Facts, fallacies, and future of pet nutrition (Proceedings)


Veterinarians, veterinary technicians, and the general public are inundated with information, some accurate and some not, on pet nutrition.

Veterinarians, veterinary technicians, and the general public are inundated with information, some accurate and some not, on pet nutrition. Put in "dog nutrition" or "cat nutrition" in Google, and you get 13- 17,000,000 hits. Add to this, articles and books in print, advice from neighbors and store employees, and commercials on TV and in print, and the information is overwhelming. Discussing pet nutrition is sometimes akin to discussing religion or politics; people are passionate about their beliefs. There are many "fallacies and facts" that could be discussed; however, due to time and space limitations, I will limit it to the more common ones.

Pet food companies are poisoning pets

Fallacy. This is probably one of the more popular "conspiracy theories". Most pet food companies are involved with only one business, producing pet foods. It makes no sense from a business perspective for a business to produce a product that would be detrimental to its consumers. The internet is replete with accusations, most of which have not been substantiated or are based on occurrences from years ago. This is also true in human medicine, e.g. use of thalidomide and DES in the 1950's. Unfortunately, pet food toxicities have been in the news in recent years, which fuels this belief. Interestingly, The CDC estimates that 76 million Americans get sick, more than 300,000 are hospitalized, and 5,000 people die from food borne illnesses each year. After eating contaminated food, people can develop anything from a short, mild illness, often mistakenly referred to as "food poisoning", to a life-threatening illness.

Pets end up in pet food

Fallacy. This was popularized in the last 5 to 10 years in part because pentobarbital was found in some pet foods and the assumption was that it was present because pets that had been euthanized with pentobarbital were present in the food. A subsequent FDA study did find that some foods had very low levels of pentobarbital in them; however, no dog DNA was found. Another concern is that pet food contains horse meat. The use of horse meat in foods for human and pet consumption is frowned upon in the United States/ As a result, almost all horses slaughtered in the U.S. are shipped overseas for consumption, which decreases the chance of horse meat being included in products manufactured here. If horse meat were present in a pet food, it would need to be listed on the label. And while pet foods may contain "by-product or by-product meal", it is usually designated as to what animal (e.g. poultry, beef, etc) it comes from. The AAFCO definition (2009) of meat by-products is "meat by-products is the non-rendered, clean parts, other than meat, derived from slaughtered mammals. It includes, but is not limited to, lungs, spleen, kidneys, brain, livers, blood, bone, partially defatted low temperature fatty tissue, and stomachs and intestines freed of their contents. It does not include hair, horns, teeth, and hoofs." The FDA requires that all ingredients be listed on pet food labels. Foods that list "meat by-product meal," as one of their ingredients can contain any number of meats, so you may want to watch for that and instead, choose foods that include "chicken by-product meal," or are more specific with their list of ingredients. Keep in mind that unless a hot dog is "all beef" or "pork" it may be made of meat by-products.

You get what you pay for

Fact. Manufactures may be small "garage operations" whereby an individual or small group has small batch production and markets locally in Pet Specialty Stores, Pet Bakeries or on the Internet. These small operators generally avoid any regulation or oversight as long as they do not sell across state lines. A business license is all that is needed. However, the label on the product is a legal document and must meet minimum standards suggested by AAFCO. Because of the number of small niche products, there is very little scrutiny of small operator labels or products unless there is a consumer complaint. These small specialty foods companies typically do not have the same level of quality control and ongoing monitoring as the Large Global Pet Food Manufacturers. Within small specialty food manufacturers, there is a wide spectrum of quality and nutrition. In general, many of these small operations are making treats and snacks. Thus, the nutritional balance is not much of an issue unless it is marketed as a complete and balanced food. The focus on private treat products is often flavor and general safety (free of toxins and microbial contamination, etc.). Large companies are very complex and typically have detailed quality control. There are some simple questions to ask when evaluating a new food (From CAKirk, VIN; http://www.vin.com/Members/CMS/Misc/Default.aspx?id=13313&pid=245 ; published 2007):

1. Who is manufacturing the product? A co-manufacturer or co-packer is a company that makes products on contract for both small and large companies as well as private labels. Small companies typically rely entirely on a co-manufacturer to help them with the formula (or even provide the formula recipe), use the co-packers ingredients, and use any co-packer quality control. A large company may use a co-packer because they need a special piece of equipment (like that needed to make chunks and gravy in pouches), they need extra capacity, or they are making smaller test batches and don't need to occupy their full scale production plant while they tweak the formula and production process to optimize the product. Large companies that use co-packers generally use their own ingredients, food scientist and engineers, and quality control process. In other words they control the process and more or less "rent" time on the co-packers equipment.

2. Who formulated the product? Was it a nutritionist, a food scientist, or a pet owner with no formal training? For small "back yard" producers, they often have come up with their own formula that will be modified as needed to be commercially produced. Private label brands are generally produced by food scientist and sometimes a nutritionist employed by the co-packer. Small niche companies (eg. holistic, organic, human grade) often hire or contract a nutritionist or food scientist to formulate a recipe according to their nutrition concepts. The Large global companies have their own formulas that have been formulated by a team nutritionist, food scientist, and sometimes veterinary specialist.

3. What is the level of quality control? Unfortunately, quality control and animal testing is expensive; however, it is important to ensure safety and adequacy of a product.

4. What nutritional testing has been done? There are usually several tests that are performed for a pet food including a proximate analysis, a full analysis, a feeding trial, a palatability trial, and ingredient testing. These, of course, add expense.

5. What is the level of knowledge of the company? Call the company and ask for the full nutritional profile (full analysis) and the calorie content. If a company can't give me this information very quickly then they don't really know what they are doing or the product is not well tested. This also means a contact phone number must be on the bag. I find this one of the most telling tests of how well a company knows its product.

6. What ingredients are used? Ingredient quality is a huge topic with lots of controversy. Many of the claims and criticisms of specific ingredients are marketing hype. But from a pet food safety standpoint, evaluating the company's quality control (not always easy to do) is a better measure than reading a label. Digestibility and ash content data provides an indication of quality. Especially with protein, high digestibility and low ash is equated to higher quality more so than the product description (meat by-product vs a meat meal).

There aren't "good" or "bad" ingredients

Fact. There is no specific designation of a good or bad ingredient and ingredients that are used in pet foods must be acceptable to AAFCO. Many of the "bad" ingredients are sensationalized by the public and pet food manufacturers give into this myth or use it to a marketing advantage. For example, ehtoxyquin is a synthetic anti-oxidant that has been used to prevent fat rancidity in diets. It is no longer used because of public pressure despite the fact that scientific studies failed to prove any danger in its use. Another example is that corn is a "bad" ingredient. Corn may be associated with food allergies; however, this may be true because of its widespread use in pet foods relative to other sources of grain, e.g. rice or barley. As a wider variety of ingredients are used in over-the-counter products, the likelihood of their association with problems increases.

Human grade food is best for dogs and cats

Fallacy. There is no definition of "human grade" food and many ingredients used in pet foods are suitable for human consumption. "The U.S. Food and Drug Administration (FDA) Center for Veterinary Medicine has taken the position that if every ingredient in a product is edible, meaning that it was processed according to rules of sanitation required of food sold to people, then the product may be labeled "human grade". However, an edible ingredient becomes inedible when you add it to other inedible ingredients." - Dr. William Burkholder, veterinary medical officer for the FDA CVM (January 2009).

Natural and organic food is best for dogs and cats

Fallacy. According to AAFCO, "natural" is "...only acceptable in reference to the product as a whole when all of the ingredients and components of ingredients meet the definition....the use of 'natural' is false and misleading if any chemically synthesized ingredients are present in the product; however, AAFCO recommends that exceptions be made in the cases when chemically synthesized vitamins, minerals, or other trace nutrients are present as ingredients in the product, provided that the product is not a dietary supplement and that a disclaimer is used to inform the consumer that the vitamins, minerals, or other trace minerals are not natural. For example, 'Natural with added vitamins, minerals, and other trace minerals.'" AAFCO defines "natural" as "a feed or ingredient derived solely from plant, animal, or mixed sources, either in its unprocessed state or having been subject to physical processing, heat processing, rendering, purification, extraction, hydrolysis, enzymolysis, or fermentation, but not having been produced by or subject to a chemically synthetic process and not containing any additives or processing aids that are chemically synthetic except in amounts as might occur unavoidably in good manufacturing processes." "Organic" does not have a specific AAFCO definition other than in reference to processing, "organic (process): a formula or a specific ingredient within a formula feed that has been produced and handled in compliance with the requirements of the USDA national Organic Program (7 CFR Part 205)." The USDA National Organic Program (NOP) "develops, implements, and administers national production, handling, and labeling standards for organic agricultural products. The NOP also accredits the certifying agents (foreign and domestic) who inspect organic production and handling operations to certify that they meet USDA standards."

Different breeds have different nutritional requirements

Fallacy. There is no scientific basis for different breeds requiring different nutrition based on their breed heritage.

There are raw food diets that have been through AAFCO feeding trials

Fact. There are several raw food diets that have been tested using AAFCO feeding trials. It is important to read the label and find the nutritional adequacy statement of any dog or cat food to find this information. The nutritional adequacy statement must be included and is designed to ensure that the product, when fed as the sole source of nutrition, is complete and balanced for one or more life stages, including how this adequacy was verified. The four recognized life stages by AAFCO are pregnancy, lactation, growth, and adult maintenance, and nutritional adequacy can be determined by feeding trials or by calculation. The calculation method involves determining the amount of nutrients in the diet and comparing to AAFCO nutrient profiles for that/those life stage(s). Feeding trials are performed by feeding the diet to the animals in that/those life stage(s) following AAFCO protocol. Feeding trials, while not perfect, provide indirectly information on bioavailability of nutrients and is preferred method for validation of nutritional adequacy. Therapeutic diets, supplements, and treats often do not carry a nutritional adequacy statement. Therapeutic diets are formulated for specific non-healthy conditions, which are not recognized by AAFCO and for which no nutrient profiles exist (e.g. renal failure, liver failure, etc); they usually carry a statement such as "intended for intermittent use" or "use only under the supervision or direction of a veterinarian". Snacks and treats are not formulated or intended to be the sole source of nutrition; therefore, they are not required to carry a nutritional adequacy statement.

High protein diets cause renal failure

Fallacy. There is no scientific basis for this statement. Nor is there is evidence that dietary protein intake should be restricted in older dogs or cats to "take the workload off of the kidneys". In fact, studies of laboratory beagles showed that older beagles required higher dietary protein intake to maintain nitrogen balance and muscle mass than younger beagles.

Dry food is better for teeth

Fallacy. Over-the-counter dry foods provide no additional prevention of dental disease than canned foods do, although there are kibbled foods that are manufactured with specific dental prophylaxis.

Table scraps are bad

Fallacy – for the most part. Most foods consumed by humans are safe for pets. Table scraps can be bad when fed excessively (e.g. added source of calories not accounted for resulting in obesity) or if the wrong foods are fed (e.g. chocolate or raisins/grapes). Table scraps and pet snacks and treats should account for less than 5-10% of the daily intake of a pet. Certain foods should be avoided such as chocolate, macadamia nuts, and raisins/grapes. In certain situations, table scraps when fed to the wrong individual animal can be harmful, e.g. fat to a Miniature schnauzer with hyperlipidemia or prone to pancreatitis.

Canned foods and low carbohydrate foods are better for cats

Fact or fallacy? Good question. The notion is based on the carnivorous nature of cats and that non-domesticated cats would consume prey composed of higher meat, fat, and water than a dry, kibbled cat food. Cats, and dogs, do not have a nutritional requirement for carbohydrates (except in late gestation); therefore, feeding diets with 40-60% carbohydrates seems counter-intuitive. Despite this, cats can and do utilize dietary carbohydrates effectively and there is no scientific evidence that "high" carbohydrate or low moisture intake causes disease including diabetes mellitus. More likely, it is a combination of factors that may explain the rise in incidence of diabetes mellitus in cats.

So – What does the future of veterinary nutrition hold?

Also an interesting question for which I can only speculate an answer. The use of nutrigenomics may change or refine veterinary nutrition. Nutrigenomics deals with the influence of genetic variation on nutrition by correlating gene expression or single-nucleotide polymorphisms with a nutrient's absorption, metabolism, elimination or biological effects. By doing so, nutrigenomics aims to develop rational means to optimize nutrition, with respect to the subject's genotype. By determining the mechanism of the effects of nutrients or the effects of a nutritional regime, nutrigenomics tries to define the causality/relationship between these specific nutrients and specific nutrient regimes (diets) on human health. This may aid, in part, with development of more refined dietary formulations for health and disease. Other future developments that may be beneficial include clinical trials with therapeutic foods and development of disease-specific nutrient profiles. Currently, AAFCO only recognizes nutrient profiles for four healthy life stages: gestation, lactation, growth, and adult maintenance. Hopefully with continued research, we will continue to get a better handle on nutritional requirements and nutritional management of different diseases beyond "low protein and phosphorous with renal failure". Through continued research especially with naturally occurring disease and the continued formulation and development of diets and perhaps nutritional supplements we may be able to continue to improve on our ability to prevent and manage disease in dogs and cats.

There are many resources available including

The ACVN (http://www.acvn.org)

Angell Memorial: 617 / 522 – 7282

Michigan State: 517 / 432 - 7782

Ohio State : 614 / 292 – 1221, http://www.vet.ohio-state.edu/nssvet.htm

Tufts University: 08 / 839 – 5395 ext 84 696

UC Davis : 530 / 752 – 1387 , www.vmth.ucdavis.edu/vmth/services/nutrition/nutrition.html, http://www.ucvmc-sd.vetmed.ucdavis.edu/nutrition.cfm

University of Missouri: http://www.vmth.missouri.edu/clin_nu.htm

University of Tennessee: 865 / 974 – 8387 utvns@utk.edu

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