Dogs Are Still Dying From Grain Free Diets

Updated January 6, 2024

This is the story of Rowdie. She’s a survivor where many others aren’t. As you’ll see, I got lucky twice before solving the puzzle.

The food that nearly killed her is a leading brand of grain-free dog food you can buy at nearly any Australian supermarket. I wish I could tell you its name.

Here’s what happened.

Rowdie’s Collapse

That’s Rowdie in the picture. She’s a 12-year old Beagle who’s always been in good health, including at a checkup early this year.

On the 16th of May, she was having a bath when she suddenly collapsed, rolled on her side and remained stiff and unresponsive for 10 to 15 seconds. She was taken to an emergency vet and had blood taken. The cause was thought to be a seizure.

I saw Rowdie a few days later. The first thing I thought was that it probably wasn’t a seizure: these go on for at least 30 seconds and have lots of muscular activity. Her history contained a further clue: she’d recently developed a moist cough.

Heart Disease, Not Seizure

More clues came from her examination. Her heart rate and her breathing were faster than expected, and I could feel fluid in her abdomen. Most importantly, she had a grade 3 heart murmur that wasn’t there just four months earlier.

The final clue was the bath. Seizures happen at any time, even during sleep. Rowdie’s collapse on the other hand happened at a time of increased activity.

I strongly suspected a heart problem and so we took chest xrays straight away. These showed an enlarged heart with pulmonary oedema (fluid on the lungs). Heart disease was confirmed.

Why Rowdie Though?

You see, Rowdie’s problem wasn’t typical. She’s not of a breed prone to heart problems, and she’d been normal so recently. Most cases of heart failure don’t come on without warning because we’ve been listening to the murmur getting louder for months or years beforehand.

Here’s where Rowdie’s luck turned the first time. Here in Adelaide we’ve always had a shortage of vets skilled enough to offer cardiac ultrasound, called echocardiography. Well just the week earlier I’d received news that a board-certified ultrasonographer was setting up a freelance service.

We started Rowdie on heart medications and booked her in for the soonest available appointment.

Echocardiography Saves The Day

dilated cardiomyopathy ultrasound
Abnormal jet (regurgitation) from Rowdie’s left ventricle (large dark cavity) into the left atrium

The ultrasound exam saved her life. That’s because the results showed she had a very unusual form of heart disease that I never would have predicted: dilated cardiomyopathy or DCM.

DCM is when the heart muscle gets thin and weak, and it normally has a very short survival time. However, not in Rowdie’s case. It was while I was talking over the results with her owner that she got her second lucky break.

I remembered those reports about grain free foods. And so I asked about Rowdie’s diet.

Grain Free Diets & Heart Disease

It turned out that earlier in the year, Rowdie’s owners had started buying a grain-free dog food. Like most people, they assumed that if it was being proudly marketed as grain free, it must be better.

Vets have known for some time that this is not true, but we can’t get the message out to dog owners. The reality is that grain free diets are being regularly linked to dogs like Rowdie.

You can read more here. We don’t know exactly why, but theories include B vitamin deficiency, inhibition of taurine or carnitine metabolism, or unidentified, potentially cardiotoxic compounds. 89% of DCM-associated diets reported to the FDA contained peas1.

Treatment of Diet-Related DCM

I advised Rowdie’s owners to put her back onto a quality grain-based diet, and added a taurine supplement as a precaution. She also needed to stay on the heart medications. There was no way of knowing if my suspicions were correct except by trying.

Even when DCM is caused by the diet, not all affected dogs can recover. It depends how much damage is already done, and her case was severe.

I saw Rowdie two weeks later. She was doing very well, which was probably just the effect of the heart meds. A month later she was doing even better, which by now was not what we expected for regular cases of DCM.

By the way, the best way to tell is by measuring sleeping or resting respiratory rate.

A Stunning Response

On the 11th of August we repeated the echocardiogram. Here is a summary of what was found:

  • The dilation of the left ventricle had vastly improved, but was not completely resolved
  • The left atrial enlargement had completely resolved
  • The measurements of heart contraction (fractional shortening and EPSS) were now normal
  • The regurgitation jet at the mitral valves was no longer visible

And here are the numbers:

Scan 26 MayScan 11 AugNormal
Ao (mm)18.419.425
LA (mm)35.126.926

The improvement was so great that it was debatable whether Rowdie needed to stay on heart medications any more. We’ve got one more ultrasound exam planned and then we’ll probably stop them.

A Warning To Dog Owners

What is critical for you, the reader, to understand here is how rarely dogs receive a cardiac ultrasound. Heart disease is one of the most common problems of dogs, but we lack the skilled sonographers to do all but a tiny fraction. I only ordered this test because there was something not quite right about Rowdie.

As nearly every case of canine heart disease has just one cause, it’s reasonable for vets to make assumptions. Especially in a user-pays system where any further investigation will add costs and delays. However, for Rowdie this would have been deadly.

There is no doubt in my mind that most cases of DCM caused by grain free diets will go undiagnosed. This would have happened to Rowdie too if she was a more ‘typical’ breed or had a more typical history. Which matters because this specific form often responds well to treatment especially if recognised early.

Without a realisation that the diet was to blame, Rowdie would have died quickly. Like the more regular cases of DCM, she would have responded briefly to the medications, but then started declining again.

These days I ask a lot more about the diet every time I hear a heart murmur. And I hope that the lesson for you is to avoid these diets until we can report which ones are faulty, and either fix or remove them.

Related: Why I can’t warn you about bad dog foods (yet)

Have something to add? Comments (if open) will appear within 24 hours.
By Andrew Spanner BVSc(Hons) MVetStud, a vet in Adelaide, Australia. Meet his team here.


  1. Smith, C. E., Parnell, L. D., Lai, C. Q., Rush, J. E., & Freeman, L. M. (2021). Investigation of diets associated with dilated cardiomyopathy in dogs using foodomics analysis. Scientific Reports11(1), 1-12 Full text

8 Replies to “Dogs Are Still Dying From Grain Free Diets”

  1. Hi Andrew. Thanks for the article.
    I’m wondering about adding grain to doggo’s diet myself – does brown (or white) rice fulfil the requirements?
    We’ve tried some dried foods that include grains and had significant change in stools. She gets a bit of mince, pumpkin and rice added to her dry food and we’re wondering if that will do the job

    1. Hi Peter. It’s unlikely that adding grains to these diets will make them safer, as most people suspect the diets themselves contain substances that interfere with taurine uptake or metabolism. There’s sure to be a solution for your dog’s problem that doesn’t require the use of grain free diets.

  2. Hello Dr Andrew, reading your comments /concerns regarding Australian Dog food being unregulated, has brought me to you to request your assistance if at all possible.

    My dog for various reasons is now eating an Australia brand (bought at a pet store) and I am now worried if we have done the wrong thing. It’s a grain free salmon kibble which he absolutely loves and is just about to complete the first 3kg bag. After reading a few of the above blogs and your kind responses I’m now concerned we have made the wrong choice.

    We actually asked (the large Pet Store) if the products they are selling are regulated and we were advised yes, they are if they are sold in pet stores but not if the foods are purchased in supermarkets.

    How can we ever make informed decisions when the information provided changes from one place to another. Is there some tell tail sign on packaging that gives us a hint.

    My head remains to spin wondering if I am looking after my dog to my best ability.

    I understand if you are unable to comment, I just wish I didn’t have to bother you but we do follow your site and thoroughly enjoy your effort, ethics and advice.

    1. Hi Janet. You’ll find answers to these questions by following the links found in this article. They explain the difference in regulation between Australian food and food from the USA and Europe.

  3. Yes I DO NOT buy Australian Made Dog food NO more until Australian Made pet foods are REGULATED..
    I rotate my boy kibble brands – 1 brand is Royal Canin.
    Royal Canin Pet food is a really good brand. R/C is made in France Europe. Europe have Strict Pet Food laws in the world also they use Dehydrated Chicken , Dehydrated meat is heaps better quality, the meat is NOT cooked & cooked till the meat has no nurtrience left..
    My staffy suffers with IBD & Allergies the only food he started to get better on was Royal Canin dog food, also I rescued a cat her back leg would give way when walking & running, I started her on Royal Canin Light Weight Cat dry/wet food, her wobbly back leg got better & stopped colapsing when she was walking & running. R/C is properly balanced & now she’s finally getting what was missing in her diet.

  4. Thank you so much for sharing Dr Andrew. I am consistently trying to explain to people that just because we haven’t seen many cases here in Australia, it doesn’t mean it isn’t a problem here. Like you mentioned, cardiologists are few and far between, so to get a diagnosis is difficult. It’s most likely due to underreporting, rather than a true freedom from cases. I continue to recommend my clients to steer clear of these diets and alert them to the concerns around this condition – thank you so much for sharing this case with us.

  5. Hi Dr Andrew, firstly thanks for you blog. I read all of the dog articles and appreciate the time you put into writing them despite the fact my dogs will likely never be patients living on the other side of the country!

    My curiosity led me to reading over your dog food related articles tonight after forgetting to pick up the usual premium food on the way home and having to do a supermarket run.

    While I don’t want to be adding something time consuming to your workload…

    I know you said you couldn’t name bad foods but maybe doing a list of favourites instead? Taking into account evidence regarding nutrition levels, quality of ingredients, fillers, testing standards etc?

    Maybe include different categories – premium, supermarket, subscription favourite picks and then overall favourite picks? So readers could get your thoughts on regular food but have something to consider if they have to do a last minute run to the supermarket at 9pm

    Anyway, just a thought!

    Thanks again, Parker

    1. Hi Parker. That’s a very good thought but I’m also afraid that such hardline advice will be unacceptable to most. With the current state of pet food regulation, the safest thing to say is just don’t buy food from countries like Australia that refuse to regulate. I believe that only the countries in the European union or the United States have decent enough systems in place to govern pet foods and detect faults. Therefore foods either manufactured in these places or sold into these markets are objectively safer. Of course there are bound to be many good, ethical Australian food manufacturers but the system doesn’t allow us to differentiate them. It’s still worth avoiding grain free diets in general until the mechanism is better understood.

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