Soy allergy in dogs is sensitivity to soy protein. Soy allergy is not particularly common among canines, despite popular opinion. 

The cause of soy allergy in dogs is unknown, but genetics is believed to play a role. Breed, sex, and age are not predisposing risk factors for soy allergy in dogs.  

Symptoms of dog allergy to soy include stomach upset, itchy skin, ear infections, paw biting or licking, poor coat condition, and weight loss. 

Soy allergy in dogs is diagnosed with food trials. The treatment for allergy to soy for dogs is based on removing soy from the diet.  

Soy is a common pet food ingredient because of its low price and high nutritional value. The dietary benefits mean that soy in dog food is safe and helpful for canines not allergic to soy. Soy is no longer believed to increase the risk of gastric dilatation and volvulus.

What is Soy Allergy in Dogs?

Soy allergy in dogs is immune-mediated sensitivity to soy protein. Soy allergies develop when the dog’s immune system misidentifies the proteins in soy as a threat. 

The reaction starts when the body comes into contact with soy proteins and makes antibodies of the immunoglobulin E (IgE) type. IgE binds with the soy protein and signals the immune system to trigger an attack manifesting as an allergic reaction. 

Soy allergies in dogs are less common than pet food brands typically advertise. True soy allergies are rarer than beef, chicken, or dairy allergies. 

“A proprietary dried fish, corn, and soya-based diet effectively manage skin and gastrointestinal symptoms in dogs with food allergies,” according to a study, “Food Hypersensitivity in 20 Dogs with Skin and Gastrointestinal Signs,” published in The Journal of Small Animal Practice in 1995. 

Soy is a viable ingredient in hypoallergenic dog food formulas. Hydrolyzed soy protein does not cause soy sensitivity symptoms in dogs with soy allergies. 

“Soy-sensitized dogs do not show oral reactions to hydrolyzed soy protein,” reports a study, “Immunologic Responses Against Hydrolyzed Soy Protein in Dogs with Experimentally Induced Soy Hypersensitivity” published in the American Journal of Veterinary Research in 2006. 

Can Dogs Have Soy Milk?

Yes, dogs can have soy milk. Soy milk is rich in protein, vitamins (folic acid and vitamin D), minerals (calcium and potassium), and antioxidants (isoflavones) while low in fats and calories. 

Soy milk is an excellent alternative to regular milk for lactose-intolerant dogs. Soy milk is unsuitable for dogs with soy allergies. Soy milk is loaded with soy proteins that trigger allergic reactions in sensitive dogs. 

Can Soy Upset a Dog's Stomach?

Yes, soy can upset a dog’s stomach. Dogs have sensitive stomachs, and sudden or excessive soy or other food ingestion triggers abdomen upset. 

The telltale signs of stomach upset, including diarrhea, vomiting, appetite loss, gas production, and abdominal discomfort, are similar to soybean allergy symptoms. 

Food allergies and irritation to the digestive system in dogs are hard to distinguish. 

Soy is an excellent source of protein when introduced to the dog’s menu gradually and provided in moderate amounts. Soy is easily digestible and beneficial for dogs that are nonallergic to soy.

What is Gastric Dilation Volvulus?

Gastric dilatation volvulus, known as GDV or bloat, is a life-threatening condition affecting the dog’s stomach. Bloat is more common in large and giant breeds with deep chests. 

Cases of GDV involve the stomach accumulating fluid, gas, and food, which results in bloating or dilatation. The extended stomach twists on its own axis, preventing the stomach content from leaving. The trapped stomach content continues to cause dilatation and puts excessive pressure on the surrounding tissues. 

Ingesting soy and cereal-based proteins was believed to be critical in developing gastric dilatation and volvulus. The theory has since been proven inaccurate. 

The presence of soy and cereal among the first four ingredients in dry dog food formulas does not influence the GDV risk, according to a study, “The Effect of Ingredients in Dry Dog Foods on the Risk of Gastric Dilatation-Volvulus in Dogs,” published in the Journal of the American Animal Hospital Association in 2006. 

Is Soy Sauce Bad for Dogs?

Yes, soy sauce is bad for dogs. Soy sauce contains excessive salt. Dogs ingesting disproportionate amounts of salt are at risk of salt or sodium ion poisoning. 

One tablespoon of soy sauce features around 2.3 grams of salt, enough to make a 10-pound dog or a Miniature Dachshund unwell. 

Signs of sodium ion poisoning include excessive vomiting, diarrhea, thirst, loss of coordination, tremors, and seizures. Salt poisoning causes kidney failure and is potentially life-threatening. 

What are the Causes of Soy Allergy in Dogs?

The causes of soy allergy in dogs are listed below. 

• Soy and Edamame: Soy and edamame (immature soybeans in a pod) are the two most prominent causes of allergies in dogs sensitive to soy. Soy is frequently used in many dog food formulas due to its low price and high nutrient value. 
• Soy-Based Foods: A common cause of soy allergy is soy-based foods such as tempeh, tofu, and textured vegetable protein (TVP). Soy-based foods are present in vegetarian and vegan dog food recipes. 
• Soy-Derived Ingredients: Soy-derived ingredients include soy lecithin, soy flour, dried soy protein, and powdered soy protein, often listed under different names. 
• Soy Additives: Soy is present in many additives. For example, soy is a protein carrier in natural flavorings, and Vitamin E contains soybean oil. 
• Contaminated Products: Foods made in facilities that process soy often contain soy residues due to cross-contamination. Cross-contaminated foods cause allergies in susceptible dogs. 

What are the Symptoms of Dog Allergies from Soy?

The symptoms of dog allergies from soy are listed below. 

• Stomach Upset: Manifesting diarrhea bouts, mucus or blood in the stool, vomiting, excess gas production, bloating, loss of appetite, abdominal pain, and stomach upset are common signs of soy allergy in dogs. 
• Intense Itchiness: Soy allergies cause itchy skin and make dogs obsessed with itch-relieving through scratching. Excessive scratching disrupts the normal skin barrier, increasing the chances of secondary bacterial infections.  
• Foot Licking or Chewing: The itchiness extends to the paw pads, which become red, swollen, and inflamed. The dog licks or bites its paws to provide temporary itch relief. 
• Chronic Ear Infection: Chronic or recurrent ear infections are typical for soy and food allergies in dogs. Head shaking, pawing at the ears, foul odor, and waxy ear discharge or wax buildup are telltale signs of ear infections. 
• Poor Coat Condition: Soy allergies affect the gut’s ability to absorb nutrients, causing poor coat conditions. The coat becomes brittle, broken, and dull. The intense scratching contributes to dull coat sheen and hair loss. 
• Weight Loss: Dogs with soy allergies are prone to unexplained and sudden weight loss. The weight loss is due to frequent stomach upset episodes and impaired ability to absorb nutrients in the intestines. 

How to Diagnose Soy Allergy in Dogs?

Diagnose soy allergy in dogs with food trials. Food trials, which include two phases, elimination, and challenge, are the standard for diagnosing food allergies. 

Give the dog hydrolyzed protein or a novel protein diet in the elimination stage. The hydrolyzed protein diet comprises minuscule protein pieces the immune system does not recognize as threats. The novel diet contains foreign, exotic protein sources like kangaroo or alligator meat. 

Feed the hydrolyzed or novel protein diet for eight weeks to give the dog time to cleanse itself from previous allergens. 

Challenge the dog by reintroducing the suspected soy allergen to the menu. A flare-up in the dog’s allergy symptoms following the soy reintroduction confirms the allergy diagnosis. 

Visit the veterinarian before commencing the food trial and follow up once the trial is over. Allergies of different types co-exist in some dogs, and consulting the vet helps with the diagnostic process. 

Do not use at-home tests to diagnose soy allergies. Hair and saliva allergy tests are inaccurate, according to a study, “Hair and Saliva Test Fails to Identify Allergies in Dogs,” published in The Journal of Small Animal Practice in 2018.

What are the Effects of Soy in Dogs?

The effects of soy in dogs are listed below. 

• Muscle Mass: Soy contains plenty of protein dogs need for muscle mass and growth. Plant-sourced proteins are secondary to animal proteins but beneficial. 
• Energy: Soybeans and soy foods have a high protein content, which fuels the dog’s energy and allows it to be physically active. 
• Endocrine Function: Soy estrogens affect the activity of the thyroid gland, so they are not recommended for dogs with hypothyroidism. 
• Flatulence: Soy is similar to all legumes that cause flatulence or excess gas production when overconsumed. 

What are the Treatments for Soy Allergy in Dogs?

The treatments for soy allergy in dogs are listed below. 

• Create a Food Spreadsheet. List the dog's food intake, including treats, dental sticks, home remedies, supplements, and flavored medications, such as dewormers or anti-flea chews. 
• Read the Labels Carefully. Study the labels of the products listed on the spreadsheet and check for soy presence. Soy is sometimes labeled under tofu, lecithin, edamame, tempeh, and textured vegetable protein (TVP). 
• Eliminate Soy from the Diet. Remove all foods, treats, and soy supplements from the dog’s diet. Soy is a cheap protein source and a standard dog food ingredient, but many pet brands offer soy-free formulas.  
• Consider Cross Contamination. Remove potentially cross-contaminated products to ensure successful soy allergy treatment. For example, peanut butter is often processed using the same equipment as soy, resulting in cross-contamination. 
• Consult the Veterinarian. Consult the veterinarian and ask for tests to determine if the dog has another allergy co-existing with the soy allergy. Dogs often have more than one food allergy. 

What Happens if a Dog Consume Soy?

Several benefits occur if a dog consumes soy. Soy is an excellent ingredient when fed responsibly to dogs without known soy allergies. 

Soy is packed with proteins, rich in vitamins, minerals, and antioxidants, and low in fats. Dogs digest soy quickly and utilize most of its nutrients efficiently. 

Soy and soy-derived ingredients are found in commercially available dog food formulas under different names, such as soybean meal, soybean germ meal, soybean oil, soy protein, soy flour, soy protein concentrate, soy grits, soy lecithin, and soy isoflavones. 

Stomach upset and itchy skin occur if a dog with a soy allergy consumes soy or a pet formula containing soy or soy-related ingredients. 

How can a Dog Develop a Soy Allergy?

A dog can develop a soy allergy if its immune system overreacts to soy proteins. Genetics is believed to play an important role in the development of allergies. Malnutrition is a suspected factor linked to allergies.  

Soy allergies in dogs are rare. Soy is responsible for just 6% of all canine adverse food reactions, according to a study published in BMC Veterinary Research in 2016. The study, “Critically Appraised Topic on Adverse Food Reactions of Companion Animals (2): Common Food Allergen Sources in Dogs and Cats,” reports that soy accounts for just 6% of all canine adverse food reactions. 

The study concluded that allergies to beef (34%), dairy (17%), chicken (15%), lamb (14.5%), and wheat (13%) are more frequent than soy allergies in dogs. 

Are there Specific Dog Breeds that are Allergic to Soy?

No, there are no specific dog breeds that are allergic to soy. Soy allergy has a genetic component similar to dog food allergies. The allergy does not show a breed, age, or sex predisposition despite the inherited factor. 

Food allergies in dogs have a general breed predisposition. The top three breeds with a higher-than-average risk of allergies are West Highland White Terriers, Cocker Spaniels, and Labrador Retrievers. 

Are Allergies Genetic in Dogs?

Yes, food allergies are genetic in dogs. Allergies are suspected to have a genetic component. Certain dog breeds are more prone to specific allergies, which confirms the theory. 

The exact mechanism behind dog allergies is still being researched. The causes of dog allergies are unknown, but it is known why some canines from the same breed develop dog allergies, and others do not.