What's in My Cat's Food?: Designer Diets, Grain Free Diets

By Lynn Buzhardt, DVM

Nutrition

Cats are special creatures that often eat special diets. But are these ‘special’ diets better than ‘ordinary’ diets? Do cats need unique cuisine? Are organic, gluten free, grain free, hypoallergenic designer diets necessary?

What are ordinary diets?

Ordinary diets usually contain a protein source (often chicken, beef, pork, or fish), a starch (grains), and perhaps a vegetable. Most commercial pet foods are made from byproducts of human food production. That means your cat may have chicken in his food, but it may not be an entire chicken breast like the one on your dinner plate. Premium brands may contain higher quality, more digestible ingredients than lower cost foods.

Premium or not, all commercial pet foods should meet the requirements set by the Association of American Feed Control Officials (AAFCO) to be certified as ‘complete and balanced’. AAFCO approved pet foods include all the ingredients necessary to provide adequate nutrition for the specified pet.

What are designer diets?

Designer diets are preparations ‘designed’ with a specific goal in mind. These diets target cats or owners who need or prefer certain qualities in cat food. For example, designer diets may be grain free or gluten free to prevent complications in cats with specific sensitivities. They may be totally organic to avoid contamination by pesticides. They may include a novel protein source such as venison, tuna, turkey, duck, fish, rabbit, bison, or even kangaroo to reduce the effects of food allergies. Like ‘ordinary’ diets, ‘designer’ diets should be AAFCO certified.

What do cats need in a balanced diet?

Whether they are eating a regular or designer diet, felines need protein. Cats are considered to be carnivores (meat eaters) while dogs are thought of as omnivores (they eat meat and plants). Cats need much more protein in their diet than dogs do. Like most mammals, cats use most of the protein they consume for growth and body maintenance; however, cats also use protein as an energy source. For this reason, kittens require 1.5 times more protein than puppies and adult cats need two to three times more protein than adult dogs.

"Cats need much more protein in their diet than dogs do."

Cats don’t just need any old protein, they need specific amino acids found in protein. For example, cats, unlike dogs, need a certain amount of the amino acid taurine to stay healthy. Taurine is found in animal muscle, particularly in the heart and liver. Plants don’t have taurine, so cats don’t eat as many greens or grains as do their omnivorous dog friends.

Without adequate taurine, cats are more likely to develop a heart disease called dilated cardiomyopathy (DCM). This is a serious disease of the heart muscle resulting in an enlarged, weakened heart. DCM is associated with congestive heart failure and can be fatal. Reputable AAFCO approved commercial cat foods are supplemented with taurine to prevent deficiencies. Owners who make homemade diets should verify that their cat’s food contains sufficient quantities of taurine. Even with adequate amounts of taurine, deficiencies can occur if there is a problem with bioavailability or an interaction with other ingredients. Researchers and the FDA are monitoring ongoing research into this serious condition.

Cats are unique in their protein requirements, but like other mammals, they may benefit from consuming carbohydrates, roughage, vitamins, and minerals in their diets.

What’s up with grain free diets?

Grain free diets are popular among cat owners who think that they are more suited for cats. Some people reach for grain free food in a misguided effort to reduce food allergies such as in gastrointestinal (GI) upsets and itchy skin issues. While a small percentage of cats may have sensitivities to grains, the vast majority of food allergies are linked to common protein sources like beef and poultry, not carbohydrates like grains.

"While a small percentage of cats may have sensitivities to grains, the vast majority of food allergies are linked to common protein sources like beef and poultry, not carbohydrates like grains."

Pet owners may also think that grain free diets control weight. As with high protein human diets, grain-free pet food may be lower in carbohydrates, but higher in fat and calories. Grain free doesn’t guarantee weight-control or weight-loss because they may substitute grains like wheat, oats, or rice with different carbohydrates like potatoes, carrots, cranberries, sweet potatoes, lentils, beans, or peas.

Unlike grain, these carbohydrate-rich ingredients provide little fiber and may precipitate GI issues. The fiber in grains aids in elimination and prevention of hair balls. Grains also provide important nutrients to the diet. Iron, thiamine, calcium, riboflavin, folate, and niacin are all in grain. Grain free diets may result in a deficiency of these essential nutrients. Plus, these carbohydrate sources cost more. Depending on your cat’s health status and specific nutritional needs, a diet with grain may be better than one without.

Here’s the bottom line: There is no conclusive evidence that whole grains are harmful to the general cat population. And grains are more than just 'fillers’. Grains are a good source of fiber, vitamins, minerals, and essential fatty acids. Some grains also provide easily digestible protein. And even though cats are historically carnivores, their digestive tracts are pretty efficient at processing carbohydrates from grain. Research regarding the value of grain in cat diets is ongoing. There may be a link between grain free diets and heart disease, so stay tuned.

 What’s up with gluten free diets?

Gluten free diets may be popular, but cat owners should be aware of a few facts. Gluten is a protein that is found in certain grains including barley, wheat, and rye, but there are grains that do not include gluten. Gluten free does not mean grain free. All grain free cat foods are gluten free, but not all gluten free cat foods are grain free. Some gluten may actually be beneficial. Gluten is sticky and helps bind food together into kibble pieces. Gluten sensitivity is rare in cats, so gluten may be a safe, useful part of a diet that includes grain.

What about DIY designer pet food?

If you choose to prepare your cat’s food, make sure the recipe meets your cat’s nutritional needs. Follow directions carefully for preparation and storage. Home-made cat food doesn’t contain preservatives and needs to be stored safely.

There are nutritional resources with sophisticated computer programs to help calculate the amounts of protein, fat, minerals, and vitamins in a recipe. Some programs take into account a cat’s age, health status, and activity level in formulating an appropriate diet. But it can still be tricky verifying that your DIY pet food is nutritionally balanced, i.e., the bioavailability and metabolism of taurine is different in a lamb vs chicken. Also, the absorption of nutrients may vary with the amount and type of fiber in the diet.

What about commercially prepared designer diets?

Designer diets can also be purchased. So if you don’t want to cook, you can still feed your kitty designer food….even if you aren’t the designer. As an added plus, when you feed your cat a commercial food, you are actually being ecologically responsible since most pet foods are made with by-products of human food that would otherwise be discarded.

What cats need designer diets?

Whether home-cooked or store-bought, all cats need food with proper amounts of protein, carbohydrates, and nutrients. But ‘proper amounts’ vary with age and health status. For example, young growing kittens have different nutritional needs than adult cats. Cats with urinary problems eat different formulations than cats with heart conditions. Cats with sensitive skin have a different menu than cats with sensitive stomachs. So, some cats need designer diets.

What about the average healthy adult cat? Does she need a designer diet?

For now, there is no documentation proving that designer diets have any health benefits over more traditional, commercially prepared diets. But keep watching, research is ongoing! Talk to your veterinarian to help you decide what to feed your kitty. Cats are 'special' creatures, but their diets don’t always have to be ‘special’.

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