Does your dog itch and scratch, especially after eating certain foods? Does she suffer from recurrent ear infections, hot spots or hair loss? If so, she’s not alone.
Food allergy is a growing concern. In fact, it’s the third leading cause of allergy symptoms in dogs, after flea bite allergies and atopy. You may be surprised to learn a major reason for the explosion of allergies in dogs.
Food Allergy or Intolerance
First, it’s important to know the difference between a food allergy and intolerance.
Food intolerance is the result of poor digestion. The symptoms normally include diarrhea or other chronic, low-level symptoms.
Food allergies are an over-response of the immune system to a food protein. Nearly all food your dog eats contains protein and these proteins can all trigger food allergies. The most common proteins that cause allergy symptoms in dogs are beef, dairy and chicken. Some plant based proteins like corn, wheat and soy can also be triggers.
Food allergies are an increasingly large problem in dogs. Most vets treat them with food elimination diets or immune suppressing drugs. If you’ve ever had a dog with allergies, you know they’re notoriously difficult to treat, so focusing on prevention is essential. And the first step toward prevention of allergies is identifying their cause.
How Food Allergies Happen
When dogs eat food protein, it’s first digested in the stomach where stomach acids and enzymes break complex proteins into smaller pieces. This partially digested food then moves into the intestines, where the proteins are further broken down into their smallest parts: amino acids.
The amino acids are then absorbed by the body, where they pass through special cells called enterocytes. Enterocytes can reject any amino acids they see as a threat or foreign invader.
What Happens When Food Proteins Are Injected?
When food proteins are injected directly into the blood stream via vaccination, they can cause a type 1 hypersensitivity reaction against the new allergen. That creates a response in a type of immune cell called a TH2 lymphocyte … which belongs to a subset of T cells that produce a cytokine called interleukin-4 (IL-4).
These TH2 cells interact with other lymphocytes called B cells, whose job is to produce antibodies. Coupled with signals provided by IL-4, this interaction stimulates the B cell to begin production of a large amount of a type of antibody specific to food proteins, known as IgE.
Secreted IgE circulates in the blood and binds to an IgE-specific receptor on the surface of other kinds of immune cells called mast cells and basophils, which are both involved in the acute inflammatory response. The IgE-coated cells are then sensitized to the allergen (food proteins).
When The Same Protein Is Eaten …
If your vaccinated dog now eats these foods, the food proteins bind to the IgE held on the surface of the mast cells or basophils. Fc receptors are cell surface molecules that recognize the Fc portion of Ig molecules and antibodies. Cross-linking of the IgE and Fc receptors occurs when more than one IgE-receptor complex interacts with the same food allergenic molecule … and activates the sensitized cell.
Activated mast cells and basophils undergo a process called degranulation. This means they release histamine and other inflammatory chemical mediators (cytokines, interleukins, leukotrienes, and prostaglandins) from their granules into the surrounding tissue, causing several systemic responses, such as vasodilation, mucus secretion, nerve stimulation and smooth muscle contraction.
This is what causes food allergy symptoms like itchiness and inflamed ears.
Depending on your individual dog, the food allergen and how it’s introduced, the symptoms can be system-wide (anaphylaxis) … or localized to a particular body system like the skin.
So, to summarize, your dog has an allergic reaction to the food proteins that were present in the vaccine. But why are food proteins in vaccines in the first place?
The Role Of Vaccines
Most viruses (like distemper and parvovirus) need to be first grown and harvested to make the vaccine. This process begins with a small amount of virus, which needs to be grown in cells. Various types of cells can be used, including chicken embryos, calf serum, or other cell lines that reproduce quickly and repeatedly.
Once the antigen is grown, vaccine manufacturers try to isolate it from the cells. But proteins and other food particles can still be present in the vaccine. Then an adjuvant to stimulate an exaggerated immune response may be added, along with stabilizers or preservatives. Many vaccine adjuvants are made from vegetable oils, such as soybean, corn and peanut … so these plant-based oils can also cause food allergies. (It’s no wonder so many children have peanut allergies.)
Research Into Vaccines And Allergies
The Centers for Disease Control and Prevention (CDC) published a document called General Recommendations on Immunization. This paper was revised in 2011 and references a Japanese research study by Nakayama et al, showing that …
“Most anaphylactic reactions and some urticarial reactions to gelatin-containing measles, mumps, and rubella monovalent vaccines are associated with IgE-mediated gelatin allergy. DTaP immunization histories suggest that the gelatin-containing DTaP vaccine may have a causal relationship to the development of this gelatin allergy.“
The CDC also cited research by Sakaguchi et al, who concluded:
“We reconfirmed a strong relationship between systemic immediate-type allergic reactions, including anaphylaxis, to vaccines and the presence of specific IgE to gelatin.“
In October 2015, Vinu Arumugham published a case report titled Evidence that Food Proteins in Vaccines Cause the Development of Food Allergies and Its Implications for Vaccine Policy. He reviewed over 20 relevant studies, and summarized:
“Numerous studies have demonstrated that food proteins contained in vaccines/injections induce food allergy. The IOM (Institute of Medicine)’s authoritative report has concluded the same. Allergen quantities in vaccines are unregulated. […] The vaccine schedule has increased the number of vaccine shots to 30-40 and up to five vaccines are simultaneously administered to children. Vaccines also contain adjuvants such as aluminum compounds and pertussis toxin that bias towards IgE synthesis. Given these conditions, the predictable and observed outcome is a food allergy epidemic.“
“Applying prudent avoidance means we should immediately stop multiple vaccines being administered simultaneously. It is likely to reduce the probability of developing food allergies by reducing the amount, number of food proteins and adjuvants that are injected at one time. Perhaps no more than a vaccine a month should be allowed.“
Sound familiar? Keep this point in mind next time your veterinarian wants to give your dog a DHPP or other four- or five-way combination vaccine!
RELATED: Does your dog need the DHPP vaccine?
Gelatin in Vaccines
Several vaccines contain gelatin (which is derived from collagen, normally from cows or pigs), as well as other food proteins. This is the same conclusion Nobel Prize-winning French physiologist Charles Richet arrived at more than 100 years ago. Richet found that injecting trace amounts of milk and meat proteins into animals created sensitivity to the injected protein, so that repeated exposure to that same protein caused reactions in the animals.
Vaccines may have changed in the last century, but their ability to cause food allergy hasn’t. And of course, these injected food proteins can cause a myriad of other health concerns. Robert S Mendelsohn MD, professor of pediatrics at the University of Illinois warns:
“No one knows the long term consequences of injecting foreign proteins into the body. Even more shocking is the fact that no one is making any structured effort to find out.“
The day may come when scientists, vets and doctors make an effort to learn more about how these injected foreign proteins cause allergies and many other autoimmune diseases in our dogs (and ourselves). Until that day, the best approach to food allergies is prevention.
As allergist Warren Vaughan said,
“We find ourselves in somewhat of a dilemma, faced with the necessity for choosing the lesser of two potential evils.“
But as savvy vets and pet owners delve more deeply into the safety and even the necessity of vaccines, perhaps more objective vaccine research in the future will change which of the two evils dog owners will choose.
Nakayama T, Aizawa C, Kuno-Sakai H. A clinical analysis of gelatin allergy and determination of its causal relationship to the previous administration of gelatin-containing acellular pertussis vaccine combined with diphtheria and tetanus toxoids. J Allergy Clin Immunol. 1999 Feb;103(2 Pt 1):321-5.
Sakaguchi M, Nakayama T, Inouye S. Food allergy to gelatin in children with systemic immediate-type reactions, including anaphylaxis, to vaccines. J Allergy Clin Immunol. 1996 Dec;98(6 Pt 1):1058-61.
Arumugham V (2015) Evidence that Food Proteins in Vaccines Cause the Development of Food Allergies and Its Implications for Vaccine Policy. J Develop Drugs 4: 137.