Читать книгу Gluten Exposed: The Science Behind the Hype and How to Navigate to a Healthy, Symptom-free Life - Rory Jones, Dr. Green Peter - Страница 38

When the right thing can only be measured poorly, it tends to cause the wrong thing to be measured well. And it is often much worse to have a good measurement of the wrong thing, especially when it is so often the case that the wrong thing will, in fact, be used as an indicator of [what is] right.

—JOHN TUKEY, PROMINENT STATISTICIAN

In the following chapters—notably those in Part V, which examine several psychiatric and neurological conditions—we refer to “antigliadin antibodies” that are found in the bloodstream of people with these disorders. While not part of current standard-of-care testing, they are the focus of many research studies on gut-brain interactions, and therefore a quick primer on immunoglobulins is in order.

What Do Antibodies Do?

Antibodies (also known as immunoglobulins) are a critical component of the immune system. They can do many things:

 Recognize and bind to a target and inactivate or destroy it

 Attract other cells when they do bind

 Set in motion a number of immune functions

 Initiate a cascade of other chemicals

 Cross-link other molecules

Antibodies are designed to recognize and neutralize toxins in the body by inactivating bacteria and viral products. They may also inappropriately recognize and react with specific “self” proteins. So, developed by nature to fight infection, they then fight us. The by-product is autoimmunity.

Antibodies to gluten (antigliadin antibodies or AGA) are targeting gliadin, the protein portion of gluten. They are markers that indicate an abnormal immune system response to gluten in people with celiac disease but are not specific for the disease. They have, however, been seen in the blood of some patients with autism spectrum disorder (ASD), attention deficit hyperactivity disorder (ADHD), schizophrenia, and cerebral palsy. These are not celiac antibodies, and the significance of this immune response has not yet been explained.

Immunoglobulin Primer

Antibodies/immunoglobulins (Ig) are classified by their specific features, structure, targets, and locations. Important to our discussion are:

IgA—antibodies that are found throughout the GI tract and other body surfaces that are exposed to the environment and foreign substances. They deal with surface and mucosal immunity and are seen in celiac disease.

IgE—antibodies that circulate in the bloodstream and trigger the immediate immune response in an allergic reaction. They are present in much smaller quantities than the other major classes. Allergies are IgE mediated: When IgE antibodies bind to pollen, venom, dander, or food antigens they cause the release of histamines that trigger symptoms such as swollen airways and other reactions found in food allergies.

IgG—the most common in the body, they fight bacterial and viral infections. They are the only antibodies that can cross the placenta. They are also seen in food sensitivities.

Both IgA and IgG antibodies recognize and react to gluten. IgG antigliadin antibodies are found in some people with autism spectrum disorder, ADHD, schizophrenia, and cerebral palsy. IgG antigliadin antibodies are also found in the bloodstream of healthy people.

If some patients with psychiatric and neurological conditions have antigliadin antibodies, they may be the best candidates to benefit from a gluten-free diet. However, we do not know if the antibodies develop due to an intestinal issue or are the result of the neuropsychiatric condition influencing intestinal function. Also, the gut-brain axis may be bidirectional.

The presence of antigliadin antibodies must be shown to have a direct effect on function to be considered significant. At this point, the direct effect on neural function of antigliadin antibodies is still being debated. If it is possible to eliminate these antibodies through a strict gluten-free diet, it may have important therapeutic implications, though this has not been demonstrated. It is still unclear if these antigliadin antibodies are cause, effect, or simply innocent bystanders.

“Nonsense on Stilts” Testing

Tennis superstar Novak Djokovic was supposedly diagnosed by a doctor who was a family friend by putting a slice of bread on his stomach and holding up his arm as the doctor pushed against it.^fn1 While Djokovic felt it was “madness,” he noticed a difference in his ability to resist the pressure. This form of kinesiology is not reliable or accepted testing. As writer Alex Gazzola noted, “I cannot help but wonder how a top athlete can come to be convinced of this stuff. ‘What matters is that you are open-minded’ is Djokovic’s take. Yes—but not so open-minded that your brains fall out.” A gluten-free diet has apparently changed Djokovic’s game and life, but his diagnostic journey is not a medical testing game changer.