Artificial sweeteners are a class of natural or synthetic
compounds that are capable of interacting with sweet sensors on your tongue
causing the sensing of sweet taste.
These compounds are used extensively as sugar substitutes in food and
beverages to reduce the caloric content in these products and have long been promoted
as aids to weight loss and diabetes prevention.
However, for years, data seems to suggest that non-caloric artificial
sweeteners do not seem to assist in weight loss. On the contrary, some studies actually
suggest that artificial sweeteners may even have an opposite effect.
A recent study published on Nature magazine reported that
artificial sweeteners, even though they do not contain sugar, nonetheless have
a direct effect on the body's ability to utilize glucose. The researchers report that artificial
sweeteners could actually hasten the development of glucose intolerance and
metabolic disease, and they do so in a surprising way: by changing the
composition and function of the gut microbiota -- the substantial population of
bacteria residing in our intestines.
In the study, the scientists gave mice water laced with the
three most commonly used artificial sweeteners, 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.
Knowing artificial sweeteners are not absorbed in the
gastrointestinal tract but simply pass through while encountering trillions of
the bacteria in the gut microbiota, the researchers wondered if the phenomenon
is somehow caused by the artificial sweeteners’ effect on the gut
microbiota. To test the hyphothesis, 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 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. The group even
found that incubating the microbiota outside the body, together with artificial
sweeteners, was sufficient to induce glucose intolerance in the germ-free mice.
A detailed characterization of the microbiota in these mice revealed profound
changes to their bacterial populations, including new microbial functions that
are known to increase tendency of obesity, diabetes, and related metabolic
syndrome in both mice and humans.
Does the human microbiome function in the same way? The researchers looked at data collected from
their Personalized Nutrition Project (www.personalnutrition.org), 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. They next 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 showed that many of the volunteers had begun to
develop glucose intolerance after just one week of artificial sweetener
consumption. Similar to the mice study, the
researchers discovered gut bacteria that induced glucose intolerance when
exposed to the sweeteners from the composition of volunteers’ gut microbiota.
Next time, when you reach out to grab that pack of Stevia,
you might want to think about taking your coffee black, or in my case, with raw
sugar.
Journal Reference: Jotham Suez, Tal Korem, David Zeevi, Gili
Zilberman-Schapira, Christoph A. Thaiss, Ori Maza, David Israeli, Niv Zmora,
Shlomit Gilad, Adina Weinberger, Yael Kuperman, Alon Harmelin, Ilana
Kolodkin-Gal, Hagit Shapiro, Zamir Halpern, Eran Segal, Eran Elinav. Artificial
sweeteners induce glucose intolerance by altering the gut microbiota. Nature, 2014; DOI: 10.1038/nature13793
Thanks for reading.
Connie
connie@cherruby.com
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