The Simple Truth about Dog Food and Heart Disease

The pet food industry is in a dynamic state, which is both good and bad for our pet’s health. On the one hand, they have recently eliminated the problematic grains – wheat, barley, rye and corn – while on the other they have added a new culprit to pet foods, legumes.

Legumes such as green peas, lentils, and chickpeas (garbanzo beans) are the new darlings of pet food manufacturers. These controversial protein sources made their debut in pet foods nearly 20 years ago, being incorrectly labeled, alongside of carrots, as vegetables. Most can remember the commercials showing peas and carrots falling from above along with the “healthy grains that pets crave” (wheat, barley and corn). I still have a bag of the most popular offering in my exam room on which I pasted a skull and crossbones just to get my clients attention. This particular formulation not only had the unhealthy grains and the debut legume but also dairy products and two forms of sugar. I could not say enough bad about this “illness in a bag”.

Why are legumes included in what I lovingly call “the Big Four” – gluten grains (wheat, barley, rye), dairy (cow’s milk) products, corn and legumes? These are the only four food groups that are capable of inducing the kind of intestinal changes (villous atrophy) seen in gluten intolerance, which leads to a myriad of health woes including IBS, allergies, malnutrition and generalized inflammation.

Nineteen years ago, I learned about my own celiac disease and began writing about the devastating effects of gluten intolerance. It was clear back then that this health issue was a sleeping giant among populations, both human and animal. In fact, I learned about gluten intolerance in dogs in veterinary school over forty years ago. Yes, the Irish Setter was known to suffer from celiac disease and that was before wheat even made it into pet food. It wasn’t until the late 1980’s that wheat became a component of commercial kibble. Before that, the only sources of wheat were table food and dog biscuits. At the time of my graduation in 1979, wheat was already the number two dog food allergen behind dairy products, the latter being attributable to the milk-coated puppy and kitten formulas that were popular at the time. Corn was number four on the list.

Why were these foods such common food allergens? The “Big Four” foods are rich in lectins, tiny little protein complexes that attach to tissue and cause inflammation, starting with the lining of the intestinal tract (the villi). As they do their harm, the body forms antibodies to these culprits and food allergies develop. Initially, this process is covert, all taking place under the covers as the antibodies do their job of protecting us from further harm by disabling and removing these inflammatory lectins. But, eventually the process does come to the surface and symptoms arise, such as nasal congestion and upset intestinal tracts in people and skin and ear issues in pets.

One of the most dramatic food reactions is peanut allergy. Food allergy symptoms comes in many shapes and sizes but none compare to the potentially lethal reaction that some have to peanuts, which “incidentally” is a legume. There are 33 lectins in peanuts, three of which are responsible for the dramatic reactions about which most have heard. People have been known to become so sensitive to peanuts that they cannot be breathed upon by someone who has recently consumed peanuts without having a fatal reaction. Wow! How can that be?

Lectins are tiny. Lectins are smaller than viruses, which are 100 times smaller than most bacteria. That’s pretty small. If one can smell the peanuts on another’s breath, it is the lectins of peanuts registering on the olfactory (smell) receptors, which is enough in some individuals to experience a severe, even fatal, allergic response. Once in the body, lectins can cause inflammation anywhere they come to rest including the joints, lungs, liver and kidneys.

So, why do foods contain these lectins? In nature, these lectins help to protect the plant against consumption by insects. How do legumes grow underground without being destroyed by bugs?? Lectins protect them. Wheat also contains lectins, the most recently discovered being wheat germ agglutinin (WGA). WGA binds to receptors (glucosamine receptors) on the bug larva’s outer covering and prevents the larva from developing its protective outer shell, which is made of chitin. Thus, another name for WGA is chitin-binding lectin (CBL). In this way, the invasion of the wheat grain by bugs is limited by WGA for the plant’s protection.

The high lectin foods are the gluten grains (wheat, barley, rye), dairy products, corn and legumes. A fifth group that affects some to a lesser degree are the nightshade family – tomatoes, white potatoes, eggplant and peppers. Fortunately, cooking these foods reduces the harm done by lectins but does not eliminate the trouble they can cause in sensitized individuals. Once again, think peanut allergy.

Fortunately, the pet food industry has eliminated most of the aforementioned culprits by formulating grain-free diets that are devoid of three of the Big Four. But…their love affair with legumes is very troubling. In my mind, they are only getting away with it because pet food is cooked to death, which not only helps to inactivate lectins but also degrades the overall quality of healthy ingredients. Sadly, the average consumer does not know the truth about the potential harmful nature of legumes. They are not a part of the Paleo Diet for good reason.

With all that being said, the main reason that the consumption of grain-free diets has been associated with heart disease in dogs is not the presence of legumes but the relative absence of animal-origin protein (meat, fish and eggs). Yes, the pet food manufacturers have managed to formulate diets that look good on the label but there is no way that any dried kibble has more animal protein than other ingredients unless the animal products are freeze-dried or the entire product is refrigerated.

Knowing that dried kibble is made to last 2-3 years on the shelf, just how much animal protein can there be in one of these products?? The truth about pet food labeling is that the leading ingredient simply has to be more plentiful than each of the following ingredients on the list, not the sum total of any of those ingredients. In other words, the pet food manufacturer uses multiple carbohydrate sources – and now multiple forms of legumes (even distinguishing between peas, pea protein and pea fiber) – so that there is more chicken or salmon that each of those individual components, but…if you added up all of the carbs and/or legumes, then they would be the first ingredient. Manufacturers know that the owner wants to see animal protein as the first ingredient and by having multiple non-animal-origin ingredients (e.g. potatoes and legumes), they can place it first on the list even though, in reality, there are more potatoes and legumes than meat in that product.  

Herein lies the main problem with grain-free diets and their association with heart disease in dogs. We learned 40 years ago that dried cat foods were contributing to heart disease (dilative cardiomyopathy) in the cat. These formulations were deficient in a very important amino acid called taurine. Taurine is considered an essential amino acid in some species, meaning that it must be supplied in the diet. In other species, taurine is a non-essential amino acid because that species can make taurine from other amino acids. However, some researchers are now applying the term “conditionally essential” to taurine, meaning that some individuals within a species cannot manufacture taurine from other amino acids under certain circumstances. That could prove very problematic for people and dogs as taurine is not only essential for the health of the heart but is also the most abundant amino acid in the mammalian brain. (Maybe that is why the main place people have seen taurine listed is on the label of a very popular energy drink.)

So, we wiped out one of the most devastating diseases is the cat, dilative cardiomyopathy, over 40 years ago by adding one simple ingredient to their food, namely taurine. We’ve answered the $60,000 question of “What is taurine?” It is an amino acid. But what is the answer to the million dollar question: “Where does taurine come from naturally?” Meat! Yes, the only rich taurine rich food sources are meat, fish and eggs.

What does that tell us about the cat food?  There’s not enough meat in it! After all, cats are carnivores. We are feeding them meat-flavored granola and wondering why they are living to a fraction of their life expectancy. Yes, the oldest cat on record lived to be 38 years of age while the average cat in the US lives to be 13-14 years old. No, they are not dying of heart disease anymore thanks to the addition of taurine, but…they are dying of kidney disease, liver failure or cancer, all of which are the result of chronic inflammation. What do lectins do again??

What about the dog? Why has it taken 40 years for us to take what we learned about the cat and apply it to the dog?? Dogs are basically carnivores as well. 75% of their natural diet would be animal protein. Perhaps they have been better at converting other amino acids to taurine than the cat but this apparently is changing, or…the pet food industry has finally reached that critical threshold amount of animal protein in  the dog’s food by substituting non-animal protein (legumes, potatoes, grains) for the much needed animal products. Perhaps it is a combination of the two. Perhaps the inflammation that the lectins from legumes can cause is also partly responsible.

Regardless, it has become apparent that dilative cardiomyopathy is on the rise in dogs. It has always been an entity, primarily among the giant breeds. Well, duh… What does one feed a 100+ pound dog? Whatever they can afford, right? Although all dry dog food is suspect, you do get what you pay for to an extent when it comes to purchasing a pet food. But all dry food are going to be deficient in animal protein – and, thus, taurine – relative to the natural diet of dogs and cats.

Ever since I began studying nutrition through the eyes of food intolerance, I have been recommending against feeding the Big Four – gluten grains, dairy, corn and legumes – and promoting the addition of healthy “table food” (meats, eggs, fruits and vegetables) to the diets of dogs and cats in order to provide them with more of the nutrients they would acquire through their natural diets. I have told countless clients over the years if they did one thing to improve the quality of the food they are feeding it would be to add some real meat or eggs to the diet. Never has this been a more important recommendation.

Most of the articles on the subject of dog food and heart disease have not addressed these specifics yet but I believe with all of my being the above explains why we have seen a rise in heart disease with the advent of grain-free diets. It is not that all grain-free diets are innately bad and cause heart disease. I am glad that pet food manufacturers have succumbed to public pressure and eliminated wheat, barley and corn. (By the way, rice is still a healthy grain, as are sorghum, millet, flax, tapioca and quinoa). But, I am very concerned that the addition of legumes has been to such an extent that the amount of animal protein content is suffering. (Hey, the grained diets weren’t much better when it comes to the amount of animal protein.)  In addition, the damage done by the lectins of legumes may be contributing directly and indirectly to the development of heart disease. A brief study of food intolerance will lead anyone to that conclusion.

In conclusion, the diet is crucial in all aspects of the health of pets and their people. Heart disease has recently taken center stage and presents an opportunity for us to reexamine the feeding practices we have instituted for our beloved pets. Those who have breeds of dogs that are prone to dilative cardiomyopathy (Boxers, Dobermans, German Shepherds, Saint Bernards, Irish Setters, and occasionally Cocker and Springer Spaniels) should pay very close attention to the points made in this article and consider starting a taurine supplement for their pet. But…all pet owners need to know the truth about the inadequacy of pet foods and take steps to make their four-legged friend’s diet more nutritious and biologically appropriate.