By Jean Hofve, DVM
Packaged, manufactured pet food is a great convenience to dog and cat guardians. But responsible consumers who want the best for their animal companions have a bewildering array of foods and claims to choose from. So, how do you know what’s best for your animals?
The most reputable manufacturers of “superpremium” and “natural” foods agree with holistic veterinarians that the very best diet for your animal companion is one that you make yourself. A homemade diet, carefully balanced nutritionally, and using raw and organic foods, is closest to what Mother Nature intended. However, many of us do not have the resources to make our pets’ food, especially for multiple animals or large dogs. So, for those of us who rely, partially or entirely, on commercial foods for our animals, here are some guidelines to use in selecting a good-quality diet.
The name of a pet food is strictly defined and tells us what is actually in the food.
- “Chicken Dog Food” must contain at least 95% chicken (excluding water).
- “Fish and Giblets for Cats” must be 95% fish and giblets together, and there must be more fish than giblets, since fish appears first on the label.
- If the label says “dinner,” “platter,” “entree,” “nuggets,” “formula,” or similar term, there must be 25% of the named ingredients. That is, “Fish Dinner” must contain 25% fish.
- If more than one ingredient is named, such as “Fish and Giblets Entree,” the two together must comprise 25% of the total, and the second ingredient must be at least 3%. A food labeled “Fish and Giblets Entree” may contain anywhere between 13% fish and 12% giblets, to 22% fish and 3% giblets.
- Ingredients labeled as “with” must be present at 3%, such as “Fish Dinner with Giblets.”
- An ingredient labeled as a “flavor,” such as “Beef Flavor Dinner,” may not actually contain beef meat, but more likely will contain beef digest or other beef by-products that give the food a beef flavor.
That said, there are a couple of caveats that you should be aware of:
- It used to be that non-meat ingredients didn’t count on the main label, so food labeled “Chicken and Rice Dinner” still had to contain 25% chicken. However, the rules have changed, so now “Chicken and Rice Dinner” could contain 13% chicken and 12% rice and be legally labeled.
- Multiple studies have found many mislabeled pet foods and treats. In some cases, ingredients are present in the food but not disclosed on the label; this is a serious problem if a pet has a food allergy, because the food may contain undeclared allergens. On the other hand, some products contained none of the primary ingredient as stated on the label. The pet food industry has thusfar demonstrated no interest whatsoever in fixing the problem, although regulators are aware of it, and are looking for a solution.
Even on many high-priced, premium, and veterinary brands, you will notice one of the major ingredients listed is “by-products” of some sort. By-products are basically “parts other than meat.” These may include internal organs not commonly eaten by humans, such as lungs, spleens, and intestines, other parts such as cow udders and uteri, and in the case of poultry by-products, heads, beaks and feet. By-products must be from “freshly slaughtered” animals, although there is some question as to how fresh they really are by the time they reach the pet food manufacturer, as they may be shipped in unrefrigerated trucks.
By-products are usually found in canned foods, where they are often the only source of animal protein. While a hunting cat or wild canine would eat the by-products as well as the meat, a named meat should be the mainstay of a carnivore’s diet.
Rendering (basically a process of slow cooking) produces two major items: animal fat or tallow, and a processed product usually called “meat meal,” “meat and bone meal,” or “by-product meal.” (Due to historical quirks in naming, the term “by-product meal” refers to poultry, while the equivalent mammal product is “meat and bone meal.”)
Animals that are dead, dying, diseased, or disabled prior to reaching the slaughterhouse are known as “downers” or “4D” animals. These are usually condemned, in whole or in part, for human consumption, and are generally sent for rendering along with other by-products, parts and items that are unwanted or unsuitable for human use – such as out-of-date supermarket meats (along with their plastic wrappers), cut-away cancerous tissue, parasitized livers, and fetal tissue (which is very high in hormones).
Rendered ingredients vary greatly in quality. Some rendering facilities are closely associated with slaughterhouses, which are in turn connected with feedlots or poultry farms. These “captive” rendering plants are more likely to produce good quality, relatively pure meals. Such meals are typically designated with the name of the source animal, such as “chicken meal.” Independent renderers take all materials from an area, from roadkill to dead livestock.
Many independent renderers accept for processing such items as road kill, euthanized shelter dogs and cats, and other unappetizing ingredients. These items can be segregated from the food stream, and are not supposed to find their way into the pet food chain, but this is not always done. They are supposed to be converted for use in fertilizers, livestock feeds, and industrial applications. Over the years there have been numerous unsubstantiated reports of this material being processed into dog and cat food. The Center for Veterinary Medicine, a branch of the Food and Drug Administration, admits that dead dogs and cats are commonly rendered, and although there is no legal prohibition against using dogs and cats in pet food, they do not “condone” the practice. All the large, reputable pet food manufacturers certify that they do not use such materials in their products.
Because of the way they are processed, most dry foods use meals as their major animal-source ingredients. Meals do contain more protein than whole meat, since the fat and water have been removed.
Many dry foods advertise that they contain some type of “meat” (such as chicken or beef) as the first or a top ingredient. However, because of the high water content of fresh meat, and the water added to it, the actual percentage is small. The first named meal is usually the primary protein source in these foods. (See Pet Food Marketing Hype for more information on this and other tricks the pet food industry uses to persuade you to buy their food.)
Rendered products are found almost exclusively in dry food (which we do not recommend for cats; see Why Cats Need Canned Food for more information.)
“Complete and Balanced”
A food may be labeled as “complete and balanced” if it meets the standards set by a group called AAFCO, the Association of American Feed Control Officials. These standards were formulated in the early 1990s by panels of canine and feline nutrition experts. Standards set by AAFCO have been adopted by most states, which are then responsible for enforcement.
A food may be certified by AAFCO in two ways: (1) meeting published standards for content, or (2) feeding trials.
(1) Nutrient Profiles. These standards set the required amounts of protein, fat, vitamins, minerals, and so forth. These theoretically have the benefit of extensive research behind them. However, according to researchers at the University of California at Davis, the fundamental research supporting standards for adult cat food includes one study on protein requirements, one study on amino acid requirements, and ZERO studies on vitamin requirements. Yet AAFCO publishes standards specifying exactly how much of each vitamin must be included in adult cat food. Where do these values come from? They are interpreted and extrapolated from research in kittens (which has been a little more extensive) and from research in other species, mostly chickens and rats. Is this valid? We do not know. The current very old standards are being updated, but the process is slow, and the “new” standards–many of which do have the benefit of research in dogs and cats–will already be over a decade out of date by the time they are published in 2016.
Moreover, any manufacturer can synthesize a food containing sufficient amounts of each ingredient according to the standards, yet an animal will ultimately starve to death on it. How could this happen? Because the standards do not address the issues of “bioavailability” of nutrients to the animal. Certain forms of vitamins, minerals, and amino acids are poorly absorbed from the digestive tract. A noted veterinary nutrition textbook claims that a food can be created from old leather boots, wood shavings, and crankcase oil that will meet the technical requirements for protein, carbohydrates, and fats, yet would be completely indigestible. Unfortunately, given the ingredients used by some manufacturers, “Old Boot” may be closer to the truth than anyone wants to admit!
(2) Feeding Trials. These are considered the “gold standard” of pet food formulation. However, when you look at the actual AAFCO protocols for an adult maintenance diet, a manufacturer must feed exclusively the test food to only six animals for six months. (Eight animals are required at the outset; however, two of them may be dropped from the trial for non-diet-related reasons.) Foods intended for growth and reproduction must be tested for only 10 weeks. Most of the large, reputable pet food producers, such as Hills, Walthams and Purina, maintain their own colonies of dogs and cats, and test their foods on hundreds of animals over years or even multiple generations. Other manufacturers rely on facilities that keep animals for this purpose to do the studies for them.
It is easy to see how a poor quality diet could be fed for only six months without seeing adverse health effects, and legitimately be labeled as meeting AAFCO standards. In fact, studies have confirmed that even foods that pass feeding trials may still be inadequate for long-term maintenance. Worse still, AAFCO passed the “family rule” making it okay to put the feeding test statement on the labels of foods that were not actually tested, but are “similar” to one that was. The criteria for being “similar” are very loose. Since there’s no way to tell which food actually passed a feeding test, this label designation has become fairly useless.
Keep in mind, too, that the standards, such as they are, set only “minimums” and “maximums,” not “optimums.” Commercial foods are designed to be adequate for the average animal, but may not be suitable for an individual animal’s variable needs.
Additives and Preservatives
Preservatives are necessary for some ingredients, and for dry food in particular, since it tends to be stored for long periods before using. Some of the most dangerous synthetic chemical preservatives are BHA, BHT and ethoxyquin. Monsanto, manufacturer of ethoxyquin (a rubber stabilizer), in 1993 was ordered to conduct a new study of this preservative due to faulty test protocols and alleged doctoring of data in its initial report. Not surprisingly, the second study, completed in 1996, found no problems associated with ethoxyquin in pet food. Given Monsanto’s track record and reptuation, do you believe this? Ethoxyquin is banned from nearly all human food products (except certain spices) due to its cancer-causing properties.
Another concern is pesticide residues, antibiotics, and molds in various pet food ingredients. Meat from downer animals may be loaded with drugs, some of which are known to pass unchanged through all the processing done to create a finished pet food. One toddler who habitually snacked from the cat’s bowl of dry food died of an allergic reaction to penicillin, which was found to be in the cat food at levels over 600 times the limit allowed in human food products. In the 1990s there were two major recalls of dry dog food by different manufacturers due to mold contamination of grain ingredients. Some fungal toxins are very dangerous. The second recalled food killed more than 20 dogs. In 2006, more than 100 dogs died from another food contaminated with a fungal toxin.
What to do?
When selecting a commercial food for your animal companion, be sure to read the label. Although percentages are misleading due to the variable moisture content of processed foods, they are often the only data available.
- Avoid foods containing “by-product meal,” “meat and bone meal,” or euphemisms like “beef and bone meal,” which tend to be the least expensive (and thus poorest quality) animal-source ingredients. “Meat and bone meal” (MBM) is the mammal equivalent to “by-product meal” (which applies only to poultry). MBM was reported as the ingredient most likely to contain the drug used for euthanasia (sodium pentobarbital) in a study conducted by the FDA. .
- A named meat or meat meal should be the primary protein source, rather than a cereal like corn gluten meal. Corn in all its forms must also be avoided. The feed-grade corn used in pet food is certain to be genetically engineered. In low-priced foods, corn gluten meal is often substituted for expensive meat ingredients. Wheat is also a common allergen; wheat products should be avoided. All grains are susceptible to mold and other toxins.
- Because the pet food makers have gotten pretty clever about marketing, it’s important to know how to see through the hype. For more about pet food marketing ploys, see this article.
- Never feed “semi-moist” type foods, which are full of additives, colorings, texturizers, and preservatives.
- Avoid foods containing chemical preservatives such as ethoxyquin, BHA, BHT, propylene glycol, or propyl gallate. Many brands are now preserved with Vitamins C and E instead of chemical preservatives. While synthetic preservatives may still be present, the amounts will be less.
- In general, select brands promoted to be “natural.” While they are not perfect, they tend to be better than most.
- Stay away from “light” or “senior” or “special formula” foods. These foods may contain acidifying agents, excessive fiber, and inadequate fats that will result in skin and coat problems.
- Avoid generic or store brands; these may be repackaged rejects from the big manufactures, and certainly contain cheaper – and consequently poorer quality – ingredients.
- Change brands or flavors of dry food every 2 or 3 months to avoid deficiencies or excesses of ingredients, which may be problematic for your animal. Whenever you are changing foods, remember to GO SLOWLY. Add a tiny amount of new food to old, and gradually increase the proportion of new food. It will take a week or two to properly transition a cat. Click here for more info on why and how to change foods.
- With canned food, you can change flavors daily if you wish–my cats prefer it that way!
- Cats need at least 50% of their diet (preferably 100%!) in the form of wet food (canned or homemade). Include a variety of meats and flavors to prevent finicky behavior and food allergies and intolerances. Cats who are overweight, diabetic, or have a history of or current liver, pancreas, bladder or kidney disease, should not eat any dry or semi-moist food at all. The low moisture and high carbohydrate content are known to contribute to these problems. There is no benefit to the cat from dry food, and many adverse effects on health. Dry food is popular because of its cost and convenience, but it is definitely not healthy for your cat to eat. (And no, dry food does not clean the teeth!)
- If you must feed dry food, remember to never get it wet. Do not mix with canned food, milk, broth, or water. All dry foods have bacterial contamination on the surface, and moisture will allow those bacteria to grow. Some are dangerous, and cause vomiting and/or diarhhea.
Above all, supplement with organic raw meats (meat should be frozen at -4oF for 72 hours, then thawed prior to use; follow safe meat-handling procedures at all times). If desired, a small amount lightly steamed, pureed or finely grated non-starchy vegetables (they cannot be very well digested by carnivores otherwise). Dogs may be supplemented with tofu and cooked grains; however, cats should receive minimal carbohydrates in the diet. Be aware that plant products tend to raise urine pH and may contribute to bladder stones and urinary tract disease. Other helpful supplements include Omega-3 fatty acids, acidophilus, digestive enzymes, and Vitamins C and E.