taken from Lab Animal vol 43 No. 11, November 2014 pg 385
Recent findings about the effects that calorie-free sweeteners can have on metabolism may leave a bad taste in the mouths of some consumers. Eran Segal and Eran Ellnav (Weizmann Institute of Science, Rehovot, Israel) found that artificial sweeteners can induce glucose intolerance by altering intestinal microbial communities. The conclusion is based on results from multiple experiments in mice and is supported by limited data from human consumers of the sweeteners.
Normally ingested food is broken down into carbohydrates, primarily glucose, which enters the bloodstream, causing blood glucose levels to rise quickly. The body responds either by signaling glucose to be used as fuel or by storing it for later use, often as fat, and blood glucose levels drop. Failure to respond to elevations in glucose level is called glucose intolerance and is correlated with metabolic disorders.
After 11 weeks of consuming water containing one of three commercial sweeteners (saccharin, sucralose, or aspartame) at doses equivalent to the maximum daily intake in humans recommended by the US Food and Drug Administration, healthy young mice developed glucose intolerance (Nature doi:10.1038/nature13793:published online 17 September 2014). Further experiments showed that saccharin induced composition and functional changes among gut bacteria in the mice. The researchers believe that widespread consumption of artificial sweeteners should be reassessed.