Study Suggests Link Between Diet Soda and Heart Disease
NBC Nightly News
Maggie Fox

Researchers trying to figure out whether artificial sweeteners really
do make people fat think they’ve found a possible explanation — they
may disrupt the bacteria in some people’s bodies.

Their findings may shed light on why studies often contradict one
another, with some finding that people who drink lots of diet drinks
are more likely to be obese, with others finding they may help people
keep weight off.

Their answer: it may depend on what kind of gut bacteria you have to
start with.

They found clear evidence that artificial sweeteners, including
saccharine and sucralose, can affect gut bacteria, which in turn
affect how food is digested and metabolized. Mice and a very few
people given artificial sweeteners for the first time showed distinct
changes in the way their bodies processed sugar.

It’s not a final answer, but the study, published in the journal
Nature, may point research in a new direction. “Our findings suggest
that non-caloric artificial sweeteners may have directly contributed
to enhancing the exact epidemic that they themselves were intended to
fight,” they wrote in their report.

“I think we must stress that by no means are sugary drinks healthy."

“By no means do we believe that based on the results of this study are
we prepared to make recommendations as to the use and the dose of
artificial sweeteners,” said Eran Segal of the Weizmann Institute of
Science in Rehovot, Israel, who worked on the study. But, he added,
“In none of these experiments have we seen any beneficial effects.” He
said the findings should at least prompt closer examination of the
very widespread popularity or artificial sweeteners.

How could artificial sweeteners, which have no calories, affect
metabolism? Segal pointed out that bacteria in the guts of both mice
and people digest compounds that animals normally cannot, and they
could thrive on chemicals that would not normally be used as food by
people or animals.

It’s another example of how the microbiome — the population of
microbes living in and on our bodies — can have huge effects on
health.

Most of the study was done in mice. They fed the mice large amounts of
sweeteners of all kinds and measured their gut bacteria and tested
their metabolisms. Bacteria living in the intestines and colon are
known to help digest food, and more and more studies are showing they
can affect obesity and even appetite, as well as a tendency to
disease.

Mice fed the sweeteners had definite changes in both gut bacteria and
metabolism. Sugar did not have the same effect. To make sure it was
the gut bacteria, the researchers removed bacteria from mice that had
not eaten sweeteners, and grew them in lab dishes along with
artificial sweeteners. They then put these sweetener-fed bacteria into
new mice. The new mice began to show the same changes in metabolism as
mice directly fed sweeteners.

The main flaws? Artificial sweeteners seemed to encourage a group of
bacteria called Bacteroides and seemed to kill off another group
called Clostridiales. Scientists are just beginning to understand what
kinds of bacteria people have living inside their digestive systems
and what balance might be healthy. But having too many Bacteroides and
too few Clostridiales is a pattern sometimes seem in people with
diabetes.

The researchers used mostly saccharine in their controlled
experiments, but they said in early tests the mice responded the same
whatever sweetener they used – saccharine, sucralose, aspartame or
others. This baffled them, because the sweeteners are chemically very
different from one another.

It’s worth more research, they said.

Mice are different from people, of course, but they tried the
experiment in a small group. Seven people who did not normally use
artificial sweeteners were given large amounts for a week. In four of
them, their blood sugar shot up and they had other changes to
metabolism associated with weight gain and pre-diabetes.

Larger studies have also suggested similar patterns – some people are
adversely affected by sweeteners, while others are not. It may be a
very individual thing, Segal said.

"Water is the best drink to control our blood sugar.”

“We are identifying many foods which are considered as healthy food to
have potential adverse effects for large subsets of individuals,” he
told reporters in a telephone briefing. Genetic differences already
demonstrate that some people can smoke tobacco with little effect,
while most develop heart disease or cancer.

“What was super-striking and interesting to us was that we could
predict ahead of time (who would be affected by the sweeteners),”
Segal said. They profiled the microbiomes of their volunteers and
found two distinct patterns. While everyone’s microbiome is different,
there were larger overall patterns, and these predicted who would be
affected by the sweeteners, Segal said.

“I think we must stress that by no means are sugary drinks healthy and
that sugary drinks should be brought back as a healthy part of our
nutrition,” added Eran Elinav, who led the research.

Researchers not involved in the study were skeptical, but most said
it’s worth looking into more.

“The study is based primarily on mouse experiments and only seven
human subjects were studied,” said endocrinologist Dr. Katarina Kos of
the University of Exeter in Britain.

“Meanwhile, these findings support the widespread understanding that
water is the healthiest drink option and that we should avoid sweet
and sweetened drinks. Water is the best drink to control our blood
sugar.”

First published September 17th 2014, 11:01 am