Researchers at the University of Adelaide contend that artificial sweeteners are generally safe.

In a study published in the journal Diabetes Care, scientists from the university's School of Medicine and Nerve-Gut laboratory said sugar substitutes produce no different response in the "healthy human gut" than a glass of water.

"This is a controversial area because there's a lot of conflicting research into artificial sweeteners," Chris Rayner , senior author and professor, said in a statement.

Rayner, who is also the consultant gastroenterologist at the Royal Adelaide Hospital, said the scientific debate centers on whether artificial sweeteners have a negative impact on the body, such as leading to the storage of fat or a positive impact, such as producing responses that signal fullness to the brain.

Researchers found that artificial sweeteners are inert and produce no impact.

"In our most recent study involving healthy men, we found that the gut's response to artificially sweetened drinks was neutral -- it was no different to drinking a glass of water," Rayner said.

Richard Young, senior postdoctoral researcher in the University's Nerve-Gut Research Laboratory, said population-level studies have yet to agree on the effects of long-term artificial sweetener intake in humans.

However, a recent study has shown an increased risk of developing type 2 diabetes in regular and high consumers of artificially-sweetened drinks.

"Those studies indicate that artificial sweeteners may interact with the gut in the longer term, but so far no-one's managed to determine the actual mechanisms through which these sweeteners act," Young said in a statement. "It's a complicated area because the way in which the sweet taste receptors in our gut detect and act on sweetness is very complex.

Young adds that so far it appears that artificial sweeteners have limited impact in the short term, but may be harmful for people who frequently drink artificially-sweetened drinks.

"People in a pre-diabetic or diabetic state, who are more likely to be regularly high users of artificial sweeteners, it might be a different story altogether. This is why more research is needed," he said.