Posted Mon Sep 22, 2008 12:37 pm AEST
Updated Mon Sep 22, 2008 11:08 am AEST

Scientists say so-called good bacteria in the intestine may have a role in stopping our bodies from developing type 1 diabetes.

The research published in the latest edition of Nature has also found the presence of such bacteria in the gut may also reduce the severity of the illness.

Scientists in Chicago studied genetically engineered diabetic mice with immune systems that lacked a key protein that allows them to respond to bacteria.

The mice were raised in a completely germ-free environment and 80 per cent of them developed severe type 1 diabetes.

But when they were fed a cocktail of a bacterial flora, normally found in the gut, only one third of the mice became ill.

Scientists say the bacteria appeared to stop the rogue immune response that triggers the disease.

"Potentially, if the study turns out to be confirmed, it's possible that manipulating the kind of bacteria in the gut of humans might also protect them from diabetes," Professor Tom Kay, from the St Vincent's Institute for Medical Research in Melbourne, said.

Professor Kay says protection would apply to humans found with a genetic predisposition to diabetes.

"You could potentially identify people at risk by their genetic make-up and you can also detect the very early signs of diabetes developing using blood tests," he said.

"And if an effective therapy like this did turn out to be effective you could identify people in the community today at high risk of developing diabetes."

Director of Endocrinology at South Australia's Flinders Medical Centre, Professor Nikolai Petrovsky, says if that bacteria is present, it sends out signals across the human body.

"The good gut bacteria, they don't just live in the gut but they also generate signals which cross the gut wall, and so we would speculate that those signals change the way in which our immune system behaves and in fact stop the immune system malfunctioning in those people who might be at risk of type 1 diabetes," he said.

Professor Kay says the findings are further evidence of the link between hygiene and illness.

"People have known for a long time that exposure to infections and bacteria appeared to influence the progression of immune system disorders like allergies or auto immune diseases," he said.

"This has been expressed as the hygiene hypothesis - that somehow being too clean can be bad for you in terms of getting immune system diseases.

"But this simple idea that you might change bacteria in the gut by providing healthy bacteria, that's a little more direct evidence than has been previously available." 

Based on a report by Emily Bourke for AM