Understanding grain-free dog foods and heart problems

Do grain-free foods cause heart problems in dogs?

In every dog community on every social media platform you’ll see regular discussions about grain-free dog foods causing heart problems.

Many vets also advise against grain-free dog foods, saying they can cause heart failure.

This may scare you into switching to one of the big brand grain-based dog foods by Mars or Nestle Purina, or one of the expensive vet-endorsed brands by Mars or Colgate-Palmolive.

Don’t do that just yet.

In this article I’ll take you through the background of the “grain-free causes heart problems” rumours, where they originated, whether you should treat them as a fact or myth, and what we can really learn from them.

The origin of the “grain-free causes heart problems” rumours

The questionable Dr Lisa Freeman & an inconclusive FDA investigation

The origin of many a vet’s advice combined with reams of viral social media posts stem back to an FDA investigation launched in July 2018 into a “potential link between certain diets and canine dilated cardiomyopathy”.

Note the words “potential link” – in other words, a theory.

This came off the back of an article from a name we see often with “science” such as this, and that’s Dr Lisa Freeman from Tuft’s University. The article, publised in June 2018 under “Clinical Nutrition Service”, is titled Risk of heart disease in boutique or grain-free diets and exotic ingredients.

This article went viral despite text in the copy “It’s not yet clear if diet is causing this issue”.

That’s right, so it was merely a hypothesis. Similar to saying apples may cause cancer because many cancer victims have eaten apples.

So who is Dr Lisa Freeman, and why is this the first big clue “grain-free dog foods cause heart problems” is a mere myth?

The following article published in 2021 on Nature.com under “Scientific Reports” titled Investigation of diets associated with dilated cardiomyopathy in dogs using foodomics analysis also features Dr Lisa Freeman as a collaborator.

Note the following entities Lisa Freeman has received funding from over the prior 3 year period:

Understanding grain-free dog foods and heart problems
Dr Lisa Freeman Funded by Pet Food Manufacturers

Hill’s Pet Nutrition, Nestle Purina PetCare, Mars, and Royal Canin are all grain-based pet food manufacturers.

That’s a conflict of interest.

Also note who funded this “scientific” research:

Understanding grain-free dog foods and heart problems
Research Funded by Nestle Purina PetCare

Yep, that’s a huge conflict of interest.

Unlike usual FDA practices, the investigation they subsequently launched after Dr Lisa Freeman’s hypothesis was publicised immediately. Yes, the public were alerted prior to any investigation.

The launch of the investigation was publicised by world media, such as an article in The Guardian titled US study finds potential dog food link to canine heart disease. Many news programs aired a report, not just in the US but everywhere from Australia to the United Kingdom. It also went viral on social media.

A year after the FDA investigation was launched, in 2019, they subsequently released a list naming (and severely damaging) 16 brands of grain-free dog foods. The list failed to mention all brands of dog foods fed to the affected dogs in the study, with grain-based dog foods oddly omitted.

Still with no conclusive findings, it was questionable why the FDA would release such a list to the public.

Again, world media coverage, and all of these brands as well as other grain-free brands have remained tarnished to this very day.

Another less publicised announcement by the FDA in 2019 concludes the potential association between diet and DCM in dogs is a complex scientific issue that may involve multiple factors.

In short, there were no conclusive findings. Ever.

Even today, in 2022, there remains a big ❓ over the entire investigation, yet the repercussions have had a global affect on our beliefs about dog food and canine nutrition.

Many vets, who understandably do not have time to research and understand the situation, recommend against feeding grain-free dog foods, instead advising only grain-based dog foods are safe.

Interestingly, the original announcement by the FDA in July 2018 has been removed from the FDA website.

You could deduce from this alone it’s nothing more than a grain-free dog food myth, but read on…

Did the investigation into canine dilated cardiomyopathy have any findings?

Any study can be interpreted in many different ways. Despite the study showing no conclusive evidence there are a number of interesting points to be raised, and a number of possible inclusions.

Firstly, the affected dogs in the study were questionable, with a social media community for Retrievers being “ground zero” as it were. The community were verbal about good and bad diets, with certain brands of dog food held in high regard.

Many of those brands, such as ACANA and Taste of the Wild, remain highly rated on this website, both on ingredients, but also from thousands of consumers worldwide who have success on these brands with no ill effects.

Important point #1 – Most dogs in the study were fed a single brand of commercial dog food (some grain-based).

This is a little (if any) discussed point which can easily be drawn from the study, and I consider this highly relevant.

Most dogs were fed an unvaried diet.

This is important as it has complete reliance on that commercial dog food product being nutritionally perfect.

Imagine if us humans ate only one food “product” in dry nugget form every single meal, and we relied on it for our health. It’s crazy, right? More crazy when you consider we know much more about human nutrition than pet nutrition.

Yet that’s how we feed our pets…

Some dogs in the study were fed grain-based food. These have largely been ommited from publications.

A small subset were fed other diets, with 13 fed raw, home cooked, or mince. Many were listed as unknown.

88% of the dogs in the study were fed commercial dry dog foods.

Important point #2 – Many dogs in the study tested taurine deficient.

Taurine is an amino acid sourced from animal ingredients. Until recently it was not considered essential in a canine diet, only in a feline diet.

A theory arose regarding the taurine deficiency, suggesting pulse ingredients may prevent absorption of taurine.

Given the emphasis of most commercial dog foods being formulated predominantly of non-animal ingredients, I would consider that a more rational theory.

Important point #3 – Canine dilated cardiomyopathy is rare

It was noted canine dilated cardiomyopathy (DCM) is extremely rare as a diet-related illness (although I’m sure many cases go unreported or uncorrelated with pet food, as they do with most diet-related illnesses).

To put it into perspective, more Australian dogs were affected in the megaesophagus outbreak of 2017 with the confirmed cause grain-based dog food Advance Dermocare by Mars.

Important point #4 – The investigation was publicised with no scientific evidence

Simply put, a speculation is not valid science, launching an investigation is not science, being viralised globally and taken as scientific evidence is still not science.

So, what’s really going on?

A little backstory – insight from the director of a pet food manufacturer

I’ve reviewed pet foods for over 15 years. I’ve liaised with all manner of folk in the pet food industry, veterinary industry, media, and prominent figures in canine and feline research at Australian universities. I’m also a qualified pet food nutritionist (if that offers credibility). I’ve been around the block with pet food and noted trends from a more unique angle.

Two years prior to the 2018 DCM scare I was having coffee on Perth’s Swan River with the director of a prominent European pet food manufacturer. We were discussing amino acid taurine, which at the time was considered an essential inclusion in a feline diet, but not a canine diet.

The director had research conducted by a corporate pet food manufacturer (namely a manufacturer who produces pet foods made significantly from grain). The research was in regard to the potential for dogs to be taurine deficient, which would mean, unlike previously thought, taurine was an essential amino acid in a canine diet.

To reference the Wikipedia information on taurine, it’s an organic compound widely distributed in animal tissues.

If you look at the ingredients of your pet food and find taurine listed lower down the list, this would suggest insufficient taurine from animal ingredients in the product. Hence the supplementation.

Without too much ado, this simply means taurine is sourced from animal ingredients, so neither grain or grain-free ingredients.

At this point you may wonder what on earth this has to do with the DCM grain-free dog food scare, but keep reading and the pieces should fit together.

All you need to know for now is taurine deficiency in dogs is very rare, yet many of the dogs in the FDA grain-free dog food investigation tested taurine deficient.

The fundamental truths about commercial dog foods

If you’ve read our article on the intricacies of whether a dog is a carnivore or omnivore, you’ll understand why our reviews show an emphasis on animal ingredients.

Almost all dog foods sold worldwide are made mostly of grain or grain-free alternatives. Only a few focus on ingredients true to a true canine or feline carnivorous diet.

In layman’s terms – most pet foods lack animal ingredients.

When you understand this, you may draw a conclusion as to how some dogs become taurine deficient. Taurine, after all, is sourced from animal ingredients.

You’ve likely seen the term complete & balanced on many brands of pet food. This is a term which may be printed on the packaging when the product meets minimum nutritional requirements by The Association of American Feed Control Officials (commonly referred to as AAFCO).

The AAFCO requirements are based on what we currently understand to be the nutritional requirements of a cat or a dog. Sometimes new research or information comes to light which shows an omission from the requirements, with taurine being one such important amino acid previously omitted.

To look at this another way, prior to taurine being recently added to AAFCO requirements for dog food, many products labelled complete & balanced did not in fact cover all nutritional requirements for a dog.

That means anyone feeding any of those products exclusively were potentially putting their dog at risk of taurine deficiency, and possibly canine dilated cardiomyopathy. Many of these cases would likely have not been associated with diet when diagnosed by a vet.

None of this has any relation to a dog food being formulated with grain or grain-free alternatives.

One further point about AAFCO requirements for complete & balanced is worth keeping in mind:

Only a small portion of a pet food product will be the required nutrients such as vitamins, minerals, and fats, with a great deal of leniency in how the protein requirement is met (corn rather than meat is one example). The rest of the product, usually around 50% (or more), can be filled with a cheap carbohydrate which may prove very unhealthy for your pet in the long term.

This is the reason most dog and cat foods are made significantly of grain or grain-free alternatives, which is more about keeping production costs down and profits up rather than the health of your pet. Non-meat ingredients are far cheaper inclusions in a pet food than meat ingredients.

The role of science in pet food marketing

Ironically, at the time of writing, many social media evangelists state if something is not backed by “science” it’s a “conspiracy theory” and must be thrown out with the bathwater without any consideration.

Unfortunately, at least in terms of pet food, that’s somewhat of a myth.

Most science in pet nutrition is conducted by the entities who can afford it, and in pet food the conglomerate manufacturers reign. Mars (Royal Canin, Advance, Optimum, Pedigree, Whiskas, et al), Nestle (Purina), and Colgate-Palmolive (Hill’s Science Diet, Prescription Diet, and in other countries Hill’s Science Plan), are three of the most powerful conglomerates in the world, with insane marketing budgets, and influence on every aspect of the pet market.

If science is conducted by an entity selling a product, it’s understandable any scientific research released by that entity will never damage their own product.

I won’t delve much further into this, it’s well worth noting given the root publication on grain-free foods causing hearth problems having an author on the payroll of numerous pet food companies.

Putting 2 and 2 together – How would a “grain free causes heart failure” scare benefit corporate manufacturers?

Historically the pet food aisle was controlled almost in it’s entirety by corporate manufacturers selling grain-based kibbles. Prior to the year 2000 consumers simply thought dog food was dog food, with little consideration what it was actually made from.

Even today most consumers feed their pet a pet food without any idea what’s in it. It’s the nature of consumerism, and a key reason we’re very susceptible to marketing. Repeated ads of cute kittens eating mush from a bowl is all that’s needed for us to blindly trust a brand.

I digress.

Since 2000, and largely in part due to the evolution of the Internet and social media, consumers began to grow an awareness of pet food. This led to a dramatic rise in smaller pet food manufacturers selling “better” alternatives, many without the grains, or namely “grain-free”.

These smaller grain-free pet food companies rode the wave of growing consumer awareness and have become the biggest threat to the profits of corporate pet food manufacturers since day dot*.

When you consider this, a widespread belief grain-free dog foods will cause heart problems works wonders for corporate pet food manufacturers. It damages most of their competitors in one blow.

One very successful blow.

* I should mention raw/fresh pet food companies and raw pet food communities as the other sector which threatens the profits of corporate pet food manufacturers. In respect to those, you may’ve heard “raw chicken causes paralysis” or many other slurs against feeding essentially carnivorous animals raw animal products.

Is canine dilated cardiomyopathy (DCM) a grain-free dog food myth?

To offer my opinion, based on my background and understanding of the world of pet food, pet food marketing, and pet nutrition “science” I would question everything about the “grain-free dog food causing heart problems” rumour.

This isn’t to say grain-free dog foods (or cat foods) are safe to feed. No matter what you feed your pet, they’re all products and should be considered as such.

The pet food space is dominated by some of the largest corporate players in the world, and many articles published under the guise of “science” are questionable.

Given the information on this page, with the root of the rumour conducted by a person and entity funded by corporate pet food manufacturers, and an ensuing FDA investigation which found no conclusive evidence, that would make it a myth, right?

Or at the current time, lets say a conspiracy theory.

We are what we eat, and our pets are no different. Any pet food can lead to short or long term health conditions, and I’ll offer some insight in the next section as there are useful conclusions we can draw from the FDA investigation.

What can be learned from the FDA investigation?

The biggest contributory factor I can deduce from the group of dogs in the investigation is nearly all were exclusively fed one brand of dog food. Needless to say these brands were labelled complete and balanced.

This factor alone puts absolute trust in AAFCO guidelines covering every extremely complex nutritional requirement of a biologically complex animal, and absolute trust in the product being 100% perfect in this respect.

That’s crazy if you think about it.

Another key factor was canine taurine deficiency. To reiterate an earlier point, taurine is from animal sources, so neither grain or grain-free alternatives.

The fact most commercial pet foods are significantly grain or grain-free ingredients and lack meat ingredients should never be ignored and always considered when feeding your pet. Cats are obligate carnivores, dogs are also from the Order Carnivora and more similar to cats as carnivores than us as omnivores (just look at their jaws for one big clue).

Other than that, many widely publicised conclusions from the DCM dogs in the investigation are as follows:

The group showed a bias towards grain-free dog foods. This may be nothing more than highlighting market trends rather than bare any relation to the condition.

The use of pulses such as peas, lentils, and other legumes is common in grain-free diets. The reason is likely more about ingredient cost and assumed nutritional benefit to a dog rather than baring any relation to the condition (especially when we consider taurine deficiency as a more likely factor).

What is absolutely clear from the FDA investigation into DCM…. is how easily it is for information to be misconstrued, spread across the entire globe, without scientific proof.

To keep diet-related canine dilated cardiomyopathy information in one place, the remainder of this page will be a FAQ.

If there is anything you feel needs to be added please say so in the comment section below, or through our Facebook page.

If you want more information on how to feed a dog (or cat) then read this.

If you want more information on your current pet food then refer to our cat food reviews and dog food reviews.

Which grain-free dog foods are associated with canine dilated cardiomyopathy?

Note this list is included for brevity. The FDA investigation did not find any evidence these brands caused DCM:

1. Acana
2. Zignature
3. Taste of the Wild
4. 4Health
5. Earthborn Holistic
6. Blue Buffalo
7. Nature’s Domain
8. Fromm
9. Merrick
10. California Natural
11. Natural Balance
12. Orijen
13. Nature’s Variety
14. NutriSource
15. Nutro
16. Rachel Ray Nutrish

Brands sold in Australia and reviewed on this website are linked.

Calling Aussie pet lovers – join the mailing list!

David D'Angelo

David D'Angelo has worked as a scientist since graduating with a BSc (Hons) in 2000. In addition, David holds a CPD accredited Diploma in Pet Nutrition as well as being CPD accredited VSA (Veterinary Support Assistant). However, his experience and involvement in the pet food industry for 15+ years has given true insight into pet food, formulations, science, research, and pet food marketing. Facebook | LinkedIn | Instagram | Pinterest

  1. Seriously people?! It doesn’t have to be that complicated! Dogs are animals just like us but being predominantly carnivorous naturally require a high animal protein diet in the form of a variety of raw meats including fish, or fish oils, eggs with the shells (for calcium). Here’s a thought… if you really want to see a happy dog, how about the occasional raw meaty bone? Mine get a raw brisket bone twice a week. They each eat the whole thing on their own towel on the kitchen floor. Happy days! How healthy do you think you or your family would be if you were given nothing but the same dried food morning and night day in and day out? Would you feed your children that way even if the label (marketing) stated ‘balanced diet’? Is there any wonder that our dogs are having to deal with all sorts of health issues… obesity, diabetes, gum disease, skin issues, arthritis? Not to mention anxiety and depression resulting in obsessive compulsive and or destructive behaviors? Do some research into raw home made foods for dogs and take control of your dog’s health and ditch the money making corporates. They’re not in it for the health of your dogs. It’s all about the $$$$

    • Agree! It does not have to be expensive or difficult. Chuck a sardine in their food, chicken hearts (which are $3-$5 at woollies.) If you’re worried about balancing their diet, use a premium air dried or freeze dried dog food and add to it to keep costs down. A bit of yogurt, tinned sardines, egg, some frozen berries and whatever meat is on sale, and a chicken neck here and there is not going to break your budget.

    • Reply
      Pet Food Reviews (Australia) January 12, 2024 at 1:20 am

      Very well said

  2. Hi
    I have an Australian Terrier 8 years old who has been diabetic for 3 years now, on quite high insulin requirement. Feeding a variety of food would be challenging, and is hard to find a consistent feed resume to stay on, having a variety, with adequate animal protein, enough good fibre, low calorie diet, which has to be weighed correctly. It would be detrimental to him to keep changing his food resume and would be very hard to monitor his insulin. Generally I agree with all your information, but am in an extremely difficult situation keeping him healthy, with good suitable food. Any advise would be appreciated. Thank you

    • Reply
      Pet Food Reviews (Australia) October 3, 2023 at 12:02 am

      Hi Liz, what have you been feeding him so far? Low fat dog foods tend to be higher in carbohydrates which I consider counter-productive. I’ve written about this more on the page on pancreatic and low fat dog foods which may offer useful information.

      If you’re feeding a vet recommended diet then the wet formulas are less carbohydrates and usually more meat-based.

  3. I think most dog parents miss the point. Instead of debating on grain-free vs. grain-based diets, we should be paying closer attention to the unique needs of our pets. Some dogs might do well on a grain-free diet, while others will need carbs to stay healthy. It’s best to consult a vet or read product labels on sites like Petco or PetCareRx before switching your dog to any new diet.

  4. Hello Pet food reviews,
    I’m wondering if you have seen this report and if so what your thoughts may be. I have recently changed my dogs to grain free dry food and would be interested to hear your opinion. I had read your review regarding the research into grain free and agreed with your comments. I would be interested for your thoughts about the research done and the conclusions.

    Thank you


    • Reply
      Pet Food Reviews (Australia) June 14, 2023 at 6:49 pm

      Hi Suzanne, the first red flag is the conflict of interest statement – “Dr. Adin acknowledges research support from Nestle Purina PetCare”. It may say the findings or conclusions did not influence the study, but that doesn’t mean the purpose of the study wasn’t influenced. It was also a retrospective study based on pet food formulations no longer in production today.

      The key point neglected by all these studies is lack of animal ingredients. Whether packed out with grains or grain-free ingredients is completely misleading, and makes these studies laughable. The findings in the study may not be anything to do with grain or grain free ingredients whatsoever, instead being a difference in the added vitamin and minerals which make up a small percentage of the formulas. These are often the minimum required nutrition (as per current understanding) for a dog to stay healthy. Get that wrong, with consistent feeding of a processed commercial dog food, will have severe repercussions.

      Real considered studies would investigation how lack of animal ingredients in processed commercial dog foods can cause not only DCM, but most diet-related illnesses in dogs. Unfortunately science as rational as this doesn’t sell product.

  5. In the event that the DCM link is not a sham, what would be the best grain inclusive product to include in my feeding rotation? I already include a variety of grain free, fresh, cooked and raw foods but I guess it couldn’t hurt to include a quality grain inclusive product if it exists?

    • Reply
      Pet Food Reviews (Australia) March 1, 2023 at 8:25 pm

      Hi Tim, when it comes to grain-inclusive foods I tend to prefer those with grains such as oats or barley, or brown rice to an extent. I see wheat (or “cereals”) as a red flag, and in my experience seem to be common causes of health issues. Brands like LifeWise and Canidae All Life Stages spring to mind, but there are many others. Holistic Select is another possibility available at some of the bigger pet stores.

  6. Hi, I stumbled across the topic of DCM in one of the review boards and looked it up. The first article I came across was this one,


    I didn’t interpret the article to blame grain free products even if the inference was that the initial attention to a rise DCM cases coincided with the rise in popularity of grain free diets.

    I must admit I’m still confused on a couple of points though. The article states that Taurine deficiency is the likely cause. It then tells us that taurine is available in animal/meat products and that dogs (but not cats) can also make Taurine from a couple of amino acids available in many grains.

    So my question is whether it be grain or grain free dry dog food what happened to the taurine from the Meat / Meat meal or meat by-products – is it destroyed in the cooking process or is there just so little actual meat product in these products
    to cause taurine deficiency.

    Secondly – assuming our fine furry (barking) loved ones can manufacture taurine from methionine or cystine it could explain why this has become a concern more recently as more people try to provide a healthier feed for their pets by going grain free. In the event that this is the case it would have to be more of a serendipitous coincidence than by design from the commercial pet food colossuses that use cheap grain as fillers had a positive outcome. If this is so I assume that the grain free advocates/products are supplementing taurine now ??


    • Reply
      Pet Food Reviews (Australia) January 12, 2023 at 7:14 pm

      Hi Rohan,

      I think with most pet foods we need to consider they don’t have as much meat as we may be led to believe, and taurine is generally sourced from animal ingredients (although their are alternatives). And yes, heat does damage nutrients which is another factor.

      It has been widely believed for many years a cat needs taurine in the diet whereas dogs can synthesise it, but the evidence is there that dogs too can become taurine deficient. Not surprising given the ingredients of most dog foods.

      Most research into canine and feline nutrition is instigated by the big players in pet food manufacturing. For a period of time I noticed those brands included taurine, whereas other smaller “boutique” brands didn’t because it wasn’t a requirement by AAFCO. This has now been amended. I think a good way of looking at AAFCO nutrient requirements is they’re based on what we currently know and understand, which is why the standards are amended over time as new research comes to light.

      Personally, when it comes to situations like the “DCM scare”, I usually attribute these conditions more to inappropriate diets rather than whether they’re made of grain or potato for what I consider essentially carnivorous animals. It also should be noted, more so now than ever, that such events may just be power plays and clever marketing.

  7. Thank you so much for this. As soon as I came across the supposed link between heart failure and grain-free foods, I smelled a rat. I really wish people would stop feeding their dogs kibble of any description. I know I have extended the life of my Sheltie who I rescued at 8 years of age when he was at death’s door, by feeding a quality, mostly grain free diet with plenty of variety. It’s common sense when you think about it, but so many have been brainswashed by corporate marketing.

  8. hi, I read that you suggest changing food and not giving one food source only forever, how often do you recommend this? we have a almost 5mth old and switching from hills vet essentials ( last food we tried gave him severe bowel issues and the vet popped him on this food and probiotics) to lifewise, which he is doing well with over the change over currently and just ordered a big bag. thanks

    • Reply
      Pet Food Reviews (Australia) April 25, 2022 at 9:02 pm

      Hi Natalie, it’s always struck me as odd how in human nutrition we know it’s bad to eat the same thing all the time, yet this is rarely translated to pet nutrition. The idea we need to feed our dogs the same thing all the time I believe stems back to pet food marketing, when the truth is they want you to keep feeding their product for the life of your pet. Great to hear your dog is doing well on Lifewise!

      • Hi. I am so confused knowing which dog food to feed my dog. After reading your review on taste of the wild I was going to go with that but now reading your article on grain free diets you have said taste of the wild is associated with dialated cardiomyopathy. Please what is a good option for dog food in Australia? Everything seems to be poor quality, recalled, cause heart problems, dilated cardiomyopathy, have bad ratings and reviews and the debate between grain free or grain based foods leaves me at a complete loss. Any advice will be greatly appreciated.

        • Pet Food Reviews (Australia) October 11, 2022 at 4:44 pm

          Hi Nathan, I have always seen the FDA investigation into grain free foods somewhat of a sham, which I also believe was largely instigated by pet food manufacturers to damage their small grain-free producing competitors.

          So with Taste of the Wild, I wouldn’t personally have any concerns whatsoever feeding Taste of the Wild, a dog food which in my experience has proven very reliable – plenty of evidence of that.

          I see lack of variety in a dog’s diet much more an issue, especially when dogs are fed one of the many high carbohydrate grain-based kibbles which are rated poorly in my reviews.

          So hopefully that helps?

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