Grain Free Dog Food Causes Cardiomyopathy? I think there is more to the story…

On these pages, and countless others on the web, people have gained health benefits from grain elimination. So, many pet owners want to help their pets and do the same. I deployed this tactic after my daughter’s dog had a stroke, and it was I believe an essential part of the recovery (as evidenced by another problem after grain returned to the diet).

I was a bit surprised to hear from my wife, who is a small animal veterinarian, that grain-free diets are now being implicated in causing Dilated Cardiomyopathy (DCM) all over the country. Highly regarded cardiologists are backing this up due to the number of cases referred. This still hasn’t sat right with me in any regard, as there is simply no cardioprotective benefits to grains and their insulinogenic properties that I can come up with. Then she messaged me a link with an article to read.


Before continuing, I think it is important to bring into the discussion bias. It is not a bad word, we all have experiences and exposures that form our positions. To leverage the value of these experiences, they need to be declared. My bias on this topic is that for a variety of reasons grains are problematic as a major part of any healthy diet. I have experienced personally and professionally many improvements from simply avoiding grains (wheat and corn in particular). This bias is what lead me to keep pondering and inquiring about this messaging my wife was seeing in her industry.

Now, switching gears, since I declared my bias I am going to put on the record the bias of the author who’s article was part of the firestorm. The link my wife sent above was an update on an earlier article this person had written, and it is the original article that helps us sort out her bias.

Within the past 3 years, Dr. Freeman has received research support from Aratana Therapeutics, Nestlé Purina PetCare, and Royal Canin; has consulted with Aratana Therapeutics and Nestlé Purina PetCare; has given sponsored talks for Aratana Therapeu- tics, Hill’s Pet Nutrition, and Nestlé Purina PetCare; and has served on a scientific advisory board for Aratana Therapeutics. Within the past 3 years, Dr. Rush has received research support from Aratana Therapeutics, Nestlé Purina PetCare, and Royal Canin and has consulted with Aratana Therapeutics and Nestlé Purina PetCare. Within the past 3 years, Dr. Adin has received research support from Nestlé Purina PetCare. All other authors report no relationships relevant to the contents of this editorial to disclose.

These acknowledgements are, of course, buried at the end of the article. At the beginning is this:

“Lisa M. Freeman DVM, PhD; Joshua A. Stern DVM, PhD; Ryan Fries DVM; Darcy B. Adin DVM; John E. Rush DVM, MS
Department of Clinical Sciences, Cummings School of Veterinary Medicine, Tufts University, North Grafton, MA 01536. (Freeman, Rush); Department of Medicine and Epidemiology, School of Veterinary Medicine, University of California-Davis, Davis, CA 95616. (Stern); Department of Veterinary Clinical Medicine, College of Veterinary Medicine, University of Illinois, Urbana, IL 61802. (Fries); Department of Clinical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, NC 27607. (Adin)”

The initial article “Diet-associated dilated cardiomyopathy in dogs: what do we know?” got “more than 180,000 page views in the first week and continues to get more than 2000 page views a day.” which we learned in the update.

This is how I started my inquiry on this topic, I got the update article from my wife, then backtracked to see where the author was coming from; i.e. her bias. My interpretation is that the authors are supported by big food companies.

With that out in the open we can proceed.

“Diet-associated dilated cardiomyopathy in dogs: what do we know?”

That is the title of the article Freeman posted in June, note that the title is in the form of a question. The June article’s summary:

Pet food marketing has outpaced the science, and owners are not always making healthy, science-based decisions even though they want to do the best for their pets. The recent cases of possible diet-associated DCM are obviously concerning and warrant vigilance within the veterinary and research communities. Importantly, although there appears to be an association between DCM and feeding BEG (Boutique, exotic-ingredient, and grain-free), vegetarian, vegan, or home-prepared diets in dogs, a cause-and-effect relationship has not been proven, and other factors may be equally or more important. Assessing diet history in all patients can help to identify diet-related cardiac diseases as early as possible and can help identify the cause and, potentially, best treatment for diet-associated DCM in dogs.”

At this point, the takeaway is to be concerned about switching away from standard diets to grain-free or BEG, but they really don’t know. This scientifically formatted journal article to me really comes off as a theory development advocacy. Some time was spent looking at taurine levels as a basis, but again was part of theory development.

Now we move to the update article my wife forwarded that Freeman posted.

“It’s Not Just Grain-Free: An Update on Diet-Associated Dilated Cardiomyopathy”.

My editorialized summary:

  • it’s not just grain free, it is basically anything different; “BEG” diets – boutique companies, exotic ingredients, or grain-free diets or even raw or homemade. ALERT, do NOT prepare any food for your pet, leave it to something from a conveyor belt only or your beloved companion could develop DCM!
this is an image I found online of my first real job…at a pet food manufacturing facility (I kid you not!)

  • Taurine does not appear to be related now (despite theory pushed on first article)
  • What’s causing diet-associated DCM in dogs? For the vast majority of dogs, we do not yet know what is causing this disease. “
  • If my dog is eating a BEG diet but has no symptoms, should I test for DCM or switch to a different diet? It’s unlikely that most dogs eating a BEG diet will develop DCM. However, given the fact that we don’t yet understand why BEG diets are affecting some dogs and because DCM is a life-threatening disease, I recommend you reconsider your dog’s diet until we know more. 

Basically, the theory has now been enhanced (?) by removing taurine as a possible cause, while still advocating for conventional diets as THE safe course. That safe course is naturally a significant funding source of their research. I see ZERO motivation to continue this research. Right now, a problem is defined in which ALL alternative food preparations (i.e. competitors) are dangerous. Time to move on?

My theory for consideration

Understanding it is hard for veterinarians to recommend non-conventional diets with the DCM scare hanging out there, I offer this theory for further exploration. Magnesium deficiency.

Our pets only source of nutrition is the food we provide, for the most part (labradors, beagles, and others are quite resourceful in many cases when we aren’t looking). Magnesium is involved in HUNDREDS of enzymatic processes in the body, including the production of ATP, the major energy currency. A major consumer of ATP is the heart. So can magnesium play a role in cardiomyopathy? Turns out yes! See this quote from an article by a researcher I trust (James J DiNicolantonio), who happens to be a pharmacist:

Magnesium deficiency has been implicated in the cause of cardiomyopathy in both animal models and studies involving humans. In animal models, hamsters fed a magnesium-deficient diet developed a cardiomyopathy with foci of myocardial necrosis, calcification and modest mononuclear and giant cell infiltration. Additionally, hamsters given nifedipine had a dose-dependent reduction in lesion abundance and diameter, while hamsters given digoxin produced a dose-dependent increase in lesion abundance and diameter. These results support the hypothesis that the lesions are secondary to calcium overload following an increase in myocardial sodium due to inhibition of the Na+–K+–ATPase and secondary sodium, calcium exchange in a magnesium-deficient state.37 In a different study involving Syrian male hamsters fed either a magnesium-deficient diet or identical diet supplemented with 100 mmol/kg of MgCl, animals were found more vulnerable to ischaemia-induced damage to the heart when magnesium deficient at the time the animals were sacrificed.38 The release and effects of catecholamines have been shown to intensify during cellular magnesium depletion. The detrimental effect of catecholamine excess and magnesium deficiency has been found to be synergistic in the myocardium. In rabbits, magnesium supplementation has been found to reduce the ultrastructural features of myocardial damage induced by epinephrine injection without an effect on changes in intracellular distribution of calcium induced by epinephrine.39
In humans, studies also support the role of magnesium in cardiomyopathy. Patients with hypoparathyroidism can manifest cardiomyopathy, which responds to magnesium supplementation.40Cardiomyopathy and magnesium deficiency are commonly observed in patients with heavy alcohol consumption.41 Additionally, people who live in low magnesium equatorial areas, and those consuming a magnesium-deficient diet, have developed spontaneous endomyocardial fibrosis of undetermined aetiology.41–43″

Magnesium is available in many foods, including those found in grain free preparations, so let me expand on why I think this may contribute to DCM when switched off of conventional diets. Phytates?

From the Weston A. Price site (a great resource):

“Phytic acid is the principal storage form of phosphorus in many plant tissues, especially the bran portion of grains and other seeds. It contains the mineral phosphorus tightly bound in a snowflake-like molecule. In humans and animals with one stomach, the phosphorus is not readily bioavailable. In addition to blocking phosphorus availability, the “arms” of the phytic acid molecule readily bind with other minerals, such as calcium, magnesium, iron and zinc, making them unavailable as well. In this form, the compound is referred to as phytate.”

and also

“There are many studies in which researchers have tried to find out how to make the bran of different grains digestible and to provide additional nutrition. But small additions of phosphorus- and calcium-rich dairy products, such as milk and cheese, or phosphorous-rich meat will make up for the moderate reductions in mineral intakes from grains without the bran. In one study, the calcium, magnesium, phosphorous and potassium in diets made up with 92 percent flour (almost whole wheat) were less completely absorbed than the same minerals in diets made up with 69 percent flour (with a significant amount of bran and germ removed).61 This study involved yeasted bread. With sourdough bread, the phytate content of bran will be largely reduced if a phytase-rich starter is used and the flour is fermented at least twenty-four hours.”

So whole grains that are often portrayed as being more healthy, can actually bind important minerals including magnesium, rendering them unavailable.

Let’s look at a Royal Canin link here:

“Why Are Grains Important?

Grains Many people will tell you that corn causes allergies and has no nutritional value. And while a food reaction may affect some dogs with rare, documented food allergies, there is no evidence to support claims that grains in general cause health problems.

When processed properly, grains like corn can be a healthy part of any cat or dog’s diet. In fact, properly processed corn contains far more nutrients than ingredients commonly used as replacements for it in grain-free diets.

Royal Canin grinds the corn very finely before it’s added to any of our formulas. This makes it a very effective and digestible carbohydrate source.

We also recently added corn gluten meal and wheat gluten to some of our feline and canine formulas. Both are great sources of highly digestible protein, and wheat gluten contains amino acids that support gastrointestinal health. Both corn and wheat gluten are good complements to chicken meal.”

Ok, so they process heavily the grains, meaning in many cases getting rid of the bran (whole part of whole grain) in which case magnesium would be more bioavailable.

The we can compare to a popular (or scary rather from Dr. Freeman’s perspective) natural food company Blue Buffalo (emphasis mine):

“Brown Rice: A natural whole grain rice that is associated with natural health foods. The bran portion provides essential B vitamins, minerals and fiber. Brown rice is an excellent, high–quality complex carbohydrate source for energy and fiber for colon health.”

Whole Barley is the whole grain with the hull and bran and is an excellent source of soluble fiber. It is a good carbohydrate source for energy, B vitamins and fiber for colon health.”

Oatmeal is an excellent carbohydrate source for energy. It is a high quality grain source that is rich in B vitamins. Whole oats are the whole grain with hull and brand.

These ingredients, touting the whole grain presentation, are among the first listed which typically means higher quantities. High phytates mean less bioavailable magnesium in most cases.

Testing the theory

The theory again is that the magnesium is more bioavailable in the highly processed grains of the conventional foods, and less bioavailable in the other diets due to the lack of processing and using whole grains which can make magnesium unavailable.

Testing this becomes a little difficult.

“The definitive test that would tell you your magnesium levels, the ionized magnesium blood test, is not available to the public. A helpful but less accurate test, magnesium RBC, must be used in conjunction with your clinical symptoms. The serum magnesium test is highly inaccurate, yet it is still the standard test used in hospitals, clinics, and most clinical trials—however, it doesn’t even appear on an electrolyte panel. .Carolyn Dean Md Nd, The Magnesium Miracle (Second Edition), loc. 226″

Apparently, veterinary labs don’t even offer an RBC test. The serum test is basically useless, so we don’t have a way to really prove this unless a reasearchinstituion can do RBC or ionized. I wonder if Tufts would be interested validating in this? After all, they left this door open in the journal article:

“For example, BEG diets could possibly be more likely to have deficiencies of nutrients other than taurine, such as choline, copper, l-carnitine, magnesium, thiamine, or vitamin E and selenium, that have been associated with cardiomyopathies.19 “


Unfortunately, it looks as though the way the incentives line up, there is much to gain for this crew to be pushing conventional diets as the only way to stay clear of your pet developing DCM. I believe the magnesium angl is a reasonable theory that others should investigate promptly. To me, it is irresponsible to create a cloud of confusion that harms a competing business model leveraging funding incentives published through university personnel, which to the naked eye could seem like an un-biased opinion. Again, bias isn’t bad, it just needs to be part of the discussion. We will be supplementing magnesium in our pets on grain free diets. After all, it is hard (at least in humans) to get too much magnesium from pill supplements, and most managed agriculture fields are deficient in magnesium and many other minerals.


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