FEATURE THE BRAIN CHANGERS“THE BRAIN NEEDS A
CONSTANT SUPPLY OF
TRYPTOPHAN AND THE
MICROBIOTA PLAY A
PART IN PROVIDING IT ”
GETTY IMAGES, SCIENCE PHOTO LIBRARY2 anyone in the field who is saying
there’s no link between your gut microbes
and mental health.”EVIDENCE OF THE BRAIN-BIOME LINK
Such mind-body associations sound like
they belong to the province of alternative
medicine. But doctors have long known
that mental health problems, such as
bipolar disorder and even autism, are
often associated with gut problems, for
example inflammation. Until recently,
the main clues that this had something
to do with the bacteria in our bowels
came from animal experiments. Studies
on mice indicated t hat t he bacteria
in their guts were creating some sort
of pathway between their bowels
and their brains.
For exa mple, resea rch f rom t he
University of Colorado Boulder has
shown that stress disrupts the normally
stable relat ionsh ip bet ween g ut
bacteria and their host, resulting in gut
inflammation. Giving rats a probiotic
containing a bacterium known to be
important to immune system function
not only clears up the inflammation but
reduces stress-related behaviour.
On ly i n t he pa st yea r have la r ge
populat ion studies provided st rong
evidence that the same principle appliesto humans. Patterns of anxiety and depression tally with
certain patterns of gut microbes. An analysis of data from
more than 1,000 people in Belgium and Holland found that
the presence of some types of gut bacteria was consistently
associated with higher quality of life, while their absence
was consistently associated with depression. After the results
were published, author Prof Jeroen Raes, a microbiologist
at Belgium’s Katholieke Universiteit Leuven, said: “If you
would have asked a neuroscientist 10 years ago whether they
thought the gut microbiota could be linked to depression,
many of them would have said you were crazy.”
Spector, whose microbiome research forms the basis of
his book The Diet Myth, agrees that new studies are making
scientists think differently. “But we still haven’t done the
really big studies in humans,” he says. “We’re over the first
hurdle of saying there’s a link, but we’re a long way from
pinning down the exact mechanisms and treatments.”HOW THE LINK WORKS
The Alimentary Pharmabotic Centre (APC), part of University
College Cork, Ireland, is at the forefront of trying to explain
the microbiome-gut-brain axis. Scientists there were the firstRIGHT The wall of the
large intestineFEATURE THE BRAIN CHANGERS“THE BRAIN NEEDS A
CONSTANT SUPPLY OF
TRYPTOPHAN AND THE
MICROBIOTA PLAY A
PART IN PROVIDING IT ”
GETTY IMAGES, SCIENCE PHOTO LIBRARY2 anyone in the field who is saying
there’s no link between your gut microbes
and mental health.”EVIDENCE OF THE BRAIN-BIOME LINK
Such mind-body associations sound like
they belong to the province of alternative
medicine. But doctors have long known
that mental health problems, such as
bipolar disorder and even autism, are
often associated with gut problems, for
example inflammation. Until recently,
the main clues that this had something
to do with the bacteria in our bowels
came from animal experiments. Studies
on mice indicated t hat t he bacteria
in their guts were creating some sort
of pathway between their bowels
and their brains.
For exa mple, resea rch f rom t he
University of Colorado Boulder has
shown that stress disrupts the normally
stable relat ionsh ip bet ween g ut
bacteria and their host, resulting in gut
inflammation. Giving rats a probiotic
containing a bacterium known to be
important to immune system function
not only clears up the inflammation but
reduces stress-related behaviour.
On ly i n t he pa st yea r have la r ge
populat ion studies provided st rong
evidence that the same principle appliesto humans. Patterns of anxiety and depression tally with
certain patterns of gut microbes. An analysis of data from
more than 1,000 people in Belgium and Holland found that
the presence of some types of gut bacteria was consistently
associated with higher quality of life, while their absence
was consistently associated with depression. After the results
were published, author Prof Jeroen Raes, a microbiologist
at Belgium’s Katholieke Universiteit Leuven, said: “If you
would have asked a neuroscientist 10 years ago whether they
thought the gut microbiota could be linked to depression,
many of them would have said you were crazy.”
Spector, whose microbiome research forms the basis of
his bookThe Diet Myth, agrees that new studies are making
scientists think differently. “But we still haven’t done the
really big studies in humans,” he says. “We’re over the first
hurdle of saying there’s a link, but we’re a long way from
pinning down the exact mechanisms and treatments.”HOW THE LINK WORKS
The Alimentary Pharmabotic Centre (APC), part of University
College Cork, Ireland, is at the forefront of trying to explain
the microbiome-gut-brain axis. Scientists there were the firstRIGHTThe wall of the
large intestine