Recent research revealed that total IgA levels were significantly lower in subjects with Tourette syndrome, OCD, and PANDAS than in controls. To understand the importance of this finding related to food allergy, let’s look at IgA in four steps:
• What is an IgA deficiency?
• Effects on the body with a focus on food allergy
• Possible causes of an IgA deficiency
• What you can do about it
What is an IgA deficiency?
Immunoglobulins are the body’s antibodies or immune defenses. They are divided into 5 major classes. Of these, the three main types are IgG, IgA and IgM, and these constitute 85 to 95% of the human antibodies. These generally protect normal individuals against bacterial and viral invaders.
IgA is the “secretory immunoglobulin” because it is present in mucous membrane secretions. These secretions are found in tears, nasal mucus, saliva, and bronchial mucus. Increased amounts of IgA are also found along with other immunoglobulins in secretions of the gastrointestinal and respiratory tracts in allergic individuals. IgA is even found in vaginal secretions.
Effects of an IgA deficiency with a focus on food allergy
IgA deficiency is considered the most common type of immunodeficiency with a frequency of 1:500. Although many with IgA deficiency are healthy and may not even be aware they have low levels, others experience frequent sinus and pulmonary infections. In cases of severe deficiencies, it can cause critical illness.
The mucosa of the gastrointestinal tract is the monitor of the particles that are absorbed into the systemic blood circulation. The secretory antibodies of IgA help prevent the absorption of allergens into the bloodstream. Other immunoglobulins (IgE, IgG, IgM) also play a role in the body’s defense against food allergens and infectious agents (such as strep) that may enter the gastrointestinal tract. (2,4) When this defense is weakened and these allergens/agents enter the blood stream and cross into the brain, disruptive neurologic reactions can occur.
While research in many areas is not yet conclusive, chronic diseases may be affected adversely by IgA deficiency including certain autoimmune diseases, neurologic problems including autism, and arthritis. It has also been associated with an enhancement in tumor growth. (1)
A significant number of allergic individuals have associated IgA deficiency, and there is evidence that IgA deficiency is linked to the development of gastrointestinal food hypersensitivity. (5)
Increased susceptibility to food allergies is now associated with IgA deficiency. (2,4)
The fact that secretory IgA protects the mucosal barriers of the body against toxins and infections while also playing a significant role in food allergy is supportive of a hypothesis that IgA levels could play a role in brain inflammation triggered by foods.
Individuals who are more susceptible to viral and other infections may have a hereditary predisposition related to an IgA deficiency. These individuals may also be more susceptible to food allergies. (2)
Low IgA levels have been linked to vaginal allergy or allergic vulvovaginitis; genitourinary allergy is related to an increase in food allergy. (3)
IgA deficiency is much more common among those with celiac disease (gluten intolerance) than the general population.
Possible Causes of an IgA deficiency
The cause for this deficiency is often unknown, although a hereditary predisposition is suspected for some people. It is possible to have a deficiency occur from drugs or viral infections, and it has also been associated with intrauterine infections. (6)
Studies have shown that stress may have an influence on IgA levels, and a decrease can occur during severe stressful events.
What can you do about symptoms linked to an IgA deficiency?
Individuals with IgA deficiency who also have gastrointestinal symptoms should be evaluated through a comprehensive stool analysis for hidden gut infections such as parasites, candida, or bacteria. In general, avoid alcohol and dairy products as these can increase inflammation in the gut.
Testing for food and chemical allergy (intradermal skin tests and/or RAST IgE/IgG blood tests, or cell mediated blood test-ALCAT) are recommended to determine where your main allergies lie. Then, a reasonable low-allergy nutritional plan can be prescribed and avoidance measures can be put into place.
Use a dairy-free probiotic to improve gastrointestinal health; consider the use of digestive enzymes; adapt a low-stress lifestyle as much as feasible.
A healthy Mediterranean diet and lifestyle is recommended. This diet has been proven to help reduce body-wide inflammation.
In serious cases, consult an immunologist.
1 Krause, Helen MD, Otolaryngic Allergy and Immunology, Saunders 1989
2 Breneman, James MD, Basics of Food Allergy, Charles C. Thomas 1984
3 Speer, Frederic, Handbook of Clinical Allergy, Wright 1982
4 King, Heuston MD, Otolaryngic Allergy, Elsevier North-Holland 1982
5 Jonathan Brostoff, Food Allergy and Intolerance, Healing Arts Press, 2000
6 Shaw, William PhD, Immunodeficiency, gastrointestinal Candidasis, wheat and diary sensitivity, abnormal urine arabinose, and autism: A Case Study
First published August 2010
• If this article was of interest you will find many other articles on unlikely allergies and allergy connections here – and links to many relevant research studies here.
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