Evidence Update: Grain-free and other “BEG” Diets Associated with Heart Disease in Dogs

I have been following with great interest the emerging evidence about grain-free and exotic protein diets as a possible risk factor for heart disease in dogs. I first raised the subject in response to several cases of dilated cardiomyopathy (DCM) I saw in my practice, and which became part of a study which has recently been published looking at the issue in this breed. There have been several other papers recently published touching on the relationship between diet and DCM in dogs, and I want to quickly discuss each of them

Freeman LM, Stern JA, Fries R, Adin DB, Rush JE. Diet-associated dilated cardiomyopathy in dogs: what do we know?J Am Vet Med Assoc. 2018 Dec 1;253(11):1390-1394. doi: 10.2460/javma.253.11.1390.

This is an excellent summary of what we know and don’t know about this issue so far. The bottom line is that a suspicious number of cases of DCM have been appearing in dogs eating what have been called BEG diets- boutique, exotic protein, grain-free. What this means is that diets without grains, diets with a high proportion of legumes, and diets with animal proteins that have not been traditionally used in dog food, and which consequently have not been studied as thoroughly in terms of their nutrient content and other factors, have been associated with DCM in a variety of breeds. This is not proof that the diets, or any particular characteristic of them, is causing this disease. Such proof will require different kinds of research studies. However, this is a potential warning sign that deserves to be acknowledged and followed up with appropriate research.

In some cases, the diets and disease has also been associated with a deficiency in the amino acid taurine. This is an amino acid that dogs do not normally require in the diet since they can make as much as they need. However, in some breeds there appear to be genetic factors that make individuals more susceptible to taurine deficiency, and associated heart disease. These may include reduced production of taurine, increased loss of taurine, or increased need for taurine. Certain diets that have low levels of the ingredients from which taurine is made or that contain substances, such as legumes and some types of. Fiber that make reduce absorption or synthesis of taurine and its precursors or that encourage taurine loss make act in con cert with these genetic factors to lead to deficiency and disease in some dogs. Many of the details in this hypothetical series of steps remain to be understood. 

An example of how this problem may work comes from another recent paper looking at golden retrievers with DCM, including several of my patients.

Kaplan JL, Stern JA, Fascetti AJ, Larsen JA, Skolnik H, et al. (2018) Taurine deficiency and dilated cardiomyopathy in golden retrievers fed commercial diets. PLOS ONE 13(12): e0209112. 

In this study, the dogs with DCM had taurine deficiency, and most were eating BEG diets. Changing the diet and supplementing taurine, along with other treatments, seemed to improve or cure the disease in most, but not all of the dogs.  Again, this was not a study designed to determine if the diets caused the taurine deficiency or the DCM, but the fact that all the dogs were on the diets that we are concerned about, and the fact that changing the diet and adding taurine, among other interventions, seemed to help most of these dogs, does make looking more closely at these diets worthwhile. It also makes it reasonable to consider avoiding these diets in golden retrievers, and perhaps other breeds known to have a higher-than-average risk of taurine deficient DCM even if we are not certain if the diets are the cause or, if so, how exactly that works.

It is important, however, not to get too fixated on taurine. Many of the dogs seen with DCM and eating BEG diets are not taurine deficient, so golden retrievers appear to be experiencing a different problem than these other breeds. It is possible that other aspects of these diets besides their effects on taurine levels could be a risk factor for DCM, and we know even less about how this might work.

This is illustrated by the third new study, which looked at dogs with DCM and evaluated the differences between those on grain-free diets and those on grain-based diets. 

DarcyAdin, Teresa C.De Francesco, BruceKeene, SandraTou, KathrynMeurs, ClarkeAtkins, BrentAona, KariKurtz, LaraBarron, KorinnSaker. Echocardiographic phenotype of canine dilated cardiomyopathy differs based on diet type.J Vet Cardiol. 2019;21:1-9.

In this group of dogs, grain-free diets were associated with some signs of more severe heart disease than that exhibited by dogs on diets containing grains, though the differences did not appear in all measures of heart disease severity. None of the dogs in this group were taurine deficient, so whatever the relationship between diet and DCM here, it had nothing to do with taurine.

The great deal we don’t know about DCM and diet is frustrating to all of us. We have to try and resist the temptation, however, to substitute our own beliefs and theories for the missing facts. Proponents of grain-free and other unconventional diets will point to the gaps in our knowledge as evidence that we can’t really blame these diets and that there is no need to change what they feed. While it is true that we can’t be certain what role, if any, such diets are playing in causing heart disease, the fact that they are consistently associated with DCM in several different groups of dogs is, at the least, reason for concern and further research. What is more, none of the claims for the health benefits of grain-free and other unconventional diets have any compelling scientific support, so there is no good reason to choose such diets even if the evidence for their potential risks are still very preliminary.

Bottom Line
We cannot say with certainty that BEG diets cause heart disease. We can only say that they have been associated with DCM in both golden retrievers with taurine deficiency and in other breeds without taurine deficiency. We can also say that changing diets appears to have benefitted some of these dogs, though many other treatments were employed at the same time, which limits out ability to know how important a factor this diet change was in the dogs’ recovery. 

We can also say that none of the claims for health risks from grains in pet foods, or for health benefits from grain-free or other BEG diets, are supported by any reasonable scientific evidence. Certainly, the evidence for such diets is weaker than even the very limited evidence against them. 

As pet owners and veterinarians, we need to proportion our confidence in any conclusions to the strength of the available evidence and be willing to change our minds as new evidence emerges. We also need to make our decisions now, even before we have perfect evidence. Right now, there is no solid reason to think grain-free diets have any health advantages, and there is weak evidence to suggest they might have health risks for some dogs. If you have a golden retriever, it seems reasonable to avoid the diets that have been associated with taurine deficiency and DCM in this breed. Even if you don’t have a golden, you should at least give some thought to why you might want to feed or avoid BEG diets. The evidence can’t make the decision for you, but it should certainly be considered.

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15 Responses to Evidence Update: Grain-free and other “BEG” Diets Associated with Heart Disease in Dogs

  1. Rodman says:

    What sucks is that changing dog food isnt always like changing toothpaste. We went through about 5 brands trying to find one that didn’t upset our new Boxer puppys stomach. We finally settled on Taste of the Wild Pacific Stream which is grain free of course.

    Will be nice when we get more facts and if it’s really grain free causing the issue of something else. Heck it would be really nice if we could just add in our own grain (e.g. rice) to our existing dog food and not have to change anything…

  2. Yankee Hammond says:

    We would like a listing of dry kibble that is acceptable for our taurine deficient dog. Obviously the listing must be longer than just Royal Canine and Purina

  3. skeptvet says:

    There is no such list. If you have read my articles on the subject, you know that the relationship between diet, taurine, and DCM is complex and evolving, so there is no way to make a simple “good food/bad food” distinction. I would suggest looking at the resources on the subject available the Tufts University Veterinary Nutrition Service or arranging a personal consult with a veterinary nutrition specialist.

  4. Jazzlet says:

    Thank you for the update. There is clearly a lot we don’t yet know about the relationship between nutrition and DCM in dogs, do you know if anyone is doing studies to tease out what is going on?

  5. L says:

    https://drjeandoddspethealthresource.tumblr.com/post/180983083351/pet-food-industry?fbclid=IwAR0uwpU5dAAodWeb1NlGUwAccKAfnwP0qftp0L3t5b1W3w7vb4kvj8vy2JQ#.XBmMdS4o62e

    Saw this article posted on another forum. Comments? I will share.
    I am concerned someone might be live this stuff.
    Thanks

  6. Martha Gonzalez says:

    What is considered a BEG diet? What ingredients?

  7. J Lee says:

    I’m offering an anecdote. We adopted a 2+ year old mini Aussie Shepherd about a year ago now. When we first got him, he was on a grain free dry kibble (Authority). My wife figured it was probably best to continue with his same food, since he was going to a new environment and we didn’t want to change too much things on him. Anyways, after some time, we noticed that he was atypical of the breed.

    He is quite lazy, so we stopped forcing him to go on walks. Often, he would just plant himself and not want to walk anymore. We would have to pick him up and carry him home. But, we live behind a golf course, and whenever we left him off leash there in the evenings, he would just go hog wild, sprinting around as we walked the course for half an hour. He is super happy being off leash. Whenever we would get home, though, he would have his happy pant, but I noticed his respiration rate to be quite high: about 60 breaths / min. Where we live, it’s always cool out (Coastal California) — in the 50 – 60F’s during the early evenings. So, I was sure it wasn’t the heat. When I grew up in Hawaii, our small dogs would sprint around the house for hours on end, and as they rested, their heavy panting would eventually subside to normal breathing. We always fed them Purina or whatever other vet recommended dog food was in the 90’s. No grain free or exotic foods. They lived till 18 years of age. So, I was pretty concerned that our new dog would be breathing rapidly for hours after running himself ragged for 30 minutes on the golf course. Luckily, the DCM grain free story broke out, and I thought we should investigate.

    We switched him to Hills Science Diet. We found that the Lamb Meal and Rice formulation had grains, and none of the legumes or potato products that might be associated with DCM. It was also supplemented with taurine. We have had him on this for 3 months now, and wow, he’s much more energetic now. And his respiration rate has gone down quite a bit after running the golf course. After we get back from the course, his breathing rate is around 48 breaths / min as opposed to the 60 before. However, by 2 hours, he’s breathing normal at 30 breaths / min. The biggest change we’ve noticed is his poops. On the grain free kibble, he would go 3 to 4x a day and take BIG poops. On the Hills Science, he goes twice a day, and his poops are much smaller now and a much more brown as opposed to light tan. I’m not sure what to make of this, but after reading about how high fiber diets may play a role, and how the dog’s digestive system is different than human’s, I wonder if before he was just pooping out all of his nutrition. Probably why he was lethargic.

    Anyways, thank god for the vet nutritionists. You guys are doing god’s work. Keep it up.

  8. skeptvet says:

    Yes, there are ongoing studies at several universities, and the FDA is looking into this as well. Unfortunately, with such small numbers of dogs and many variables, figuring out what is happening will take time.

  9. skeptvet says:

    I don’t see anything obviously inaccurate in this post. Diets marketed as “limited ingredient” do appear to frequently have traces of protein sources in them which are not listed on the label.It is unclear whether this is sufficient to interfere with their use in elimination trials to identify food allergies, but it is possible. Hydrolyzed protein diets are considerably more reliable, though in one study a single hydrolyzed-protein diet did also appear to have traces of ingredients that should not have been present. Again, whether this is clinically relevant is unclear, but certainly manufacturers should be expected to label their diets accurately and to have sufficient quality control mechanisms to prevent cross-contamination between diets that are intended to have different and limited ingredients.

  10. skeptvet says:

    Because we don’t know exactly what is happening in these dogs and what the relationship between diet and DCM is in various breeds and individuals, the term BEG Diet is just a descriptive term for the varied diets that have been fed to dogs affected by this problem. It isn’t a precise scientific term so much as a shorthand for the characteristics so far noticed in these diets, which have mostly been diets which are grain-free, which contain protein sources not widely used in dog foods until the last 5-10 years, and which are made by small manufacturers with less experience and expertise in diet formulation and production. Here’s what the recent article describing the current situation says about these diets:

    …it also appeared that these dogs were frequently eating BEG diets containing foodstuffs such as kangaroo, duck, buffalo, salmon, lamb, bison, venison, lentils, peas, fava beans, tapioca, barley, or chickpeas as major ingredients…the apparent link between BEG diets and DCM may be due to the grain- free nature of these diets (ie, use of ingredients such as lentils, chickpeas, or potatoes to replace grains), other common ingredients in BEG diets (eg, exotic meats, flaxseed, fruits, or probiotics), possible nutritional imbalances, or inadvertent inclusion of toxic dietary components. Or, the apparent association may be spurious.

    Dr. Lisa Freeman, a nutrition specialist at Tufts University, appears to have coined the term, and she has written more about this here and here.

  11. Sheila says:

    I’m wondering if anything similar has been found in cats? I have noticed that since weaning my cat (nine yr old female) from the food containing grains to a higher protein, grain free brand that she often suffers from constipation. To ease that I make up a ‘slurry’ by adding water to canned pâté to be sure she gets the fluids. She doesn’t seem to drink as much water as she used to, either. Do commercial pet food contain salt? If so, maybe she drinks less because she’s not consuming as much salt?

  12. Joanne Styslinger says:

    Maybe it is not the food but other factors? Or the excessive amounts of drugs that veterinaries are giving dogs? Since opening our store five years ago I am amazed how many dogs are given so many different drugs mostly to cover up or to soothe the dog instead of finding out what exactly is wrong with the dog or cat. Vets down here in the south seem to favor cortisone a very dangerous drug. Or just maybe it is the flea & tick treatments that are given only a monthly basis either the spot on treatment or the pills all that insecticide going into or onto the animal. Waiting for several of the veterinary schools come out with a major study on the issue and at least 3 have the identical results. Too many questions and not enough answers. My advice take your pets to your vet for their yearly check up and pay attention to what your dog is trying to tell you.

  13. skeptvet says:

    1. “Vets just treat symptoms, not the cause of disease” Complete nonsense. Science-based medicine is all about looking at how health and disease work and understanding in verifiable detail as much as possible about them. We don’t always have the answers, but the answers we do have are based on facts, not mystical nonsense like that behind homeopathy, Chinese Medicine, and the grain phobia that is behind these diets.

    2. “Everything bad is caused by drugs and vaccines” Again, bollocks. There is zero evidence of any association between these things and taurine deficiency or cardiomyopathy, another is no plausible explanation for how they could be responsible. Even though we don’t have a. complete picture of what the cause is, you can’t just make up stuff and insinuate it’s “the chemicals.” The diets, at least, are clearly associated with he problems, and whether this is causal or confounding will require more research to evaluate.

  14. Gloria says:

    I have been following this now for a few months. My dogs are on grainfree and have been for years. I have 2 of my 4 that do have food issues. One was actually tested recently and cannot have corn, soy, flaxseed, fish/fish oil, milk products. That alone leaves out most dog foods. My other chow mix has not been tested but has displayed food sensitivity. All four of mine are on Canidae raw coated mixed with Pure red. They are doing great on it with very very limited scratching.

    My vet says go to a grain product until this is figured out. My response is there are very few foods that Misha can eat because of all the crap put in them.

    Now concerning grain products. rice has arsenic in it and what about all the genetically altered veggies and grains.

    I do find it strange that this all started with the big 3 grain based dog manufacturers starting this. To be honest most of those dog foods are not up to standard. Smaller dog food companies have been working hard to come up with better higher quality dog foods. lots of recalls with most of these brands.

    I think there are more dogs with food issues than what was stated here. Considering I have 2 out of 4 and possible another one.

  15. skeptvet says:

    This is not about “the big 3 grain-based manufacturers” at all. This started because vets were seeing these diseases, and academics at universities investigated and found the connection. IO have personally seen nd treated some of the first causes, and I have nothing to do with pet food companies. This kind of baseless suspicion is really dangerous because it leads people to ignore any evidence that conflicts with what they want to believe, and this is not in the best interests of our pets.

    The GMO fear is also not consistent with the evidence, and pets are not getting arsenic poisoning from rice. You have some underlying concentre that are simply not consistent with the facts, and these will only lead to false conclusions and bad decisions.

    Raw diets have no demonstrated health benefits and some serious risks, so again, this is not a wise choice.

    And for whether your pet is at risk from a grain-free diet, or one of the rare dogs with true. adverse reactions to grain proteins, that’s something you have to investigate with your own vets, or ideally veterinary nutrition specialists in your area. But I’m afraid you have been given a lot of misinformation, and it’s leading you in an unproductive direction.

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