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Nutrition Nuggets is the newest offshoot of petMD's Dog Nutrition Center. Each week Dr. Coates will use her expertise and wisdom to blog about the intricacies of dog nutrition.

Is Grain-Free Really Better for Dogs?

November 21, 2014 / (4) comments

Doesn’t it seem like “grain-free” dog diets are taking over the pet food aisle? I’m surprised at just how omnipresent they’ve become. While there is nothing inherently bad about grain-free dog food, I worry that owners are being led to believe that grain-free foods are necessary for dogs. This is simply not the case.

 

Let me first say that there are times when a particular individual will benefit from a grain-free diet. For example, a dog who is allergic to wheat should obviously not be fed a food containing that type of grain. The question I want to look at, however, is, “Are there any benefits from going grain free for healthy dogs?” I believe the answer is “no” and that the popularity of grain-free diets is based on a couple of basic misunderstandings.

 

First of all, “grain free” is not the same as “carbohydrate free.” Starch, a type of carbohydrate, is essential to the formation of dog food kibble. Therefore, if you are feeding dry dog food, it has to contain a certain amount of carbohydrates. A quick look at the ingredient list will reveal the presence of potato, sweet potato, tapioca, or other carbohydrate sources. The phrase “grain-free” is not a substitute for “carbohydrate-free” or even “high-protein,” which is what most owners who buy these products seem to be looking for.

 

Contrary to what you might have heard, dogs do have all the digestive enzymes needed to break down, absorb, and utilize nutrients from grains. I’ve heard proponents of grain-free diets argue that dog saliva does not contain the enzyme amylase, which is needed to break down carbohydrates from grains. While it is true that dogs don’t make salivary amylase, their pancreas does make the enzyme, and since dogs tend to swallow large chunks of food without chewing, the need for salivary amylase is questionable. The lining of the dog’s small intestine also produces brush border enzymes that are responsible for much of the carbohydrate digestion.

 

Don’t get me wrong. Even though dogs digest carbohydrates quite well and grains are a healthy source of carbohydrates for most dogs, pet food manufacturer can overdo it. Carbohydrates are cheaper than animal-based sources of protein, so the financial lure of maximizing the former while minimizing the latter is hard for some companies to resist. If what you’re looking for is a low-carb, high protein dog food, you need to be looking at the guaranteed analysis on the back of the bag rather than the marketing hype on the front.

 

A food’s carbohydrate percentage does not have to be included in the guaranteed analysis, but it’s quite easy to estimate. Add up the percentages for crude protein, crude fat, crude fiber, moisture, and ash and subtract the result from 100%. The result is a ballpark figure for the food’s carbohydrate percentage. If a number for ash is not provided, use 6% as an estimate for dry food and 3% for canned.

 

If you want to compare dry and canned foods, you’ll probably need to do a bit more math because most companies report their guaranteed analysis on an as fed rather than dry matter basis.

 

  1. Find the percent moisture and subtract that number from 100. This is the percent dry matter for the food.
  2. Divide your carbohydrate percentage by the percent dry matter and multiply by 100.
  3. The resulting number is the carbohydrate percentage on a dry matter basis.

 

Analyzing a food’s guaranteed analysis is not as simple as buying into the buzz around grain-free, but the work will let you make an informed decision about what to feed your dog.

 

Dr. Jennifer Coates

 

 

Image: Jaromir Chalabala / Shutterstock