Root cause of CDM from grain free diets?

[FutureOTMax]

Not sure if this is the right spot for this post, but I was just talking with the doctor I work for about the ongoing studies regarding the links between CDM and grain free (or lentil,pea, potato etc heavy diets)..... I was wondering if anyone has seen research regarding the reason these diets cause heart disease, as the last thing I could find from the FDA was dated from 2019 and stated that the exact cause has not been established, but maybe someone else on here has more knowledge than I would. Thank you!

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[WildZoo]

My impression is there are ongoing studies and no one knows for sure yet

 

[battie]

My impression is there are ongoing studies and no one knows for sure yet

This is also what our cardiologists are saying as we rotate through cardio. We had 5 patients with grain-free related DCM during my 2 weeks on cardio. There was a 5 month old puppy diagnosed last week.

 

[WildZoo]

Yeah. Basically what I tell clients is the correlation is there, we just haven't identified causation yet. So ultimately up to them but I believe that the risks are high enough and the benefits of grain free diets low enough that it makes sense to avoid them, or at least avoid the ones that have been linked (FDA had a whole list of brands).

 

[PippyPony]

Some of the research on this came out of my school. You can keep up to date on it by reading our veterinary bnutrition blog, petfoodology.com . The last update was in 2019, though.

Diet-Associated Dilated Cardiomyopathy (DCM): Update, July 2019

On June 27, 2019, the FDA posted an update on their investigation into diet-associated dilated cardiomyopathy (DCM). Since then, there have been many news reports, company responses, and internet/social media interpretations of the update.

vetnutrition.tufts.edu

@InFreudWeTrust In terms of general guidelines for cats, our nutritionists advocate for feeding diets that are guaranteed to meet the needs of adult cats. Typically, that will include some grains, but may vary based on the nutritional requirements of that specific pet. There is more information linked here. Pet Food Decisions: How Do You Pick Your Pet’s Food?

 

[cohen2000]

I believe it has to do with the high legumes typically found in these diets interfering with taurine absorption or causing a functional taurine deficiency.

 

[battie]

For what it's worth, the taurine link isn't what is being taught by our cardiologists, both in the classroom and on the clinic floor. They don't think there is enough evidence to support it as a likely candidate at this point.

 

[JaynaAli]

For me personally, while we don’t know what exactly is causing it, it does seem to be happening and diets with grain in them don’t seem to be associated with it. Yes, it’s fairly rare and many dogs do just fine on a grain free diet. With that said, if I knew I could reduce my dog’s risk of getting -any- disease, I would do it. I mean that’s why I give heartworm and flea and tick prevention, keep him at a good weight, take it easy on his joints while he’s growing, etc. I personally know if my dog got sick from a choice I made, I’d feel guilty. I don’t feed grain free, but if I did, I would personally choose to transition my pet over to a diet with grain while it is sorted out just to be safer. If I absolutely had to feed grain free, at minimum I’d swap to one that is not on the FDA’s list of implicated brands. Grain free diets being “better” is one of the worlds best marketing schemes and not one I’ve seen endorsed by many nutritionists anyway. But if your dog or cat seems to do great on their grain free diet and you’re okay taking the risk, that’s fine.

 

[Caitlin329]

Not sure if this is the right spot for this post, but I was just talking with the doctor I work for about the ongoing studies regarding the links between CDM and grain free (or lentil,pea, potato etc heavy diets)..... I was wondering if anyone has seen research regarding the reason these diets cause heart disease, as the last thing I could find from the FDA was dated from 2019 and stated that the exact cause has not been established, but maybe someone else on here has more knowledge than I would. Thank you!

Hey Max,
Everyone here has covered the major points-- we don't have an exact pathophysiology or underlying etiology for this yet, but there is a concerningly strong correlation between grain-free/legume-rich diets and DCM in atypical breeds. What makes it more concerning is that many dogs reverse with diet change, indicating that diet is very likely a major risk factor for and/or causative in the disease process.

I just wanted to provide you with some additional links since there have been updates since 2019! Everything is hyperlinked.

The FDA participated in a Kansas State University Virtual Forum with some updates-- they have received over 1100 complaints at this point, and are tracking disease reversal in these patients. They also provided opening remarks that discussed the fact that the investigation has hurt some bottom lines for people, and they don't intend to issue further updates to the public until they have "substantial" scientific evidence. Following this forum, the FDA issued an 'inflection point' release to the public where they dubbed this issue 'non-hereditary DCM' and clarified that while they are still investigating diet, they are also investigating other factors like genetics and co-morbidities.

There are also three important additional studies that have been published, one prospective and two retrospective.

Ontiveros et al. 2020
This one looked at Golden Retrievers. This was a prospective study that found a statistically significant correlation between non-traditional diet types and abnormal heart parameters (and I think abnormal taurine status but I'd have to check again) in Golden Retrievers.
Freid et al. 2020 This one was retrospective but found that dogs eating non-traditional diets that switched to a traditional diet at time of diagnosis had an improved prognosis.
Walker et al. 2021
Hot off the presses, this one also found that dogs eating grain-free diets at presentation that switched to a grain-inclusive diet as part of their therapy had improved outcomes from dogs eating grain-inclusive diets, the latter which had survivability comparable to past studies on DCM. This suggests that at least a significant portion of the dogs presenting eating grain-free diets had an atypical, diet-responsive form of the disease, consistent with the ongoing investigation.


Unfortunately, this is an issue complicated by the substantial impact that it has had on certain arms of the pet food industry, and there has been significant pushback and delegitimization of the issue by pulse farmer lobbyists and makers of grain-free or otherwise non-traditional diets. I can link some sources on that, as well, if you're interested. VIN News also published several news pieces on this throughout 2020. Hope thats helpful!

 

[Caitlin329]

Hey Max,
Everyone here has covered the major points-- we don't have an exact pathophysiology or underlying etiology for this yet, but there is a concerningly strong correlation between grain-free/legume-rich diets and DCM in atypical breeds. What makes it more concerning is that many dogs reverse with diet change, indicating that diet is very likely a major risk factor for and/or causative in the disease process.

I just wanted to provide you with some additional links since there have been updates since 2019! Everything is hyperlinked.

The FDA participated in a Kansas State University Virtual Forum with some updates-- they have received over 1100 complaints at this point, and are tracking disease reversal in these patients. They also provided opening remarks that discussed the fact that the investigation has hurt some bottom lines for people, and they don't intend to issue further updates to the public until they have "substantial" scientific evidence. Following this forum, the FDA issued an 'inflection point' release to the public where they dubbed this issue 'non-hereditary DCM' and clarified that while they are still investigating diet, they are also investigating other factors like genetics and co-morbidities.

There are also three important additional studies that have been published, one prospective and two retrospective.

Ontiveros et al. 2020
This one looked at Golden Retrievers. This was a prospective study that found a statistically significant correlation between non-traditional diet types and abnormal heart parameters (and I think abnormal taurine status but I'd have to check again) in Golden Retrievers.
Freid et al. 2020 This one was retrospective but found that dogs eating non-traditional diets that switched to a traditional diet at time of diagnosis had an improved prognosis.
Walker et al. 2021
Hot off the presses, this one also found that dogs eating grain-free diets at presentation that switched to a grain-inclusive diet as part of their therapy had improved outcomes from dogs eating grain-inclusive diets, the latter which had survivability comparable to past studies on DCM. This suggests that at least a significant portion of the dogs presenting eating grain-free diets had an atypical, diet-responsive form of the disease, consistent with the ongoing investigation.


Unfortunately, this is an issue complicated by the substantial impact that it has had on certain arms of the pet food industry, and there has been significant pushback and delegitimization of the issue by pulse farmer lobbyists and makers of grain-free or otherwise non-traditional diets. I can link some sources on that, as well, if you're interested. VIN News also published several news pieces on this throughout 2020. Hope thats helpful!

Also just to add on to this, there are several ongoing prospective studies trying to figure this out. The universities that immediately come to mind are UC Davis, Ohio State, University of Florida, and Cummings at Tufts. Hill's and Embark are also partnered to screen for any common genetic factors.

 

[Caitlin329]

Does this correlation hold with cats as well? I feed both my cats Orijen, not because it's grain free but because the ingredients seem top notch and they were raised on it when they were rescued as kittens. They love it but will switch if necessary. Thank you in advance, from a concerned cat lover.

The FDA has received a few complaints RE cats. Its not clear why there are substantially more dogs reported-- cats may not be as susceptible, cats may not be as symptomatic (classically, heart disease is not as overt as in dogs, and even in dogs symptoms and clinical signs can be subtle), and cats are already less likely to visit the vet than dogs. I personally wouldn't feed Orijen or Acana because despite their small market share, they are overwhelmingly represented in the FDA's complaints. They've (IMO) downplayed this issue despite the overrepresentation of their diets, and because of that I don't trust their company as a food manufacturer, for dogs or cats. Ingredients actually arent the best way to evaluate a pet food.

This resource might be helpful: Pet Food Decisions: How Do You Pick Your Pet’s Food?