That is the very same condition that we often aim to prevent by consuming sweeteners instead of sugar, said Dr Eran Elinav, an immunologist at the Weizmann Institute of Science in Israel, at a news conference to discuss the findings.
The scientists performed a multitude of experiments, mostly on mice, to back up their assertion that the sweeteners alter the microbiome, the population of bacteria that is in the digestive system.
The different mix of microbes, the researchers contend, changes the metabolism of glucose, causing levels to rise higher after eating and to decline more slowly than they would.
The findings by Dr Elinav and his collaborators in Israel, including Eran Segal, a professor of computer science and applied mathematics at Weizmann, were published in September by the journal Nature.
Cathryn R Nagler, a professor of pathology at the University of Chicago who was not involved with the research but did write an accompanying commentary in Nature, called the results very compelling.
She noted that many conditions, including obesity and diabetes, had been linked to changes in the microbiome. What the study suggests, she said, is we should step back and reassess our extensive use of artificial sweeteners.
Previous studies on the health effects of artificial sweeteners have come to conflicting and confusing findings. Some found that they were associated with weight loss; others found the exact opposite, that people who drank diet soda actually weighed more.
Some found a correlation between artificial sweeteners and diabetes, but those findings were not entirely convincing: Those who switch to the products may already be overweight and prone to the disease.
While acknowledging that it is too early for broad or definitive conclusions, Dr Elinav said he had already changed his own behavior.
Ive consumed huge amounts of coffee, and extensively used sweeteners, thinking like many other people that they are at least not harmful to me and perhaps even beneficial, he said. Given the surprising results that we got in our study, I made a personal preference to stop using them.
We dont think the body of evidence that we present in humans is sufficient to change the current recommendations, he continued. But I would hope it would provoke a healthy discussion.
In the initial set of experiments, the scientists added saccharin (the sweetener in the pink packets of SweetN Low), sucralose (the yellow packets of Splenda) or aspartame (the blue packets of Equal) to the drinking water of 10-week-old mice. Other mice drank plain water or water supplemented with glucose or with ordinary table sugar. After a week, there was little change in the mice that drank water or sugar water, but the group getting artificial sweeteners developed marked intolerance to glucose.
Glucose intolerance, in which the body is less able to cope with large amounts of sugar, can lead to more serious illnesses like metabolic syndrome and Type 2 diabetes. When the researchers treated the mice with antibiotics, killing much of the bacteria in the digestive system, the glucose intolerance went away.
- Kenneth Chang