Category Archives: Nutrition Resources

Pet Food: What You Need to Know

This article, originally published in 2010 by Dogs in Canada, addresses some core underlying issues in relation to commercial pet food.

Hot buttons: Pet food facts and fallacies

First published by Dogs in Canada in February 2010

What do you look for when you choose a food for your dog? If you’ve committed to a home-formulated diet, it should be one that has been created and tested by a veterinary nutritionist. For those choosing commercial foods, some of the issues most often raised by consumers are not, in fact, the most pressing considerations. Let’s take a look at pet food facts and fallacies.

Unappealing ingredients

Humans tend to have a visceral reaction to food items that are beyond the norm of their experience. The Scottish dish haggis is viewed with repulsion by almost anyone who didn’t grow up eating lamb heart and lungs stuff into a sheep’s stomach. Brains seem to be another taboo food item in much of North America, yet in his lecture on pet food myths, David Dzanis, D.V.M., Ph.D., D.A.C.V.N., showed a slide of a can of pork brains in gravy, intended for human consumption.

So ingredients we find repulsive can have a rightful and nutritious place in dog food, and shouldn’t be dismissed out of hand. Some people readily eat liver, kidneys and intestinal casings, and it shouldn’t be a shock to find them in lists of dog food ingredients, though they may also be called simply “meat by-products”. According to the AAFCO (Association of American Feed Control Officials) definitions, all such ingredients must come from the clean parts of slaughtered animals. No 4D (dead, dying, diseased or disabled) animals are allowed. And though the AAFCO has no regulatory authority in the United States or Canada, most reputatble pet food companies choose to follow their definitions and guidelines.

Wheat gluten became the champion of unappealing ingredients following the 2007 pet food recalls. But it’s important to remember, as Dzanis pointed out, that the ingredient for all the trouble was not wheat gluten at all, but wheat flour, and that it had been intentionally adulterated with melamine and related compounds to falsely raise its protein levels. There is nothing inherently wrong with wheat products, gluten products or any combination thereof.

One of the lessons we can take away from the pet food recall is to worry less about the presence of an unappealing ingredient and much more about the source and trustworthiness of all ingredients.

Controversial ingredients

Here, the issues are a little thornier, as specifics on both sides of the ingredients in question have some merit.

Flouride has long been controversial in human health, touted as preventing tooth decay and routinely added to drinking water and toothpaste, but also implicated in fluorosis and osteosarcoma. In 2008, Health Canada lowered its maximum allowable level for fluoride in water from 1.5 milligrams per litre to 0.7.

In 2009, fluoride suddenly became an issue in pet food, with the U.S. Environmental Working Group releasing a report on fluoride levels it detected in dog food. Trace amounts of fluoride are found in almost all foods, so it’s not surprising that the group detected fluoride. But the EWG claimed to have found levels 1.6 to 2.5 times greater than the U.S. Environmental Protection Agency’s maximum allowed concentration in drinking water.

There’s a bit of sensationalism going on here, because the EPA maximum for fluoride in drinking water is based on a safety margin 100 times lower than levels found to have an effect on people. The National Research Council 2005 publication Mineral Tolerance of Animals lists 180 milligrams per kilogram – 16 times the maximum level found by the EWG – as the lowest level necessary to produce a slight reduction in food intake. Still, if you’re on the “anti” side of the fluoridation issue, you may want to be aware of its presence in commercial dog food.

An uglier ingredient that has long been rumoured to appear in pet foods is the pets themselves. Critics of commercial pet food often point to the rendering of dogs and cats, often those euthanized at shelters, and the use of rendered products in pet foods, and consider their case made. But there are two types of renderers – an animal pick-up service (which does pick up euthanized animals from shelters) and a slaughterhouse-dedicated plant. There are many uses for rendered products other than in pet foods, and the products from the former type of renderer are of lower quality, so there is no incentive for pet food manufacturers to use them. The Food and Drug Administration (FDA) conducted an analysis of a number of commercial pet foods and found no evidence of any dog or cat materials in them. Still, disturbingly, they did find residues of pentobarbital (a euthanasia drug), and could not determine a source. So the actual concern should not be that there are dogs and cats in pet food, but that there is pentobarbital.

Substantiation of nutritional adequacy

Here, we do have something of a thorny issue. Pet food products can be tested for nutritional adequacy either by chemical analysis to determine if a formulation meets nutrient standards, or by feeding trials. Each method has some shortcomings.

With chemical analysis, the levels of nutrients in the food may be actually determined via analysis in the lab or by estimates of nutrient content based on the food’s ingredients. The results are then compared to the accepted nutritional requirements of the animal. Though this method has the advantage of being easily verifiable by regulators, it has the disadvantage of not being able to examine the actual bioavailability of the nutrients. A formulation can look good on paper but not provide the nutrients to the animal eating it.

Feeding trials are generally preferred by veterinarians and dog owners, but they also have their drawbacks. The pet food manufacturer often conducts its own feeding trials, with no oversight, so you are relying on the integrity and competence of the company. Questions have been raised about whether the trials are long enough or sensitive enough to actually reveal deficiencies in a food.

The two methods tend to counteract each other’s shortcomings. So your best assurance of adequate nutrition in a food is if it has been tested with both methods. Most products that declare having been through a feeding trial also meet the nutritional profile. That fact is even starting to appear on the labels of some foods, in response to consumer concerns.

Author info: Cheryl S. Smith is an award-winning writer and certified pet nutrition consultant who has attended and addressed many nutrition conferences. She and ‘Nestle’, a Border Collie mix, are enjoying their hobby, finding letterboxes while out on wonderful hikes.