Can My Dog Eat Grains and Legumes?

When it comes to feeding our dogs, the debate over whether grains and legumes should be part of their diet has become increasingly prominent. Whilst these ingredients are common in commercial dog foods, providing sources of carbohydrates along with some protein, vitamins, and minerals, their necessity in a dog's diet is questionable. Dogs, unlike humans, do not have a strict dietary requirement for carbohydrates, leading some pet owners to rethink the inclusion of grains and legumes in their dog's bowl. We’re going to explore the nutritional implications of grains and legumes for dogs, the potential risks associated with anti-nutrients like lectins, and the ongoing concerns raised by grain-free diets, particularly in relation to heart health.  

Understanding Grains and Legumes in Dog Food

Grains, such as wheat, corn, and rice, and legumes, including peas, lentils, and chickpeas, are often included in commercial dog foods. These ingredients serve primarily as sources of carbohydrates, but they also offer some protein, vitamins, and minerals. However, it's important to understand that dogs, being facultative carnivores, do not have a strict dietary requirement for carbohydrates. Unlike humans, dogs can synthesise glucose from proteins and fats, meaning that they do not need carbohydrates to thrive.

Lectins: The Anti-Nutrient Factor

A point of concern with grains and legumes is their content of lectins. Lectins are a type of protein that can bind to carbohydrates and resist digestion. They are sometimes referred to as anti-nutrients because they can interfere with the absorption of essential nutrients in the gut. In large amounts, lectins have the potential to cause gastrointestinal upset and may even contribute to chronic inflammation. There are some researchers who have linked lectins to poor gut barrier health and the growth of potentially harmful bacteria in the gut.  However, it's worth noting that cooking and processing significantly reduce lectin levels in food.  

Whole Grains vs. Refined Grains

There are also differences between the types of grains available.  Whole grains contain all parts of the grain kernel—the bran, germ, and endosperm—offering a fuller nutritional profile that includes fibre, vitamins, and minerals. Refined grains, on the other hand, have been processed to remove the bran and germ, stripping away much of their nutritional value and leaving primarily starchy carbohydrates. Whole grains are generally considered healthier for dogs, just as they are for humans, because they provide more nutrients and support better digestive health.  This is why whole oats can be an energy dense addition to your active dog’s diet, if you so choose.  

The FDA Investigation and Grain-Free Diets

In recent years, grain-free diets have been under scrutiny due to a possible link to dilated cardiomyopathy (DCM), a serious heart condition in dogs. The FDA's investigation into this issue has suggested that dogs on grain-free diets might be at an increased risk of developing DCM (potentially due to a taurine deficiency caused by the grain free diet), although the exact cause is still unknown. Interestingly, some dogs included in the FDA investigation were not found to be taurine-deficient.  

In 2023 researchers investigated the feeding of grain and pulse diets to dogs. They concluded that feeding peas to dogs did affect heart function, but feeding lentils did not.  Taurine levels in the dogs remained unchanged in all diets fed, which negates the theory that low taurine levels cause DCM.  It’s essential to also recognise that DCM can be caused by factors other than diet. These include myocarditis (inflammation of the heart, which can be infective, toxic, or immune-mediated), mitochondrial dysfunction, hormonal disorders and various nutrient deficiencies.

In summary, whilst grains and legumes can be included in a dog’s diet, we should be asking whether our dog needs them.  Grains and legumes provide carbohydrates and some other nutrients, but dogs, as facultative carnivores, do not require carbohydrates to thrive. The presence of lectins, an anti-nutrient in these foods, raises concerns about nutrient absorption and gut health, though processing and cooking does reduce these risks. Whole grains, with their richer nutritional profile are generally preferable to refined grains however.  The FDA's investigation into grain-free diets has raised concerns about a potential link to dilated cardiomyopathy (DCM) in dogs, particularly related to certain ingredients like peas, though the exact cause remains uncertain.  In addition, there are many other causes of DCM in dogs. Feeding grains and legumes to dogs sits in some muddy waters, which is why we recommend feeding a fresh food diet. My recipes are naturally grain/legume free, rich in nutrients and perfectly digestible for your dog.