The key parts of gluten that are toxic to people with celiac disease have been identified, a discovery which Australian researchers say opens the door to a more targeted treatment.

People with celiac disease are currently required to refrain from food and drinks containing gluten — such as cereal, pasta and beer — for their whole lives. About half of adults with celiac disease still have intestinal damage five years after adopting a gluten-free diet.

Gluten in grains like wheat, barley and rye leads to an immune response in the lining of the small intestine in people with celiac disease that hampers their ability to absorb nutrients.

Three components of gluten accounted for most of the immune response seen in people with celiac disease, Prof. Bob Anderson of the Walter and Eliza Hall Institute of Medical Research reported in Thursday's issue of Science Translational Medicine.

Researchers discovered gluten was an environmental cause of celiac disease 60 years ago.

"In the years since, the holy grail in celiac disease research has been to identify the toxic peptide components of gluten, and that's what we've done," Anderson said. "It changes the way that we understand celiac disease."

In the study, 244 people with celiac disease in Australia and the United Kingdom ate bread, rye muffins or boiled barley over three days. About a week later, blood samples were taken to measure the strength of their immune responses.

The findings could be used to develop a treatment, known as peptide-based immunotherapy. It involves injecting people with celiac disease with the toxic peptides to gradually build up their tolerance.

It would be a "miracle" if people with celiac disease could stop worrying about accidentally eating gluten, said Geraldine Georgeou, a dietitian on the board of Australia's Gut Foundation. "That could be quite a way off unfortunately," said Georgeou, who has celiac disease herself.

Georgeou continues to advise people to eat a gluten-free diet and take care to avoid trace amounts in restaurant or takeout foods.

It is estimated that one in 133 persons in Canada is affected by celiac disease, according to the Canadian Celiac Association. Common symptoms include anemia, chronic diarrhea, weight loss, fatigue, cramps, bloating and irritability.

The research was supported by the National Health and Medical Research Council in Australia, Coeliac UK, the Coeliac Research Fund, Nexpep Pty Ltd., BTG International and the Victoria provincial government in Australia.

With files from The Australian Broadcasting Corporation