Some people who have the classic symptoms associated with being celiac never test positive for celiac disease – but that doesn’t mean they aren’t gluten sensitive. Until quite recently, it was believed that individuals who complained of the classic abdominal symptoms associated with celiac disease, but who did not test positive for anti-gliadin antibodies, anti-transglutaminase antibodies or villous atrophy (intestinal damage) were not celiac, and were advised that continuing to eat gluten was safe.
Gluten is a very large molecule which is difficult for the digestive system to break down. When digested, gluten breaks down into smaller units called peptides. One of these peptides is gliadin, which is a glycoprotein – i.e. a carbohydrate plus a protein. Gliadin is a very hard glycoprotein for humans to digest and is the substance which causes the autoimmune reaction in the gut, resulting in the production of anti-gliadin antibodies. CD sufferers are found to have long, toxic gliadin peptides in the small intestine. In people who are sensitive to gluten, but not celiac, the intestinal defense system, including the innate immune response, cannot counterbalance the toxic effect and these toxic peptides may cause an inflammatory response in the intestine which differs from that of celiacs. Unlike the intestinal permeability (leaky gut) common in celiacs, these individuals may have normal intestinal permeability but still show signs of activation of the innate immune system. Such people may have intestinal biopsies that indicate no damage to the lining of the intestine, but what occurs is an autoimmune reaction that brings into play various aspects of the immune system causing high numbers of certain types of immune cells to be produced in response to wheat proteins.
This spectrum of auto-immune reactions to gluten and its components is termed by some experts “gluten syndrome”, but the term “non-celiac gluten sensitivity” (NCGS) is rapidly gaining acceptance in the medical world. For every person who tests positive for celiac disease (CD) there may be as many as 30 people who are gluten sensitive and don’t even know it. Estimates vary as to the prevalence of this condition, but NCGS may now affect as much as 30% of the population.
As well as the typical symptoms of gluten intolerance, other likely symptoms to be experienced by NCGS sufferers include headache, migraine, sleep disturbance, fatigue, muscular disturbances, bone or joint pain, attention deficit hyperactivity disorder, and psychiatric disorders such as autism or schizophrenia.
Moreover, some individuals may return biopsies that show no intestinal damage. This test which is dubbed by the medical profession a “gold standard” test for CD, is widely considered by doctors to definitively confirm whether someone is suffering from celiac disease, but it is not as reliable as most doctors believe. Taking biopsies from the small intestine only randomly removes small portions of the intestine. Damage may not be evident on the particular biopsied tissue, even though damage may be occurring elsewhere within the organ.
How common is non-celiac gluten sensitivity?
About one third of the population carries the genes for gluten intolerance, but only about 1% of the population has confirmed celiac disease. About 50% of individuals with NCGS carry the genetic marker for celiac disease (HLA-DQ2 or HLA-DQ8) but do not develop full-blown CD.
Many people with NCGS are related to individuals who have been diagnosed celiac. The elderly, in particular, are particularly prone to this condition. There is a commercial genetic screening test available that can indicate whether an individual is likely to be susceptible to gluten intolerance.
It is not well understood why some people develop celiac disease or NCGS. Possible risk factors may include viral or bacterial infection, stress, onset of puberty, pregnancy, surgery, trauma or injury, immune suppression or autoimmune diseases, damage to the gut caused by medications such as NSAIDS (non-steroidal anti-inflammatories) or antibiotics which cause changes in gut flora (friendly bacteria). The degree of sensitivity is related to immune status, the existence of any intestinal injury and the extent of exposure to gluten, as well as well as the person’s genetic type.
A doctor who runs a gastroenterology and allergy clinic in NZ conducted an audit of 921 children who attended his clinic. He found that half of the children who had tested as non-celiac reported health improvements after adopting a gluten-free diet. Interestingly, improvements in well-being experienced by people who have tried low carbohydrate diets could well be due to the low gluten content of these regimes. Many people have reported improvements in fatigue, bloating, headaches, musculoskeletal pain and other symptoms after adopting low carbohydrate diets.
As with celiac disease, people who have tested negative for CD but have many of the symptoms, can easily find out if they are suffering from gluten sensitivity by eliminating all gluten-containing foods from their diet for 2-3 months. If health improvements ensue swiftly, this confirms the diagnosis of non-celiac gluten sensitivity.