Vegetables for dogs – to feed, or not to feed?

January 10, 2015 at 1:09 am

This is a topic that I am pretty sure I’ve written about before, but every time someone asks me – which is frequently – I can’t seem to find where. So today, I thought I might revisit the whole topic with a new post.  Vegetables in the canine diet seem to carry a little controversy, largely due to the recent trend of prey model diet, wherein raw foods are used in amounts that attempt to mimic what a wolf or other wild canid would consume (I won’t say wild dogs, because dogs are domestic, and if we are talking about ferals, I highly doubt anyone would be trying to mimic what those dogs eat). Recent awareness about overconsumption of carbohydrate foods has led many to feel that all carbs are undesirable and that, sadly, includes fruit and more importantly, vegetables.

animal-vegetable-300

There seem to be 5 main areas we need to evaluate here, that cover the pros and cons of feeding veggies to dogs.  First – as always – I am not going to come out on any kind of a side – not the side of “dogs don’t need them” as that is kind of an absurd remark to me, and not on the “side”  that supports feeding a whole lot of veggies all the time, either, although to be fair, I like to see them used intelligently. For those who follow my blog, you’ll already know why – I don’t see nutrition as that simplistic, and I always evaluate pros and cons, with an eye to what best serves the individual.
With that in mind, let’s look at areas I think are worthy of exploration.

 

1) bioavailability of nutrients

2) concerns about “anti-nutrients”

3) health benefits of phytochemicals

4) potential effect on stool

5) potential contamination with pesticides etc.

6) concerns about feeding anything containing carbohydrate

All of these are important considerations, and after we’ve looked into them a bit more, you will see why I don’t take a single point of view here, but evaluate each case as I see them. In a client case, I develop recipes initially with usually only a starchy vegetable such as sweet potato, and once the goals of the consultation are met, and the dog is on a balanced diet that agrees with him, then I have people experiment with and add rotated greens, and other vegetables and fruit. I don’t rely on them for a significant portion of energy, or nutrient for that matter – although they do provide some, but I do want to have dogs eating a sensible amount of veggies specifically for the phytochemicals. More on those in a second entry.

opening-colorful-veggies-fruits-antioxidants-ss

Let’s look at these issues a little more indepth.

1) Bioavailability of nutrients from plants.

Despite what you may have heard, dogs can indeed digest and utilize nutrient from plants.
It’s as simple as that.
Anyone who says they cannot, is misguided.
The reality here is that dogs are not actually obligate carnivores like cats; they can convert nutrients to some extent, such as beta-carotene from carrots, into a bioavailable form.  They can indeed digest cooked carbohydrates.
Fiber is another issue –  fiber is really an umbrella term that applies to those parts of plants that are not digested (not by them, not by us either). There are different types of fiber and we know, study after study shows, the value of fiber in the diet (again, canine and human). I wrote a fair bit about this here: http://www.thepossiblecanine.com/carbs-part-two
But because fiber is not digested, but fermented in the colon, in no way means that all other types of carb is “undigestible”.  Furthermore, the fermentation process provides  food  for the “good” microorganisms we want to see proliferating away in there.  So we can safely say that the indigestibilty of fiber is no reason to avoid the many health benefits of fruits and vegetables.

Now to be clear, I personally feel that carbs should not be relied on for more than 25-30% of the total energy intake(calories) unless indicated by the individual, and often much less, many of my client’s dogs are on 10-15%, which is really very little. . and for that portion of the diet I much prefer cooked starchy vegetables, a little bit of well prepared legume, and nutritious seeds such as buckwheat and quinoa. Rice is not high on my list, mostly due to  the arsenic issue – but again, in some cases we need to use rice (and again, the source and preparation are key).
And also to be clear – I do not rely  on fruits and vegetables as major means to providing  energy. A cup of broccoli has 40 calories, give or take, so if I need 500 calories of carb in a given recipe, to achieve that 25% – you can see how much broccoli we need! whereas sweet potato gives us a whopping 200 – 240 calories. So I can use much less.
But don’t be fooled by sites that claim dogs cannot derive any nutrients from plants. They certainly are not as efficient at it as we are, or the herbivores – but they’re MORE efficient than a cat species.
Sidenote: I admit I find it a little strange to hear people oppose veggies in the diet using the”unnecessary”, at the same time that they give turmeric and coconut oil and whatever else is currently trending!   Thinking like a nutritionist here – dogs don’t actually “need” ANY specific foods, they require vitamins and minerals, fats and fatty acids, – in other words, nutrients. Some foods are better sources. And not all dogs, I repeat! are the same. 🙂

I am adding here that it is very important to either lightly cook or grind up veggies, when feeding them to dogs – doing so will liberate nutrients that may pass through undigested if simply fed raw. If your dog likes a raw carrot to chew on, great! But to optimize beta-carotene, or any other nutrient/phytochemical you want to emphasize – steam them before feeding.

2) Concerns about “anti-nutrients”

This is a point that carries some validity, but again, once we identify what these anti nutrients actually are, which foods they are found in, how to prepare foods to minimize content and how much to feed,  we can see that there really isn’t a case for withholding veggies unless a specific medical condition indicate that we do. I will be fairly brief here – the top problems are as follows:

-Solanine from  plants in the Solanaceae family, eg nightshades. This includes tomatoes, eggplant, peppers and white potato. While there is disagreement amongst researchers as to just how much of a  problem this is, I simply don’t use these foods. I suffer from Solanine sensitivity myself, with joint pain and GI upset after I eat potatoes, so I am fairly sure it’s a real concern. In addition, I don’t see any real call to use these foods if there is risk of exacerbating a problem. My approach is – don’t feed nightshades to any dog with arthritis, with a history of GI distress or food intolerance, at all. Feed them judiciously to others. If you have a sensitive dog and you use white potato, watch stool. And don’t overdo it. This, from where I sit, is just common sense.

– Glucosinolates from Brassica family vegetables .Restriction, in my view, really only applies to dogs with thyroid disease, whom I feel should not have veggies from this family on any regular basis. If your dog has had a proper thyroid evaluation and is fine, I encourage you to add brassicas in moderation to his or her diet. Use broccoli, cauliflower,  – always cooked gently, and no more than 3 times a week. yes, these veggies offer protection from cancer. So do many other foods and herbs. Use wisely.
“Glucosinolates are water-soluble compounds that may be leached into cooking water. Boiling cruciferous vegetables from 9-15 minutes resulted in 18-59% decreases in the total glucosinolate content of cruciferous vegetables.”
much more info here: http://lpi.oregonstate.edu/infocenter/phytochemicals/isothio/

-Oxalate –  here we have a problem only if the high oxalate foods are used all the time, or if the core diet is low in calcium, or lastly, if the dog has suffered from calcium-oxalate stones in past. In this last case I recommend  restricting the higher oxalate foods altogether.  Many fruits and veggies that have a lot of oxalate also offer phenomenal health benefits – so  do use them, but again, in moderation. Here is a listig of oxalate content in foods, so if your dog has a predisposition toward stones, or if you are homefeeding and concernend about losing calcium – you can choose from low or moderate sources. http://www.ohf.org/docs/OxalateContent092003.pdf

-Phytate – another constituent of plant foods that can have a negative impact on nutrient absorption is phytate. When I was starting out in canine nutrition, people were all up in arms about phytate, as it does hold some potential to bind to some minerals and affect absorption. These days,  we know a fair bit more,and phytate – a potent antioxidant – can be reduced in plant foods via pre-soaking and careful preparation. Given that only aout 25% of a canine diet is going to consist of plants, ideally, I think this is one worry we can relax about. Here’s Dr. Andrew Weil on the matter, a nice succinct read: http://www.drweil.com/drw/u/QAA400758/Are-Phytates-Bad-or-Good.html

Note:  “You also should be aware that phytates themselves have some health benefits, including anti-inflammatory effects. In laboratory research, phytates have helped normalize cell growth and stopped the proliferation of cancer cells. “

Again – the pros outweigh the cons, significantly so.

 

3) Health benefits of phytochemicals

There is really no question about the power of all kinds of phytochemicals in plants, to offset the development of illness, reduce inflammation, support health. It is for these compounds, more than anything, that I personally emphasize the use of vegetables and fruit in the canine diet.  To keep this entry from becoming overlong, and because beneficial phytochemicals deserve a whole entry of their own, let me offer a link  from the American Cancer Society, with regard to  a (very general)overview of the benefits of fruits and vegetables.
http://www.cancer.org/treatment/treatmentsandsideeffects/complementaryandalternativemedicine/herbsvitaminsandminerals/phytochemicals

 

4) Potential effect on stool – This is another concern that needs to be addressed individually. Just like humans, dogs digestive systems do vary!  In my work with literally thousands of cases, I see dogs who can tolerate extraordinary amounts of both soluble and insoluble fiber, and dogs who are incredibly sensitive to small amounts, and everything in between. The volume of vegetables added, the type of fiber, and the context of the total diet all play a role in whether an individual dog develops diarrhea from added vegetables and fruits. So again my advice is simple; start with one vegetable at a time, cook it lightly, and feed a small amount to your dog, increasing a little over a few days.  For a small dog you might think about as little as a tsp or two a day, working to 1/4 cup; for a medium dog,  start with 1/8 of a cup and work up to 1/4 or  1/2 (daily) and you can go much higher with the big guys, but again, methodically, please! Working with the idea that both the amount of a vegetable and the type  can influence response, you will soon find out what your dog’s unique system reacts best to.

5) Potential contamination with pesticides: This is a VERY real concern,  and one I believe is not looked at closely enough, especially with the serious rise in canine cancer over the past decade. Organic produce is entirely the way to go, if you can – or at the least, rinse anything you buy extremely well. If possible, grow your own – but be aware that many soils are now contaminated too, sad to say. http://nypost.com/2014/03/16/lead-found-in-community-gardens-soil-may-affect-produce/

My own sense of this issue is this; if you evaluate all our food supply, you will be confronted with a n alarming array of contamination – from pcbs and flame retardant in fish, to antibiotics in factory farmed cows and chickens, to the myriad issues with imported foods and of course, arsenic in rice.  It is completely impossible to avoid contaminants, but with vegetables and fruits, organically grown or just very thoroughly washed – we can minimize intake of the nasty stuff while ensuring our dogs get all the health benefits plant foods can offer. So be aware of where your produce comes from, and be careful. That said, don’t let this concern prevent you from adding some vegetables, the cost/benefit analysis comes out on the side of  the plants here. One idea might be, to buy organic when using the “Dirty DOzen” pictured below, and use the others carefully, washing well and trying to find local sources as much as you can.

EWG-ShoppingGuide_thumb

Concerns about carbohydrates: This is such a touchy subject and so hotly debated, I don’t think for one moment that I can change anyone’s mind who is convinced that carbohydrates are all dangerous and should not be fed to dogs in any way shape or form, ever. The best science we have refutes that idea, and my own clinical experience shows otherwise, with dogs whose health issues (or the preference of the vet) mandated I use diets very high in carbohyrates, and living well past  life expectancy. It is purely ridiculous to claim that dogs cannot digest carbs (see above) or that the intelligent use of them is a negative practise. So I will discount this idea, if you are reading this blog you likely already understand that carbs can be, like any food group, overfed and deleterious to health or used wisely and health-supportive. Let’s not belabour this point.

In conclusion; I hope the takeaway message here is that vegetables and fruits offer great health benefits, with a few potential drawbacks that can be avoided or minimized, and in general are excellent and important foods to add to your dog’s diet. Whether you raw feed, or prepare a cooked recipe, or feed a commercial diet, think about using a wide variety of veggies in moderate amounts. Spend some time reading more deeply in the science we have with regard to antioxidants, phenolic compounds, carotenoids and more. you can think of whole fresh veggies as THE best supplement you can add – if you are adding lots of lifeless items in little plastic jars – because they’re trendy – do revisit nature’s pharmacy. And be sure to save a little for yourself, too.

 

dog_running

11 thoughts on “Vegetables for dogs – to feed, or not to feed?

  1. I don’t usually feed my dogs veg but they do like them.
    I have a pup of 8/9 months who at every chance she gets will steel some veg and chew and eat it. She’s had a cabbage and a cauliflower and carrots. Love a bit of apple and just yesterday stole and was half way through eating a kiwi fruit.
    She’s part Aussie but mostly border collie and I bought her to get her away from a puppy farm, she was reared in a barn until I got her.
    Do you think there is a reason why she should be so attracted to fruit and veg?

  2. I personally don’t see the need for fruit & veg, and consider them harmful when dogs have certain health challenges. My dog cannot have any carbs or processed food whatsoever, or it triggers yeast blooms. There is no need to give supplements or prepare veg and fruit for our carnivores, unless the dog has health challenges, or the dog needs fiber and the owner does not have access to fur/feather-on whole prey.
    Wild dogs certainly eat carbs, primarily because they’re scavengers, and there are times of famine or food shortage. There is no shortage of food for most dogs living with families.
    While they’re not cats, dogs’ gi tracts are designed the same, and the fact that carbs have to be prepared before serving speaks for itself. There is no harm in avoiding carbs in a dog’s diet. There is no harm in adding properly prepared and properly sourced carbs to some dogs’ diets.
    There is no need to be dogmatic about diet, but if people oppose or support one way or the other, they should not be ridiculed for it, as you do in the above post. I don’t find it sensible to anthropomorphize my dog and feed him the same diet I eat, but that’s my choice and I choose what is most healthy for my dog. I also aim to make feeding my dog simple, hence why I feed prey-model. Nothing is easier than opening a package of raw meat, putting meat on a tray, and cutting something open or in half if needed. It’s why I avoided barf and home-cooked, which make things excessively complicated.

    • Hi Raven, While I appreciate that your dog has difficulty with the carbs you’ve tried, and that you place a high value on convenience, there are several points here I’d like to address.
      First, I re-read this whole article and I can’t see where I’m ridiculing anyone.I do see certain ironies in many places – people all riled up about adding veggies, for example, but adding a ton of expensive supplements – it’s gentle humour, not a slam. In my line of work, you see all kinds of stuff, and sometimes, a little humour is in order. No offense was intended here at all.

      Next: I’ve been in practise for 16 years and have always used carbs in the diet for a whole range of reasons – the amount, and type will vary according to the dog.There are, actually, all kinds of potential problems associated with a diet that consists only of protein and fat; it’s great that your own dog is doing fine with it, but as a nutritionist I could write a very long blog entry on some of the problems a carbfree diet entails.You are making very “dogmatic” statements here, several of which are not supported by the science, so I will try to address them briefly and hope it is useful for you and my readers.

      1) The canine digestive system is not at all identical to that of he cat.I have an entry called Preferential Carnivore which you can find on this blog, it details some of the differences.And even cats can benefit from the antioxidants in a small amount of plant matter, but dogs benefit greatly.

      2) In no way do I “anthropomorphize” the canine diet! When I develop a recipe I calculate the dog’s requirements for every nutrient from A to zinc, and they are significantly different from that of a human. For example, My 75 pound dog requires more calcium per day than I do, and I weigh about twice that. With dogs as with humans, there is a a great deal of variance with regard to which macronutrient levels work best, but micronutrient requirements remain consistent. I have studied human and canine nutrition and there is absolutely no confusion in my mind between the two.

      3) I disagree there “is no need for supplements” – it really depends on what you are feeding!There is a disturbing trend towards using a PMR diet but not really using whole prey; this can mean the dog is short-changed on several fronts, for essential nutrients. Even worse is the home made COOKED recipe that has no supplementation – really scary and increasingly popular. And what about the dog who simply has to eat a lower calorie diet – if you’re using less than the 2% level of the PM method, or in my own (NRC) method you are below a certain caloric range, you simply CAN’T get all the nutrients form the food. What’s wrong with knowing what nutrients are needed, which may be low and then supplementing? Vegetables, herbs, and supplements all add major health benefits if used intelligently.

      I’m sorry you took personal offense to this article, but really, it’s simply here to help people make informed choices for their dogs.
      All the best, Cat

  3. This is a refreshing, balanced, unbiased and informative article, thank you. N.B. I cannot see any evidence of ridicule in the article.

  4. I see nothing here other than the excellence of this article, just like many of the other articles posted here to help us. Always intelligently written and full of so much detail. Written from the perspective of one willing us to do the best for our dogs and helping us to understand the individual needs of our dogs too. In fact we are very lucky to have this resource! So thank you very much Cat for taking the time to share all you do with us, its pretty fantastic….. and please keep posting.

  5. Pingback: - The Possible Canine

  6. I am curious about the need to slightly cook the veggies. My dogs love to forage out of the garden. They pick their own green beans and turnip greens, and love green peppers. I’ll monitor the green peppers this year b’c of what I have read in this article, plus having one dog with arthritis. But otherwise, that they are choosing their own food seems like a natural behavior.

  7. One of the best reviews I have found regarding cruciferous vegetables and dogs. Our mini schnauzer has a history of oxalate bladder stones and we have been feeding him a special diet for almost three years. It contains about 50g/day of broccoli and cauliflower. Cruciferous vegetables are low in oxalates while most other vegetables are not. I have had his thyroid checked in the past and the T4 level is normal. We have not seen any adverse effects. The vegetables we use are frozen and probably blanched before freezing which can inactivate the enzymes which break down glucosinolates. But of course, this hydrolysis can occur in the gut by bacterial enzymes. We have seen a lot of vets over the years and not one has cautioned about using these vegetables in his food. I just saw this caution online the other day.

Leave a Reply

Your email address will not be published. Required fields are marked *