Saturday, February 16, 2008

Pet Foods: notes from the experts

Towards a greater understanding (part 2)

There are many variables that go into making informed decisions regarding what to feed a healthy dog or cat. Having a solid veterinary/ client relationship forms the foundation from where information can be sifted taking into account each pets unique circumstance in order to come up with a reasonable dietary plan.

Among the most important issues with respect to pet food is that we have to make dietary choices based on the best science and evidence available and avoid the allure of unsubstantiated claims. The big challenge here is that things aren't always clear cut. For example dog food companies, whole food advocates, and purported alternative nutritionists all -in one form or another- fall under the sway of faddism, premature nutrient recomendations, consumer driven demands, and market pressures.

The more informed we are the better. If our information is balanced, dispassionate and accurate then picking a path through this quagmire is easier. With that in mind, we can go back to the Veterinary Forum nutritional expert panel for more interesting discussion regarding pet food and the state of the industry.

On ingredients

This appears to be one of the most pressing issues when it comes to some of the common general misunderstandings. Part of the problem stems from a general lack of basic skills in science and general nutrition which can impede a more nuanced perpective of this complex issue.

At least some of the details regarding food ingredients, preservatives, additives, and other constituents need to be understood enough so that prudent choices can be made by veterinarians and pet owners. For example, a pet food company might cut corners too much, or someone may claim a certain chemical additive is just poison. Armed with the right tools, a person could effectively analyze the issue at hand and make a rational more balanced determination of the problem or claim and what to do about it.

One of the interesting points mentioned in the discussion was that people in general seem to lose sight of the fact in spite of the huge number of available foods products on the market, animal needs have not changed too dramatically. Delaney notes “the nutritional needs of dogs and cats really haven’t changed. Yet, so many new products are being introduced. Veterinarians need to start by understanding the nutritional needs of dogs and cats and the individual factors that affect those needs.”

A rough analogy is that a shirt and jeans are always the basic and essential part of a teen’s attire. You can dress it up, loosen the pants, change the colors, add jewelry, or add whatever puffery the teen demands; but in the end the jean and t-shirt never goes away.

A detailed discussion of all the common components of food such as micro and macronutrients is beyond the scope if this post. However, we will touch on one topic mentioned by the experts on the panel as an example of some of the issues involved with food sources and pet food ingredients.

There is a lot of misunderstanding regarding the meaning of macronutrients in pet food. These are the main components of a diet and comprise the bulk of for example proteins, fats, and carbohydrates. Freeman notes “There’s so much misinformation about ingredients on the list. For example, lamb listed as the first ingredients is sometimes perceived as better than a by-product, which has become a frightening term to some people. Yet, some labeling might list the first ingredients as beef heart, beef liver, or beef lung without the word by-product.” This belies a very basic problem with the attitude and general perception of what an acceptable macronutrient might be. Daristole adds that “Consumers may not understand that most of the macro-ingredients in commercial pet foods are indeed by-products of the human food industry, not because they are bad for anyone but because of food preferences.

If one stands back and thinks for a moment, it becomes evident that these are big issues and could be barriers towards comprehending nutrition at the most basic levels. Roudebush very eloquently reminds the panel that “My grandfather and father grew up on farms, and when an animal was slaughtered, all of it was used. There were no by-products. We have gotten away from that practice. People who are entering veterinary medicine today have less of that background. Then, so much of it is cultural in the United States, where people are less accustomed to having contact with where our food comes from and how it is used.” This is not really a yearning call for days of old. It is an important observation that requires our attention as we try to navigate through the issues of pet food ingredients.

On the other hand, a promising and positive development has been the increasing consumer awareness of “greener” and more wholesome (organic) food ingredients as well as concern for how our food sources are handled and treated. This opens the doors to perhaps a more balanced approach to a host of agricultural practices and animal husbandry techniques.

Roudebush states that “The AAFCO manual defines organic as a formula feed or a specific ingredient within a formula feed that has been produced and handled in compliance with the requirements of the USDA natural organic program.”

The problem seems to be, that due in part to a “disconnected” consumer, terms and descriptions like “organic”, “nature”, and “human grade”(1) that supposedly denote some type of superiority either in production methods or nutritive value over “conventional” methods turn out to be more semantics than anything real.

In other words, we shouldn’t throw the baby out with the bath water when it comes to evaluating the pet (or human) food industry. Though a laudable ideal, the organic industry has its own “foot print” to contend with. The book “An Omnivores Dilemma” is a good introduction to the realm of food production and the challenges of feeding the masses well while balancing food gathering and distribution.

Raw, commercial, and homemade pet food

In and of itself, the concept of raw food diets is simply another way of delivering food to pets. The problem is when people claim that it is a superior method for feeding dogs and cats. Though still a fairly rare practice in the US (more common in Australia) it is on the rise and there are several companies that distribute different types of commercial raw food mixes.

According to Freeman “ there are no proven benefits linked to raw diets, yet there are multiple studies showing nutritional imbalances, both in commercial and homemade raw diets, and multiple studies showing contamination in the vast majority of raw diets. There is a risk for the people in the household but also for the pets themselves. So, in terms of raw-food diets the risks far outweigh any potential benefits.”

Freeman, Curchill, Laflamme and Tefend note that there are more reports of nutritional deficiencies and excesses with raw and homemade diets than with many commercial diets. Roudebush notes that no AAFCO maintenance feeding trials have been done on any homemade prepared diets and this is a problem when looking for evidence.

Laflamme mentioned that there have been two independent studies that “compared dogs fed commercial pet food with dogs fed homemade diets. The study (1999) I’m most familiar with involved 1,000 dogs in three different groups…There were significant differences in terms of health problems being greatly reduced by the feeding of commercial pet foods.”(2)

On the other hand, this is not to say that home made foods in general don’t have a place “on the table” and indeed can often be a critical part of the nutritional puzzle for some pets and for any owner willing to put in the effort needed to do it right.

However, they need to be complete and balanced and Churchill cautions that “I frequently see well meaning owners make substitutions to the recipe, until over time, ‘diet drift’ occurs, and the diet may no longer resemble the original formulation.”

McChesney and Churchill also add that salmonella risk is higher when dealing with the day in/ day out processing of homemade and especially raw diets and extra care needs to be given for maintaining routine hygienic standards. Cooking homemade food does not significantly diminish its dietary quality (problems with heat labile substances can be corrected) and reduces the risk of food borne disease.

Again, it is more advantageous to take note of the evidence, science, and -to a degree- the opinions of experts in the field. No, it’s not perfect and problems abound, but the ability to make the best decisions regarding what to feed our pets lies here and not on assumption, hearsay, what we’d like to believe.

(Part 3 touches very briefly on the recall and regulatory issues)


1) Roudebush notes “According to AAFCO the term human grade cannot be used anymore. However the term continues to be used on websites, in brochures and on some labeling.”

2) Interestingly, there is an often repeated study alternative veterinary nutritionists fondly allude to that claims to support raw foods or the broad use of nutritional supplements. It is an old 1940’s report known as “Pottingers cats” that seemed to evidence multi-generational deficiencies in cats with cooked or “processed” foods. The more likely reality was that the affected cats suffered from other confounding issues such as a species specific sensitivity to taurine deficiency, a heat labile protein, that when added to a cooked diet corrects this problem.


MIchael Palka said...

food should contain added spirulina glucosamine

wandering primate said...

Both of those are a bit overhyped and fall partly into either nutritional faddism or jumping the gun with limited info (i.e; cheaper ways to get the limited nutrients spirulina might add- probably superfluous anyway, evidence for adding glucosamine is getting less & less convincing).