Changes in Grain Free diets: Could this be causing DCM? PART TWO

Disclaimer: These blog posts are based entirely on my personal opinions, experience and (general) research. I am not involved with the FDA report in any way or affiliated with any of the brands of dog food discussed in these articles. My intention in writing these posts is to share my opinions how to best feed and care for your animals in light of this developing story.

I have written two blog posts that specifically look at the Grain Free diet and DCM connection. They are separated into two topics:

Part ONE Exploring the myths: Grain Free Diets and DCM

Part TWO Changes in Grain Free diets: Could this be causing DCM?

I have also put together a PDF available for download that includes my recommendations on dog foods, supplements and what to feed your pets in light of these recent DCM controversies (COMING SOON)

It is very sad and unfortunate that we are seeing these new incidences of dilated cardiomyopathy, or DCM, in our dogs. I extend to you my deepest sympathy if your pet has been affected by this disease.

It is a confusing time, but hopefully some of the information I provided here will offer you some more clarity on this situation.

Feel free to join our group on facebook if you would like to discuss this topic, or other topics in holistic pet medicine further.

Grain free diets have been around for over 20 years. I have been a veterinarian for over a decade now, with the majority of my clients only feeding Grain Free diets. I have personally never seen or diagnosed any dogs with dilated cardiomyopathy, or DCM that were eating these diets.

This made me suspect that there may be a recent change that may have instigated this surge of cases.

One counter argument to this idea is that dogs may have always been developing DCM, but it had just gone under the radar.

However, I think this is unlikely for a few reasons.

The reality of the economics and social factors in our world today are that Grain Free diets, being more premium diets, are quite expensive. The crossover of the population that feed more expensive foods are also likely the same people that would spend the money to take their pet to a cardiologist. (This is not to say that people feeding other diets would not take their pet to a cardiologist, it is just to point out that the people who do feed these diets are a population that would also likely spend money on a consultation with a specialist).

The second reason that cardiologists and veterinarians missing this problem is unlikely, is because DCM is a disease that has historically been linked to diet in the past.

In the 1980s, cats were developing a host of symptoms (one of which was DCM). Researchers discovered that these health problems were directly caused by taurine deficiency in the commercial cat foods at the time.

Through this, we learned that taurine is an essential nutrient for cats.

It was believed, then and now, that dogs do not need extra taurine added to their diet, but that their bodies can synthesize it from precursors: two amino acids called methionine and cysteine.

It would be unlikely that cardiologists would have seen even one dog with DCM and would have not asked questions about the diet.

There is a chance that, because the incidence of this disease is so low, that the dispersed cases did not become more apparent until Grain Free diets really exploded into the pet food market.

This is possible.

However, it seems strange that even a few cases weren’t filtering into the general awareness of cardiologists even before 2018. Like I said in previous posts, Grain Free diets have been around now since the early 2000s. So if this were happening on a smaller scale even before 2018, I suspect we would have already been seeing it in previous years.


In this chart of the recent complaints to the FDA, one can see the clustering of cases starting in 2018.

The FDA report offers a similar sentiment of this being a new problem, when they say in their most recent report:

“Another puzzling aspect of the recent spike in DCM cases is that they have occurred just in the last few years. The FDA is working with the pet food industry to better understand whether changes in ingredients, ingredient sourcing, processing or formulation may have contributed to the development of DCM.”

So if your pet has developed this disease, just know that you did nothing wrong by feeding a Grain Free diet!

I am suspicious that recent changes in the Grain Free diet formulations may be responsible for this increased incidences of DCM in dogs. Changes that unfortunately no one could have foreseen would be a problem for some dogs.

Let’s take a look at them now.

So what the heck is happening?

It is important to keep in mind that the chances of your dog developing this disease are still relatively small.

I am not saying this to downplay the significance of this problem.

Even one dog dying prematurely due to improperly formulated pet food is one dog too many.

My thoughts in conveying the statistics are to show that this is not really happening on a large scale in all dogs eating Grain Free diets, as some of the articles would have you believe.

By conservative estimates, there are currently around 77 million dogs living in households in the United States (that number has been more or less stable for a few years). Grain free diets occupied about 20% of the pet food market share in 2016. And while this is not a perfect measurement but a very rough estimate, if we use these numbers, we can say that around 15 million dogs were eating Grain Free diets in 2016. With 320 diagnosed cases in 2018, this means that if your dog is eating a grain free diet, the chances of developing this disease are 0.002%. So roughly 1 dog per every 50,000 dogs that ate this food developed dilated cardiomyopathy, or DCM.

However, diseases caused by dietary deficiencies have a lag time and can take months to years to show up. So we may be seeing more cases now and also going forward.

Changes in grain free formulations

Like I said in previous articles, I have been recommending Grain Free diets for over a decade now. The majority of my patients eat Grain Free diets and I have never seen a DCM case associated with it. I have only seen two DCM cases, and in both cases the dogs were eating vegan diets (vegan diets have a well known association with DCM due to lack of animal protein).

I understand that the incidence of this disease is very low (I calculated it at 1 out of every 50,000 dogs).

But it still seemed strange to me that I had never seen a case of it in the past 10 years.

Because most of the cases were clustering in 2018, I wanted to see if there were any obvious changes in formulas in the past few years.

In order to track these possible changes, I decided to look through the internet archives, using the website: Wayback Machine and track any ingredient changes over the past few years.

I specifically wanted to look at the ingredients in the varieties implicated in the DCM complaints.

Here are some examples of the formula changes that I found:

Here is a snapshot of the Acana Pacifica Dog food label from September 20, 2012 (Date visible on top right in black box).

Now here is a screen shot of the ingredients today (August 15, 2019):

The ingredient change happened sometime in the year 2016.

In the image below, you can see that the company changed their formula in “spring of 2016.”

(At this time, Acana also changed the name of this variety to Wild Atlantic. It appears they have recently gone back to the Pacifica name. The name change doesn’t matter, but I am only mentioning it here to decrease confusion.)

Here is Zignature’s Kangaroo formula from July 14, 2016:

And here it is at it currently stands on August 15, 2019:

Earthborn Coastal Catch variety from 2014 (The archives were finicky and could not allow me to see 2016 ingredients):

EarthBorn Coastal Catch today (August 15, 2019)

Blue Buffalo Wilderness High Protein Grain Free Dog Food Salmon in 2016

Blue Buffalo Wilderness High Protein Grain Free Dog Food Salmon today (August 15, 2019)

Taste of the Wild Pacific Stream 2015

Taste of the Wild Pacific Stream ingredients today (August 15, 2019)

In comparison, here is a formula also produced by Taste of the Wild called Wetlands Formula, that does include peas, but only once. It is also a lower ingredient.

They had no changes to their formula.

They also have no cases of DCM associated with eating this variety in the recent FDA complaints. (This also happens to be the variety that I found helped dogs with dry skin in my early years as a vet):

Taste of the Wild Wetlands formula ingredient list today August 15, 2019

There were more companies that changed formulas around this time that I did not include on this list.

Once I started looking into it, I was a shocked at how many Grain Free companies changed their formulas around 2016 to add more peas or lentils or move them up in the ingredient list (meaning that there is now a high quantity of them in the diet). Not ALL of the varieties implicated in the DCM cases changed their formulas, but most/many of them did.

Could these formula changes be the reason for the recent spike of DCM cases?

I don’t know, but it is worth looking into.

Why the changes?

The first question I asked myself was: Why did all these brands change their formulas around this time?

One possibility is obviously economic: Some estimates show that Grain Free diets have grown by almost 10% of the market share every year in the past few years.

This growth could have meant that smaller companies were being bought out by larger corporations with different values.

Or perhaps due to the sudden growth, using high quality and expensive meat products became financially challenging. Meat by-products, such as those used by the Grain-Inclusive brands are cheap. Grain Free companies pride themselves on sourcing better quality meats, and those are expensive. And so, the Grain Free companies needed to add more carbohydrate sources (lentils and peas) in order to stay profitable.

Or maybe they were just looking to increase their profit margins.

Or perhaps something else was happening entirely: Did all of these companies add more peas and lentils because there was a cheaper source of peas and lentils available on the market in 2016? And could something about the processing/production of these cheaper peas/lentils be causing the recent DCM cases?

We learned from the melanine toxicity scandal in 2007 that many dog food companies source their ingredients from the same places.

If the supply-side that produces and sells peas and lentils changed their procedures to decrease costs – could those changes be negatively affecting nutrient absorption?

Perhaps the producers added a new preservative, a new chemical or did things a little differently when preparing the peas and lentils for shipment to the pet food companies.

Or maybe it is something more basic.

Adding in too many peas and lentils could have just been a problem in itself.

We know that rice can be a problem with DCM. Rice binds taurine and removes it in the feces. Could peas and lentils be affecting taurine absorption or bioavailability through a similar mechanism?

Peas and lentils are part of a class of foods called Legumes.

Legumes are high in anti-nutrients such as phytates and lectins. These compounds found in certain foods have all been shown to block the absorption of certain nutrients.

Lectins and Phytates decrease the absorption of Zinc, Iron, Magnesium, Phosphorus, and Calcium.

Perhaps the anti-nutrients also affect the absorption of taurine?

Or perhaps they block taurine indirectly.

For example, in one study, when rats were deprived of zinc in their diets, their bodies started excreting taurine.

If the lectins in the peas and lentils were theoretically binding zinc in the diet and preventing its absorption, the decreased zinc levels could have led the body to excrete more taurine.

One thing that we do know about anti-nutrients, such as phytates and lectins, is that they can be inactivated with certain cooking methods. Ancient civilizations have known this for years. Through historical records, we found that many ancient peoples prepared foods high in anti-nutrients, such as corn and beans, in such a way that most of the anti-nutrients were deactivated. Proper soaking and cooking dramatically decreases the anti-nutrient content.

This is why even a simple change in the way the peas and lentils were processed before or during making dog food could have affected their anti-nutrient content.

There are various complicated mechanisms that could be at play here. The body is a complex organism and many parts affect each other in different ways. The answer may or may not be a linear explanation (ie one thing is missing and that is causing the whole problem).

The only thing that doesn’t entirely fit the anti-nutrient/ lectin theory is that grains also contain them.

This has been something that veterinary nutritionsists have known about for years and take into account when formulating diets with ingredients such as corn, soy and wheat. However, even with grains, we don’t have a perfect formula for eliminating anti-nutrients or supplementing with additional nutrients. Many of the tactics are just educated guesses.

I have been unable to find a list that shows me which food items contain the most anti-nutrients (it seems, such a list is not available). So at this time, it still could be that legumes have higher levels of anti-nutrients than grains.

Bowls fill with seeds, grains, and lentils

Too many peas and lentils

Besides the theory of anti-nutrients, a change in processing or procedures, another problem could just be plain and simple: nutrient dilution.

Even though peas and lentils are good sources of nutrition for omnivores, dogs are more on the carnivorous spectrum and need more nutrients that come from animal protein sources. By adding too many carbohydrate sources in general, the animal protein nutrients may have been diluted down and become inadequate.

There is a common practice in the dog food industry as a whole (both Grain Free and Grain-Inclusive pet food) called ingredient splitting, where a few different versions of the same ingredient are listed under slightly different names.

For example, you may see pea protein and pea fiber listed as two separate ingredients, even though they are both peas. By separating ingredients, one can make it seem like there is less of that ingredient (in this case, peas) and more animal protein.

Pet food companies are required to list ingredients in descending order, from most to least, based on pre-cooked weight of that item. By splitting up some ingredients, they can list the more desirable ingredients first, even though by volume there may be more carbohydrates than protein.

If peas and lentils are somehow binding taurine or preventing its absorption, throwing in an extra pea or lentil ingredient into a formula could send susceptible animals over the proverbial edge and into DCM.

Nutritional deficiencies can take a while to show symptoms, so it would make sense that if formula changes happened in 2016, clusterings of cases started to pop up in 2018 and are continuing to show up today.

It does appear that the addition of the extra peas and lentils became a problem for some dogs. However, I do NOT believe that this was some shady practice performed by these companies.

No one knew that adding too many peas and lentils was going to be a problem for some dogs!

You can argue that feeding trials should have been performed on these new formulations. However, as I talked about in the previous post, feeding trials conducted so far on high legume diets show no cardiac changes. So this problem would have likely been missed, even with feeding trials.

Our current feeding trial standards only last 6 months. Many dietary problems can take years to show up.

And yes, it is not ideal that the companies added more peas and lentils to their formulas.

But, to be fair, peas and lentils are traditionally considered to be healthy, whole food ingredients. Certainly better, in my opinion, than industrial corn.

The Taurine- DCM connection

Historically, dilated cardiomyopathy, or DCM, has been linked (in some cases) to a taurine deficiency.

What has been confusing about these recent cases, is that some dogs had normal or even high levels of taurine in their blood. So the taurine connection to DCM has been less clear in these recent cases. However, because diet change + supplementing taurine has improved or eliminated the DCM for many dogs, there may be an association.

There are a few aspects of the recent cases, however that still point to a connection with taurine deficiency.

When I looked at the 515 canine FDA complaints between January 1, 2014 and April 30, 2019*, I found some interesting things. The four most common offenders (diets with the most cases) were diets made with either Kangaroo or Lamb.

*If you want to read the actual complaints to the FDA, google the phrase: “PDF list of FDA complaints Grain Free Dog Food.” Because it is a PDF link, I cannot link to it from this blog post.

Here are the four dog food varieties with the most associated DCM cases:

  1. Zignature Kangaroo Limited Ingredient (43 cases)
  2. Acana Lamb and Apple Singles (19 cases)
  3. Earthborn Meadowfeast with Lamb (16 cases)
  4. California Naturals Kangaroo with Red Lentils (12 cases) *this variety has since been discontinued*

Lamb has historically been implicated in DCM cases going back as far as 2003, when it was found that Golden Retrievers were developing DCM after being on Lamb and Rice diets.

The pet food industry has known about the problem of lamb mixed with rice for a long time. Lamb is low in taurine. In another study from 1998, it was found that some preparations of lamb meal have low bioavailabilities of sulfur amino acids.* This means that the taurine (a sulfer amino acid) found specifically in lamb, was not easily absorbed or utilized by the dog’s body. p. 134 NRC

I was unable to find the taurine content of kangaroo. However, given the disproportionate amount of dogs that developed DCM on the kangaroo diets, my suspicion is that the taurine levels are low.

Dog foods made with pork, another low taurine meat, were also implicated in a disproportionate amount of cases in the DCM complaints (I am not going by the FDA report/analysis, but rather by the number of cases associated with individual varieties of dog food).

In cats, (the traditional model species for taurine deficiency), a study showed that rice bran increased the need for taurine, apparently by binding taurocholic acid and carrying it out in the feces (p.134 NRC).

It seems that this combination: the rice that pulled out the taurine, combined with the low taurine lamb was a bad combination for susceptible breeds in the past.

And now, through a series of unfortunate events, we have learned about a new bad combo:

It appears that the combination of low taurine proteins, most notably: kangaroo, lamb and possibly pork with high quantities of rice, or legumes such as peas and lentils, seems to lead to the development of DCM in susceptible animals.

If you look at the ingredients of the diets that the affected dogs were eating in the DCM cases, the majority of the dog foods fell into this category. Either they used a low taurine protein, or a high quantity of rice or legumes. There were some exceptions, but most followed this paradigm.

And so, once again I reiterate that I do not believe that it is the “lack of grains” causing this problem, but rather a series of unfortunate food combinations.

High legume diets appear to be a problem for some dogs.

And, recent diet formulation changes, unfortunately went a little too far with the amount of legumes they added into their diets.

If you would like diet suggestions and recommendations on what to feed in light of these findings, I have created a PDF on my DCM/Grain Free Diet page that is available for purchase and download. Click here to learn more.

Some final food for thought

  1. Dogs may be more carnivorous than we originally thought. One of the main criteria that some nutritionists have used as proof that dogs are omnivores is their ability to synthesize their own taurine. This may not be true for all dogs. In an ironic twist of fate, it was this belief (that dogs are carnivores and not omnivores) that led to the creation of the Grain Free diets to begin with.
  2. We don’t know everything about dog nutrition! When you start looking at the data (which I have) you find vast gaps in our knowledge about dog nutrition. We don’t even fully understand human nutrition! And you can imagine how much scientific inquiry has gone into that pursuit.
  3. The vast majority of dogs that developed the DCM were eating only dry food. Never rely on dry dog food alone for your dog’s nutritional needs! We don’t know enough about a dog’s nutritional needs, or what would be an optimal diet vs a survival diet to be able to create a perfectly balanced synthetic pet food.
  4. Always supplement your pet’s diet with some fresh food. If you are worried about taurine deficiency, supplement with foods with a higher taurine content (see my PDF for more detailed information). Taurine supplements on their own did not always fix the DCM changes in affected pets, even though the markers for taurine increased in the blood. Pets, like humans, need real food, not just synthetic supplements.

Thanks for reading!

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