THE BRAIN CHANGERS FEATUREMICROBIOME
GUT BRAIN AXIS
to discover that transplanting gut microbes from a depressed
rodent to a non-depressed rodent causes behaviour changes
that indicate depression. They are trying to use this new
knowledge to develop ways of making us healthier and happier.
According to Ted Dinan, professor of psychiatry at University
College Cork and the APC’s lead investigator on the microbiome-
gut-brain axis, there are three likely communication routes
between gut microbiota and the brain.
First, chemicals produced by bacteria may influence signals
being sent from the millions of nerve endings in the digestive
system to the brain via the vagus nerve, which runs all the
way from the colon to the brain stem.
Second, research at the APC has indicated that some gut
bacteria such as Bifidobacteria produce an amino acid called
tryptophan. This is an important building block for the
neurotransmitter serotonin – an essential brain chemical
known to influence mood. “The brain needs a constant supply
of tryptophan and the microbiota play a part in providing
it,” says Dinan.
The third possibility is that bacteria are influencing gene
expression in the brain. When microbes digest fibre, short-
chain fatty acids are released as a by-product. It now seemslikely, explains Dinan, that these acids
travel through the bloodstream to the
brain, where they act as epigenetic
modulators, reprogramming some brain
functions and influencing mood.POTENTIAL TREATMENTS AND PREVENTION
Researchers at the APC are focusing on
the effects of probiotics and prebiotics
on healthy volunteers, rather than those
with clinically diagnosed depression.
But already the evidence suggests doctors
will, one day, be recommending such
supplements to fill microbiota gaps that
may be contributing to their patients’
mental health issues.
“We w ill see a scena r io where
probiot ics or prebiot ics w ill be
recommended for people with milder
forms of depression or anxiety,” says
Dinan. “We don’t have the trials
at the moment to make those 2It’s thought that there are as
many bacteria living in you as
there are human cells in your
body. The lodgers in your gut
metabolise the food and drink
you consume, eking out extra
nutrients for your body as they
do. But the diversity of these
bacteria and the way they interactcan a ect the signals that are sent
to your brain via the nerves and
chemical pathways based in your
digestive system. As such, any
nutritional deficiencies in your
diet that lead to a drop in the
diversity of your gut bacteria
population could have negative
impact on your mental wellbeing.THE BRAIN CHANGERS FEATUREMICROBIOME
GUT BRAIN AXIS
to discover that transplanting gut microbes from a depressed
rodent to a non-depressed rodent causes behaviour changes
that indicate depression. They are trying to use this new
knowledge to develop ways of making us healthier and happier.
According to Ted Dinan, professor of psychiatry at University
College Cork and the APC’s lead investigator on the microbiome-
gut-brain axis, there are three likely communication routes
between gut microbiota and the brain.
First, chemicals produced by bacteria may influence signals
being sent from the millions of nerve endings in the digestive
system to the brain via the vagus nerve, which runs all the
way from the colon to the brain stem.
Second, research at the APC has indicated that some gut
bacteria such asBifidobacteriaproduce an amino acid called
tryptophan. This is an important building block for the
neurotransmitter serotonin – an essential brain chemical
known to influence mood. “The brain needs a constant supply
of tryptophan and the microbiota play a part in providing
it,” says Dinan.
The third possibility is that bacteria are influencing gene
expression in the brain. When microbes digest fibre, short-
chain fatty acids are released as a by-product. It now seems
likely, explains Dinan, that these acids
travel through the bloodstream to the
brain, where they act as epigenetic
modulators, reprogramming some brain
functions and influencing mood.POTENTIAL TREATMENTS AND PREVENTION
Researchers at the APC are focusing on
the effects of probiotics and prebiotics
on healthy volunteers, rather than those
with clinically diagnosed depression.
But already the evidence suggests doctors
will, one day, be recommending such
supplements to fill microbiota gaps that
may be contributing to their patients’
mental health issues.
“We w ill see a scena r io where
probiot ics or prebiot ics w ill be
recommended for people with milder
forms of depression or anxiety,” says
Dinan. “We don’t have the trials
at the moment to make those 2It’s thought that there are as
many bacteria living in you as
there are human cells in your
body. The lodgers in your gut
metabolise the food and drink
you consume, eking out extra
nutrients for your body as they
do. But the diversity of these
bacteria and the way they interactcan a ect the signals that are sent
to your brain via the nerves and
chemical pathways based in your
digestive system. As such, any
nutritional deficiencies in your
diet that lead to a drop in the
diversity of your gut bacteria
population could have negative
impact on your mental wellbeing.