Are Grain Free Diets causing Heart Disease? An Overview.

I wrote this blog post series in order to explore the connection of grain-free diets with dogs developing the heart disease known as DCM, or dilated cardiomyopathy. I have always recommended grain-free diets. As you can imagine, I was concerned when in the summer of 2018, the FDA received over 500+ reports of dogs developing this relatively uncommon type of heart disease. 91% of the dogs affected were eating grain-free diets. Since then, there have been more cases, although as of this month (June 2020), the FDA has not released any updates. So the current tally of cases is unknown.

I have spent the past year researching and preparing information on this topic. I joined facebook groups where pet owners shared their experiences and heart-breaking stories about their dogs developing DCM while on a grain-free diet. With everything I’ve read and researched, I do believe that there is a connection between grain-free and the new DCM cases. However, I do not think it has anything to do with the presence or absence of grains. I also do not think that it is due to lack of science backing up grain-free diets or lack of feeding trials.

Rather, I am most suspicious of a change in the ingredients that went into grain-free diets around 2016. In this blog series, I will show you what those changes were and why they are worth paying attention to.

The Grain-Free Diet Philosophy

In the early 2000s when they first came on the market, being “grain-free” was just one way that the new, health-conscious brands differentiated themselves from the traditional grain-inclusive brands. But the grain-free brands were and are actually unique in more ways than just avoiding grains.

The grain-free brands introduced a new philosophy of feeding altogether:

• They eliminated by-products
• They sourced higher quality ingredients, some of which were “human-grade,” which differentiated them from “feed grade” ingredients that traditionally went into pet food.
• They focused on a more carnivorous diet with more animal protein and organ meats
• They avoided grains BOTH because of the high carb load, but also because the low quality, highly inflammatory, genetically-modified grains in most pet food brands were (and are) creating problems for the pets that consumed them.

These are the initial aligning principles that many grain-free brands aspired to. “Grain-free” became synonymous with a more wholesome, natural approach to dog food.

All of that being said, not every brand in the grain-free category followed all these rules. This created a spectrum of quality within these brands. There’s no organization or representation behind the grain-free label. There is no independent monitoring of these foods. Some grain-free brands continue to be high quality while others are not.

Low-quality grain-free brands actually include high levels of carbohydrates. Even worse, some still use GMO ingredients that happen not to be grains. And some even include by-products. But as long as they “avoid grains” then they are able to benefit from the “natural and healthy” reputation of these pet foods.

While not perfect, in my opinion, the offshoot of grain-free brands were and still are a step in the right direction. As a veterinarian, they allowed me to treat pet allergies without having to resort to questionable prescription diets made from soy or chicken feathers.

They also pushed for a new conversation within the pet-owning and veterinary community asking the question: what SHOULD we be feeding our carnivorous animals? Is it ok to put sugar, by-products, and inordinate amounts of corn into pet food? And even with the new concern with grain-free diets, this is still a conversation worth having.

Grain-Free Diets and Recent DCM Cases

In 2018, a cluster of dogs that were eating grain-free diets developed dilated cardiomyopathy, or DCM. This is a type of heart disease that is often associated with a nutritional deficiency, and in particular, a deficiency of the amino acid taurine. The connection to taurine deficiency in these new cases appears less straight-forward.

While I do believe that there is a link between the recent DCM cases and certain grain-free dog food formulas, I am most suspicious of a new ingredient/ contaminant/ new way of processing happening with these diets.

DCM began as a “cluster” of cases. This is a new problem and unlikely something that has been happening under the radar for the past eighteen years. DCM has been known to have a possible nutritional cause since the 1980s. The first thing a cardiologist asks when a dog is diagnosed with DCM is “what are you feeding?” It is unlikely that cardiologists missed multiple cases of DCM in dogs eating grain-free diets in previous years and only in 2018 did they start to report it. Grain-free diets have been on the market since the early 2000s.

The vast majority of my clients over the years fed grain-free, and except for pets on vegan diets, I have never seen one case of DCM (until recently where I have seen a few). Grain-free sold 3 billion dollars worth of pet food in 2016. As a very rough estimate, if each bag costs about $50 and dry food accounts for most pet food sales, that would mean that 60 million bags of grain-free pet food were sold in 2016. And yet, only 2 DCM cases were reported in that year (and based on the FOI report, these early incidences were mainly in cats):

Many are suspicious that DCM may be caused by the inclusion of specific ingredients in grain-free diets: peas, lentils, and legumes. And there is validity to this concern. However, I am suspicious that it is not the ingredients themselves (ie. peas and lentils being bad for dogs, even if they are high in phytates), but rather something is specifically wrong with THESE peas and lentils going into pet food and/or their unique combination with low-taurine meats.

When I started looking into this trend, I found a strange thing: almost all grain-free companies changed or altered their ingredients in 2016 to include more peas and lentils in their formulas. The DCM cases first appeared in 2018, just long enough for a nutritional deficiency/ problem to begin showing up.

If many companies all of a sudden added more peas and lentils to their formulas, it is highly likely that there was a cheap(er) source of peas +/- lentils available on the market. One thing we learned from the melamine pet food toxicity scandal in 2007 is that most pet food companies source ingredients from the same places. I believe that we should look more closely at these sources.

I do not know what exactly changed – could there be an unknown contaminant (herbicide, pesticide) that incidentally allowed the price of peas and lentils to come down? Was there a change in processing of raw materials?

I am not discounting that there may also be a problem with canines consuming too many pulses (legumes, peas, beans) in the diet. Or that there is also not a genetic or breed predisposition. However, I feel this may only be adding to the problem, rather than the primarily cause. After all, the genetic predispositions have always existed but for some reason only became a problem in 2018.

Why I Don’t Recommend Traditional, Grain-Inclusive Brands of Dog Food

With the recent spike in DCM, many veterinarians are recommending switching dogs to traditional grain-include diets, such as Purina, Hills Science Diet, Royal Canin and Iams/Eukaneuba. And while these diets may be less likely to cause DCM, they can instead cause a whole host of other problems.

I confidently believe that grains themselves aren’t the ‘bad guys.’ And including or not including grains in the diet doesn’t matter too much. In fact, dogs do quite well eating oatmeal or brown rice. Rather, the problem is the specific type and quality of grains going into traditional, grain-inclusive dog food. And because not all of the problematic ingredients found in this type of food are grains, I often lump them all together under the title “grain-inclusive ingredients.”

Corn, canola, soybean, and sugar beets—all of which are genetically modified— are some of the most common ingredients used in traditional grain-inclusive dog food formulas. One large scale study in people showed that the people who ate diets high in government subsidized grains (corn, soy, wheat) had a 37% increased chance of having inflammation in their bodies, 34% increased chance of becoming obese and 21% increase in abnormal blood sugar levels. In addition to being genetically-modified, these foods have been selectively bred for mass production. This makes our wheat and mass-produced corn today completely different than the wheat or corn our grandparents ate.

In addition, most GMO crops are all sprayed multiple times before harvest with the carcinogenic herbicide Roundup. Look at the ingredient label of what your pet is eating: if there is some form of corn, soy, wheat, canola or beet pulp (derived from gmo sugar beets), then your pet is consuming large amounts of Roundup. Why is this true? Because these crops have been SPECIFICALLY genetically modified to not die when sprayed with RoundUp. That is the most common genetic modification. Which means they can safely be sprayed on these crops and the plants won’t die. Which also means, anyone who eats foods with these ingredients is consuming Roundup. And probably lots of it.

Roundup, also known as Glyphosate, has been shown in studies to disrupt the microbiome (or the good bacteria in the gut), even at “safe levels.” More and more studies are showing the importance of having the right bacteria in the gut. Bad bacteria have been shown to be linked to obesity, inflammation, anxiety, chronic diarrhea, and a whole host of other diseases. Even if you give your pet probiotics, but feed a corn and soy-based diet, the good bacteria is likely not surviving the onslaught of RoundUp in the diet.

As a veterinarian, I disproportionately saw the development of diabetes and skin disease in pets fed grain-inclusive diets such as Science Diet and Purina. I see diabetes very rarely in dogs that eat grain-free. In particular, dogs that ate Beneful and Purina seem predisposed to developing diabetes. And I understand that this is anecdotal and entirely my experience, but I believe that THIS is something that few veterinarians or companies talk about. We just assume that diabetes is something that “happens” rather than look into its possible connection with certain diets.

Skin disease, showing up as bacterial skin infections, ear infections, yeast overgrowth and itchy skin in general is also more common in pets eating high corn and grain-inclusive diets. The most common reason that pet owners switched their pet to a grain-free diet over the past 10 years is because of itchy skin. Success stories about itchy skin and bacterial skin disease disappearing when taken off a grain-inclusive diet abound. In fact, I noticed it worked so well back in 2009 when I first graduated from vet school, that I used it as my first line of defense in itchy skin and chronic ear infection dogs.

The last myth that I will dispel in great detail in my posts is the idea that “lack of science” in grain-free diets created the DCM problem. Stay tuned to learn more about this convoluted story.