In July 2018, FDA alerted veterinarians and pet owners about a possible link between canine dilated cardiomyopathy (DCM) and certain dog food diets. Since then, a lot has been written about this issue. My aim with this article is to at least try to clear some of the fog around this, and what’s it all about. And perhaps most important, what it’s NOT about!
What Is DCM?
DCM is short for dilated cardiomyopathy, a condition that makes the heart large and weak. This can lead to congestive heart failure, which means that the heart lacks the pumping power needed to supply the body with enough blood. This can be a life-threatening condition.
Fluids may also build up in the chest and belly. Dogs suffering from DCM may get tired quickly, cough and struggle for breath.
In dogs, DCM is usually caused by heritage. Certain breeds are genetically prone to acquiring the condition. Most of these are large or giant breeds, such as Irish Wolfhounds, Great Danes, Saint Bernards, Newfoundlands, Boxers, and Doberman Pinschers. English Cocker Spaniels are an exception to this size rule.
Some of the reported DCM-cases that FDA have decided to investigate further are about breeds that have not yet been known to be genetically predisposed to the disease.
In addition, most of these dogs have also been fed dog food where peas, lentils, other legumes and potatoes are among the main ingredients. These are often labeled “grain-free”.
What’s The Connection Between Canine DCM And Grain-Free Dog Food?
Well, we don’t really know yet. The FDA is still investigating. Note that this is still only a correlation, not a proven cause and effect. There may be many other factors playing a vital role that we are not yet aware of.
Also, please note that the FDA does not even speak of lack of grains as a possible cause for the increase in DCM cases. Dog food recipes that have a lot of legumes and potatoes are also often labeled “grain-free”. This has caused some confusion and misunderstandings.
This is from a Q&A page on the FDA site about canine DCM and diet: “The common thread appears to be legumes, pulses (seeds of legumes), and/or potatoes as main ingredients in the food. — Recently, the proportion of legumes and/or pulses has increased significantly in certain diets, including many labeled as “grain-free” or “zero-grain.” “
Update, New Status Report From FDA June 27, 2019
The FDA released a third status report on the DCM and grain-free dog food issue on June 27, 2019. To me, one thing stands out in this report:
The FDA actually points to the fact that there are an estimated 77 million dogs in the US. 560 dogs have been reported to have developed DCM, potentially linked to their diet. They also say that it’s actually not known how commonly dogs develop DCM.
This made me flinch. We actually don’t know if there even is an increase in DCM cases! The FDA continues to say that “the increase in reports to FDA signal a potential increase in cases of DCM in dogs not (yet known to be, my addition) genetically predisposed.”
This means that it could all be about an increase in reports, not an actual increase in DCM cases. Please note that I’m not saying this actually is the case. I’m merely trying to bring some perspective to this conundrum. An interesting observation is the fact that the vast majority of the DCM cases with a potential link to diet were reported to the FDA after the alert in July 2018.
Well Then, Do Dogs Get Heart Disease From Lack Of Grains?
As far as I can find, there is nothing whatsoever to suggest this. Dogs have developed the capacity to tolerate grains in their diet, but they do not need it or thrive from eating it.
In fact, the high grain content in some dog foods may be contributing to the growing dog obesity epidemic. Many of these are for sale in vet clinics.
So, it’s grossly misleading that certain sites and writers talk about grain-free dog food for adults or puppies causing heart disease. There is no such connection.
No Diet-Related DCM In Europe – How Come?
To make matters even more confusing, it seems that Europe is not experiencing an increase in diet-related canine DCM. It’s difficult to understand why, but TruthaboutPetFood.com has an interesting theory.
Pet food regulations in the US state that if a dog food manufacturer wants to use the term “complete and balanced” on a bag of food it must meet the nutrient levels in one of the nutrient profiles established by the AAFCO. (You can read here about the AAFCO dog food nutrient profiles.)
The same holds true for dog food manufacturers in the EU. (Except that in Europe, the AAFCO, of course, has no say!). There is one vital difference though:
Some dogs are very active and thus consume a lot of food, whereas some dogs are less active and consume less food.
In the US, the nutrient profiles do not acknowledge the difference in activity between dogs.
In the EU, there are different nutrient profiles for low activity dogs and high activity dogs.
So how is this relevant when it comes to the DCM and grain-free dog food issue?
Well, the nutrient levels in the US nutrient profiles are about the same as the ones for high activity dogs in the EU. This means that less active dogs in the US, eating less food, also will receive less nutrients from their food. Less, as in not enough.
This is true also for methionine and cysteine, the amino acids dogs convert into taurine. Taurine is known to prevent heart disease. This meas that a lack of the amino acids needed to build taurine could very well be a contributing factor to the rise in diet-related DCM.
Note though that this is just a theory. There may well be other reasons that Europe is not experiencing an increase in DCM cases in breeds not known to be genetically predisposed for acquiring the disease.
BEG Diets – What’s That, And What’s The Connection To DCM?
This is not a concept the FDA uses. Instead, it’s coined by Lisa M. Freeman. She is a Ph.D. in veterinary medicine. She is also a board-certified veterinary nutritionist at Cummings School of Veterinary Medicine.
The letters BEG stand for boutique companies, exotic ingredients, and grain-free diets.
A “boutique company” usually offers highly specialized products, and often charges premium prices for them. In this case, the products are dog foods containing exotic meats and other exotic ingredients.
Exotic meats are for example duck, rabbit, venison, bison, ostrich, and kangaroo.
Exotic ingredients may also be chick-peas, lentils, fruits and vegetables not commonly found in dog food.
Lisa Freeman suggests that these often small companies do not have the nutritional expertise needed to manufacture healthy dog food. This could potentially cause health issues for the dogs eating the food they produce.
She also, like the FDA, suspects that the ingredients used to replace grains could be responsible for the increase in diet-related DCM.
But she also states, like the FDA, that we do not yet know the cause.
A Few Words About Taurine, Fibers And Dogs
Taurine is an amino acid that dogs need to maintain a healthy heart. They can either get it directly through the food or synthesize it themselves from the amino acids methionine and cysteine.
In some of the case reports that have reached the FDA, samples of blood have been taken to check the dog’s taurine levels. The results have varied from low to normal levels. At first glance, this may appear to rule out that their DCM diagnosis is due to taurine deficiency.
The FDA has also tested most of the dog food products involved for taurine and methionine/cysteine (and other nutrients) levels. All foods contained at least the amounts stated in the AAFCO nutrient profiles.
But, there is more to this than just the levels in the food or found in the blood of the dogs.
For example, there are many factors that influence the results when measuring the taurine content in the blood. If the dog has an increased platelet count because of infection the taurine levels may appear normal when they are actually low in the heart.
This could explain why some dogs that have been diagnosed with DCM appear to have normal levels of taurine in their blood.
One also has to take into account the bioavailability and digestibility of the amino acids in the food. This is still a field for research.
A lot of dietary fibers in the food may also contribute to taurine depletion. The taurine simply goes out with the poop. It may also be used up by the bacteria colonies that thrive on the fermentable fibers.
As you can see, this whole issue is very complex.
It’s much too soon to draw the conclusion that grain-free dog food is the culprit here. There simply is no such established connection.
The authors of the peer-reviewed article “Special topic: The association between pulse ingredients and canine dilated cardiomyopathy: addressing the knowledge gaps before establishing causation” even take it as far as saying that the perhaps hasty FDA alert “may harm consideration of protein alternatives, such as pulses” in both dog and other pet foods, as well as in human food.
There are a lot of factors that together may contribute to the DCM diagnosis in the reports the FDA has received. The dog’s breed, age, sex, genetical make-up, and health status also has to be taken into consideration. All these factors may increase the amount of taurine needed to maintain a healthy heart.