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.
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, said in a statement: "Despite the addition of these non-caloric artificial sweeteners to our everyday diets, there has still been a drastic rise in obesity and diabetes.
"In our studies, both sugar and artificial sweeteners seem to exhibit negative effects linked to obesity and diabetes, albeit through very different mechanisms from each other."
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. "We also observed that replacing these sugars with non-caloric artificial sweeteners leads to negative changes in fat and energy metabolism."
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.
"If you chronically consume these foreign substances (as with sugar) the risk of negative health outcomes increases. As with other dietary components, I like to tell people moderation is the key if one finds it hard to completely cut something out of their diet," Hoffman said.
Further research is now needed to answer whether sugar or sweeteners are worse for our health, and to investigate how they behave in the human body.
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. But 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 which points to negative impacts of sweeteners are based on animal (specifically mice and rat) studies, 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 piece has been updated to provide further background information.
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