60 | March• 2018
GUT BACTERIA – THE NEW FRONTIER OF SCIENCE
million genes in the microbes in the
gut, compared to just 23,000 that make
up the human genome. While there’s
only ever about 0.5 per cent difference
in the genes between humans, the ge-
netic make-up of the bacteria we all
carry in our belly can vary by as much
as 90 per cent.
It seems the effects of the small
molecules produced by bacteria in
our bodies may be as important as
our own DNA.
It’s All About Balance
On the weekend, when Jim’s away
from his routine, he’s able to enjoy
more glasses of wine, rich dinners
out and sugary desserts. When he
does, the colonies of good bacteria in
his gut are ravaged and the colonies
of harmful bacteria rise up, causing
Jim to bloat and become gassy. And
so, by Monday morning, more often
than not, he’s feeling lethargic and
depressed.
There are about 1000 different spe-
cies of bacteria living in the human
gut. Like the ecosystem of the Am-
azon rainforest, each bacteria’s sur-
vival depends on a complex pattern
of interdependent relationships. Most
of the time they live in harmony, but
a change in their environment caused
by us eating certain foods, falling ill
to an infection or taking a course of
medicine can kill off some species and
cause others to take over.
If you eat a diet full of biscuits and
soft drinks, you’ll feed the bacteria
that thrive on sugar, while those that
prefer protein will starve. As the bac-
teria help to digest food, they produce
small-molecule by-products (called
metabolites) that enter the blood-
stream and influence your health.
If you feast on protein and don’t eat
enough fibre, the bacteria that thrive
on this diet will produce hydrogen
sulphide and ammonia, making your
farts smelly.
Like the Amazon rainforest’s role
in the health of the planet, cultivating
a healthy gut is essential for health.
Disrupt the balance, and you’re more
likely to develop any number of dis-
eases ranging from cancer to obesity,
type 2 diabetes, heart disease, aller-
gies, autism or Alzheimer’s disease.
The good news is that it’s relatively
easy to change the composition of
bacteria in your gut. If Jim drinks a
little too much diet soft drink one
week, feeding colonies ofBacteroides
bugs, then replacing that artificial
sugar with high-fibre fruits can help
restore the balance.
“Everything you eat will in some
way affect your gut,” says Loughman.
“You can definitely change your gut
microbiome with your diet. The tricky
thing is that we still don’t fully un-
derstand in exactly which ways you
would want to change it.”TheMicrobiomeToday
Formorethan100years,medicine
hasfocusedonkillingoffbacteria
with antibiotics and antibacterial