Artificial Sweeteners

Artificial sweeteners have long been promoted as "better" for us – diet sodas help us stay slim, sugar-free cookies provide a treat for diabetics. But breaking research from the Weizmann Institute of Science’s Dr. Eran Elinav and Prof. Eran Segal has dropped a bomb on such thinking: in fact, they say, artificial sweeteners may even be causing the very conditions they were presumed to prevent. 

Dr. Elinav and Prof. Segal are scaling up their Personalized Nutrition Project, which aims to precisely measure how we as individuals process and metabolize food. While studying artificial sweeteners, they found that even though such products are not digested, they are detected by our trillions of gut bacteria. These bacteria, in turn, may trigger metabolic changes that have a number of negative health effects, such as increasing blood sugar.

Artificial sweeteners do not contain sugar; however, as the team found, the products still have a direct effect on our 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 down the path to metabolic syndrome and adult-onset diabetes.

A number of related experiments were performed, such as having mice drink water that was treated with the three most commonly used artificial sweeteners. These mice developed glucose intolerance; the mice that drank plain water – or, surprisingly, even sugar water – did not. The test results all pointed to the same thing: these substances were somehow inducing glucose intolerance.

The team also found conclusive proof that changes to the gut bacteria are directly responsible for the harmful effects to their host’s metabolism. In fact, looking closely at the mice’s gut bacteria showed profound changes to their bacterial populations, including changes known to infer a propensity for obesity, diabetes, and complications from these problems.

Despite these somewhat alarming results, the scientists emphasize that they are conducting basic research, not making recommendations. Further studies are needed (and will be taking place), and many more factors weighed, before general health guidance is changed.

Donor support helped make this research possible, and is enabling the Personalized Nutrition Project to expand. The project is an excellent example of the type of multidisciplinary work that is a Weizmann Institute strength – Dr. Elinav is in the Department of Immunology; Prof. Segal, the Department of Computer Science and Applied Mathematics. Friends as well as research collaborators, the two bring critical, but different, skills and alternate perspectives to the project.

Media all over the world has covered their findings. For example, within mere hours of the news release, several prestigious publications had picked up the research, and in less than 24 hours, it had become the most e-mailed story on The New York Times site. Clearly, even when it is basic science fresh from the lab, people everywhere want to know why they struggle to lose weight, and this shocking research could ultimately lead to new, healthier ways of living.

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