In the first of a new series on “controversial topics”, we asked vet student Joe Dunne to review the evidence on Grain-free foods for dogs, and the potential health issues. Here’s his take on the situation!

Pet food manufacturing is a big industry. Every day there are more products on our shelves, more adverts featuring cute dogs on TV, and more recommendations on social media. It can certainly make us feel a bit clueless while shopping for kibble. While choice is always a good thing, an increased consumer appetite (pun intended) for ‘exotic’ pet diets, such as grain-free diets, may be causing unintended health issues in our dogs. One of the most talked-about is a potential link to these diets and heart disease in dogs. Today we will be discussing these unusual diets and their potential risks. You can make an informed decision on what your dog devours daily.

What’s the Deal with Fancy Food?

In the last few decades, perhaps fuelled by rising awareness of human diets, social media recommendations and clever marketing, ‘BEG diets’ (boutique, exotic and grain-free diets) have become more and more mainstream among consumers. This term actually covers a huge variety of unique diets and products. Ranging from products from pet food giants with unusual ingredients, tailored pet food from smaller companies, home-cooked, vegetarian and even vegan diets. Grain-free diets specifically exclude grains like wheat, corn and rice, often replacing them with legumes, peas and potatoes. BEG diets are incredibly varied, which makes it hard to quickly identify if they are adequate for your dog or not. Many are not fully tested for their nutritional value.

There are a myriad of reasons why you may choose to feed your dog BEG diets. Reasons such as the belief they are healthier or more natural than traditional processed dog food, trying to avoid specific diseases such as allergies (note that grain-related food allergies are quite rare), weight-control, personal reasons such as vegetarianism, and many more. No doubt, owners want to do what is best for their pet. We do not want to shame anyone for their choice; indeed, it would be remiss of us to simply paint all BEG diets as inappropriate and untested; some are probably perfectly safe for pets. However, we do not want to beat around the bush. Many diets are pushed by companies and social media as ‘trendy’, with a lot of claims of what they can do without any proper evidence. As such, there is increasing evidence that BEG diets can result in health issues, which the rest of this article will be discussing. 

In the USA, a number of vets have noticed an increase in a heart condition called dilated cardiomyopathy (DCM) in their patients – DCM is a heart disease that is relatively common in certain breeds of dogs, due to genetic factors. It is caused by abnormal contraction of the heart muscle that leads to abnormal movement of blood and changes in the shape of the heart. Dogs with DCM have large hearts with thin muscle that cannot pump effectively. This causes the dog to become breathless, have exercise intolerance, weight loss, fluid build-up, further heart problems, and eventually death if left untreated. Interestingly, many of these new cases are in breeds of dog we don’t normally see DCM in.

So how does DCM relate to BEG diets? First, we must go back a few decades, where DCM was common in cats. In 1987, scientists found that cats with DCM were deficient in an amino acid called taurine. Taurine is important for heart muscle health, and their pet food lacked enough of it. Taurine supplementation helped the cats, and extra taurine has been added to cat food ever since. The incidence of DCM in cats is now very low thanks to this discovery. However, recently DCM in cats has been on the rise again, almost always due to being fed certain BEG diets that may be deficient in taurine. The relevance of all this is that there is some growing evidence that taurine-deficient BEG diets may be resulting in DCM in dogs as well.

Studies found that the dogs with DCM and low taurine improved with the addition of taurine into their diet. All of these dogs were on BEG diets when their DCM was diagnosed. This is strong evidence that BEG diets that are low in taurine are causing DCM. There were also groups of dogs that were on BEG diets with enough taurine, but they had DCM regardless. Tis points to some other issue with BEG diets. This may be because another important nutrient for the heart is deficient in BEG diets, or that there is a component of BEG diets that is actually is toxic to the heart; currently we are unsure. In either case, halting BEG diets for a more traditional diet was shown to improve DCM in both groups.

Other Risks of Designer Diets

There are also a number of secondary issues with BEG diets that vets are aware of, so we should mention these now. Many of these diets are not properly tested before being available for purchase. This means that their nutritional content may not be known (hence why many are low in taurine), and can lead to other deficiencies or toxicities if consumed. Others may cause stomach upset if your dog isn’t used to them. It really is a gamble buying some of these products.

We also want to mention vegetarian and vegan diets. Dogs are facultative carnivores – this means that they need primarily meat to survive, but can digest plant material. So vegetarian and vegan diets are technically safe for dogs to consume. However, it is very difficult to ensure your dog is receiving all the appropriate nutrition it needs. We don’t recommend these sorts of diets for dogs unless guided by your vet. As an aside, cats are obligate carnivores, meaning they only consume meat and cannot digest plant material. Cats should never be given vegetarian or vegan diets, as a lack of meat can make them very ill and even die.

What’s the Verdict?

As we mentioned above, DCM does occur in dogs due to genetic or other factors, so we are not saying that all dogs on a BEG diet will get DCM, or that all DCM is caused by BEG diets. However, the growing evidence that dogs on BEG diets are at higher risk of DCM than normal. Either due to taurine-deficiency or another diet-related reason, means you should be wary of giving your dog a special diet. There is not definitive proof yet, and further study is needed. However the risks of DCM and other issues from BEG diets are high enough that we recommend avoiding BEG diets unless necessary.

If you decide that you still wish to feed your dog a BEG diet, we have some advice. Only do so after discussing it with your vet. Talk about your reasons why you wish to use a BEG diet, and take recommendations on which would be safest for your dog. Your vet may recommend blood tests, such as taurine levels, before to see if the risk would be low enough. Use a BEG product from a reputable company that has performed full testing on the product. Once on a BEG diet, you should have regular check-ups that look at your dog’s heart and taurine levels. Taurine supplementation may be necessary. You can also keep an eye out on pet websites and veterinary information for new updates on the safety of BEG food, as more evidence is presented. You may find some diets start to be recommended once they have been proven safe. These recommendations are true if your vet prescribes a BEG diet, such as for food allergies, as well.

Traditional commercial dog food is not perfect, and no one product is perfect for every pet; some dogs may genuinely not do well on normal diets, for various reasons. However, pet food is constantly evolving, and big brand pet food is getting better year on year. Furthermore, the fact it is rigorously tested should place it top of the list of what food to buy for your pet. BEG diets, including grain-free foods, are too new and untested for us to recommend except under the guidance of your vet. The next time you’re thinking about what food is best for your dog, consider sticking to well-known brands with normal recognisable ingredients that are more likely to be perfect for your pet. 

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