March• 2018 | 61READER’S DIGESTcleaning products and soaps. As a
result, we’re far less likely to die of
the infections and diseases that once
ravaged communities – but at the
same time, we’re seeing a rise in anti-
biotic resistance and a dramatically
altered gut microbiome.
Scientists think the key to good
health is having many diverse spe-
cies of bacteria in the gut, especially
in the colon and large intestine. Some
studies have looked at fossilised
human remains from the Neolithic
Age and from modern hunter-gath-
erer communities in Africa, neither
of whom suffered from diseases such
as diabetes or obesity that plague
modern society. They have found that
these peoples had a gut microbiome
dramatically different and far more
diverse than the microbiome most of
us have today.
Our overuse of antibiotics isn’t
just killing the bacteria that lead to
infection – it’s killing the bacteria
we need for good health, too. Even a
short course of antibiotics, especially
broad-spectrum antibiotics, can alter
the gut microbiome for up to a year.
This imbalance of the normal gut
microbiome is called dysbiosis and
is linked to obesity and other health
conditions including cardiovascular
disease and mental illness.
The impact antibiotics and hand
sanitisers have on gut bacteria might
also explain the ‘hygiene hypothesis’- the theory that our modern, sterile
world is giving rise to an increase in
immune system problems such as
allergies and asthma.
Scientists still don’t fully under-
stand how changes to the micro-
biome cause disease. But studies that
have analysed the gut microbiome of
people with diseases such as type 2
diabetes find it’s very different to that
of healthy people. “You can look at
almost any disease – I haven’t found
a single negative study where the
microbiome is found not to be
affected,” says Loughman.
It’s not just antibiotics that are al-
tering the composition of the mod-
ern gut. The food we eat also causes
dramatic changes to our gut micro-
biome: a diet low in fibre and high in
OUR OVERUSE OF
ANTIBIOTICS ISN’T
JUST KILLING THE
BACTERIA THAT
LEAD TO INFECTION- IT’S KILLING
THE BACTERIA WE
NEED FOR GOOD
HEALTH, TOO