Today, the term "gluten-free" is familiar to almost every American, and usually refers to food products that are free of gluten protein. You'll also commonly hear the terms gluten sensitivity, gluten intolerance, celiac disease, gluten allergy, and others.
There's a lot of misinformation on the different "levels" of gluten sensitivity or intolerance. While many terms are bandied about, medical experts have recently begun to classify gluten intolerance at three different severity levels. They are Non-Celiac Gluten Sensitivity, Celiac Sprue Disease and Type I/Type II Refractory Celiac Disease.
Non-Celiac Gluten Sensitivity
While the word 'sensitivity' may seem relatively mild, this form can still have a major impact on one's quality of life. Up until recently there were two tests performed on individuals suspected to be gluten intolerant. One test focuses on the antibodies triggered by ingesting gluten, and the other is a genetic test that can indicate susceptibility to celiac disease. A person who tests positive for either one is considered gluten sensitive or prone to celiac disease. A person who tests negative for both is considered to be free of gluten sensitivity.
Research has since shown that a vast number of people have an immune response to gluten in the small intestine. These individuals won't test positive for the raised level of antibodies or celiac genes indicated in the two tests discussed above, but their body still reacts negatively to gluten. Non-Celiac Gluten Sensitivity is therefore a newly-accepted term for mild to severe sensitivity that's gaining greater acceptance.
Celiac Sprue Disease
The second severity level for gluten sensitivity is known as Celiac Sprue disease, a permanent, hereditary autoimmune disorder caused by an allergic reaction to the gluten protein (typically gliadin, and to a lesser extent glutenin) found in wheat and other common grains. This allergic reaction causes inflammation in the intestinal tract, which impairs the ability of the digestive system to absorb nutrients, leading to malabsorption, damage to the digestive tract, and eventually malnutrition. The symptoms of celiac disease are numerous and vary considerably depending on the severity of the condition.
Type I/Type II Refractory Celiac Disease
The most severe levels of gluten intolerance, Type I and Type II Refractory Celiac Disease are found in persons who experience no relief when adopting a strict gluten-free diet, and who don't respond to any specialized medications. This form is so severe that some practitioners and researchers now consider it a form of malignant cancer from a treatment standpoint. Thankfully the incidence of this level of severity is relatively rare.