Trick or Treat? Artificial Sweeteners Impact Gut Bacteria, Could Alter Glucose Tolerance – Study
Sugar is more deadly than gunpowder

Non-nutritive artificial sweeteners duplicate the taste of sugar but have fewer calories. As such, sugar alternatives like saccharin, sucralose, aspartame and stevia are often consumed in large quantities by people looking to watch their weight or shed a few pounds.

But a team of researchers from Israel’s Weizmann Institute of Science said these alternative sugars should no longer be assumed safe because they can cause harm. In some people, they alter their microbiome (gut bacteria) and change blood sugar levels.

“Our trial has shown that non-nutritive sweeteners may impair glucose responses by altering our microbiome, and they do so in a highly personalized manner, that is, by affecting each person in a unique way,” said Prof. Eran Elinav of Weizmann’s Systems Immunology Department, who led the study.

Altering the Composition and Function of the Biome with Artificial Sweeteners

Building off an animal trial conducted in 2014 that showed that some artificial sweeteners might contribute to changes in the sugar metabolism they are meant to prevent, a new team of researchers worked with 120 people who avoided artificially sweetened foods or drinks.

The volunteers were divided into six groups: two controls and four who received one of four artificial sweeteners – saccharin, sucralose, aspartame or stevia – at lower than acceptable daily intake levels.

In just two weeks, the researchers found consuming any of the sweeteners altered the composition and function of the microbiome and the small molecules that the gut microbes secrete into people’s blood.

Moreover, saccharin and sucralose were found to alter glucose metabolism – the way a person disposes of glucose – which could contribute to metabolic disease, they said.

No changes in either the microbiome or glucose tolerance were found in the two control groups that did not consume any alternative sugars.

The findings were published on August 19 in the peer-reviewed journal Cell.

“These findings reinforce the view of the microbiome as a hub that integrates the signals coming from the human body’s own systems and from external factors such as the food we eat, the medications we take, our lifestyle and physical surroundings,” Elinav said.

Artificial Sweeteners
Changes in the composition and function of gut microbes were observed in all four groups of trial participants who consumed non-nutritive sweeteners. Each group consumed one of the following: saccharine, sucralose, stevia or aspartame. The diagram shows increases in glucose levels in the saccharin and sucralose groups (two graphs on the left), compared to the stevia and aspartame groups (middle) and to the two control groups (right)

Still Unproven That Sugar Is Healthier

To help validate their findings and confirm that changes in the microbiome were responsible for impaired glucose tolerance, the researchers next implanted feces from more than 40 of the trial participants into healthy mice who were bred to have no gut bacteria of their own and who had never consumed artificial sweeteners. 

Those who received microbes from participants with the most pronounced alterations in glucose tolerance had more alterations in glucose tolerance themselves.

This was compared to those mice that received microbes from people who had the least changes in glucose tolerance, and also had less changes.

“The health implications of the changes that non-nutritive sweeteners may elicit in humans remain to be determined, and they merit new, long-term studies,” Elinav said.

Previous studies have shown the detriments of eating artificial sweeteners, including weight gain, brain tumors and cancer. 

A BMJ study by French researchers in 2019 reinforced the link between consumption of sugar-laced sodas & fruit juices and cancer incidence, in particular breast cancer.

Nonetheless, Elinav cautioned, the findings of this latest study do not imply that sugar is healthier than alternative sugars.

Image Credits: Marco Verch.

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