A new study published in Nature recently revealed that artificial sweeteners, which have always been promoted as a means for weight loss and diabetes prevention could actually be hastening and encouraging the development of glucose intolerance and metabolic disease. It is done by changing the composition and role of the gut bacteria.
Dr. Eran Elinav of the Weizmann Institute’s Immunology Department, who worked on this together with Prof. Eran Segal of Computer Science and Applied Mathematics Department, said that the rampant use of artificial sweeteners in food and drinks these days may be contributing to the rise in obesity and diabetes across the population.
Researchers have long been of the opinion that artificial sweeteners do not really assist in weight loss. In fact, they might be having an opposite effect. Even though these sweeteners do not have sugar, they do have a direct effect on the body's ability to utilize glucose. Typically, glucose intolerance is known to happen when the body is unable to cope with large amounts of sugar in the diet. It is the first step on the path of the onset of diabetes in adults.
For this study, experiments were carried on mice, which were given water in which three of the most commonly used artificial sweeteners were mixed. It was observed that these mice that drank such water developed glucose intolerance while the mice that drank water and even sugar water were fine. The experiment was repeated with different types of mice and in different doses. The results were the same these substances induced glucose intolerance.
The researchers then investigated a different aspect of the result. They hypothesized that gut microbiotas might be involved in this phenomenon. It was assumed that the gut bacteria might be reacting this way because of contact with new substances like artificial sweeteners. Artificial sweeteners are not absorbed in the gastrointestinal tract, but when they pass through the gut, they encounter trillions of the bacteria present the gut microbiota
In the next step of the experiment, the researchers treated the mice with antibiotics to kill many of the gut bacteria. This resulted in a full reversal of the artificial sweeteners effect on the glucose metabolism. The microbiota from the treated mice was then transferred to germ free' mice and surprisingly it resulted in a complete transmission of the glucose intolerance into the recipient mice. . The research by the Weizmann Institute showed that the artificial sweeteners induce glucose intolerance by changing the composition and function of the gut microbiota.
This proved that the gut bacteria are directly responsible for the harmful effects to their host’s metabolism. When the microbiota in these mice was characterized in details, it was found that profound changes occur in their bacterial population such as new microbial functions that infers a propensity to obesity, diabetes in both mice and humans.
After these findings the question that remained was if the human micro biome worked in a similar way? For this Elinav and Segal looked at data collected from their Personalized Nutrition Project, which is the largest human trial to date to look at the connection between nutrition and microbiota. He did found a significant association between artificial sweeteners intake, personal configurations of gut bacteria and the onset for glucose intolerance. In the next step, they asked a group of volunteers who did not generally consume artificially sweetened foods to have them for a week. After a week they were made to undergo tests to find out their glucose levels and also their gut microbiota compositions.
The results revealed that some of them did begin to develop glucose intolerance in just a week. It was discovered that there were two different populations of human gut bacteria one that was indifferent to artificial sweetener intake and the second that induced glucose intolerance when exposed to such sweeteners. Elinav came to the conclusion that in people who developed glucose intolerance, certain bacteria in their gut reacted to the chemical sweeteners and secreted substances that provoked an inflammatory response akin to sugar overdose and promoted changes in the body’s ability to utilize sugar.
The results of this research call for reassessment of today’s massive, unsupervised consumption of such artificial substances. It is ironical that these substances which were designed to help in glucose intolerance and promoting it.