Hello.
This is 6 Minute English from
BBC Learning English.
I'm Sam.
And I'm Neil.
In recent years new diets with names
like 'vegan', 'keto' and 'paleo' have
become very popular.
Are you a
vegetarian, Neil?
Do you follow
any particular diet?
Well, I eat lots of fresh fruit
and vegetables and only a little
meat from time to time.
Well, while many diets claim to
improve health or help you
lose weight, recent research
shows that what counts is not
what you eat but how
your body reacts.
Yes, and that reaction doesn't
happen where you might think - not
in the brain, or tongue, or even
the stomach, but in the gut - another
name for the intestines - the
long tube inside your body
which digests food.
Inside everyone's gut are millions
of microbes - tiny living organisms,
too small to see without a
microscope.
Some of them are good
for us, some bad.
Microbes help digest food, but
they influence our bodies more
than we know.
Think of them as
chemical factories that cause our
individual reaction to
the food we eat.
This mix of gut microbes is
unique and different for everyone,
even identical twins.
And it's the reason why some
doctors now recommend a
personalised diet, one that
perfectly fits your own unique
combination of microbes.
We'll hear more soon, but first
I have a question for you, Neil,
and it's about the gut - the
tube which includes the large and
small intestine.
It's very
long - but how long exactly is
the average adult's gut?
Is it:
a) 3 and a half metres?
b) 5 and a half metres?
or,
c) 7 and a half metres?
Well, everybody is different
of course, but I'll say on average
the gut is b) 5 and
a half metres long.
OK, Neil, I'll reveal the answer
later in the programme.
Among the first to investigate gut
microbes was Dr Tim Spector, author
of bestselling book, The Diet Myth.
He wanted to check whether the
dietary advice he had heard and
believed, advice like 'eat little
and often' or 'avoid fat',
was really true.
Listen as Dr Spector explains
how he started to doubt some of
this advice - 'food myths', he
calls them - to BBC Radio 4
programme, The Life Scientific:
All these so-called myths that
I'd believed, whether it was
about calories, about fats,
when to eat, how to eat, were
based on flimsy or no evidence,
very old, very poor quality,
and had been repeated so much
that people didn't
think to question them.
One of the food myths Dr Spector
questioned was counting calories - the
units which measure the amount
of energy food provides.
He discovered that much of
the dietary advice he had
heard was either incorrect or
based on flimsy evidence.
If
evidence is flimsy, it's
weak and unconvincing.
As Dr Spector questioned these
food myths, he remembered an
earlier study involving
identical twins, pairs of brothers
or sisters with the same genes.
It was the surprising differences
in weight between one twin and
another that made Dr Spector
realise that no two people
have the same gut - even
identical twins' guts are different.
But, as he told BBC Radio 4's,
The Life Scientific, the discovery
came in a very smelly way - by
asking his volunteers to send
samples of their poo in the post!
We collected lots of these
samples, sequenced them,
and looked at twins where
one was overweight and one
was skinny... and we found
in every case, the skinnier
twin had a more diverse
microbiome, greater numbers
of different species and
they also nearly always had
high numbers of a couple
of microbes that just
stuck out of the crowd - and
one was called christensenella
and the other was
called akkermansia.
Although genetically identical,
one twin was overweight, while
the other twin was skinny,
or very thin.
Because the weight difference
could not be explained
genetically, Dr Spector
suspected the microbes in
the skinnier twin's gut
held the answer: the more
diverse someone's microbes,
the better their gut was at
digesting food, regulating
fat and maintaining health.
Two microbes, christensenella
and akkermansia, were especially
effective.
Dr Spector says these
microbes stuck out of the crowd,
meaning they were easy to notice
for their positive effect.
And since everyone's microbes are
different, it follows that a
personalised diet which selects
the friendliest food for
your gut, is best.
Right,
and all this talk of eating
is making me hungry, so tell me,
Sam, was my answer
to your question, right?
Ah yes, I asked about the
length of the gut in
the average adult.
I said it was 5 and
a half metres.
Which was... the correct answer!
Well done, Neil - that took 'guts',
which is the second meaning
of the word: courage.
OK, let's recap the vocabulary we've
learned starting with gut - an
informal word for the intestines,
the tube which digests
food from the stomach.
Microbes are microscopic organisms
living inside the body.
A calorie is a unit measuring
how much energy food provides.
If an argument or evidence is
flimsy, it's weak
and hard to believe.
A skinny person is very thin.
And finally, if something
sticks out of the crowd,
it's noticeable in a good way.
Unfortunately, our six minutes
are up, but remember:
look after your gut, and
your gut will look after you!
Goodbye!