In reference to the nutrient requirement tables for dogs of all life stages, as spelled out in the report by the National Research Council in 2006[1], a dog has no real nutritional requirements for carbohydrates. Despite that, there is a place for carbohydrates in the canine diet. This essay will discuss and outline the reasons why.
What carbohydrates provide the canine body
Simply put, carbohydrates provide a quick source of energy. Being one of only three macronutrients, good carbohydrate sources spare the canine body from having to process excess proteins and fats.
At the same time, carbohydrates provide fibre (which contributes greatly to intestinal health) and other nutrients from essential vitamins and minerals to non-essential but health supportive phytochemicals.[2]Some carbohydrates also have anti-cancer properties, others perform metabolic functions such as combining with fat and proteins to form specific structural components of tissue.
Also, carbohydrates have been shown to be especially helpful (although still not essential) when dogs undergo metabolically stressful periods such as gestation and lactation.[3]
Fibre and the canine body
Fibre is a type of complex carbohydrate that cannot be digested. It provides dogs with a source of short chain fatty acid, helps with maintaining a healthy population of friendly bacteria, regulate the rate at which stool passes through the digestive system and helps to regulate blood glucose levels.
Fibre can be classified by its solubility and the rate of fermentability. Soluble fibre partially dissolves in water to form a gel as it passes through the intestine and it is highly fermentable. It helps to stabilize blood sugar levels but it also affects nutrient absorption more. The fermentation of soluble fibre produces short chain fatty acids (SCFAs). These SCFAs are an energy source for the epithelial cells in the GI tract lining, improve sodium absorption and inhibit the growth of pathogenic microbes. That helps in preventing diarrhoea. Sources of soluble fibre include seeds and nuts, fruits and many vegetables.
Insoluble fibre does not dissolve in water and is resistant to fermentation. It helps to bulk up stools, helps dogs feel more full after meals and form larger stools that pass more readily through the system. Sources of insoluble fibre include whole wheat and whole grain, cellulose in vegetables.[4]
The importance of carbohydrate sources and amounts
Having named some of the benefits of feeding carbohydrates to dogs, it is important to realize that not all carbohydrate sources are created equal. Some carbohydrate sources are better than others. Certain carbohydrates contain anti-nutrients, gluten, too much of the wrong type of fibre etc. There is also issues with certain carbohydrates like peanuts and the problems with aflatoxin, and the Dirty Dozen and pesticides[5].
The right carbohydrates have the potential to positively impact the diet of dogs and their health with the addition of the right fibres and phytonutrients from the plant-based foods. As such, the careful selection of carbohydrate sources is just as important as the selection of any other types of foods.
The ideal amount of carbohydrate in a diet varies from dog to dog and it is individual-dependent. A good place to start will be about 30%.
There are also some general guidelines:
- Carbohydrates are not mere fillers – pick good sources that have high caloric value and are complex (vs. simple sugars) (like sweet potato and brown rice instead of corn husk and white bread)
- Avoid gluten and other anti-nutrients
- Use more insoluble fibres than soluble ones, except when more soluble fibres are called for (like when a dog has problems with soft stools)
Drawbacks and some things to note about feeding carbohydrates to dogs
While there are many benefits to having dogs eat carbohydrates in their diet, there are some issues about the use of carbohydrates that should be noted. One of the most crucial drawbacks is the fact that some carbohydrate-rich foods contain anti-nutrients.
Anti-nutrients are compounds in the foods that interfere with the absorption of nutrients.[6]
Some of the common anti-nutrients are:
- Phytate: an antioxidant found in grains, legumes, nuts and seeds that can bind with and slow the absorption of certain dietary minerals including iron, zinc, manganese and calcium.
- Oxalate : naturally-occurring substances found in and made by plants, animals and humans. They are a group of organic acids converted by other substances. Oxalates affect mineral absorption, especially calcium.
- Gluten : a generic name given to the prolamins in grains. Most grains contain gluten, rice is an exception. Gluten can contribute to intestinal hyperpermeability (leaky gut).
While anti-nutrients may make one think twice about feeding carbohydrates, there are ways to overcome some of the issues caused such as soaking and cooking the foods well. Also, it is worth noting that many of these anti-nutrients have health-promoting properties such as preventing heart diseases and stopping the proliferation of cancer cells.
It is also important to know that the bioavailability of nutrients from plant foods are not always as high as they are in animal foods. One example is iron – dogs do not absorb non-heme iron well.
Conclusion
With the advent of pop-nutrition information, carbohydrates have gotten a very bad name as cheap “fillers” that only serve to rob dogs of their good health. However, there is truly still a place for them in a dog’s food bowl, and while the paper does not give enough details to describe all the benefits, drawbacks and things to note about carbohydrates and the role they have to play, I hope it has provided a good glimpse of how carbohydrates can be beneficial to dogs.
[1] Nutrient requirements of cats and dogs. (2006). Washington, D.C.: National Academies. [2] Rodier, L. (2010, October 01). Carbohydrates and Your Dog's Digestive System. Retrieved April 26, 2018, from https://www.whole-dog-journal.com/issues/13_10/features/Carbohydrates-and-Your-Dog_20103-1.html [3] Case, L. P. (2011). Canine and feline nutrition: A resource for companion animal professionals. London: Mosby/Elsevier. [4] Foods highest in Dietary Fiber. (n.d.). Retrieved April 26, 2018, from http://nutritiondata.self.com/foods-000006000000000000000-w.html?categories=1,18,9,0,13,14,4,5,42,16,17,15,3,6,2,7,11,19,21,12,10,8,22 [5] Environmental Working Group. (n.d.). EWG's 2018 Shopper's Guide to Pesticides in Produce™. Retrieved April 26, 2018, from https://www.ewg.org/foodnews/summary.php [6] Lane, C. (2016, April 22). Carbs, Part Three. Retrieved from https://www.thepossiblecanine.com/carbs-part-three