It’s not all in your head! For the first time researchers have scientific evidence that someone doesn’t have to have celiac disease to be sensitive to gluten, and that indeed, there seems to be a spectrum of gluten-related disorders. Gluten sensitivity has been suspected as the cause of a broad range of ailments, though patients have often been told their symptoms were all in their head.

Gluten, a staple of human diets for 10,000 years, is the protein found in wheat, barley, and rye. It is the protein that gives an elastic consistency to flours made from these grains. Gluten-containing grains have been used extensively in breads and other baked goods because of this property.

The research documents a sequence of reactions in the small intestine that appear to be associated with gluten sensitivity. According to Dr. Fasano, there are those who cannot tolerate the least amount of gluten in their diet and those who can eat all the pizza, beer, pasta, and cookies they want with no ill effects at all.

Many people have reported a broad range of symptoms that they suspected could be associated with their gluten intake, but for the most part, doctors have disagreed. If patients didn’t "pass the test" for celiac disease, they were told that gluten wasn’t the problem. (The diagnostic blood test used to identify celiac disease was developed in 2000.) To add to the confusion, sales of gluten-free foods were estimated at $2.6 billion last year, making it even harder to distinguish a medical issue from a fad diet.

Researchers at the University of Maryland’s Center for Celiac Research say they have proven that gluten sensitivity is not the same thing as celiac disease at the molecular level as well as in the response from the immune system. Lead investigator, Dr. Alessio Fassano, director of the Center for Celiac Research said in a press release from the university, "We found differences in levels of intestinal permeability and expression of genes regulating the immune response in the gut mucosa."

The research documents a sequence of reactions in the small intestine that appear to be associated with gluten sensitivity. According to Dr. Fasano, there are those who cannot tolerate the least amount of gluten in their diet and those who can eat all the pizza, beer, pasta, and cookies they want with no ill effects at all. In the middle is a murky area of gluten reactions, including gluten sensitivity. "This is where we are looking for answers about how to best diagnose and treat this recently identified group of gluten-sensitive individuals," said Dr. Fassano.

Celiac disease is an abnormal immune response to gluten which can cause severe damage to the intestinal mucosa, flattening out the villi which absorb nutrients. Over time, these symptoms can lead to malabsorption of many nutrients. If not diagnosed, celiac disease can lead to osteoporosis, infertility, neurological conditions, other autoimmune diseases, and in rare cases, cancer.

The symptoms of gluten sensitivity are less severe and include symptoms similar to those of irritable bowel syndrome, as well as fatigue, headache, "foggy mind," or tingling in the extremities. A subgroup of schizophrenic patients and autistic children may experience gluten sensitivity, too.

Gluten sensitivity potentially affects more than one out of every 20 people, or about 20 million people. Dr. E. Albert Reece, vice president for medical affairs at the University of Maryland, said, "The Center for Celiac Research is leading the way in the effort to better understand the spectrum of gluten disorders. I have no doubt that further research will lead to new diagnostic tools and treatments for those who suffer from gluten sensitivity."

This research was conducted in collaboration with the Johns Hopkins School of Medicine, the Department of Experimental Medicine of the University of Naples in Italy, and the Institute of Food Sciences in Avellino, Italy. It can be found online in the March 2011 issue of BMC Medicine.