Bacteria from slim people could help treat obesity, study finds

06.09.2013 17:56

Bugs that lurk in the guts of slim
people could be turned into radical
new therapies to treat obesity,
according to a new study.
The claim follows a series of
experiments which found that the
different populations of bacteria
that live in lean and overweight
people caused mice to lose or gain
The findings build on a growing
body of work that gives the
millions of microbes that live in the
gut a major role in weight control.
Scientists at Washington University
School of Medicine in St Louis said
the research paved the way for new
therapies that tackle obesity by
altering the types and numbers of
bugs that make their home in the
Researchers led by Jeffrey Gordon
recruited four pairs of women who
were twins. One woman in each
pair was obese, but the other had a
healthy body weight.
From each woman, the researchers
collected faeces which contained a
wealth of expelled gut microbes.
Through a number of tests, the
scientists then investigated what
happened when they transplanted
these into mice bred to have no gut
microbes of their own.
The scientists found that mice
stayed slim when they received
faecal transplants from slim
women, but put on much more fat
when the samples came from the
obese twin. Tests revealed that one
type of bug, called Bacteroides, was
more plentiful in slim women and
protected the animals from putting
on too much fat.
In a follow-up experiment, mice
with microbes from the slim
women shared a cage with mice
that had microbes from obese
women. Because of the animals'
proclivity for coprophagia – that is
their habit for eating each others'
poo – this caused a mixing of the
animals' gut microbes.
After the mice had spent 10 days as
cage mates, the obese ones had
become more lean. But this only
happened if the animals were fed a
healthy diet that was high in fibre
and low in saturated fats. When
the diet was switched to high-fat,
low-fibre meals the obese mice
remained overweight.
The scientists think that a healthier
diet allowed "good" microbes to
thrive in the animals' guts, and
even reverse obesity in the
overweight mice. But a more
typical western diet, high in fat and
low in fibre, blocked the effect.
That would explain why there is no
"epidemic of leanness" in the US
and elsewhere in the west, the
scientists say.
Gordon said the findings, which are
published in the journal Science ,
would steer the development of
foods and new therapies that treat
obesity by altering the makeup of
microbes in the intestines.
"In the future, the nutritional value
and the effects of food will involve
significant consideration of our
microbiota, and developing
healthy, nutritious foods will be
done from the inside out, not just
the outside in," he said.
In an accompanying article, Alan
Walker and Julian Parkhill at the
Sanger Institute in Cambridge
called the work "a step toward the
ultimate goal of developing
relatively simple mixtures of
bacteria for testing as anti-obesity