Each year, someone writes a book scaring people about food and that gets covered in the New York Times and then a whole rash of junk science studies get produced affirming exactly what the book said. This has been  a tradition since the 1960s, when Rachel Carson wrote Silent Spring, a book of anecdotes and scary claims about how someone she heard of sprayed DDT in her cellar and died, surrounded by science jargon about carcinogens.

Most recently, mainstream media is at war with both sugar and wheat but it won't be long before the cycle swings back to artificial sweeteners again. When that happens, they will not want to include a new study from the the University of Adelaide in Diabetes Care which found that artificially sweetened drinks produced no different response in the healthy human gut to a glass of water.

The findings are contrary to some studies in humans and in animal models claiming more storage of fat and other negative effects.

Effects of ingestion of either water or artificial sweeteners (sucralose, AceK, or sucralose plus AceK) (at t = −10 min) on (A) blood glucose, (B) plasma insulin, (C) GLP-1, (D) 13CO2-to-12CO2 ratio, and (E) T50 in response to 75-g oral glucose (at t = 0 min) in healthy humans (n = 10). Data are means ± SEM. The area under the curves for blood glucose, plasma insulin, 13CO2-to-12CO2 ratio, and T50 did not differ between the 4 study days before and after 75-g oral glucose (one-factor repeated-measures ANOVA). There was a time effect (P < 0.001) but not a treatment effect or treatment × time interaction for blood glucose, plasma insulin, and 13CO2-to-12CO2 ratio (two-factor repeated-measures ANOVA with treatment and time as factors). Credit and link:
doi: 10.2337/dc13-0958

"This is a controversial area because there's a lot of conflicting research into artificial sweeteners," says senior author Associate Professor Chris Rayner, from the University of Adelaide's School of Medicine and Consultant Gastroenterologist at the Royal Adelaide Hospital. "The scientific debate centers on whether artificial sweeteners have a negative impact on our bodies, such as leading to the storage of fat. There are also questions about whether they have a beneficial impact, such as producing responses that signal fullness to the brain, or if they 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.

"The fact is, the human studies have been unclear as to whether artificial sweeteners have a positive or negative effect, and this is why we're keen to better understand what's happening in our bodies." 

Co-author Dr Richard Young, Senior Postdoctoral Researcher in the University's Nerve-Gut Research Laboratory, says 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. 

"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. So far it appears that artificial sweeteners have limited impact in the short term, but in 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."

Citation: Tongzhi Wu, MBBS, Michelle J. Bound, B MED RAD (NUC MED), Scott D. Standfield, BSC, Max Bellon, DIP MED TECH AD NUC MED, Richard L. Young, PHD, Karen L. Jones, PHD, Michael Horowitz, MBBS, PHD and Christopher K. Rayner, MBBS, PHD, 'Artificial Sweeteners Have No Effect on Gastric Emptying, Glucagon-Like Peptide-1, or Glycemia After Oral Glucose in Healthy Humans', Diabetes Care December 2013 vol. 36 no. 12 e202-e203 doi: 10.2337/dc13-0958