Why dogs need vegetables

Jonathan Self

One of the questions I am often askes is why so many of our recipes contain vegetables. I should probably begin by explaining that all our formulas are complete and were created for us either by our own chief veterinary surgeon or by ‘guest’ veterinary nutritionists. When you take into account our bespoke recipes, we must have well over thirty options including food specially formulated for working dogs, overweight dogs, dogs with particular health issues and so forth. Some include vegetables, some don’t.

Our most popular formulas, however, are 66% meat and meaty bone and 33% seasonal vegetables. The meat is free range, pasture fed, certified organic or wild. It is fresh and if it wasn’t being used in our food you might expect to find it in a posh butcher. The vegetables are either grown for us – without chemicals – by a local farmer or, in the case of the organic vegetables, come from other farmers in the UK. In fact, all the ingredients are sourced from British producers.

There has been much debate over whether vegetables are a necessary part of a dog’s diet. The main argument against vegetables is that dogs are carnivores not omnivores and would barely eat any vegetable matter or fruit in the wild. I agree that dogs are carnivores, but they aren’t obligate carnivores and sometimes they definitely choose to eat vegetables and even fruit. To offer just one example, my late English pointer, Darling (much missed) used to pick her own blackberries (very delicately with her lips) and harvest her own carrots (which was extremely annoying). Moreover, canines eat the gut contents of their prey, which usually contains vegetation. They also scavenge vegetation, which includes herbs, vegetables and fruit.

Anyway, to my mind feeding vegetables to a dog can only be beneficial. Here are nine reasons why:

1. For dogs who need to come down a collar size or two they help make them feel full. Indeed, for all dogs the vegetables mean there is more food to eat… something that most dogs appreciate!
2. Some organs (the heart, liver, pancreas, etc.) work better in a more alkaline environment and the same is true of some hormones. Vegetables help to balance the alkalinity and acidity. If there’s too much acidity, it can lead to inflammation. And inflammation causes many chronic diseases.
3. Vegetables contain a wide array of nutrients – especially phytonutrients – that your dog needs. Phytonutrients are one of the most important kinds of nutrients you can give your dog ­­– they kill cancer cells, reduce inflammation, promote gut health and support a healthy liver. But they are only found in fruits and vegetables. So if your dog only eats meat, he or she is missing out. Research published in the Journal of Animal Physiology and Animal Nutrition found that phytonutrients could potentially benefit many aspects of dog health, concluding: ‘Phytonutrients possessing anti-inflammatory and antioxidant properties may have notable roles in the prevention of chronic diseases, whose underlying development involves accumulated oxidative stress and chronic low-grade inflammation or altered immune function.’
4. Vegetables help hydrate your dog.
5. Vegetables provide your dog with a host of vitamins including B vitamins, Vitamin C, Vitamin A, Vitamin E and Vitamin K.
6. Vegetables contain important minerals including calcium, potassium and magnesium.
7. Some vegetables are rich in enzymes, which can help with anti-aging.
8. Vegetables are packed full of antioxidants like lutein and beta-carotene. These help to protect your dog against unstable molecules called free radicals. Free radicals are a major cause of aging and disease.
9. Vegetables are high in fibre. Fibre passes through your dog’s intestines largely undigested. Once it reaches the colon, the bacteria living there ferment the fibre to create short chain fatty acids aka SCFAs. SCFAs are then used for energy, to build immune cells and protect the mucous lining in the gut. Fibre reduces cancer risk, has antioxidative properties, clears toxins and helps with gut health (more about which below).

Despite all the research, science still hasn’t discovered all the many ways in which food works to keep us healthy. Take something called fisetin, which is a natural plant compound (polyphenol) found in a variety of vegetables including strawberries and apples. Studies have found that fisetin reduces the effect of senescent aka ‘zombie’ cells. Zombie cells are cells that refuse to die but which hang around the body releasing chemicals that can be harmful to nearby cells, affecting cell survival and reparative potential. The build-up of these zombie cells promotes ageing and age-related conditions, including cardiovascular disease. When senior citizen mice are given fisetin their health life span improves dramatically.

There is hard research, too, showing that vegetables reduce the chances of cancer in dogs. A study involving Scottish Terriers, for example, found that feeding any type of vegetable at least three times a week produced a 70 percent reduced risk for developing transitional cell carcinoma, otherwise known as TCC, a type of cancer often found in the urinary bladder and urethra of older, smaller dogs. Feed green vegetables and you reduce that risk by 90%

There is still much work to be done about what a healthy dog’s biome looks like, but what we do know is that canine diets that exclude fresh vegetables result in considerably less healthy microbiomes.

Among the most important compounds plants provide are the polyphenols, flavonoids, and other phytonutrients. In multiple studies, adding polyphenols to the diet has been shown to significantly reduce markers of oxidative stress. Oxidative stress, to save you looking it up, reflects an imbalance between the systemic manifestation of reactive oxygen species and a biological system’s ability to readily detoxify the reactive intermediates or to repair the resulting damage. What does it matter? It is suspected to play a huge (and not very positive) role in a wide range of diseases including strokes, heart attacks, age-related development of cancer, Alzheimer’s and more.

Some apiaceous vegetables (e.g., carrots, cilantro, parsnips, fennel, celery, parsley) contain polyacetylenes, an unusual class of organic compounds that has antibacterial, antifungal, and antimycobacterial benefits. They play a key role in detoxifying several cancer-causing substances, specifically mycotoxins (including aflatoxin B1).

I could go on about other beneficial things to be found in vegetables such indole-3-carbinol, lutein, zeaxanthin, sulforaphanes and quercetin (considered nature’s Benadryl because it so good for dogs with allergies) but I feel I have made my point. Fresh vegetables can’t possibly do your dog any harm and there is plenty of evidence they will do him or her a great deal of good.