Over the course of the past week I’ve received a LOT of email about the entries on carbohydrate, some voices in support of my approach (no vilification of whole nutrient groups, multiple factors considered in dietary decision making) others who strongly oppose the use of any carb of any kind (except pulped veggies and fruit) in the diet. Well, to each their own; I have strong feelings as well, and I make no choice or statement without good reason. In this matter I do feel that moderate fiber and starch in the canine diet fulfills a host of functions – no, make that I know it does, this is not a feeling or a preference, but scientific fact. Whether anyone wants to use carbs, is a personal matter. By putting out facts, filling in the educational gaps here and there, I hope to empower people to make the right choice for their dog, based on the science. And so far we have:
1) Dogs are preferential, not obligate carnivores, and neither are they omnivores; though better adapted to an omnivorous diet than the cat, it is not optimal. Distinct anatomical, physiological and metabolic features demonstrate this. Dogs are better suited than cats to a diet featuring carbohydrate.
2) Certain types of starch and fiber are far better for dogs than others. Of the grains, oatmeal and rice are glutenfree, seeds such as quinoa and buckwheat are also glutenfree and have both benefits and potential drawbacks, like all foods; in addition, rate of fermentability is extremely important. Simple carbs are not healthful additions to the diet at all. The percentage of soluble to insoluble fiber in a diet can be make-or-break for stool quality and to minimize effect on micronutrient absorption.
3) Carbs are not “filler” per se, in a wholesome home made diet; not when they come from nutritious sources like quinoa, sweet potato, brown rice, buckwheat and assorted vegetables . Foods classified as carbohydrate provide multiple nutrients in addition to fiber, and are used for immediate energy, thus sparing protein for other uses.
4) Diets that consist of protein and fat only, pose specific issues for the healthy dog, and can be disastrous for dogs with underlying or active health conditions. It’s correct that dogs don’t require dietary carbohydrate in the sense that a specific pathology results from withholding them – but this is a narrow definition of requirement, one that has been repeatedly questioned, and I personally use it as a starting place only. FOS (fructo-oligosaccharides) or prebiotics, are carbs, and many people add them regularly to bolster colon health. Not a “requirement”, but definitely helpful, and healthful.
5) There is great individual response to carb levels and sources, so one of the first decisions I make when I read through a dog’s questionnaire is how much to start with. If there are no health issues that suggest using reduced levels of protein or fat, if everything looks good and the dog is at a good weight and exercised moderately, I start with 15- 25% of the diet from carb. This means I can still use two to three TIMEs the RA for protein. More on all this math stuff to follow. but a diet that has 40% protein by ME (Metabolizable Energy, or calories to be simpler) is not a low protein diet. Given that fat is present in a moderate fashion as well, we will have more than twice the Recommended Allowance for total protein in a diet containing 15-25% carb.
6) Many health conditions mandate that I work with lowered fat and/or protein in the diet. I see dogs on these diets doing extremely well – MUCH better than if they were to eat only the prescribed Hill’s foods for their condition. And I see it working over years, not short term. With good food choices, carefully prepared and supplemented, these dogs do very well on much higher carb than I’d ever like to use. This reinforces my belief that moderate carbohydrate in a healthy dog’s diet is not at all deleterious. Of course, it’s all individual, but as a general rule, don’t be afraid to use whole organic buckwheat, cooked sweet potato, and others I’ve mentioned as a part of your dog’s diet.
In this post I want to look at A) some popular myths about carbohydrates, B) some very real problems with foods that supply carbohydrates and C) a bit of a summary to pull it all together. In upcoming entries we’ll examine some of the specific foods I recommend – what they offer, how to use. In a separate entry coming up soon I will show you what a diet containing 25-30% carb actually looks like, and why, really, it’s not a thing to fear.
A Couple of Pervasive Myths, or at least, Semi-truths Misunderstood
1) . DOGS CANNOT DIGEST CARBOHYDRATES.
We’ve gone over this a bit but it’s always worth review. It’s not true, that dogs cannot digest carbs. It IS true that fiber, a type of polysaccharide, is fermented and not hydrolyzed enzymatically in the small intestine ( fancy talk for ‘digested’). It’s true that grains and vegetable should be either cooked or “pulped” – very well grated, for example and then mashed a bit more – in order to facilitate digestion. That’s certainly true, but once they are cooked or sufficiently pulverized, dogs do digest them and can derive more nutrient from plants than cats can. or as a colleague put it, somewhere (in a book, I can’t recall): “carbohydrate digestion in dogs is alive and well”.
Yes, indeed. The plants just need to be prepped a little.
2.) CARBOHYDRATES CAUSE CANCER.
No, actually they don’t. This is an extreme simplification that has been misunderstood out of all proportion. While there is a seed of truth in there – excess sugar (those simple carbs we discussed way back when) can increase inflammation in the body and contribute to the development of many diseases, including cancer. It’s also true that meats and fat laden with things like antibiotics, hormones, from grainfed animals and even including such things as arsenic (I kid you not) are HUGE nutritional minefields with regard to cancer; and what about the issues with fish? Household and lawn chemicals? Yearly vaccinations? Cancer is a complex disease and no one cause – dietary or otherwise – can be singled out (although things like nitrates, mercury, aflatoxin and charred meats are so bad, we can just say categorically they have to be avoided, for us as well as dogs).
But no, healthy carbs fed in moderation do not *cause cancer*. It is unwise to feed simple carbs to dogs with cancer, however fiber, and myriad plant compounds are critically important for them. I will be going much more into how to feed dogs with various types of cancer further into the blog. For now, just please know this; carbs don’t ” cause cancer”. Some forms of fiber ferment in the colon and produce Short Chain Fatty Acids like butyrate, which are actually recognized as actively protective against some cancers. Once again, it’s what type and how much. Look to a comprehensive programme of prevention, not one single issue.
3.) CARBS MAKE DOGS FAT
Again, not entirely mythical, but an oversimplification. In general, dietary carbohydrate is used up as an energy source right away if not, it is indeed more readily stored as fat, than is protein or fat. It’s also true that one strategy for reducing weight in dogs is to lower overall carbohydrate. That said, consider two things. One, overfeeding (calories) and lack of exercise remains the primary cause of obesity (of which there is more than one kind). And two – how we manipulate nutrients to achieve weight loss depends on the dog. For some, I actually increase fiber and lower fat.
All dogs are not the same. I know, you’ve heard me say this before. 🙂
4.) ALL ALLERGIES ARE CAUSED BY GRAINS.
Total nonsense, this one. True food allergies are relatively rare in the canine, although intolerances are very common. Canine and Feline Nutrition states ” It has been estimated that food-induced allergic dermatitis constitutes 1% of all dermatoses seen by small animal veterinarians, and 10% of the inflammatory dermatoses diagnosed”.
True allergy (hypersensitivity) can develop at any age, and the antigens are proteins; including lipoproteins, glycoproteins, and polypeptides. The most common true allergies are to beef and chicken as well as the proteinaceous compounds in wheat soy and corn. Food intolerance, on the other hand, can develop to anything at all. One explanation for the prevalence of canine intolerance and food allergy is the overuse of the same foods in commercial products, so repeated exposure combined with heightened antigenicity from processing play a role. As well, breeding allergic dogs passes on genetic predisposition. But all allergies are not to “grains”. I have fed hundreds of client’s dogs with allergy and intolerance and used a huge range of foods. Some can eat rice and sweet potato but not beef pork chicken or fish. Some can eat turkey and fish but no carb except wild rice (we pray this is a small dog, with the cost of wild rice). It’s important to be informed about allergy – grainfree commercial diets may or may not be the solution for an allergic or intolerant canine.
SOME DRAWBACKS (and Pitfalls to Watch For)
1) Gluten: A brief definition of gluten(from the Canadian Celiac Association):
“Gluten is a general name given to the storage proteins (prolamins) present in wheat, rye, barley, and oats. The specific names of the cereal prolamins that are toxic in celiac disease (CD) are gliadin in wheat, secalin in rye, hordein in barley, and avenin in oats. The storage proteins of corn and rice do not contain the toxic cereal prolamins and are not harmful to individuals with CD. Research is presently underway to determine the safety of pure uncontaminated oats** for celiac patients, but the results are not yet conclusive.”
It’s well known that humans with celiac disease must not consume any foods containing gluten, but current research suggests that many of us (I say us because I am adversely affected by gluten) may be intolerant of these proteins without the presence of active disease. The hypothesis suggests that, along with other factors such as repeated antibiotic use and certain illnesses, regular consumption of gluten even in a non-celiac individual, can contribute to a condition known as intestinal hyperpermeability, or “leaky gut” . Leaky gut is likely to be a factor in a variety of immune disorders including allergy and diabetes, possibly cancer. one way to promote bowel health and avoid this condition is to minimize gluten in our own diets. I concur with the many holistic vets I’ve worked with over the years who maintain that the longterm feeding of gluten-grains creates similar illness in the canine. Therefore, I do not use any of these foods in a canine diet unless it is absolutely necessary, such as a diabetic dog who can only tolerate barley. While occasional feeding of a wheat-based cookie or some oatmeal is not likely to harm a healthy dog, I prefer to avoid all of these foods as much as possible. I believe that the prevalence of barley in so many premium commercial foods is a major drawback. Gluten is a big topic and I will be going into it more deeply (I know I have been saying that a lot) but for the purposes of this overview, I can say this; try not to feed it. If you do need to use barley, for example, you can support bowel health with slippery elm, L-glutamine and probiotics. Which really, are all good things to use anyway.
More information on leaky gut (in humans) here:
2) Phytate: Ahhh, phytate. In many canine nutrition groups on yahoo this can be a contentious issue – because some foods add phytate to the diet, should we use them at all, use them just a little- or use generously, given their health benefits, and amp up the minerals affected? Predictably, I will say “it depends”. Phytate has it’s upside as well as definite problems, and it can be reduced simply by soaking the rice or legume before cooking.(Note; rice should be rinsed well in pure water, then covered with about 2 inches of fresh water to soak for several hours. In that time I often stir and rinse 5 or 6 times. Please cook the rice in fresh water once the rinsing and soaking process has been completed. More in the next entry, on selection, preparation and storage of all these foods).
Let’s look at what phytate is and why we want to be aware of it’s presence in any food we’re using for dogs on a regular basis.
First of all, what is it?
“Phytic acid (known as inositol hexakisphosphate (IP6), or phytate when in salt form) is the principal storage form of phosphorus in many plants, especially bran and seeds. Phytate is not digestible to humans or nonruminant animals, however, so it is not a source of either inositol or phosphate if eaten directly. Morever, it chelates and thus makes unabsorbable certain important minerals such as zinc and iron, and to a lesser extent, also macro minerals such as calcium and magnesium. “
Phytate is found in all whole grain foods, including rice, which I feel is a valuable food for dogs; it is also present in legumes, nuts and seeds and grains we generally don’t use (such as wheat and oats). You will often hear those that support an all fat and protein diet claim phytate in these foods as reason not to ever use them. I disagree; phytate content can be reduced by pre-soaking the rice or lentils; it can be compensated for in a home made diet by adding mineral in a meal that does not contain phytate (such as Wendy Volhard’s original diets where the carbs are fed in the morning only) and we can also recognize that current research shows some distinct health advantages to feeding phytate (although again, in moderation, not overfeeding, which in my considered opinion is a problem with just about any food).
Another potential hazard with overfeeding of some plant foods relates to the presence of oxalates. In my experience, restriction of foods high in oxalic acid is essential with dogs who form a type of bladder stone called calcium oxalate stones; in addition, I like to limit them with ANY kind of stone forming dog. In dogs without this condition, I am still mindful of the levels, because a dog has not had a stone in past doesn’t mean he or she won’t form one in future. Here is a definition of oxalate from George Mateljan of the World’s Healthiest Foods website:
“Oxalates are naturally-occurring substances found in plants, animals, and in humans. In chemical terms, oxalates belong to a group of molecules called organic acids, and are routinely made by plants, animals, and humans. Our bodies always contain oxalates, and our cells routinely convert other substances into oxalates. For example, vitamin C is one of the substances that our cells routinely convert into oxalates. In addition to the oxalates that are made inside of our body, oxalates can arrive at our body from the outside, from certain foods that contain them.”
Foods high in oxalate include all the dark leafy greens such as kale, spinach, chard, and many berries are moderately high as well – which does make me wonder when people insist on adding lots of these foods to their home made diet- because they’re “healthy” -but balk at the idea of a sweet potato (it’s too ‘starchy’). In many diets, sweet potato as a carb source is a wonderful choice, whereas overfeeding of these “healthy foods” can create diarrhea and exacerbate bladder issues. Brown rice is moderately high in oxalic acid, which means I can use some in the diet of a healthy dog, but with a stone- former I minimize it.
As with gluten and phytate, a whole blog entry at least could be devoted to oxalate in the diet. It’s mentioned here to raise awareness. All foods possess good attributes and things we need to be aware of that may not be as beneficial. (that’s what I mean by ‘thinking like a nutritionist, by the way). Oxalate is something to be aware of. It can affect mineral absorption, especially calcium – I limit leafy green veg in my diets and make sure nutrients are mostly provided by animal sources.
I’ll be doing a full entry on dietary management of uroliths in upcoming entries.
Solanine is a glycoalkaloid – chemical component of some plants – found in what we term the Nightshade family. This grouping includes all varieties of white potato (but not sweet potato or yams) as well as tomatoes, eggplant, and peppers. Most commonly the white potato is used in diets for dogs; I don’t recommend using any nightshades at all with a dog who has been diagnosed with osteoarthritis, or indeed any inflammatory condition at all. I am sufficiently wary of them I don’t use them at all, really, other than very, very occasionally. While there is still some controversy about how consumption of dietary solanine affects inflammation, I don’t risk it. The evidence is strong enough for me to arrive at a conclusion; dogs can do very well without potatoes, tomatoes, peppers and eggplant – and feeding it may very well contribute to inflammation. I avoid them all. Another thing to be aware of.
5) ” Goitrogens”
The last topic I want to take a quick peek at with regard to veggies in the diet (carbs!) is goitrogenic compounds, largely found in the Brassica family, but also in soy and millet and some fruits (which again, I rarely feed to dogs).
The most commonly used foods in this category include broccoli, cabbage, cauliflower, brussels sprouts, turnip, and kale(which has the double whammy of a high oxalate content). In any case of a hypothyroid dog – and as many know, this is a very underdiagnosed condition in the canine – I avoid all of these foods, despite their many good aspects. In dogs with normal thyroid function, I just limit them and make sure they are cooked (any clients reading this blog will know what I mean here; once the core diet is established, I recommend adding small amounts of rotated, varied green vegetables, according to the individual’s profile.) It’s important to remember that dietarily, low iodine, low selenium and OVERfeeding of foods rich in isoflavones or glucosinolates, can combine to impact the thyroid – and indeed, many of the home made diets I have analyzed over the years are low in both these nutrients. As well, foods such as broccoli have numerous well-studied health benefits. I include small amounts of broccoli in my own diets, but am a little cautious with cabbage and brussels sprouts – both an contribute to some rather formidable flatulence in the dog. Read a little on these substances, and use moderately.
A really nice article from George Mateljan on how we think about “goitrogens” and how it can be reframed in a more holistic light.I like the emphasis on “no bad foods, just better-or-worse matches with the individual”.
For me, that’s what personalized nutrition is all about.
Some more reading here, for anyone interested:
In conclusion; I look for the following in making choices with regard to carbohydrate;
1) Energy density – I want to use foods with high caloric value, so I am not feeding as much to obtain the desired percentage
2) No gluten unless absolutely unavoidable, or just occasional usage
3) Assessment of the individual dog suggests what amount of total dietary carb to use, and in all cases I limit veggies with high levels of oxalic acid; I recommend cooking the brassica family vegggies,and no nightshades at all for daily use (none ever for arthritics)
4) Soaking grains reduces the phytate content
All this said, I do see dogs on vegetarian diets doing exceedingly well (the oldest living dog in the world, allegedly 27, is a vegetarian) and I support judicious use of green vegetables as additions to the diet – just carefully selected.
The last thing I want to look at here is this; what does a diet with some of these healthy carbs I’m going on about look like? Tomorrow, I’ll post a recipe, by way of example. Just to help illustrate that using 25% carb means there’s fully 75% of protein and fat.In an upcoming Twenty Questions Installment I am posting my own dog’s diet – Danny, in his prime, ate fully 50% carb, is lean and well muscled and fit, and I fed this level because that’s what he did best on. Now he is geriatric, the total has dropped to around 15% (but so have the calories in the diet, as is the norm with older dogs). If I was stuck with a theory about diet I couldn’t let go of, he would be suffering.
We do what works, within what we know. And that includes the type, amount, and method of preparation of dietary carbohydrate.