People with celiac disease find it hard to digest products that contain gluten, a family of proteins found in certain grains — wheat, barley, rye and triticale, a wheat-rye hybrid. When children with celiac eat gluten, in foods such as pasta or bread, they experience abdominal bloating or pain, diarrhea or constipation, vomiting. The symptoms are often less pronounced in adults, who may have unexplained anemia, fatigue, canker sores, bone or joint pain, among other symptoms.

Gluten has been viewed as the culprit in celiac disease, but researchers in Europe have recently focused their research on another family of wheat proteins, amylase-trypsin inhibitors (ATIs).

ATIs can worsen the symptoms of chronic diseases that involve inflammation such as rheumatoid arthritis, multiple sclerosis, asthma, lupus, non-alcoholic fatty liver disease and inflammatory bowel disease (IBD).

ATIs make up less than four percent of the proteins found in wheat, but they can trigger immune reactions in the gut that spread to other tissues in the body. “We are hoping that this research can lead us toward being able to recommend an ATI-free diet to help treat a variety of potentially serious immunological disorders," Detlef Schuppan, lead investigator of the study, said in a statement.

The symptoms of celiac are related to inflammation. ATIs activate specific types of immune cells in the gut and other tissues, so eating foods with ATIs can cause inflammation in the lymph nodes, kidneys, spleen and brain, the researchers found.

The findings also suggest that ATIs can worsen the symptoms of chronic diseases that involve inflammation such as rheumatoid arthritis, multiple sclerosis, asthma, lupus, non-alcoholic fatty liver disease and inflammatory bowel disease (IBD).

ATIs may also contribute to the development of non-celiac gluten sensitivity. People with gluten sensitivity do not have celiac disease, but benefit from a gluten-free diet. They have symptoms, such as irregular bowel movements and abdominal pain, that can be confused with those of irritable bowel syndrome (IBS).

Symptoms not involving the gut, such as headaches, joint pain and eczema, often help doctors diagnose gluten sensitivity. These symptoms often quickly disappear after people sensitive to gluten start a gluten-free diet.

Future studies will look more at the role of ATIs in celiac and gluten sensitivity and chronic health conditions. If it turns out that gluten is not the major player in these conditions, they may need to be renamed, Schuppan believes.

The study was presented at the United European Gastroenterology conference in Vienna, Austria.