The gut microbiome may play an important role in how the immune system responds to gluten, even in people who do not have celiac disease. 

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The findings, which could help explain why some people feel sick after eating gluten, were published in the American Journal of Physiology-Gastrointestinal and Liver Physiology. The paper has been chosen as an APSselect article for February. 

Gluten is a group of structural proteins in wheat, barley, rye and other cereal grains, that gives dough its elastic texture. People who have celiac disease, an autoimmune condition in which the body reacts to gluten as a threat, encounter uncomfortable digestive symptoms as well as inflammation and damage to the small intestine when they consume products containing gluten.

Up to 15% of the population experience celiac disease-like symptoms but have not been diagnosed with the disease. Bloating, stomach pain, constipation or diarrhea are common, along with brain fog and fatigue. Unlike in celiac disease, this condition, called non-celiac wheat/gluten sensitivity (NCGS), does not harm the gut.

Blood tests and endoscopy procedures do not show definitive signs that point to NCGS. However, those who experience symptoms and test negative for celiac have also been found to have irritable bowel syndrome, chronic indigestion and higher levels of inflammatory cells, which suggests that eating gluten triggers an immune response.

Shifts in bacteria types

Researchers looked at how the gut microbiome—the bacteria that live in the digestive tract—might affect the way the body responds to gluten. They found after antibiotic treatment, which often kills beneficial as well as harmful bacteria, mice exposed to gluten had changes in the bacteria living in the gut. These shifts in bacteria types altered how they processed carbohydrates, fats and sugars which may influence how these nutrients are recognized by the immune system. In addition, there was more inflammation and a heightened immune response to gluten.

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“This work suggests that the microbiome may determine the capacity for gluten to induce an immune response and offers a valuable insight into the mechanism underlying NCGS,” the researchers wrote.

Read the full article, “Antibiotics Alter Duodenal Immune Populations Upon Gluten Exposure in Mice: Implications for Non-celiac Gluten Sensitivity.” It is highlighted as one of this month’s “best of the best” as part of the American Physiological Society’s APSselect program.