Researchers at McMaster University have zeroed in on a main cause of celiac disease. The autoimmune disorder has become increasingly common in the past 50 years. It can cause severe stomach pain and digestive symptoms and undetected, it can lead to malnutrition.

But for years, it’s origins have been a mystery. Doctors and scientists have wondered why less than 5 per cent of people who carry a gene that predisposes them to celiac go on to develop the disease. It turns out the answer is in our gut bacteria.

A team of researchers led by Dr. Elena Verdu, from McMaster’s Farncombe Family Digestive Health Research Institute, tested mice to confirm a suspicion that certain gut bacteria triggers a negative response to gluten.

They raised two groups of mice that both had a genetic predisposition for celiac disease. One group was made to have ultra clean gut bacteria and other to have complex bacteria, including E. Coli, Staphylococcus and Helicobacter. The mice with the complex bacteria reacted negatively to gluten, while the other mice didn’t. When researchers enhanced the amount of complex bacteria in their guts, their negative reactions became stronger. The team also implanted some “clean bacteria” mice with complex bacteria and found they went on to develop celiac symptoms.

These results are in line with suspicions that environmental factors are causing an increase in the prevalence of celiac disease. In the past 40 years, the number of cases has increased four-fold. Verdu explains our changing habits are partly to blame, “One of the factors is the type of lifestyle that we have, so use of antibiotics has become widely spread. the type of food that we eat also influences the type of bacteria we harbour in our gut.” Currently, an estimated 300,000 Canadians have celiac disease. Many more go diagnosed.

Verdu says this research may help to develop treatments for celiac disease that compensate for destructive gut bacteria. Those treatments would not be a replacement for a gluten-free diet, but they could act as a buffer if someone with celiac disease accidentally ingests something that’s been contaminated with gluten. They could also protect people who have a high genetic predisposition for celiac disease from developing it.

For Bev Ruffo, who has lived with celiac for 30 years, that is good news, “It would be lovely to think that if my kids and grandkids had a genetic predisposition for it, that they could avoid developing it.”