Should dogs eat vegetables?

This paper examines three commonly cited claims about vegetables in a dog’s diet –

  1. Dogs are carnivores and should only eat meat
  2. Dogs have no ‘nutritional’ requirement for carbohydrates
  3. The ‘Prey’ or 80/10/10 diet is ‘complete’

Dogs as carnivores

Dogs are classified as members of the family Canidae and the order Carnivora but this does not necessarily translate into behaviour, anatomy or feeding preferences. Panda bears are also members of the Carnivora family and they eat bamboo shoots!

Dogs are omnivores or rather, if there is such a classification, ‘opportunivores’. Strict or true carnivores have a high nutritional requirement for taurine (an amino acid), arachidonic acid (a fatty acid) and certain vitamins (niacin, pyridoxine, vitamin A) which are readily available in animal protein and fat sources. Omnivores, such as dogs and humans, don’t have high requirements for taurine and can manufacture their own arachidonic acid and vitamin A. Of course dogs are meat eaters but they also eat vegetables.

“Dogs have no ‘nutritional requirement’ for carbohydrates”

Dogs can derive energy from protein, fat or simple carbohydrates so to this extent the above saying is true. However, as well as energy they need specific additional nutrients in their diet. These nutrients are listed at Table III-3 of the FEDIAF Nutritional Guidelines (FEDIAF is the European Pet Food regulator). They need protein to derive 10 of the 22 amino acids required for metabolic functions (they can synthesise the rest). They also need the ‘essential’ fatty acids (ie those that they can’t synthesise themselves), vitamins and trace elements and it’s here that fruit and vegetables play a part.

Dogs are not good at digesting complex carbohydrates such as grains and starch (indeed in the wild they will often eat fermenting or part-digested fruit and veg). One of the problems with a dry kibble is that not only does it typically contain a high proportion of complex carbohydrate (grain is often cited as the culprit whereas many other cereals are just as bad) but it is actually sprayed with starch during the extruding process. However, this is not the place to argue the advantages of raw food over extruded kibble – the question is about carbohydrates and whether vegetables should be added to a dog’s diet.

A comparison of the nutritional analysis of a so called ‘prey’ or 80/10/10 diet with that of a commercial raw food containing 20% fruit and vegetables is attached as Appendix 1. This uses the Cronometer system (an independent nutritional calculator). Both diets have more than adequate levels of fat and protein but  the 80/10/10 diet (comprising 80% ground beef, 10% beef neck bones and 10% offal) has the following major shortcomings when compared to the FEDIAF guidelines  –

  • Omega 6 is 22% below the recommended level
  • Vitamin B1 is 38% below
  • Magnesium is 47% below
  • Manganese is 86% below
  • Vitamin D is 68% below
  • Vitamin E is 83% below
  • Iodine was undetected

The beef recipe from Cotswold RAW has 20% vegetables plus a smattering of herbs (in its Butcher’s Blend, which can be purchased separately to add to a DIY diet), a little flax seed and wheat germ oil. It has none of the above shortfalls. Also, the above are just the adverse variances from the FEDIAF recommended amounts which don’t cover every vitamin or trace element. Some startling differences between the recipes for vitamins and minerals can be observed.

Is an 80/10/10 diet ‘complete’?

The FEDIAF Nutritional Guidelines state in their introductory paragraph “A complete and balanced diet is essential for the health and wellbeing of dogs and cats. Appropriate diets provide the nutrients needed for reproduction, growth and for a long, healthy, active life. They also prevent the nutrition related disorders which can occur due to nutritional deficiencies or excesses”

The Guidelines define (and this definition carries legal weight) ‘complete’ as the daily ‘ration’ required to satisfy all of the dog’s energy and nutrient requirements and lists the nutrients for consideration at Table III-I. It is the recommended amount of these nutrients that is compared in the attached appendices.

Artificial supplements can always be added to such 80/10/10 diets but they are not complete without them. Such diets could easily be made ‘complete’ by natural means by adding some vegetables and herbs.

Postscript – the cause of canine obesity

This paper is not advocating feeding dogs a vegetarian diet, far from it. Indeed, it is in our view positively dangerous without careful supplementation. It is merely stating that adding a small amount of vegetables (say 20%), which are a natural source of antioxidants, vitamins, phytonutrients, fibre and trace minerals, is appropriate. There is little doubt that canine obesity is the result of dogs being fed too much carbohydrate. Dogs will metabolise fats in preference to carbs for their energy needs leaving the surplus glucose from the carbs to be stored as fat.

So used sparingly, vegetables are an excellent and necessary addition your dog’s diet.