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Why Have So Many People Decided That Dogs Can't Eat Grains?

A human eating disorder appears to be having an impact on the health of dogs.

This image is public domain CC(0)
Source: This image is public domain CC(0)

A human eating disorder affecting pet owners is producing consequences that are now impacting the health of pet dogs. Recently the popular press and broadcast media have been reporting a warning from the US Food and Drug Administration (FDA) that the use of certain high-end dog foods may be associated with an increased risk of one form of heart disease (canine dilated cardiomyopathy). What all of these brands of dog foods have in common is that they are advertised as being "grain-free," and many of the manufacturers claim that they have reduced the amount of gluten in the food to nearly zero. The reason dogs are being fed this type of food has to do with possibly unjustifiable anxieties of dog owners.

The Psychological Question

The interesting psychological question is why people would decide to feed their dogs a grain-free diet in the first place. To begin with, these boutique dog food brands are considerably more expensive than regular dog kibble. Most of the popular dog food brands contain substantial amounts of various grains (particularly wheat, corn, barley, and rice). In the grain-free products, these are replaced with legumes (such as peas or lentils) and other sources of carbohydrates (such as sweet potatoes). When I checked the prices of some of these brands I was astonished to find that the combined bill for feeding my small dog (a Cavalier King Charles Spaniel) and medium-sized dog (a Nova Scotia Duck Tolling Retriever) would amount to a bit over $160 a month using one of these products. This is a lot more expensive than the $25-$30 monthly sums that I currently spend on dog kibble for my pair of pets.

Let's go back to see what might be going on to cause people to decide that such an expense is worthwhile. Gluten has become a "red flag" ingredient in many foods. This seems to have come about because of rising awareness of the existence of gluten intolerance in the form of celiac disease in some people. This condition is associated with an immune response that can damage parts of the small intestine and interfere with the absorption of nutrients from food as well as producing severe gastric discomfort. Gluten is a protein in many grains such as wheat, barley, oats, and rye. It gives bread that chewy texture and bakers sometimes add it to their dough for that reason. As a special source of protein, it was considered to be a "health food" in the 1960s and 1970s.

People aren't always great at interpreting what science says about their diets. As the general public became more conscious of the existence of gluten sensitivities, the idea of avoiding gluten containing grains (as a preventative health measure) became popular around 2010. The incidence of celiac disease is not all that high and medical statistics indicate that less than 1% of people have any form of gluten sensitivity. Nonetheless, some surveys found that by 2015 as many as 30% of Americans were trying to reduce their gluten intake despite the absence of scientific evidence that gluten is harmful to people who do not have celiac disease.

Judging by some magazine articles and blogs, there are a lot of people out there who attest to the health promoting aspects of gluten-free diets. They claim that changing to such a regime helped them lose weight, feel more energetic, have a better sex life and so forth. Unfortunately, the real culprit may not actually be gluten itself. Often observing a gluten-free eating rule produces its beneficial effects by causing dieters to cut out unhealthy foods that also happen to contain wheat, like pizza, cookies, and other baked goods, and also processed packaged snacks.

Orthorexia Nervosa

Underlying these growing concerns about gluten may be the fact that in the North American population, there seems to be a rising occurrence of orthorexia nervosa (although the term is not listed in the DSM). The term "orthorexia" first appears in the psychological literature in 1998 and it is defined as an obsession with proper or "healthful" eating. Although being aware of and concerned with the nutritional quality of the food you eat isn’t a problem in and of itself it can become one. Orthorexia is classified as an eating disorder because people who have this obsessive-compulsive problem become so fixated on their idea of what constitutes healthy eating that they can actually damage their own well-being. The obsessive nature of orthorexia is often associated with rather extreme measures that people use to control their food intake, and these can ultimately result in damage to health, increased anxiety, and even the disruption of social relationships.

Some estimates suggest that the incidence of varying degrees of orthorexia may be higher than 20% in some populations (such as millennials). One important aspect of orthorexia is that the individual's obsession with the relationship between their own diet and their health spills over to include intrusive concerns over what their family and loved ones are eating. Since dogs are often considered to be family members, it is not surprising that people with orthorexia have apprehensions about the health implications of what their dog is eating.

The concern about gluten in dog foods most probably was triggered in 2007 when there was a headline making recall of tainted Chinese dog kibble. This occurred because the wheat gluten from a particular supplier was contaminated with melamine (which can cause kidney failure). Those news reports may have been enough to usher in the wave of fear about wheat and gluten in dog food. It seems that this initial scare then spiraled out of control, expanding to include worries about all grains, including corn, barley, and even rice.

As often happens with the dissemination of information concerning human diets, bits of real knowledge are blown up and mixed with misinformation. Ultimately the resulting flawed combination of assertions then becomes an entrenched popular belief. Because this material is spread through the media and the Internet such opinions can become widespread with a disconcerting speed and ease.

Acting on the basis of such widespread imperfect information, pet owners who have the financial resources to buy specialized foods for themselves and their pets have generated demands that manufacturers have started to meet by creating lines of expensive, grain-free, specialty dog foods. Now things become self-reinforcing, since, at least in North America, the expense and rarity of items are regarded by many as proof of the high quality of those products. Thus in the past five years, the number of such grain-free dog food brands has more than tripled.

Do Dogs Need a Grain-Free Diet?

Notice that in all of this discussion so far we have not addressed the basic question of whether or not dogs actually do get celiac disease. The veterinary literature suggests that dogs do not suffer from true celiac disease except for a small percentage of Irish Setters. There is some suggestive evidence that it may also be found in a tiny proportion of Soft Coated Wheaten Terriers, but the data on that is still scanty. While some veterinary texts report that gluten sensitivity is a possibility in any dog, they also seem to conclude that such cases are so rare that it is not necessary to normally check for them routinely, unless there are specific symptoms. In fact, recent data suggests that our domestic dogs have genetically co-evolved with humans in such a way that they now have genes which are specifically designed to help in the digestion of wheat and grain-based food products. These genes are rare in wolves and other wild canines and seem to be an evolutionary adaptation that domestic canines have made because they share our human diet which includes many such carbohydrate sources (click here for more about that).

Still, we should ask: Is it intrinsically harmful to place a dog on an exclusively grain free diet? The FDA is certainly suspicious about this practice. According to their data, there is a trend that is consistent with the recent explosion in the popularity of grain free dog foods. Specifically, they find that there has been a sudden spike in the reports of canine dilated cardiomyopathy in the past couple of years. This appears not to be a simple statistical association since over 90% of the dogs who are reported to have this form of heart disease were being fed on grain-free diets. Such data suggest a cause and effect relationship.

The FDA has only recently started collecting data on this issue and so it is unwilling to issue a blanket warning instructing people to stop feeding their dogs on a grain-free diet. However, they do warn pet owners to be alert to the possible symptoms of this heart condition, which includes decreased energy, cough, difficulty breathing and especially episodes of collapse. If these occur in their dogs, pet owners are instructed to immediately contact their veterinarian.

I suppose that I must be considerably more conservative than the FDA. When it comes to the health of my dogs, in the absence of any specific symptoms indicating gluten sensitivity, I will avoid grain-free dog foods and continue to feed my pets standard dog kibble (which contains wheat, barley, and corn as the sources of carbohydrates). If I do become concerned about the amount of gluten in my dogs' diet, I do not need to turn to the expensive boutique grain-free dog foods. I can always switch to brands of kibble made up predominantly of chicken and rice or lamb and rice. Rice contains virtually no gluten, and popular brands with meat and rice as the only ingredients are usually no more expensive than other common dog foods.

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FDA Investigation into Potential Link between Certain Diets and Canine Dilated Cardiomyopathy (27 June 2019).…