Some dog owners are turning to grain-free diets in an attempt to combat health problems caused by food intolerance.

Perhaps your dog has eaten the same food for years. And yet, recently, you notice excessive scratching, ear inflammation, tail chewing or hair loss. These canine health issues can be symptomatic of food allergies. Dogs can eat the same food for long periods without any reaction, then like people, suddenly develop a sensitivity or allergy to a particular ingredient.

Food allergies occur in dogs when their immune systems react adversely to one or several ingredients in the diet. Adverse food reactions are more likely to occur after repeated exposure to the allergen.

“It’s similar to a person who might be allergic to peanuts,” says Jennifer A. Larsen, D.V.M., Ph.D., Dipl. ACVN, assistant professor of clinical nutrition at the University of California, Davis, William  R. Pritchard Veterinary Medical Teaching Hospital. “You probably won’t have a response the first time you eat peanuts, but if you keep eating them, your immune system recognizes them for the next time.”

Many dog owners believe that certain grains inherently cause allergies or gastrointestinal distress in their pets. “That’s nothing more than Internet myth and folklore,” says Joseph J. Wakshlag, M.S., D.V.M., Ph.D., Dipl. ACVN, assistant professor of clinical nutrition at the College of Veterinary Medicine at Cornell University in Ithaca, New York.

“When we see published lists of the most commonly reported allergens in dogs and cats, it’s more reflective of what’s commonly found in commercial pet food versus something specific about those ingredients,” Larsen says. “There’s no scientific evidence that there is anything inherent about the grain chemical structure that makes it more likely to be an allergen versus any other kind of protein.”

Wakshlag cites the example that lamb was considered hypoallergenic 15 years ago because it wasn’t commonly found in foods. “Corn has been in foods for a long time, so there are more dogs with corn allergies,” Wakshlag says. “Now that lamb is in a lot of foods, we’re seeing just as many lamb allergies as we do corn. I don’t think there’s anything magical about corn that makes it an allergen other than the fact that it’s in a lot of dog foods.”

But as is true with humans, dogs can react differently to different food ingredients. Although grains may not cause problems for all dogs, evidence suggests that some dogs are more sensitive to grains than others. These dogs may benefit from diets that don’t include any grain sources.

Because every dog is unique, it can be difficult to determine what causes food-related allergies. Grain offenders may include corn, rice, wheat and barley, which are common ingredients in most commercial dog foods. However, various proteins also create problems for some dogs.

The purpose of grains
Grains are the seeds of plants that nourish the plant embryo until it’s able to sprout and make its own food. Grains are a source of several different nutrients. They are generally used as a carbohydrate source, but they are also a good fat source.

“The types of grains that are used in dog food are processed in such a way that a particular portion of the grain fulfills a specific purpose,” Larsen says. “A grain starch will be used to supply the carbohydrate calories in the diet, and the grain hull supplies the fiber. Grains also have amino acids, so they are a source of protein.”

Dogs require more than two dozen different nutrients for metabolic and energy activities. These nutrients include vitamins, minerals, amino acids and fatty acids. Dogs can synthesize about half of the nutrients internally, but they need to ingest the remainder through their diet. Grains are often used in commercial dog food to fulfill that role. “Grains taste good, they’re cheap and they’re plentiful,” Wakshlag says.

Choosing grain free
Today, grain-free dog food has emerged as a niche market because many owners believe grain free is nutritionally better. Some dogs are sensitive to gluten. ‘For those dogs, it’s not just the glutens in the grains, but also the glutens in byproducts, such as corn-gluten meal, that create a gluten allergy,” says Nancy Scanlan, D.V.M., a certified veterinary acupuncturist and past president of the American Holistic Veterinary Medical Association. “I see problems with diarrhea or inflammatory bowel disease from corn gluten meal in a lot of my patients.”

Many owners who choose grain-free diets see positive results in their dogs, including fewer skin and allergy problems Similar to humans, dogs also face an obesity problem. A diet that contains a lot of grains is usually a diet high in carbohydrates, which tend to add weight.

A grain-free diet isn’t appropriate for all dogs. “In certain dogs with certain diseases, the absence of grains can cause problems?’ Scanlan says. As long as the kidneys function properly, most dogs do well when fed a diet high in meat. However, if a dog has a problem with kidney function, a high-meat diet can make it feel worse, increasing both its urination and its thirst. “For these dogs, research has shown that a lower protein diet is beneficial, not just to make them feel good, but to actually prolong their life,” Scanlan says.

Grain-free diets can be more expensive. Because grains are typically cheaper than protein sources, foods without grains cost more money to produce. But a dog on a denser-energy, higher-protein diet won’t eat as much, somewhat balancing the extra costs associated with grain-free products.

Carbohydrates
Grain free doesn’t necessarily mean carbohydrate free. In a grain-free diet, the carbohydrates come from non-grain sources, such as potato, sweet potato and tapioca.

“There is a group of dogs that can do well on a meat, vegetable and some fruit diet with no to low carbohydrates,” Scanlan says. “But some dogs on a meat and vegetable diet with nothing else have problems with chronic soft stools or diarrhea.” Adding white rice or potato to the diet can alleviate that problem. “There seems to be a set of animals that needs simple carbohydrates in the diet.”

Kibble can be grain free, but in order to be manufactured, it must be made with at least 30 percent carbohydrates to help bind it together. Dry kibble is made through an extrusion process, similar to making bread. Manufacturers make a dough from meat, oil and starch, then push it through a cooking press. Pressure and heat cook the dough until it is forced through a die so it can be cut into kibble. During the cooking process, the starch gelatinizes and crystallizes, which makes the kibble more digestible and helps it stick together.

Meat-based diets
It’s possible to feed your dog a well-balanced diet without any grains, but it requires some extra work. Some meats are good sources of amino and fatty acids, but others are not. “There is not one meat source that provides all of the required minerals and vitamins, so it’s important to also feed your dog supplements,” Larsen says. Speak with a veterinary nutritionist for help determining if your dog needs supplements and the correct dosages.

Owners who opt to feed their dogs high-protein diets can add vegetables. “When eating a carrot, you don’t get just beta carotene, you also get all the carotenoids,” Scanlan says. “If you add vegetables to a dog diet, your pet will get those extras, and a lot of the time, the extras can make a difference in the way animals utilize their vitamins.”

Meat provides protein, which the dog burns and uses for energy It’s not beneficial to feed your dog more protein than it needs because its body won’t store excess protein. “Protein is like a carbohydrate with a little ammonia attached,” Scanlan says. “A dog’s body will clip off the ammonia part and leave the carbohydrate. The ammonia is processed by the liver and turns into urea, which goes out with the urine. In a healthy dog, the body will get rid of whatever protein it doesn’t need.”

Although some people argue that too much protein from meat can be bad for a dog, this isn’t usually true for healthy dogs. “Too much protein is only bad if a dog has a certain disease,” Wakshlag says. “And then, it’s usually bad in light of the fact that a dog has kidney disease, therefore, it shouldn’t have too much protein.”

No matter what type of diet you feed, Scanlan recommends that all dogs have annual blood tests once they turn 7. “Seven is when we start seeing signs of kidney or liver dysfunction,” she says. “The other time we want to worry, even if [the dog is] not 7 yet, is if we give them something that can harm their liver or kidneys, such as nonsteroidal anti-inflammatory drugs for arthritis. A high-protein diet puts an additional burden on certain organs that are already burdened.”

Diagnosing food allergies
If you suspect your dog has a food allergy, the best way to accurately diagnose an adverse food response is through a dietary-elimination trial. “A lot of people advocate blood tests for determining allergies, but they aren’t really accurate in diagnosing food responses,” Larsen says. “The best elimination diet contains ingredients the patient has never been exposed to.” Certain holistic diets and veterinary therapeutic diets work best because they contain uncommon ingredients and are limited in the number of their ingredients.

“One example is the venison-and-potato diet,” Larsen says. “There is only going to be venison, potato and the necessary vitamins, minerals and fat sources in that diet. There is no other source of protein.” She recommends selecting a diet that has a single protein source and no grain source, rather than just changing brands of commercial food, which tend to have multiple protein sources. Limiting the number of sources in a diagnostic diet will make it easier to determine which ingredient is inciting the problem. Once a new diet has been successfully established, introduce grains back into your dog’s diet, if desired or needed, following the same procedure of introducing them one at a time.

Patience is necessary when trying to identify an allergen. It can take weeks of experimenting with different diet combinations before seeing positive changes.

Due diligence
As your dog’s life changes, its diet might need to change to meet different nutritional requirements. Good-quality dog food provides the nutrients needed to help your dog live a long, healthy life.

“There is no one diet that’s good for everything,” Scanlan says. “A diet that is the magic answer for one dog may be the worst thing for the next one. It doesn’t matter how good the diet is or how good it sounds; there’s always going to be some dog out there that needs something different.”

Going Organic
Organic products are generally thought to be healthier and more nutrient-dense, and to include less synthetic chemical residues and toxins. People who prefer organic believe that promoting organic farming practices is for the greater good. If fewer chemicals are applied to the fields, there’s less of a load on the environment.

Currently, no regulatory agencies enforce the natural organic designation in the pet-food industry. The United States Department of Agriculture’s organic certification for pet foods follows the National Organic Program standards set for human-food products. A lot of dog-food manufacturers follow these guidelines voluntarily. Non-certified organic claims are not regulated by the U.S. government, and therefore might or might not be true because they haven’t been verified by an unbiased third-party.

The organic certification process for an organic pet-food manufacturer includes a review of all products made by that company, organic certificates for every ingredient used and non-genetically modified organism statements for all the ingredients. It also requires regularly scheduled inspections of the production facility.

In 2006, the USDA Organic Pet-Food Task Force issued a report that outlined some regulatory changes. For a product to include the USDA organic seal on its package, it must be 95 to 100 percent organic. If the label says “made with organic,” the product must have a minimum of 70 percent organic ingredients.

This is an important distinction because some companies use variations of the word “organic” or “natural” in product names even if the product does not qualify for the organic seal or isn’t completely organic.