Preliminary Research Shows that Non Caloric Artificial Sweeteners May Cause Gut Dysbiosis in Some People.

Preliminary Research Shows that Non Caloric Artificial Sweeteners May Cause Gut Dysbiosis in Some People.

What the heck is gut dysbiosis?  According to the Fairplex and Partners medical dictionary, it is “an unhealthy change in the normal bacterial ecology of the intestines”.

In an earlier article, I discussed how the study of our gut microbes is in its nascent stages. This holds true for the study of Non Caloric Artificial Sweeteners (NAS) and their impact on our gut microbiome.

Compelling Study Links NAS to Glucose Intolerance

A study conducted by The Weizmann Institute led the researches to conclude that NAS may hasten the development of glucose intolerance by changing the composition and function of the gut.

The scientists gave mice water laced with the three most commonly used artificial sweeteners, (Aspartame, Saccharin and Sucralose)  in amounts equivalent to those permitted by the U.S. Food and Drug Administration (FDA). These mice developed glucose intolerance, as compared to mice that drank water, or even sugar water. Repeating the experiment with different types of mice and different doses of the artificial sweeteners produced the same results — these substances were somehow inducing glucose intolerance.

Was The Glucose Intolerance Caused By a Messed Up Gut Microbiota?

The researchers treated mice with antibiotics to eradicate many of their gut bacteria; this resulted in a full reversal of the artificial sweeteners’ effects on glucose metabolism. Next, they transferred the microbiota from mice that consumed artificial sweeteners to “germ-free,” or sterile, mice — resulting in a complete transmission of the glucose intolerance into the recipient mice. This, in itself, was conclusive proof that changes to the gut bacteria are directly responsible for the harmful effects to their host’s metabolism.

A detailed characterization of the microbiota in these mice revealed profound changes to their bacterial populations, including new microbial functions that are known to infer a propensity to obesity, diabetes, and complications of these problems in both mice and humans.

Might The Human Gut Microbiota Be Affected Similarly?

First, the researchers looked at data collected from the Personalized Nutrition Project, the largest human trial to date to look at the connection between nutrition and microbiota. Here, they uncovered a significant association between self-reported consumption of artificial sweeteners, personal configurations of gut bacteria, and the propensity for glucose intolerance.

Next, they conducted a controlled experiment, asking a group of volunteers who did not generally eat or drink artificially sweetened foods to consume them for a week, and then undergo tests of their glucose levels and gut microbiota compositions.

The Findings?

The findings showed that many — but not all — of the volunteers had begun to develop glucose intolerance after just one week of artificial sweetener consumption. (4 out of the 7 volunteers began to develop glucose intolerance)  

The composition of their gut microbiota explained the difference: the researchers discovered two different populations of human gut bacteria — one that induced glucose intolerance when exposed to the sweeteners, and one that had no effect either way.  Principle Investigator, Dr. Eran Elinav, believes that certain bacteria in the guts of those who developed glucose intolerance reacted to the chemical sweeteners by secreting substances that then provoked an inflammatory response similar to sugar overdose, promoting changes in the body’s ability to utilize sugar.

According to Dr. Elinav, “Our relationship with our own individual mix of gut bacteria is a huge factor in determining how the food we eat affects us. Especially intriguing is the link between use of artificial sweeteners — through the bacteria in our guts — to a tendency to develop the very disorders they were designed to prevent; this calls for reassessment of today’s massive, unsupervised consumption of these substances.”

Much More Research Is Needed

Dr. Martin Blaser, Director of The Human Microbiome Project at New York University, states that “ researchers must next determine if these findings are really true”. And the next challenge is to understand the mechanism. “How does the change in the microbial composition — how is it causing this (glucose intolerance)?

Although there clearly is a need for more robust research to confirm these findings, the results in this study were compelling enough to persuade Dr. Blaser to make at least one change to his diet.  In an interview the day after he read the study, Dr. Blaser proclaimed: “I can just tell you … as a middle-aged man who’s concerned about his diet and his waistline — and [as] somebody who drinks diet soda — I didn’t drink any yesterday.”

It should be interesting to see what future research reveals about NAS and our gut microbiome.

Stay Healthy and Strong!


  1. Great information, with clear presentation of the facts to back it up. Thanks!

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