Exploring Grain Free Pet Food

This article is written by Pet Circle veterinarian, Dr Carla Paszkowski, BVSC (Hons)

Grain free diets for cats and dogs have become exceedingly popular in recent years, moving in tandem with the rise of grain and gluten-free diets for humans.

The grain free pet food industry is not only growing, but also evolving, at a rapid pace. The popularity of grain free diets has led to an unprecedented explosion of the number of options available, encompassing concurrent 'ancestral', 'freeze dried' and 'raw' movements.

So, with an ever-growing number of grain free diets gracing the store shelves (or in our case, the web pages!), how do we navigate what seems like a simple question: Is grain-free better for my pet?

Contents:

What does 'GRAIN FREE' actually mean?

Is a Grain Free Diet better for your pet?

Does a Grain Free Diet Help with Allergies?

Does Grain Free Dog Food Cause Heart Disease?

What are the Best Grain Free Diets?

What IS Grain-Free Food?

Is 'grain free' the same as 'gluten free'?

No. Gluten refers to the proteins found in wheat, rye, barley and triticale. These are all classified as grains. However other grains exist which do not contain gluten, such as rice. Therefore, grain free food is always gluten free, but gluten free food may still contain some types of grains.

Fun fact: true coeliac disease (gluten allergy) is almost unheard of in dogs and cats, with the exception of Irish setters.

Is 'grain free' the same as 'filler free'?

No. Don't be fooled into assuming that 'grain free' also means 'filler free', or 'carbohydrate free'. A study in 2018 found that there is a misperception among pet owners of which ingredients are defined as carbohydrates, and believed that potato, barley, corn, soy and wheat should all be absent in a GFD. This study also found that many pet owners believe that grain free diets are 'free of fillers and by-products'.¹

The truth is, it's almost impossible to create dry kibble without some form of carbohydrate holding the biscuit together. This means that when manufacturers remove grains from the recipe, they often replace them with other carbohydrates such as potato, tapioca, or chick peas. Always check the ingredients if you aren't sure!

If you're after a super-low-carbohydrate diet to mirror the 'high meat' ancestral diet of your pet's ancestors, rather than home cooking (which can run the risk of nutritional imbalances), I suggest going for a scientifically balanced, high meat-content diet such as K9 and Feline Natural, or Ziwi Peak. These diets are complete and balanced in line with guidelines, and contain up to 98% meat content.

High Meat Content Grain Free Recommendations:

Where did the 'grain free' trend come from?

Like many nutrition trends, the grain free movement was founded on a few theories. Let's explore some of these:

THEORY 1: Grain free diets more closely replicate a natural diet

One big argument put forward by fans of the grain free movement is that as carnivorous animals, grains hold no place in the natural diet for dogs and cats. While cats are obligate carnivores, meaning they must eat meat, technically domestic dogs are omnivores. Dogs have lived alongside humans for tens of thousands of years eating our scraps and cast offs, including meats, vegetables and you guessed it - grains!

If we compare the genome of a dog to a wolf, it's been shown that dogs do have the ability to digest the starches found in grains. In fact, a microbiology researcher in 2012 found that dogs have multiple copies of the gene coding for the digestive enzyme, amylase, which is synthesised by the pancreas.² While dogs can have anywhere from 4 to 30 copies of this gene, wolves only have 2 indicating a reduced ability to digest starch. While their distant relative may be the wolf, the domestic dog's digestive system has undoubtedly changed a lot since then.

Curious about carnivorous diets for dogs and cats? Read my other article Raw Diets for Pets - the Risks and Benefits

THEORY 2: Grain free diets are beneficial for food allergies

The second argument put forward in favour of grain free diets is that they often manufactured with a holistic focus and can include nutraceutical ingredients and superfoods that could offer additional beneficial nutrients. Although not suitable for use as a blanket hypoallergenic diet, grain free diets may be suitable for dogs with allergies to grain based proteins such as wheat and corn. (Read more about this below!)

Want to know more? Read my other article What is the Best Dog food for Allergies?

Is grain free pet food better for your pet?

Or perhaps we should ask, 'are grains bad'? In order to answer this, let's take a look at grains themselves. Corns, oats, wheat, rice, barley... They've copped a lot of flack in the past few years, often labelled as 'cheap fillers' and 'nutritionally useless'! The truth is that grains - particularly brown rice, oats and corn - actually provide many nutritional benefits to your pet.

Do grain free diets contain more meat and fewer fillers?

That depends on the brand and variety. Just like other types of pet food, there is a very wide spectrum of quality for grain free diets. Affordable or 'budget' lines are now available which offer virtually no benefit over their grain-containing sister products, as the grain content has been substituted with alternative carbohydrate sources such as tapioca or potato - which can actually be less beneficial nutritionally for your pet than grains.

Read about which brands are highest in quality in our articles:
• What is the best grain free dog food?
• What is the best grain free cat food?

Are grain free diets complete and balanced nutritionally?

Another way to assess whether a diet is 'good' for your pet is whether it is complete and balanced. Vets in particular often worry that a grain free diet may not be balanced compared to a traditional science-based dog food - and there is even more concern nowadays thanks to the FDA's investigation into grain free diets and a link between taurine deficiency and heart disease. While every pet food brand is different and we can't speak for all of them, ultimately the short answer is: Yes! Most grain free diets are complete and balanced.

Gone are the days when 'grain free' also meant 'uber holistic' and nutritionally unbalanced. Nowadays, most premium grain free dog foods are complete and balanced in accordance with international feeding guidelines. Furthermore, many (but not all!) grain free diets tend to be high in quality when compared to many cheap grain-based recipes, with most surpassing supermarket brands and hitting the premium bracket due to their higher meat content, digestibility, and bioavailability. No empty husks of rice here, no sir!

Can dogs and cats digest grains?

In short, while your poodle's distant relative may be the carnivorous wolf, their digestive system has undoubtedly changed a lot over tens of thousands of years alongside humans.² To contrast to wolves, domestic dogs have developed plant-digesting salivary and pancreatic enzymes! So, in general, most dogs can digest grains just fine.

However, grain free dog food may benefit your dog if they are allergic to grains. Which brings me to my next point...

Will a Grain Free Diet Help With Allergies?

This is a complicated question, because allergic conditions in dogs and itchy skin in cats can be caused by a whole range of different allergens in their food or environment. To accurately determine whether a food allergy is responsible for your pet's itching, you will need to complete a proper elimination diet. For a full run-down about nutrition's role in skin allergies and the best diets for sensitive skin, take read my other article The Best Dog Food for Skin Allergies.

What it comes down to is this: If your pet isn't allergic to grains, a diet lacking in grains probably won't improve their condition. Much the same as a lactose intolerent person avoiding peanuts, a grain free diet probably won't cure a dog who is allergic to springtime grasses.

Are grain allergies common?

Actually, not really. It's important to note that true grain allergies are quite rare in dogs - in fact, poultry and beef allergies are far more common.⁶ And in cats, it's very rare to see grain allergies, if ever.

But, my dog's skin improved on a grain-free diet? Many people report an improvement in their pet's allergies when they swap to a grain-free diet, and are left assuming that a grain allergy was the cause. While it's possible that your pet may form part of the small percentage of cats or dogs that harbour a true grain allergy, it's more likely that your pet's skin improved due to the new diet's superior quality, particularly in terms of digestibility, nutrient density, and bioavailability. And if you swapped to a food with a different meat protein such as fish, this may have contributed too!

From hydrolysed diets to fish-based food, read more about food allergies and the best skincare diets in our article The Best Dog Food for Skin Allergies.

Does Grain Free Dog Food Cause Heart Disease?

In the last few years, veterinary cardiologists in the United States reported increased rates of a deadly heart condition, dilated cardiomyopathy (DCM), in Golden Retrievers and breeds which are not typically predisposed to DCM in general. Frequently these dogs were noted as being fed 'boutique, exotic or grain free' diets, or BEG diets for short.

At this stage, research is still ongoing and it is unclear as to the underlying cause of the reported cases of diet related DCM. Some possible theories include nutritional imbalances in the foods themselves, unknown effects of certain exotic ingredients such as legumes, fruits, flaxseeds etc, or even potentially an unknown toxin.

An association between DCM and the presence of certain pulse legumes has been suspected, due to the high soluble fibre and oligosaccharide content of legumes and the tendency of these compounds to deplete taurine. Low taurine levels has long been associated with DCM, so a link is generally suspected.³ A study in Golden Retrievers in 2020 found that grain free diets (most of which contained legumes such as peas or chickpeas) lead to taurine deficiency, and, concerningly, signs of cardiac symptoms consistent with DCM.⁴ However, another 2020 study in Beagles found no obvious taurine level changes in dogs fed a grain free diet compared to a grain-based diet.⁵

For pet parents concerned about nutritional deficiencies, feeding a rotational diet may help. A rotational diet offers your dog some variety while also reducing the risk of a deficiency developing from feeding a particular diet over an extended period of time. Rotational feeding involves offering your dog a combination of high quality diets, ideally varying protein sources and formats (eg. dry, freeze-dried, wet).

Want to know more? Read Dr. Teagan's full in-depth article Does Grain Free Dog Food Cause Heart Disease?

What are the BEST Grain Free Diets?

With more than 400 products in this category on Pet Circle alone, judging the best grain free cat and dog food is definitely not an easy task. Based on everything we've discussed, I've shortlisted a number of stand out pet food varieties which hit the mark in terms of quality nutrition, ingredients, reliable testing facilities, and overall brand reputability.

Winners: Top Picks for Grain Free Pet Food