What's Really in Pet Food?
The National Research Council (NRC) of the Academy of Sciences set the nutritional standards for pet food that were used by the pet food industry until the late 1980s. The NRC standards, which still exist and are being revised as of 2001, were based on purified diets, and required feeding trials for pet foods claimed to be “complete” and “balanced.” The pet food industry found the feeding trials too restrictive and expensive, so AAFCO designed an alternate procedure for claiming the nutritional adequacy of pet food, by testing the food for compliance with “Nutrient Profiles.” AAFCO also created “expert committees” for canine and feline nutrition, which developed separate canine and feline standards. While feeding trials can still be done, a standard chemical analysis may be also be used to determine if a food meets the profiles.
Chemical analysis, however, does not address the palatability, digestibility, or biological availability of nutrients in pet food. Thus it is unreliable for determining whether a food will provide an animal with sufficient nutrients.
To compensate for the limitations of chemical analysis, AAFCO added a “safety factor,” which was to exceed the minimum amount of nutrients required to meet the complete and balanced requirements.
The digestibility and availability of nutrients is not listed on pet food labels.
The 100% Myth — Problems Caused by Inadequate Nutrition
The idea of one pet food providing all the nutrition a companion animal will ever need for its entire life is a myth.
Cereal grains are the primary ingredients in most commercial pet foods. Many people select one pet food and feed it to their dogs and cats for a prolonged period of time. Therefore, companion dogs and cats eat a primarily carbohydrate diet with little variety. Today, the diets of cats and dogs area far cry from the primarily protein diets with a lot of variety that their ancestors ate. The problems associated with a commercial diet are seen everyday at veterinary establishments. Chronic digestive problems, such as chronic vomiting, diarrhea, and inflammatory bowel disease are among the most frequent illnesses treated. These are often the result of an allergy or intolerance to pet food ingredients. The market for “limited antigen” or” novel protein” diets is now a multi-million dollar business. These diets were formulated to address the increasing intolerance to commercial foods that animals have developed. The newest twist is the truly “hypo allergenic” food that has had all its proteins artificially chopped into pieces smaller than can be recognized and reacted to by the immune system.
Dry commercial pet food is often contaminated with bacteria, which may or may not cause problems. Improper food storage and some feeding practices may result in the multiplication of this bacteria. For example, adding water or milk to moisten pet food and then leaving it at room temperature causes bacteria to multiply. 8 Yet this practice is suggested on the back of packages of some kitten and puppy foods.
Pet food formulas and the practice of feeding that manufacturers recommend have increased other digestive problems. Feeding only one meal per day can cause the irritation of the esophagus by stomach acid. Feeding two smaller meals is better.
Feeding recommendations or instructions on the packaging are sometimes inflated so that the consumer will end up purchasing more food. However, Procter & Gamble allegedly took the opposite tack with its Iams and Eukanubalines, reducing the feeding amounts in order to claim that its foods were less expensive to feed. Independent studies commissioned by a competing manufacturer suggested that these reduced levels were inadequate to maintain health. Procter & Gamble has since sued and been counter sued by that competing manufacturer, and a consumer complaint has also been filed seeking class-action status for harm caused to dogs by the revised feeding instructions.
Urinary tract disease is directly related to diet in both cats and dogs. Plugs, crystals, and stones in cat bladders are often triggered or aggravated by commercial pet food formulas. One type of stone found in cats is less common now, but another more dangerous type has become more common. Manipulation of manufactured cat food formulas to alter the acidity of urine and the amount of some minerals has directly affected these diseases. Dogs also form stones as a result of their diet.
History has shown that commercial pet food products can cause disease. An often-fatal heart disease in cats and some dogs is now known to be caused by a deficiency of the amino acid taurine. Blindness is another symptom of taurine deficiency. This deficiency was due to inadequate amounts of taurinein cat food formulas, which itself occurred because of decreased amounts of animal proteins and increased reliance on carbohydrates. Cat foods are now supplemented with taurine. New research suggests that supplementing taurine may also be helpful for dogs, but as yet few manufacturers are adding extrataurine to dog food. Inadequate potassium in certain feline diets also caused kidney failure in young cats; potassium is now added in greater amounts to all cat foods.
Rapid growth in large breed puppies has been shown to contribute to bone and joint disease. Excess calories and calcium in some manufactured puppy foods promoted rapid growth. There are now special puppy foods for large breed dogs. But this recent change will not help the countless dogs who lived and died with hip and elbow disease.
There is also evidence that hyperthyroidism in cats may be related to excess iodine in commercial pet food diets. 9 This is a new disease that first surfaced in the 1970s, when canned food products appeared on the market. The exact cause and effect are not yet known. This is a serious and sometimes terminal disease, and treatment is expensive.
Many nutritional problems appeared with the popularity of cereal-based commercial pet foods. Some have occurred because the diet was incomplete. Although several ingredients are now supplemented, we do not know what ingredients future researchers may discover that should have been supplemented in pet foods all along. Other problems may result from reactions to additives. Others are a result of contamination with bacteria, mold, drugs, or other toxins. In some diseases the role of commercial pet food is understood; in others, it is not. The bottom line is that diets composed primarily of low quality cereals and rendered meat meals are not as nutritious or safe as you should expect for your cat or dog.