Australian researchers have revealed a widespread bias in industry-funded research into artificial sweeteners.

The study from the University of Sydney says the sketchy science is potentially misleading millions, by overstating the health benefits of 'sugar-free' products.

The comprehensive review of artificial sweetener studies reveals that research funded by artificial sweetener companies were nearly 17 times more likely to have favourable results.

“It’s alarming to see how much power the artificial sweetener industry has over the results of its funded research, with not only the data but also the conclusions of these studies emphasising artificial sweeteners’ positive effects while neglecting mention of any drawbacks,” said researcher Professor Lisa Bero.

“The results of these studies are even more important than the conclusion, as the actual results are used in the development of dietary guidelines.”

Alarmingly, the analysis of artificial sweetener studies also found financial conflicts of interest created bias at all levels of the research and publication process.

Almost half (42 per cent) of the reviews of artificial sweetener studies had authors that did not disclose their conflicts of interest, with about one-third of studies failing to reveal their funding sources altogether.

Studies by authors with a conflict of interest were about seven times more likely to have favourable conclusions. None of the nine studies that had authors without a conflict of interest reported positive results.

“Our analysis shows that the claims made by artificial sweetener companies should be taken with a degree of skepticism, as many existing studies into artificial sweeteners seem to respond to sponsor demands to exaggerate positive results, even when they are conducted with standard methods,” said Professor Bero.

“Ultimately it is consumers who lose out from this practice because our findings show that the results of reviews on the health benefits of artificial sweeteners cannot always be trusted. Measures to eliminate sponsor influence on nutrition research are desperately needed.”

Four of the studies assessed in the review were funded by ‘competitor companies’ that marketed sugary drinks or water, with all four of these reviews reaching conclusions which did not promote the health benefits of artificial sweeteners.

The full study is accessible here.