Your feline furball flips over fishy foods and meaty treats, and his favorite pastime is stalking squirrels through the window. There's no doubt your kitty is a die-hard carnivore. But since her food comes from a bag or a can, what kinds of protein does she really need in her daily diet? Our in-house veterinarian, Dr. Leslie, calls cats "meat-eating machines." Here she is with the lowdown on the best sources of protein to include in a healthy and nutritious cat diet.
Q: How important is protein to a cat's diet?
Dr. Leslie: Protein is one of the five essential nutrients in a carnivore's diet. Because cats have evolved to be meat-eating specialists, they require protein and amino acids from animal sources in every meal. Most cats require approximately 30% of their dietary calories to come from protein to fuel their bodies and unique nervous systems, to grow hair continuously and to ensure a functioning immune system.
Q: Does it matter whether the protein in a cat's diet is animal-based or plant-based?
Dr. Leslie: Animal protein sources provide vitamins, amino acids and fatty acids that are not found in plant sources. Cats do not have the ability to synthesize as many amino acids and vitamins as dogs or people can, making them entirely dependent on animal protein sources for these nutrients. An example of an important amino acid not found in plants is taurine, which is vitally important to normal feline retinal and cardiac function. Without these amino acids, cats can develop blindness and a specific type of heart disease, dilated cardiomyopathy.
Generally, animal protein sources are more easily digested by cats than plant-based protein sources, and even crystalline sources added to vegetarian diets are insufficient to overcome the carnivore's dietary need for animal-based nutrients.
Q: What can happen to a cat who is not fed adequate amounts of protein?
Dr. Leslie: Protein is the primary energy source for cats. Without it, serious health problems can occur. Deficiencies in certain amino acids, the building blocks of protein, can lead to specific types of illness. Arginine deficiency can lead to a build-up of ammonia in the body leading to seizures and even death. Taurine deficiency, as mentioned earlier, can lead to a host of metabolic problems, like heart disease and blindness. Many amino acid deficiencies lead to impaired immune function, poor growth, reproductive failure and congenital defects.
Q: What do you consider to be the best sources of protein in a healthy cat diet?
Dr. Leslie: Feral cats do very well hunting and eating a variety of small rodents, lagomorphs (which include rabbits and hares), insects, birds and small reptiles. When making pet food, we need to make sure the nutrients cats require are available in every meal. Highly digestible animal protein diets typically contain protein sources from poultry, meat and sometimes fish. Reptiles and insects may offer essential nutrients, but reptiles pose food safety risks because of the unique bacteria they carry. Insects may prove to be valuable protein sources as we learn more about them.
Q: What should cat guardians look for on cat food labels?
Dr. Leslie: The most objective statement on a pet food label is the Nutritional Adequacy Statement. It tells you who the food is made for and at what stage of life it should be used. It may sound silly, but you really do need to make sure the food is for cats! They are carnivores and have different nutrient needs than other types of animals.
Pregnant, lactating or growing cats should be fed a diet that states it is for "All Life Stages" or for growth. Cats who are old enough to be neutered and are no longer kittens, and non-reproducing adults can be fed any of the life-stage diets, but often "adult maintenance" diets provide fewer calories.
Other components of the label, such as the ingredient list, will help you select products that fit your own nutritional philosophies.
Q: Does canned food typically contain more or less protein than dry food, or are they about the same?
Dr. Leslie: Canned food definitely contains more water. Because of the canning process, it is easier for canned food to contain more high-moisture ingredients like fish, poultry and meat so the net result could be higher protein per calorie along with the higher moisture content; but this is not a universal statement. Something to watch out for is that higher protein ingredients often also contain higher fat. So for the calorie conscious cat, this is something to watch carefully.