A new study shows that the widespread use of artificial sweeteners in drinks and food may cause certain gut bacteria to induce glucose intolerance and metabolic disease, both significant markers for obesity and diabetes.
Long promoted as aids to weight loss and diabetes prevention, artificial sweeteners may actually affect the composition and function of your gut’s microorganisms, disturbing their balance and hastening metabolic changes. Published last September in the journal Nature, the study outlines the results of trials conducted on both mice and humans.
Researchers have long puzzled over why noncaloric artificial sweeteners do not seem to assist in weight loss, and some studies have suggested they may even have an opposite effect. Eran Elinav, PhD, et al.,
in the department of immunology at Weizmann Institute of Science, in Rehovot, ISrael, were able to show that artificial sweetners, even though sugar-free, ahve a direct effect on the body’s ability to utilize glucose. Glucose intolerance—generally thought to occur when the body cannot cope with large amounts of sugar in the diet—is the first step on the path to metabolic syndrome and adult-onset diabetes.
Following the mouse study, the researchers tested human subjects. As a first step, they looked at data collected from the Personalized Nutrition Project, the largest human trial to date to look at the connection between nutrition and microbiota. Here, they uncovered a significant association linking self-reported consumption of artificial sweeteners, personal configurations of gut bacteria and the propensity for glucose intolerance. They next conducted a controlled experiment, asking a group of volunteers who did not generally eat or drink artificially sweetened foods to consume them for a week and then undergo tests of their glucose levels as well as their gut microbiota composition.
The findings showed that many—but not all—of the volunteers had begun to develop glucose intolerance after just 1 week of artificial-sweetener consumption. The composition of their gut microbiota explained the difference: The researchers discovered two different populations of human gut bacteria: one that induced glucose intolerance when exposed to the sweeteners, the second that had no effect either way. Elinav believes certain bacteria in the guts of those who developed glucose intolerance reacted to the chemical sweeteners by secreting substances that then provoked an inflammatory response similar to sugar overdose, promoting changes in the body’s ability to utilize sugar.
“Our relationship with our own individual mix of gut bacteria is a huge factor in determining how the food we eat affects us. Especially intriguing
is the link between use of artificial sweeteners—through the bacteria in our guts—to a tendency to develop the very disorders they were designed to prevent; this calls for reassessment of today’s massive, unsupervised consumption of these substances,” said Elinav.