Artificial Sweeteners Linked to Obesity and Diabetes in New Study on Mice

Updated | Sugar may have overtaken fat as enemy number one when it comes to avoiding weight gain and chronic diseases, but a new study has suggested that artificial sweeteners could be linked to diabetes and obesity.

In what researchers believe is the largest study to assess the biochemical changes artificial sweeteners and sugars cause in the body, the team at the Medical College of Wisconsin and Marquette University tested their hypothesis on rats and cell cultures. As is the case with all rodent studies, the results may differ in humans but offer a useful insight into sugar and sweeteners that scientists can build on with further research.   

The study was presented on April 22 at the American Physiological Society's annual meeting, during the Experimental Biology 2018 meeting in San Diego.

GettyImages-519743196 A new study compared the effect of sugar and zero-calorie sweeteners on mice. Luis Ascui/Getty Images

Dr. Brian Hoffmann, assistant professor in the department of biomedical engineering at the Medical College of Wisconsin and Marquette University and lead author of the study, told Newsweek: "Despite the addition of these non-caloric artificial sweeteners to our everyday diets, there has also been a drastic rise in obesity and diabetes.

"The results suggest artificial sweeteners change how the body processes fat and how the body gets its energy; both of which are precursors to obesity and diabetes."

To make their findings, the team fed rats diets high in glucose or fructose, both types of sugar, or the common artificial sweeteners aspartame or acesulfame potassium. Three weeks later, blood samples taken from the rodents showed what researchers described as significant differences in the levels of biochemicals, fats and amino acids.

The researchers believe that zero-calorie sweeteners could change how the body metabolizes fat and how it uses energy stores. Acesulfame potassium, meanwhile, was found to build in the blood and could harm the cells that line the blood vessels. 

"We observed that in moderation, your body has the machinery to handle sugar; it is when the system is overloaded over a long period of time that this machinery breaks down," Dr. Hoffmann said in a statement. 

However, Dr. Hoffman said that simply removing artificial sweeteners from food and drink won’t solve overall health problems related to diabetes and obesity. According to the Centers for Disease Control and Prevention, more than one-third of U.S. adults are obese.

"The key to anything is moderation," he told Newsweek. "If you chronically consume these compounds your body doesn’t have a chance to recover from the biochemical changes and as these accumulate it can have health consequences."

He added: "It is important to note, that all sugars and artificial sweeteners are not created equal. They have different chemical make-ups and thus mechanisms of action so it will be important not to generalize all in one category but to study them individually more thoroughly to gain a better understanding of how each influence overall health."

The research comes after a March 2018 study on human fat-derived stem cells and fat samples at George Washington University suggested a link between between sweeteners, metabolic syndrome, pre-diabetes and diabetes.

Commenting on the findings at the time, Havovi Chichger, Senior Lecturer at Anglia Ruskin University, who was not involved in the research, wrote on the science news website The Conversation: “Given the limited number of studies on the subject—and that few studies compare low-calorie sweeteners with sugar—we do not yet have clear answers.”

A separate preliminary study on mice and 400 humans published in 2014 found that sweeteners may contribute to a spike in blood glucose levels. However Nita Forouhi, program leader at the Medical Research Council’s epidemiology unit at Cambridge University, told Reuters the research did "not yet provide sufficient evidence to alter public health and clinical practice."

Aisling Pigott, a qualified dietitian and spokesperson for the British Dietetic Association, told Newsweek that the results should be approached with caution.

“Much of the research that points to negative impacts of sweeteners are based on animal studies—specifically mice and rat—so shouldn’t be applied directly to humans as we do have different metabolic pathways.

"However, we do need to be aware that overuse or excessive use of any products—including sugar or sweeteners—is not beneficial to health. In addition, high levels of sweetener intake will still mean we are craving and desiring sugary foods without any ‘energy intake,’ and there are question marks about the impact of this on satiety.

“In summary, having sweeteners is absolutely fine, but vast amounts or not addressing the other areas of your diet will not be helpful to address concerns around weight.”

This article was updated to provide further background information and include quotes from Dr. Hoffmann.