Is Grain Free Dog Food Killing our Pets (FDA warning)?

Are grain-free diets causing our dogs to die of heart failure? Just what is the deal with the recent FDA announcement that grain-free diets are being investigated for this and should you think about changing your dog's diet?


Today I wanted to discuss the recent announcement by the FDA that a number of grain-free diets appear to be causing heart disease in dogs that don't normally suffer from this particular type of heart disease.

What is dilated cardiomyopathy (DCM)?

Now, the type of heart disease we're talking about is something called DCM or dilated cardiomyopathy.  DCM is when the heart becomes enlarged and the muscles of the heart don't work properly. As a result heart failure develops when the heart is just not able to pump blood around the body to an extent that matches the needs of that animal.

Make no mistake, DCM is serious and potentially fatal.  The reason that these cases are unusual is that normally only certain breed suffer from it.  Dobermans are a typical example. In the cases being investigated however, dilated cardiomyopathy causing heart failure is developing in dog breeds where it is not normally found.

The FDA grain free dog food announcement

The FDA announcement goes:

“The U.S. Food and Drug Administration is alerting pet owners and veterinary professionals about reports of canine dilated cardiomyopathy, or DCM, in dogs eating certain pet foods containing peas, lentils, other legume seeds, or potatoes as main ingredients. These reports are unusual, because DCM is occurring in breeds not typically genetically prone to disease. The FDA Center for Veterinary Medicine and the Veterinary Laboratory Investigation and Response Network, a collaboration of government and veterinary diagnostic laboratories are investigating this potential association." (read the full announcement here)



Grain free dog diets may cause heart failure. The FDA is investigating the link.
This is what you need to know

What questions need asking?

So, what are the issues that we need to discuss?

Well, I think the first one is the fact that the number of dogs affected is really very low compared to the total number of dogs eating these diets. Now, that's not to say that this problem is not a cause for concern. This may very well be the very tip of a big iceberg, but I think it's important to put things into perspective and not have complete panic when we're only talking about a small number of dogs.

It's certainly important, and we should definitely all be paying attention to this situation.  Especially if you're feeding a grain-free diet or thinking about switching to one. But at the moment it seems to only a small number of dogs are being affected.

So the next issue is that the statement discusses a number of diets that contain pulses and other different ingredients as the main source in their diet. So, it doesn't specifically say grain-free.  Although diets that do contain lentils or potatoes and things like that as the main component of their diet typically are grain-free, this isn’t absolutely specified.

So, we don't know for sure that we're talking about completely grain-free diets, and we don't know which diets are involved.

We also don't know whether we're dealing with just one diet, one manufacturer, or whether we're dealing with multiple diets from multiple sources.

At this very early stage, the cause is completely unclear, and this is what is really being investigated.  So, there are a number of questions:

  • Is it a lack of grain (if they are, in fact, grain-free diets)? I personally doubt this is the only cause but it certainly could be. Is it just a lack of grain?

  • Is there a common ingredient that's causing these problems? Do all of these diets have one certain ingredient, that when fed in certain quantities causes DCM and heart failure in dogs?

  • Rather than a specific ingredient, have some food actually been contaminated with something that should never have been in the food?

  • Does Taurine play a role? There have also been a number of dogs that have been affected that have had low taurine levels. Low taurine is something that we know is associated with the development of DCM, or dilated cardiomyopathy. In fact most diets have added taurine to prevent this exact problem. Having said that only about half of the dogs tested so far had very low taurine levels and the other dogs have normal levels. So, a low taurine is definitely not the only story.

  • Are we, in fact dealing with a couple of different causes, both of which result in the same disease. Highly unlikely but the investigation will find this out.

So, really it's too early to be drawing any firm conclusions. It's definitely an important development and it could, like I say, actually be affecting a really large number of dogs. Heart disease can go unnoticed and un-diagnosed for quite a period of time. Over time with DCM, the heart will become bigger and the efficiency of the heart to pump blood will slowly deteriorate.  It's only when the reduction in pumping ability reaches a critical point that your dog will start to develop signs of heart failure.

DCM can be diagnosed in a number of different ways and if you're concerned about this at all, then you should definitely be getting in touch with your vet.  They will be able to advise you if there is anything that you should be thinking about doing for your dog. This may be a blood test, an ultrasound scan of the heart or x-rays. There are a number of things that we can do to check for damage or an abnormality within the heart.

Why feed your dog a grain free diet?

What this announcement also does is raise some important or interesting questions about why we're feeding grain-free diets in the first place.

It's a topic where there are a lot of myths, misconceptions and misinformation that are being thrown around. And there is a lot of marketing involved as well, with a lot of food companies, especially smaller boutique food manufacturers, really jumping on the grain-free bandwagon that has gathered momentum in the human health world.

As far as dogs go, there is absolutely no clear evidence to suggest that grain-free diets have any benefit for the vast majority of dogs.

One of the big suggestions thrown around is that grains are a source of food allergies.  In reality, food allergies themselves are actually pretty uncommon. And in the vast majority of cases, it's actually due to the protein component (the chicken, pork or beef for example) that is present in the diet.

Sure, there are a few individuals that are allergic to grain, but it's a really tiny minority.  This risk in itself certainly doesn't justify the mass feeding of grain-free diets to my mind.

The other thing that is often quoted is that wolves are carnivores, dogs come from wolves, and so dogs really can't process, can't digest, and have no use for grain in diets.  People often go a step further and claim that this grain is not only of no benefit, it is positively harmful and responsible for cancers and a whole slew of other diseases.

This belief actually ignores an long period of evolution.  The dog genome is definitely not the same as the wolf genome.  In fact the dog genome has developed to such an extent that there are a number of genes which allow dogs to digest grains to a much greater efficiency than our wolves can.  It does vary between breeds but it has been thought that this difference allowed dogs to thrive during early domestication.

Dogs aren't wolves, and they are able to digest and utilize grains, making them a valuable component of the diet.

Are novel + exotic ingredients the problem?

The other issue with some of these grain-free diets is that, as I said before, there are a lot of more boutique or smaller food companies that are producing grain-free diets.  Not only that, they're also producing diets that contain quite novel or exotic ingredients. This might be different types of meat (such as crocodile, ostrich or kangaroo) as well as different pulses and seeds that haven't traditionally been used in pet food production.

The use of novel and exotic ingredients in itself isn't necessarily a problem.  But what it does mean is that it can be quite hard to know whether a diet is completely balanced, and whether it's being digested as would be expected.  Every different protein, every different ingredient will be digested in a different way and to a different extent. It might be that separate ingredients interact and reduce or increase absorption of different vitamins and minerals compared to our standards diets.

Also, a lot of these boutique and smaller feed companies are very unlikely to be running any long-term feeding trials to assess the quality of the diet and to assess animals that are fed on these diets for a long period of time before they are released.  Instead what they're often doing is comparing nutrient profiles between different diets and that can cause big problems.

If you're comparing one diet that contains crocodiles and lentils for example to another diet that contains chicken and rice, then, if we're just trying to get the more exotic ingredients profile very similar to the conventional diet we may run into problems.  Because digestibility and absorption will not be identical, a dog may very well end up with a nutrient deficiency (or even toxicity). It might be for this reason that we're finding a low taurine level in some of the dogs that are being investigated.

Don't always believe the hype

When it comes to pet food, we really need to be careful with marketing buzzwords. There's not really any legislation or control about the use of these terms. Grain-free diets may be promoted and more healthy and natural but are they really? Well, we don't know.  There is no evidence to support (or refute these claims). It may well be that a grain-free diet is better, but we just don't know.

Hypoallergenic is another term very often printed on food bags.  Really, unless we're talking about a very small selection of diets that we use specifically as food trials to rule out food allergies, hypoallergenic doesn't mean very much at all.  Being “hypoallergenic alone is in itself no real benefit to the majority of individuals and probably doesn’t mean what you think it does.

Also, natural, a lot of diets will claim to be natural. And really what does this mean?  I think in a lot of cases it probably doesn't mean what we think it does. And again, it's not really necessary for health. It's more of a marketing term.  A lot of these smaller brands, they really focus heavily on marketing and they produce fantastic adverts and videos and all that kind of thing (of course large companies also focus on promotion heavily as well).  This marketing can be very compelling, but perhaps the evidence behind feeding them isn't as strong as they would suggest.

So many questions...

All this is not to say that:

  • Grain-free diets aren't better than conventional diets, we just don't know.

  • It might be that feeding a home prepared, well-balanced, cooked diet is better for your dog than feeding a commercial food.

  • It might be that raw feeding is the best option when fed as a balance diet (and the majority aren’t)

  • But the fact of the matter is there's just not really any hard evidence, or compelling body of evidence, to suggest that one diet is better than the other in many, many cases.

Diet is something that it brings out a lot of passionate beliefs in a lot of people.  There are a lot of stories thrown around. "My dog was fed this food. I switched onto this food, and their health improved massively".  I'm sure you've read this kind of thing (check out my article on the Dunning Kruger effect to read more about this).

Really, anecdotes are a very poor form of evidence. In fact they're really not evidence at all.  What we need, and what would be fantastic, is some large-scale feeding trials, but they're just not available at the moment. Hopefully they will be developed in the future.  We really need to watch this space.

We certainly know that there are risks with some diets.  For example, raw feeding does come with some risks:

  • E.coli, salmonella and campylobacter are risks to both dog and owner

  • Bones, if fed, can result in tooth fractures as well as intestinal obstruction and perforation

  • Raw fed dogs may have a higher incidence of multi-resistant bacteria in their stool.

Now all of these risks of raw feeding may be negligible for healthy adult pets in healthy adult households.  In the young, old, unhealthy or immunocompromised however (dog or human), serious even life threatening disease may be a higher risk.  Raw feeding is a topic for another day but suffice to say if we have no evidence of a benefit and there are some risks (however small) we should think hard about whether it is appropriate for our dog.

Depending on the results of the FDA investigation, there may be similar concerns with grain free dog food.  Some risk without any proven benefit.

Really, there's more questions than answers, I know.  It's definitely a case of watch this space. Whatever the topic, we should try and stay well informed, and we should try and stay up to date with the latest developments and research available to us whenever possible.

What are your thoughts?  What are you planning on doing if you are feeding a grain free diet?  Are you having second thoughts if you were planning on changing your dog's diet?  Make sure you let your friends know too.

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