Dilated Cardiomyopathy: What’s Going On

This is a transcript of podcast episode 1, season 2. Listen HERE.

Hello everybody and welcome back to HPR! I’m so happy to be back recording after several months off. A quick introduction for those of you who don’t know me, I live in Leduc, Alberta and own a natural pet food store called The Bone & Biscuit. I think that owning a pet food store gives me a really interesting insight into the pet world because I get to see things from the business side as well. That being said, I always try to approach things as a concerned pet parent first, and to be really aware of my bias and to offer an objective of an opinion as I possibly can. 

So Dilated Cardiomyopathy (DCM), maybe you’ve heard of it before, maybe you hadn’t and now have just seen it all over the news these past few weeks… My hope with the episode is to help summarize the known facts that are out there and hopefully clear up some confusion because whenever the media picks up a story like this, I tend to see misinformation start circulating. 

I’m not a veterinarian, and It is never my intention to offer veterinary medical advice, the full disclaimer for all that stuff can be heard at the end of every podcast episode. Also, there are lots of amazingly well-written articles already written on this topic, I will list them at the end of this episode as well as list them in my references. If you want a more in-depth understanding of this issue, I highly recommend checking out these articles. 

I am going to be giving some sciencey information as well as my personal take on the FDA reports and all the news articles that are coming out. 

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What is Dilated Cardiomyopathy (DCM)?

DCM occurs when the muscles of the heart walls degenerate (become thinner) and lose their ability to pump blood effectively. As the pressure of the blood inside the heart rises, it will begin to stretch the walls of the heart resulting in the enlarged heart, which is characteristic of DCM. Eventually, the heart’s weakened ability to pump out blood will lead to heart failure (1). 

Signs of DCM include weakness, lethargy, coughing, weight loss, tachycardia (a fast/irregular heartbeat), collapse, and abdominal distention (3). However, in its early stages, DCM can actually be very difficult to spot without specialized testing.

If you think your dog is at risk for DCM, you can have a whole blood taurine level test done by your veterinarian although dogs diagnosed with DCM do not show low blood taurine levels (13). If you think your pet is showing signs of DCM, you’ll want to book an appointment with a board-certified veterinary cardiologist to have an echocardiogram and taurine-testing done simultaneously (4, 5). There is also a blood test called a proBNP, which will show elevated levels when the heart is enlarged and can be a more cost-effective testing option. 

To summarize a bunch of research, current thought is that there is dietary related DCM and non-dietary DCM. If a dog has non-dietary DCM this means they probably inherited the condition based on their genetics and a diet change will *likely not reverse the condition (* current information says it will not reverse the condition, but I prefer to avoid absolutes and would urge anyone whose dog is dealing with non dietary DCM to work with a knowledgeable holistic veterinarian in conjunction with their veterinary cardiologist to help with condition management). 

This categorization (diet related/non-diet related) is based on the assumption that a deficiency is the sole thing causing diet-related DCM, the truth is that things are a little less clear than that. Even dogs with diet related DCM may still have a genetic factor involved in their likelihood to develop DCM/ metabolise taurine (1). 

Breeds identified as being predisposed to DCM include: 

  • Irish Wolfhounds, Great Danes, Saint Bernards, Newfoundlands, Doberman Pinschers, and Boxers. There are also genetic factors that have been discovered in Potugese Waterdogs associated with abnormal taurine metabolism that can lead to DCM. (2) 

Apart from the genetic predispositions of several breeds, studies have also started to indicate that some dogs may have a tendency to develop DCM as a result of taurine deficiency, which was previously thought to be exclusively a feline issue as it was widely thought that dogs have the ability to synthesize their own taurine (3). 

What’s the Deal with Taurine 

If you’re reading about DCM anywhere right now, chances are you’re hearing the word “taurine” being thrown around a lot.

Let’s do a quick biology refresher: All animals (including humans, dogs, cats, etc.)  require water and “a constant source of dietary energy to survive”. The three nutrient categories that provide energy in an animals diet are fat, protein, and carbohydrates.

Focusing on protein as this is most relevant to the DCM topic… Proteins are made up of amino acids connected by peptide bonds. Dietary protein provides the essential amino acids to the body (essential meaning they cannot be made in the body and must be supplied through the diet) and they are used for many important functions in the body. 

There are 10 essential amino acids for dogs and 11 for cats. Taurine is the 11th essential amino acid listed for cats. Taurine is not listed as an essential amino acid for dogs because it can be synthesized from the amino acids methionine and cysteine (cysteine is only required in this synthesis if there is inadequate levels of methionine). Studies have suggested that taurine deficiencies may be improved by increasing the methionine intake of the diet (7). So actually rather than worrying about taurine supplementation exclusively, we should be looking at methionine and cysteine intake and bioavailability as well. 

Taurine is important for many aspects of metabolism, bile acid conjugation, retinal function, myocardium function (the function of the muscles of the heart) (3).

Taurine is found in animal tissues, with the largest concentrations being found in muscle tissue, seafood, dark meat and organs (10). 

Taurine & Cats

I want to chat super quickly about cats and taurine. It was only in the 1980s that we realized that cats could not synthesize taurine on their own and required it be added to their dry food diet. We realized this when a lot of cats were dying from heart disease and blindness ( we know taurine is important for eye and heart health so this makes sense). Eventually, nutrient requirements were updated and taurine is now listed as an essential amino acid for felines. However, what we’re seeing with dogs is eerily similar in many ways and we can likely look back on some of the research done on taurine and cats to help us understand what’s going on today. 

Absorption & Bioavailability

There is an article on Whole Dog Journal that explains that there are several ways that diet can affect the taurine status in cats, and implies we may be able to look to this for an idea of what is going on with dogs (as a reminder there is no conclusive reports yet on DCM & diets with dogs yet so this is just speculation and food for thought).  

Some of the things to consider about the diet include “the level and type of dietary protein, the amount and type of dietary fiber, and the degree of heat that was used during food processing. These factors could affect taurine status in three ways:

  1. Bile Acid Binding

Taurine is bound with bile acids in the liver to become bile salts. These bile salts are then secreted into the small intestine to help break down fats. These bile salts are reabsorbed back into the body further down the intestinal tract thus saving them from excretion and preventing a daily loss of taurine (8,9). 

Small protein chains in the food can bind with bile salts in the small intestine and inhibit their reabsorption into the body. Increasing the taurine loss in feces daily and increasing the daily requirement to make up for it. 

  1. Increased Microbial Degradation

Cooking foods at high heats can lead to a chemical reaction called the Maillard reaction (11) which can make sugars and amino acids more difficult to digest. As they accumulate in the gut, they create favourable conditions for taurine-degrading bacteria (16). 

  1. Reduced Taurine Availability

Many commercially prepared food rely on plant sources for their protein. Taurine is most readily found in animal-based protein sources and so some commercial diets may be lacking adequate amounts of taurine and its precursor amino acids methionine & cysteine (8).

Other Important Info 

I’ve cited this Raw Feeding Community article a few times, but there is some really good information in here….

This article talks about how in one of the actual studies involving Golden Retrievers and DCM, all but one of the dogs were being fed LESS than the daily recommended intake. Also, another “ study found that energy restriction resulted in methionine/cysteine, selenium, and choline intake less than the minimum requirement (MR) and tryptophan, magnesium, and potassium less than the recommended allowance (RA), even when consuming a purpose-formulated weight loss diet (17).” 

  • Possibly making these dogs more likely to develop DCM!! This is a super important fact that I haven’t seen a ton of people talking about. If you have a breed with a genetic predisposition to DCM, please ensure you feeding at least the recommended daily intake of that food to your pet to ensure their nutrient requirements are being met, if you cannot feed that food and maintain your pet’s weight switch to a different food. 

There are also indications that vitamins & minerals can impact taurine levels as well. “For example, taurine synthesis cannot occur unless adequate vitamin B6 is present . In addition, there are nutrients unrelated to taurine that have been associated with dietary cardiomyopathy, including zinc, selenium, magnesium, calcium, vitamin D, thiamine, and vitamin E. Deficiencies of these nutrients may play a role in causing or exacerbating DCM. Diet type and the extent of processing affects the absorption and metabolism of many of these nutrients (1).” 

The FDA REPORTS 

First of all, I want to say that I have a lot of issues with this whole situation. As you’ve hopefully learned throughout this episode, there are lots of things potentially going on here and the media has downplayed the actual scientific facts in place of bold headlines. 

I would recommend going to the FDA reports directly (14) to learn more and not going  through a third party site like a news article. 

The actual reports are about 78 pages long so I’m just going to give a few key thoughts and not analyze every report. 

Here are some things to consider: 

  • The media is reporting that there are 16 brands of grain-free boutique foods that are causing diet related DCM… This is EXTREMELY inaccurate. The truth is that there are actually 67 brands listed in this report including Costco’s house brand Kirkland, Performatin, Hills, Purina, V-Dog, and more)  
  • The FDA has chosen to focus on the grain-free diets so it is painting a very skewed picture in the media
  • People are touting this FDA REPORT like it is some sort of scientifically conclusive study. It’s not. It is just a summary of reports that have been submitted where DCM is suspected (some of these reports didn’t have diagnostic testing done, and some have inconclusive results). Let me reiterate: it is not a study. We do not know if there is a link between these diets and DCM occurring in these dogs. 
  • Perspective is important, there were 560 cases in the report from January 1, 2014, to April 30, 2019. That’s an average of 112 cases per year. It is estimated that there are about 60 million dogs kept as pets in the US (6). 
  • We also have to take into account the demographic of people who are more likely to report and have their dogs tested for DCM (and seen regularly by a veterinarian). These are typically going to be people feeding more premium food which may skew reports (aka we don’t know how many grocery store kibbles could be involved as well but are not being reported). 

With all of that being said, does this paint a problematic and even alarming picture for pet parents feeding kibble? It might. I don’t want to minimize these results, but I also don’t want to contribute to the mass hysteria I’m seeing. 

My thoughts on the Matter: 

I think the big issue with the FDA reports highlighting (and naming) these food brands and then the media picking this story up is that it just creates mass panic and confusion.

I am a firm believer that feeding a balanced diet of whole fresh foods is the absolute best way to feed your dogs and cats. However, I’m also not a fan of shaming people for doing the best they can. I understand that feeding kibble is a reality for lots of people for many different reasons. I think there are lots of ways they can improve the food they’re feeding, without breaking the bank or being a huge inconvenience. 

My advice would be, to all pet owners regardless of what you’re feeding, is to include fresh foods high in taurine as often as you can. There is an awesome article on The Raw Feeding Community page that has a list of taurine rich raw foods. Some examples from the list include a variety of fish & seafoods like mussels, oysters and scallops and many dark meats & organ meats all fed raw (1). There is no evidence that the addition of grains in to the diet will help with taurine deficiency or DCM. 

Another great source of information for supplementing your commercial diet was written by Savannah at Feed Thy Dog. I will link that as well and I highly recommend checking it out (15). One thing she talks about which I think is very important to mention is that the general consensus is that you can replace about 15% of your pet’s daily caloric requirement with well chosen whole food additions. Anything about 15% really should be balanced properly (aka by a nutritionist or someone who understands nutrient interacts thoroughly). She runs through a whole real life example with her own dog and I highly recommend reading the article! 

The reality is that we don’t have all the answers. The dry pet food industry is so new in the grand scheme of things, only about 60 years old, and even then it only really took off in the last 30 years. It’s become a massive industry very quickly and so that in itself has probably set us up for these issues. I don’t think it’s ever a good idea to think we have “all” the answers or that we fully understand something as complex as the nutritional requirements of a living evolving creature. 

I do anticipate seeing new “taurine supplemented” foods hitting the market soon to which I would say just still do your research and don’t just buy into the marketing claims. We may see canine nutrient requirements adjusted in the future to include higher methionine amino acids requirements as well as potentially seeing taurine switch from non essential to essential, but only time will tell on those. 

My Advice to other Pet Store Owners: 

When things like this hit the media, speaking from experience, it’s really easy to panic and worry that this is going to impact your business. That’s not to say you don’t care about your customers or their animals, but you have your own family and animals you need to provide for as well. My advice would be to try to see these instances as an opportunity to be a leader for your community, go above and beyond to make sure you help people with their concerns, offer lots of information in store, educate your staff on the issues, make sure you can actually answer people’s questions, and try to connect with a local integrative veterinarian that you can refer people to. To me, I don’t think staying quiet and riding out the storm is necessarily the best answer.

Do your own research. As a retailer, we will typically hear from the companies directly with their “public response”. Try to research from independent parties as well, to ensure you’re seeing a more well-rounded picture. 

That’s all for today folks. I really hope that was helpful and gave you some clarity on the situation.

Til Next Time. 

Amanda

 

References: 

  1. “Grain Free Diets and DCM.” The Raw Feeding Community, 27 June 2019, therawfeedingcommunity.com/2018/02/08/grain-free-diets-and-dcm/.
  2.  J. Alroy, J. Rush, S. Sarkar. (2005) Infantile dilated cardiomyopathy in Portuguese water dogs: Correlation of the autosomal recessive trait with low plasma taurine at infancy. Amino Acids, 28:1, 51-56. https://doi.org/10.1007/s00726-004-0149-6
  3. Case, Linda P. Canine and Feline Nutrition: a Resource for Companion Animal Professional. Mosby Elsevier, 2011. 21-25, 95-100, 511-517. 
  4. “Are Dogs With DCM Taurine-Deficient?” Mercola.com, 9 July 2018, healthypets.mercola.com/sites/healthypets/archive/2018/07/09/link-between-dog-food-taurine-deficiency-and-dcm.aspx.
  5. http://mercola.fileburst.com/PDF/HealthyPets/SternLetterTaurineDCM.pdf 
  6. https://www.iii.org/fact-statistic/facts-statistics-pet-statistics 
  7. C.L. Tôrres, R.C. Backus, A.J. Fascetti, Q.R. Rogers. (2003) Taurine status in normal dogs fed a commercial diet associated with taurine deficiency and dilated cardiomyopathy. Journal of Animal Physiology and Animal Nutrition, 87:9-10. https://doi.org/10.1046/j.1439-0396.2003.00446.x
  8. https://www.whole-dog-journal.com/food/dog_food/dcm-in-dogs-taurines-role-in-the-canine-diet/
  9. http://eclinpath.com/chemistry/liver/liver-function-tests/bile-acids/ 
  10. Spitze AR, Wong Dl, Rogers QR, Fascetti AJ: Taurine concentrations in animal feed ingredients; cooking influences taurine content, J Anim Physiol Anim Nutur 87: 251-262, 2003.  
  11. https://en.wikipedia.org/wiki/Maillard_reaction 
  12. https://healthypets.mercola.com/sites/healthypets/archive/2018/09/19/food-related-heart-disease-in-dogs.aspx 
  13. Darcy Adin, Teresa C. DeFrancesco, Bruce Keene, Sandra Tou, Kathryn Meurs, et al. (2019) Echocardiographic phenotype of canine dilated cardiomyopathy differs based on diet type. Journal of Veterinary Cardiology, 21, 1-9. https://doi.org/10.1016/j.jvc.2018.11.002 
  14. https://www.fda.gov/media/128303/download 
  15. https://feedthydog.com/enhance/ 
  16. Seungwook W. Kim, Quinton R. Rogers, James G. Morris. (1996) Maillard Reaction Products in Purified Diets Induce Taurine Depletion in Cats Which Is Reversed by Antibiotics. The Journal of Nutrition,126:1, 195–201. https://doi.org/10.1093/jn/126.1.195 
  17. J.L. Kaplan, J.A. Stern, A.J. Fascetti, J.A. Larsen, H. Skolnik, et al. (2018) Taurine deficiency and dilated cardiomyopathy in golden retrievers fed commercial diets. PLOS ONE, 13:12. 

 

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The contents of this blog, such as text, graphics, images, and other material contained on this site (“Content”) are for informational purposes only. The Content is not intended to be a substitute for professional veterinarian advice, diagnosis, or treatment. Always seek the advice of your veterinarian with any questions you may have regarding the medical condition of your pet. Never disregard professional advice or delay in seeking it because of something you have read on this website!
If you think your pet has a medical emergency, call or visit your veterinarian or your local veterinary emergency hospital immediately. Reliance on any information appearing on this website is entirely at your own risk. If you have medical concerns or need advice, please seek out your closest holistic or integrative veterinarian. Not sure where to find one? Check here: http://www.ahvma.org

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