Can gut bacteria play a role in causing or preventing celiac disease?
June 29, 2015
Bacteria have a pretty bad reputation. We tend to associate them with contamination and disease. But in reality, bacteria are sometimes helpful, and they may even protect people against specific diseases.
Dr. Elena Verdú, a researcher at McMaster University, is exploring the role that intestinal bacteria play in preventing celiac disease, or making it worse. Celiac is an autoimmune disorder—a type of illness in which a person’s immune system attacks his or her own body—that occurs in people who are genetically predisposed to the condition.
When a person with celiac disease eats gluten – a protein found in wheat, rye and barley – it triggers an inflammatory reaction that damages the lining of the intestine, impairing the body’s ability to absorb nutrients. It can be a very severe illness with a wide variety of symptoms, including anemia, fatigue and digestive problems. There is currently no treatment for the condition, other than a life-long gluten-free diet.
Researchers know there is a strong genetic component to celiac disease. But, while 30% of people worldwide carry the celiac risk genes, only 1% of the population actually has the condition. In addition, the number of people being diagnosed with celiac is on the rise.
“The incidence has increased about four-fold in the past 40 to 50 years, and we know it isn’t just the result of better diagnosis,” says Dr. Verdú.
Taken together, these observations suggest that there are environmental factors involved in triggering celiac disease. Dr. Verdú and other researchers believe one of these environmental factors might be the bacteria and other microorganisms that live in a person’s gut – also known as the intestinal microbiome.
Previous studies have shown that people with celiac have persistent changes in the bacteria living in their small intestines. Some intestinal bacteria break down gluten, and therefore may protect people who are at risk of celiac disease. If a person lacks these bacteria, they may be more susceptible to developing symptoms of the disease.
This knowledge could lead to new treatments, and help protect people following gluten-free diets. For example, people who have the celiac risk genes could supplement their diets with healthy bacteria to prevent the disease from developing. In addition, those who are already living with the condition could use the bacteria to protect themselves against the damaging effects of accidental gluten ingestion. However, more research is necessary to prove these assumptions.
With the help of funding from the Canadian Institutes of Health Research, Dr. Verdú’s laboratory has also shown that certain bacteria present in celiac patients, and not in healthy subjects, can make inflammation worse in gluten-sensitive mice. So it is possible that the type of bacteria inhabiting the upper digestive tract, and its activity, can increase or decrease the chances that a person with moderate genetic risk will develop the disease.
For now, Dr. Verdú urges people who suspect they might have celiac disease to get tested before they make any changes to their diets.
“It is key to undergo blood tests and a small biopsy before going gluten-free or it may be very difficult to ever reach a proper diagnosis,” says Dr. Verdú.
She also emphasizes that gluten-free diets aren’t healthy for everyone. They tend to be low in nutrients and fiber, and can alter the delicate balance of bacteria living in your intestines.
According to Dr. Verdú, if you are going to change your diet, “You need to know why you are doing it, and you need to do it well.” This includes consultation with your physician and an expert dietician.
For more information on celiac disease, visit Health Canada.
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