.
During the last 5 to 10 years the rapid growth of the natural pet foods market has
significantly expanded the viable feeding options for responsible pet owners, but
having more choices does not generally make a decision easier. On the contrary,
the more options available, the more difficult the choice becomes. In this article,
we will help make that decision a little easier for you by discussing one of the
key factors influencing pet food evaluation – proteins.
Evaluating Protein Sources
A protein molecule is made up of chains of amino acids. Different sources of protein
contain different combinations of the 22 or so amino acids. Of these amino acids,
10 are considered “essential” amino acids - because dogs and cats cannot make them
on their own, these particular amino acids must be present in the diet. When a dog
or cat consumes protein, it gets broken down during the digestive process into its
individual amino acids. Those amino acids are then reassembled into the building
blocks of body tissues such as skin, hair, muscles, and organs. Amino acids are
also utilized to produce metabolic enzymes that are necessary for many bodily functions
including the regulation of antibodies within the immune system and the transfer
of nerve impulses.
Protein from animal sources contains the most complete and most easily digested
and assimilated amino acids for dogs and cats. Animal proteins are not only more
bio-available and contain a wider array of amino acids – both essential on non-essential,
they are also more palatable for you companion. The biological value of a protein
is determined by how readily the amino acids broken down and used by the body. For
dogs and cats, egg whites are at the top of the list with a biological value of
100, followed by muscle meat (beef, chicken, lamb) at 92, and organ meats at 90.
Wheat and corn are way down the list with biological values of 60 and 54. Cooking
meat at the high temperatures required for canned foods and kibble reduces it’s
biological value, providing another reason to include raw or less processed foods
in your companion’s diet such as
freeze dried or
When evaluating the protein source on a bag of kibble, keep in mind that whole meats,
such as an ingredient listed as “chicken” or “beef,” contain 75% water. So if a
whole meat is listed first, the next ingredient should be a specific meat meal to
insure the protein in the food is from animal sources, not grains (i.e., chicken
meal or beef meal, not generic “meat meal” or by-product meals). The top-quality
pet foods on the market use USDA sources (human grade) for their meat meals. If
the ingredient lists “chicken” first followed by grains or grain by-products, you
can be sure that much of the protein in the food comes from the grains and is less
bio-available to your pet. Trying to force carnivores to derive their amino acid
requirements from grain sources is one of the main contributors to the pet obesity
epidemic facing our dogs and cats today.
Which Meat is Best?
Is chicken the best protein for cats? Is beef best for dogs, or is lamb better?
While there are strong opinions among pet enthusiasts about the answers to those
questions, the real answer is – it completely depends on your individual cat or
dog. Some research, specifically that of William Cusick, suggests that dogs do better
on a diet and protein source that most closely matches that of their ancestors:
the food that was available in the region in which the breed developed. For example:
Border Collies would eat lamb, fish and poultry as they originated in Scotland where
these were staples in the diet. he Greyhound, originating in Egypt, would
eat rabbit, pork, poultry and goat. German Shepherds would be fed beef, as
they were originally bred in the Alsation Region of Germany.
While breed specific guidelines may be helpful for some dogs, for many dogs their
heritage is quite unknown. For another large group of dogs (and cats), food allergies
will determine which protein sources are best, (see Novel Proteins below). Cats
on the other hand, are assumed to have all developed on a similar diet of rodents
– specifically mice, birds and the occasional rabbit. So which meat is best?
In the absence of food sensitivities or allergies, the answer is “at least three
different ones.” Rotation insures a broader nutritional base over time and
helps reduce the incidence of food sensitivities and allergies. Many dogs and cats
fed the same food for years on end will develop signs of intolerance such as itchy
skin or paws, or chronic digestive problems such as gas, loose stools or frequent
vomiting. Rotating between at least three or four different foods with different
protein sources, and preferably from a variety of manufactures, provides the ideal
answer to “Which food is THE best for my companion.” Only you and your companion
can really determine what is best by trying various high-quality foods and choosing
those that your dog or cat thrives on.
How Much is Too Much Protein?
With the growing popularity of grain-free and low carbohydrate foods in recent years
we hear more questions from owners concerned about feeding too much protein.
One reason for this question is the lingering myth that too much protein in the
diet can cause kidney disease, especially in older animals. Nutritional research
has disproved this falsehood, but still it lives on. This myth originated when veterinarians
began to put animals with kidney disease on low-protein diets to minimize nitrogen
levels. Today, holistic veterinarians, and increasingly even traditional veterinarians,
are suggesting a diet for animals with kidney disease containing higher quality
protein that is more digestible rather than low-protein foods. The better quality
the protein, the less waste produced through digestion creating less work for the
kidneys and lower nitrogen levels in the body.
Excess protein in a healthy dog or cat’s diet would typically be either excreted
in the urine, used as energy, or converted to fat. The one precaution when feeding
a higher protein food is watching how much you feed so as not to allow your pet
to gain weight. So the answer to “How much protein is too much?” is dependent on
your individual cat or dog, their metabolism, activity level and lifestyle. If your
feline friend spends most of the day on the window sill and rarely plays, feed her
less of the same food you feed her brother who chases anything that moves and runs
up and down the stairs a dozen times a day. They both can thrive on a high-quality,
high-protein diet - they just require different quantities of the food.
Growing puppies and kittens, as well as pregnant or nursing mothers and working
animals require more protein than normal adult animals. Most of the premium pet
foods provide adequate fat and protein levels for their needs provided they are
fed larger portions for their size. Adding
fresh meat or
grain-free canned foods to some meals is a good way to provide extra protein.
When food allergies are suspected, a dog or cat is often put on a diet consisting
of a “novel” protein and carbohydrate. A novel protein is simply one that your dog
or cat has never been exposed to. Lamb and rice foods were originally formulated
to meet this need. The idea became so popular, however, and so many manufactures
jumped on the lamb and rice bandwagon that most dogs and many cats have eaten lamb
at some point in their life. Pet food companies seeing the growing market for such
unique foods continue to produce “allergy formula” foods with ever more exotic sources
of protein. Venison, duck, rabbit, herring, and even kangaroo can be found among
the formulations available for food-sensitive dogs and cats. This makes providing
variety in the diet a little easier, but be careful not to feed every protein available
or you may run out of options should the need ever arise to put your companion on
a restricted, novel protein diet.
When searching for a novel protein food for your companion, read labels carefully.
Many canned foods and kibble will bear a name suggesting a novel protein, but upon
reading the ingredients you may find another protein listed such as eggs or chicken.
Look for food specifically designed for the sensitive pet such as
California Natural canned and kibble,
Wellness Simple Foods,
Natural Balance Allergy Formulas, or
Wysong Anergen. Better yet, choose a pre-mix such as
Honest Kitchen Preference or
Dr. Harvey’s and add your own protein source – either fresh or canned.
Evanger's offers 100% meat canned pheasant, rabbit and duck.
Innova EVO offers duck and venison. Of course, some ingredients in the pre-mixes
may contribute to allergies as well, such as alfalfa or some grains, so if a true
novel diet is required cooking sweet potatoes or rice to combine with a novel protein
may be safer.
To truly determine if the restricted diet is helping you may need to keep your dog
or cat on this single protein diet for up to 12 weeks, however, progress is sometimes
seen within 4 to 8 weeks. Once a food tolerance is established, however, find at
least one and preferably two other protein sources that can also be tolerated for
rotational feeding. A dog or cat that has developed an allergy to one protein is
more susceptible to developing additional sensitivities, so rotation in their diet
When feeding a restricted diet to a food-sensitive pet, don’t forget to read the
labels on treats, too.
Plato Smart Treats are loved by dogs and cats alike, and offer single-protein
varieties including duck, salmon and kangaroo for those on restricted diets. Many
all-meat freeze dried treats fit the bill for sensitive pets as well.
Only Natural Pet Venison Jerky Bites or
Bison Strips are also single-meat treat options.
Some dogs and many cats may have grain allergies rather than, or in addition to,
protein allergies. The increase in the availability of grain-free foods makes feeding
these individuals much less problematic than it was a few years ago. The downside
to the influx of
grain-free foods seems to be the trend to include combinations of more uncommon
or exotic meats in these formulas including buffalo, venison, duck and salmon in
combinations with each other or with more common meats such as chicken, turkey beef
or lamb. Should an animal on these diets become sensitive or allergic, the search
for a novel protein becomes much more difficult.
Nutrition is the cornerstone of health, and high-quality protein is a critical part
of proper nutrition. Read labels carefully to insure the protein your dog or cat
is receiving is from meat, not grains. The best diet for your companion depends
on their individual needs, but will ultimately include a variety of protein sources
and optimally at least some portion of fresher, less processed foods. If allergies
or sensitivities become an issue, read labels carefully and pick a truly novel diet
for the initial restricted diet. Feeding too much protein is rarely an issue, but
feeding too much food is – keep portions appropriate to each animal’s activity level
and metabolism to avoid weight gain.
The Nature of Animal Healing by Martin Goldstein
What You Need to Know About Your Pet's Food
Evaluating Canned and Dry Food for Your Companion
Catinfo.org - Veterinarian
Lisa A. Pierson on "Feeding Your Cat"
The Animal Advocate
- William Cusick on Breed Specific Nutrition