An Israeli scientist says artificial sweeteners should no longer be considered safe after his lab published peer-reviewed research suggesting they may actually increase sugar levels in the body.
Immunologist Prof. Eran Elinav of the Weizmann Institute of Science told The Times of Israel that unless his team’s concerns are proven to be unfounded, “we should not assume they are safe.”
According to the study, published in the journal Cell, consuming saccharin and sucralose impairs healthy adults’ ability to get rid of glucose in their bodies.
It’s a long-awaited human study from the Israeli team that raised the alarm about artificial sweeteners eight years ago on the basis of a rodent study.
The scientists argued at the time that sugar substitutes were introduced to satisfy the sweet tooth with less damage to glucose levels, but they “may have directly helped bolster the exact epidemic they had to fight themselves.”
Now they’ve broadly confirmed their research on rodents by following dozens of adults who normally diligently avoid artificial sweeteners when consuming them.
“Our trial has shown that non-nutritive sweeteners can reduce glucose response by altering our microbiome,” Elinav said.
This strongly challenges the common assumption that sweeteners provide harmless sweetness with no health costs, Elinav added.
The research was led by Dr. Jotham Suez, a former graduate student of Elinav and now principal investigator at John Hopkins University School of Medicine, along with Yotam Cohen, a graduate student in Elinav’s lab, and Weizmann’s Prof. Eran Segal.
The scientists experimented with the four most common sweeteners: saccharin, sucralose, aspartame and stevia. The first two appeared to significantly reduce the glucose response, but all four caused changes in the gut bacteria, the microbiome.
Elinav stated, “We found that gut microbe composition and function changes in response to consumption of all four sweets, meaning they are not inert to the human body.”
These changes were not detected in other volunteers who were in control groups and therefore did not consume sweeteners.
The scientists transplanted feces from some of the people in the experiment into rodents bred not to have their own gut bacteria. They found that mice with feces from people whose glucose tolerance was hit hardest by sweeteners also had a decreased ability to drain glucose.
They say this strengthened their theory that sweeteners affect the microbiome and that the altered microbiome can affect glucose tolerance — so clearly it has this effect even when transplanted to another species.
“Our current results strongly suggest that artificial sweetness is not inert to the human body or to the gut microbiome, as was once thought, and may mediate changes in humans, possibly in a very personal way that arises from the unique gut microbe populations of different people,” said Elinav.
“In my view, as a physician, once it has been established that non-nutritive sweeteners are not inert to the human body, the burden of proof to demonstrate or disprove their potential effects on human health lies with those who promote their use, and we should not assume they are safe until proven otherwise. Until then, caution is advised,” he said.