[MUSIC PLAYING] [APPLAUSE] Thank you very much. And again, certainly a
diverse series of talks today. So we're going to look
at a bit of the universe inside our own bodies,
opposite of what we've been seeing before. And I want to just, before
we get into that, just tell you a bit about how
I got into this myself. Basically, it was about-- at about 3,000 metres. I was doing something called
ski touring in Italy, which is a strange, rather silly sport
where you walk up for six hours and you ski down for an hour. And it's very tiring. And that last day, and I
was really not feeling well, and I started falling
all over the place. And I thought, oh, this is
just the end of a long week. Got to the bottom. And I had double vision. And this persisted. And being a medical doctor,
I realised this wasn't good news-- that it was either MS, brain
tumour, or some form of stroke. None of them were
particularly great. And so after very stressful
few months of scans and things, it turned out I had a very
small occlusion, micro stroke, if you like, of
one of the vessels supplying the eye nerves. Now, my blood pressure went up. And suddenly, I went from being
healthy to being, like most people, slightly unhealthy
with some disease, taking tablets, and wanting
to improve my health. And I thought, I'm a doctor. I've been studying obesity,
genetics for 20 years. It should be fairly
straightforward to work out the best way to lose weight
and exactly what to eat. And I was completely mistaken. Nothing could be harder. And when you went
to the internet, you were faced with masses
of quackery and obsessional religious groups stating
that their way was the only true path to salvation. And also even the government's
own advice, the Public Health England advice about nutrition. Yes, it contains
some facts which were accepted by everybody--
eat more plants and vegetables, eat a bit less of it, eat less
processed foods and less sugar. But at least half of it
was extremely contentious and without any evidence
base, such as eat less salt, have more starchy
foods, eat regularly small amounts and often
rather than in short periods. Have food supplements and use
artificial sweeteners rather than sugar, and above
all, count calories. And all this is without
any real evidence base. Some of it has
actually been disproven by other randomised trials. So the whole idea, really,
of the last 40 years in nutrition and telling
people to count calories has been totally flawed. Even the most hardened,
obsessional nutritionist cannot possibly count
their own calories. Even if they read all
the labels and you only shop from a place
that's counted it, even those have
huge errors in them. So if we've been
counting calories and obesity rates have
been going up threefold over the last 40 years,
something's very wrong. So this was all telling
me at the same time as I was working on another
field from the twins that there might be
something else going on. And that's something
else that to explain all these discrepancies. And what this was was for me
the understanding that there's a new organ in our bodies-- a newly discovered organ that
we call the microbiome, which is the community of microbes
that live in our bodies, on our bodies. We're surrounded by it
everywhere in this room. But in ourselves, 99% of them
live in our lower intestines. And this community which
includes bacteria, fungi, viruses, and other organisms
called archaea and protists all live together just like
they do in your yoghurt in their nice, happy groups. And the best way to think
of them is as a new organ. And together they
have as many cells-- they have many
organisms as there are cells in our own body. And they have maybe
1,000 times more genes. And each of those genes
is capable of being a chemical factory
that can pump out all kinds of chemicals,
proteins, hormones that our body lacks. And so we can't
live without them. And we've really
rediscovered recently how important they are
to all facets of our life and particularly how it
interacts with our diet. Now, no two people are the same. All of you would share
99.5% of your genes with each other, your DNA. And in fact, you can turn
around to everybody in this room and say, isn't it great,
we're all fifth cousins. Some of you might be third or
fourth cousins, really close. And so we realise that
actually as a group of people, we're very similar. But if I asked you to
compare your microbiomes, you wouldn't be anywhere
near fifth cousins. You'd probably like
tenth or twelfth cousins. Because you'd only share
about 25% of your microbes with each other. And all of you are going to
have very individual microbes-- unique microbes only to you. And so for some reason,
they like only you. They don't like your neighbour. And you should be privileged
that they've decided to take hold in your bodies,
not someone else's. Because generally,
these things are good. And this individuality
explains why there isn't really one diet fits all. It explains why when you put
identical twins on diets, as they've done here, as well as
differences between the twins, you also see differences
in the population-- fourfold differences in how
people will gain or lose weight on exactly the same food. And we've all seen that. We've all seen some people that
seem to do very differently. And they say, I
only eat lettuce. And the other one says, oh, I
eat masses of cake every day. And we've always said all that
must be genetic or metabolism or something weak. But it turns out genes
don't explain much of it. And most of that can be
explained by the differences in our microbes. Now, these microbes do
all kinds of things. I'm not going to
explain all this. But just to open the scope
of what these guys can do. They can alter whether
you're likely get an allergy. And we're in an epidemic,
if you haven't noticed, of food allergy at the
moment in young people. Whereas, I didn't know
anyone when I went to school who had food allergy. Now, everyone's got it. And these microbes are
the keys to allergy, about how our immune system
recognises threats and gets it wrong or right. Also, they can change
chemicals in the brain making you hungrier or thirstier
or choose certain foods. Certainly in
insects, they can do that-- decide what
you want to eat. They can also alter your mood. They produce metabolites
like serotonin, which are responsible for
anxiety and depression. And many drugs
are based on that. Then they can do all kinds
of things about controlling whether your gut
is leaking or not or all kinds of other systems
of how you digest foods. So it's huge. And we're just at the
tip of the iceberg, really, about discovering all
the things that these guys do. Now, to summarise masses
of science into one picture is tricky. But I'm at a stage in
life where I can do this without people telling me off. Because people say, well,
what is this microbiome stuff? I've heard of it. But every study varies a bit. And is there really
one microbe that is responsible for one disease? And the reality is no. The studies do differ. They've been relatively small. But there are some
consistencies. What we find in
every single study where we compare a group
of people with a disease-- say, it's diabetes
or it could be colitis or a food allergy or
Parkinson's or depression, whatever it is-- with another group
that's super healthy, we always find that the
group with the disease have a less diverse
microbiome community. They have less species. If you count them up, there just
aren't those number of plants, if you like. And so that's why I've used
the analogy here of the garden. The English country garden is
what you would like to have. So you guys are
all super healthy. You've got English country
garden type microbes. Lots of different species all
interacting with each other in a fertile soil that
contains both fungi. It's got microbes. And everything's
feeding off each other. For any keen gardeners who will
know what I'm talking about, that all those
nutrients are used. It's all being recycled. And it's very hard for invaders
to come in and take over. Whereas, the sick
people, their guts look like an Arizona backyard. A bit of toxic waste, a few
nasty bugs there taking over. It's very easy to
transform that. And you can just visualise
how a number of products, helpful products, produced
in an Arizona backyard are much less than in your
English country garden. They're producing all kinds
of aromas and chemicals and things for all the
insects and the roots. And everything is
far more productive. So the more you've got of
these guys, the better it is. That's the main key here. Now, we did something
called a citizen science project for the last few years
with our American cousins. And this was people who
were interested in their gut microbes, were donating--
they were paying for their own research really. And you can still do this if you
join the British Gut Project. You pay a small donation. And then you give a small
donation of your poo. We call it poo in the Post. And you send it back to us. And we sequence it genetically. In the same way we would
look at your genes, we look at the microbes. And that's how we discover
what all these species are. Then we put it all
together in big computers and start looking
at these patterns. And this is of 11,000 people. And we can clearly
show some patterns. We can clearly show differences
between Americans and Brits just based on their microbes. And we can tell differences
between Northerners and Southerners and
of people living in the country and
people in towns. Now, we can't go to the
individual differences in terms of microbes. We can see those patterns. And the good news is
we're not quite as unhealthy as the Americans. But I think we do pretty
badly on the world scale. And the one thing that
determined this summary gut health, if you like, which
I'm calling diversity. We want maximum diversity. The number one thing we found
was not whether you are vegan, not whether you are a
vegetarian, not whether you eat gluten free or
lactose free or any of these other religions. But actually, just the
number of different plants you ate every week. And I'm talking-- not just
you don't have to have-- that doesn't mean having 20
portions of kale every day. It means having different
seeds, different herbs, different spices. And it's mixtures of
fruits and berries and nuts and all these kind
of things together. Because each of those are
fuel for your microbes. And that was more
important than whether you self-said I'm a vegetarian. I'm a vegan. I'm healthy. I'm a paleo person. I'm whatever. So that's the key. So you can do all
those other things, call yourself what
you want, as long as you've got lots of
variety on your plate. You don't get caught in a rut. Now, the government tells
us to cut down on sugar and they also tell us
to cut down antibiotics. And we know that antibiotics
are really bad for your guts. And today, they're
given out like Smarties. But we know that children
given antibiotics do get fatter and do have more allergies. It's very hard to avoid it. Because a lot of antibiotics
are in our food, in our meat, particularly if it's
cheap or processed meat. Emulsifiers come in
all kinds of sources. And we know that emulsifiers
in processed foods do also influence your microbes,
make them stick together a bit, stop them working. Preservatives, we
know less about. But we're worried about them. But we do know that
artificial sweeteners-- I don't know how
many people here take an artificial
sweetener on the basis that it's supposed
to be healthy? Anyone admit to taking any? One of you. Well, there must be more than
that, but OK So generally, they're supposed to be inert,
not supposed to do anything. I went into metabolic
chamber and took some sucralose which
is the commonest one in the UK at the moment. And that's my-- you can
see my glucose went up. I was wearing a 24
hour glucose monitor. And so just having
sucralose it peaked. And this was telling me
that these things are far from inert. And there a number of
studies now showing they reduce diversity and
increase metabolic signals. So our whole idea of what
foods are safe and non-safe needs a new thought
when we start to think about
our gut microbiome as a novel organ in our bodies. As part of my book, The Diet
Myth, I did lots of studies. And I'd just come off a
rigorous three-day raw milk, French cheese diet. You've obviously
tried it yourselves. Helped down only with the help
of a little bit of red wine. And it was fantastic just
eating a Epoisse, Roquefort, and Brie de Meaux, which are
three unpasteurized cheese you can easily get in the UK. Because they have
extra microbes. And I was trying to
see if I could build up my microbes in just three days. I didn't, as a matter of fact. But I did enjoy very much
the day one of the diet. Day two, not so good. By day three, I'd really had
enough cheese for the week. I could tell you. And the next study
I was going to do was to do the 10 days
McDonald's challenge. Bit of a contrast there. Only eat all my
meals at McDonald's. And I wasn't very
looking forward to it. Because I'm not a big fan. But I'd do anything
for science of course. And it turned out there was
someone better qualified than me. Someone whow actually liked
eating burgers and fast food. He was a student. He was hard up for money. He was also my son. He ticked all those boxes. Fantastic. So Tom did this. And all his friends used to
follow him into the McDonald's and take pictures
of him because he was getting all this free food. And the staff knew
him for those 10 days. But he came back to me after
just four days and said, I'm really not
feeling very well. My friends say I'm
going a bit grey. And I think we
ought to stop now. And as a concerned
parent, obviously, I was worried about his health. But said, no way. We're going to carry on. We're going to publish this
in the Sunday Times, which is exactly what we did. And when we published it in-- after 10 days, he really
was feeling even worse. And we even noticed
even in him a drop in his academic achievements,
which was something. But what was worse is he'd
lost 40% of his gut microbes. So his diversity had
plummeted in those 10 days. And, really, we had to ask
the reason why that was. Because the traditional view
of junk food if you like, oh, it's just lots of
fat and lots of sugar. It's a very naive idea
and maybe chemicals. That's why you
shouldn't have it. But from a gut
microbe point of view, what happens when you
have that kind of diet, you're not getting
any fibre at all. They need fibre to live. The only fibre is a little green
gherkin that most kids throw away anyway. So he had 10 days with virtually
no fibre and lots of fat and lots of sugar. And I think it's that
imbalance that really messed up the gut microbes, messed
up his gut health. And that's why we just need to
think differently about this. It's the lack of
something rather than necessarily this idea that
these things are all toxic. We need to be stinkier. Because microbes are good. The more you've got
the healthier you are, the better you are. If we destroy them other ways,
then we're in real trouble. Now he stayed bad,
actually, for several years as he kept reminding me
when he wanted more money. But I think we may have
finally sorted them out now. Now, that's just an end
of one study, obviously, and an anecdote. In our twins that we
follow, half identical, half non-identical, we followed
a group between 30 and 80, 3,000 of them that we had
very close measurements over. Because this is the most
detailed study of twins in the world that we run. And every few years they
come in for a test and a body composition scan. And we saw that over that
time as usual middle age most people gain weight-- very unusual not to. And those that had high
fibre lost less weight and particularly
weight around the gut, the internal visceral fat, than
those that are on low fibre diets. And each extra gramme
of fibre people ate, reduced their weight
gain by 2 kilogrammes. So even a tiny amount of change
in fibre seems to have a very big effect. And this was related to
their microbial diversity. So we could directly
link what they were doing with how it
was changing the microbes. So we seem to now have a better
understanding why fibre's good for you. It's not the old days of,
oh, it's just roughage. It just passes
straight through you and gets rid of toxins,
which I was taught-- the very physical presence
of it as a substance to just cleared, scouring
out of the inside of it and cleared everything out. Now there's a real
metabolic understanding that this stuff is there
fueling your microbes. We also looked at
the genetics of this. Because in our twin study,
virtually everything we look at turns out to be genetic except
whether you like Mr. Bean or what football
team you support. And this turned out to
be a bit of an exception. It's not very genetic at all. It's about 10% or so heritable. Some microbes are genetic. But the vast majority seem
to just go with environment you live in and in your diet. That was important for us. Because it suddenly realised
the potential to change your microbiome is much greater
than to change your genes. Now, the other
thing we looked at was pairs of identical twins-- remember, these are
genetic clones-- where one was much bigger
than the other one. And you can't explain that
in terms of their upbringing, because they lived together
till the age of 18 generally. And you can't explain it
in terms of their genes, because they're identical
in every cell in their body. So this particular pair differed
by about 15 to 20 kilogrammes over most of their adult life. And when we added
up these pairs, we found that in
nearly all cases the skinny one had
more diverse microbes and had particular microbes
that liked them and not their sister. And there are a
couple of these that called Christensenella and
Akkermansia that we only found in the skinny twin. And when we looked,
about 10% of people have these
Christensenella microbe. And the people that
have it in high numbers always tend to be
on the skinny side. And some people reported
they could eat whatever they liked, snacking on things. They never got fat. Aren't they lucky? And when we took these
microbes from the twins and put them into mice we
could stop them getting fatter. Now, that shows you that it
isn't just an association due to being skinny
or being fat. But actually, it's part
of the causal pathway. And this is the clever
thing about gut microbes is you can do the
experiments in humans, but you won't know whether
it's cause or effect. And then you can
take those microbes, transplant them into these
animals and make them fat, make them thin, make them
depressed, make them anxious, do all kinds of stuff to them--
change their immune systems. And this is why we know that
they're so important and not just bystanders in
what's going on. So this is really important. And there are
companies now trying to experiment with these
microbes putting them into breakfast
cereals and things so everyone can eat as much
as they like and stay thin. They haven't
succeeded yet though. That's how to do badly. How can you improve
your microbes, I guess, is the other question. And I don't know if any of you
listen to the food programme on Radio 4. So I went with Dan
Saladino to Tanzania and an anthropologist
called Jeff Leach who's been studying
the Hadza, who are a tribe that have been
in this part of Tanzania for about 10,000 years,
possibly 50,000 years, in exactly the same way of life. So they're one of the last
hunter gatherers on the planet. And they have 30% or 40%
more microbes than we have, even the healthiest. And they don't get
chronic diseases. That don't get fat. They don't get diabetes. They don't get heart disease. They don't get cancer. They do fall out of trees
and have other injuries and infections, et cetera. But they didn't have any of the
sort of allergies or disease we have. So we think it's
their way of life. We think it's their microbes. And I went there for four
days to live with them, eat their meat, and
basically ate what they did-- no washing
facilities, obviously, in the middle of nowhere. And as well as a
fascinating time, I did manage to improve
my microbes by about 20% or so in terms of diversity. But there was only a
short-lived effect. So as I got back on
the airplane home and started eating
airplane food, I think everything dropped
back to where it was. So I need to stay
there a bit longer or keep going back
there for a top up. But it does show that by
changing diets and environment, you can actually improve, to
some extent, your microbiome. A bit about what the
foods are good and bad for your gut microbes. Everyone knows green vegetables
are good, high in fibre. And there are certain fibres
that are better than others. And the fibres-- well, at
least we've studied them more. And so the ones we've studied
is something called inulin which is particularly in vegetables
such as artichokes, both Globe artichokes and
Jerusalem artichokes also known as fartichokes that will
have masses of inulin, which the microbes break
down and convert into very helpful things
called short-chain fatty acids. So they're converting this as-- as I said, they're
chemical factories converting the
chemicals in the plants you eat into other
useful substances. So knowing which ones
these are-- onions, garlic, leeks all have very high
amounts of these in it. And also we know the
legumes are useful. And then we have things that
also have lesser amounts of fibre and have other
things that are important. So in the past we've been
told that drinking coffee is bad for you. Peanuts are bad for you. Red wine's bad for you. Olive oil's bad for you. But it turns out that
all these things-- and dark chocolate, bad for you. Turns out, the recent evidence
is that it's all good for you. But the reason it's all
good for you is not just we got it all wrong before. It's because they all have
some chemical component in them that the microbes use. And that's called polyphenols. OK so polyphenols
have been around. They used to be called
antioxidants, which was just a general way of
scientists and doctors pretending they knew what
they were talking about. Because no one
really understands why these things were helpful. It was just a general
word for things that mop up nasty things. But this is a much
better theory. Because these polyphenols, we
can't actually use ourselves, but for the microbes
it's rocket fuel. They love polyphenols. They break down. They get these polyphenols. They use them as energy sources. And they then convert that
into other helpful chemicals for the lining of our gut
and our immune system. So it's a good deal
basically we get. And that's why the
Mediterranean diet is particularly good
for you because of all these polyphenols,
despite the saturated fat that traditionally
we're told to avoid. And then we've got a few
other things in here. So you can see
some yoghurt there. How many people here
have yoghurt every day? Wow. Look at you. You're like a commercial. How many people here have kefir? Who hasn't heard of kefir? Kefir is the new super yoghurt. You will have heard-- now you've heard about it. You'll start seeing it now. It's interesting. When I my book first came
out a couple of years ago, no one had heard of kefir. And suddenly where I live in
Islington, it's in every shop. You can't move for bloody kefir. But basically it's
sour, fermented milk. And it has about five times more
microbes than the equivalent amount of yoghurt. So do get used to it. If you like yoghurt, mix it up
and start having that as a top up, if you want your microbes. How many people
here have kombucha? I've got you there. Kombucha is the next level. once you've mastered
kefir, you go to kombucha which is fermented tea. So basically you get a-- and it comes from Russia. And it's very big in California. But it's taken ages to get here. But it's a fantastic drink. And it has about two or
three times more microbes even than kefir. And you have fungi in there. But three times the fungi. Basically you grow
this mould thing. It's called a mother. It's a bit like a
sourdough mother. And you put in your tea. And after 10 days, it
converts the sugary tea into a really
refreshing drink that has a slight sour
acetic acid taste. It's packed with good stuff. OK. So we're diverging slightly. I could do the
whole kombucha talk. But just to show you that
these interesting foods all have this common theme. They're all really good
for your gut microbes either as fuel or as providing
actual microbes themselves-- these probiotics. Meat eaters, how many
vegetarians in the audience? Not many. That's probably generational. Now it's about one in six of
the population is vegetarian. Less a vegan, but a lot of
people are giving up meat. Because they say
it's bad for you. It's bad for the planet. They're partly correct. And most of the studies do
show a slight harm of red meat over not eating meat. But it's mainly processed
meat that's particularly bad. But some people maybe
don't eat meat, fine. It turns out your microbes
can determine whether you're someone who processes
meat in a healthy way or you produce waste products
that give you heart disease. And so they've done a
number of studies now that show that this is just
subtle difference in how our microbes break down some
of the carnitine in meat to other chemicals. It makes a big difference. And likely many other
examples of this what we call personalised nutrition. This was just to show you-- there was a headline a few weeks
ago that probiotics don't work. Remember that? No. Well, the idea that eating
yoghurt doesn't work, because all the
microbes get destroyed. Turns out that's partly true. That most of the
microbes get destroyed. But if you have
a billion of them they'll always be
100,000 or so that will get through and replicate. But they don't hang
around in your gut. Basically, they're there
to act as chemical signals for the others. They stimulate all
the other microbes. And you get a big
metabolic difference. So when we start measuring not
the microbes, but the chemicals they produce, we
see big differences between yoghurt eaters
and non-yoghurt eaters. And those same metabolites,
they produce the chemicals we've shown are actually
good at reducing some of the internal fat
using our twin study. So it's just another
way of looking at it. Thinking of them as
chemical factories makes you understand
a bit more why you're going through all this
and why so many of you are eating your yoghurt. Because you obviously
think it's good, despite the government
telling you it's got fat in it and you should avoid it. You should always
have the full-fat one, by the way, not the
low-fat one if you want to get most of the benefits. Now, just closing up, there was
a study a couple of years ago-- have you heard of
glycemic index of food? So this is on packets where
they tell you this is what the carbohydrate content is. And if you want to avoid sugar
spikes and things like this, you should pick low GI foods. But it turns out that an Israeli
group studied this and found that actually what was
more important than your GI index of your food was what
your microbes were doing. So for some people, what's
good turns out to be bad. So for me, if I have
grapes, my blood sugar goes up into a
diabetic range of 9.4. If I have bread, I shoot
up to about 11 or 12 which is not good. But I can have as
much pasta as I like. I can have as much
rice as I like. I can drink as much
beer or wine as I like. So I'm happy. As long as I don't
have too much bread. But I wouldn't know that if I
hadn't done my own experiments. And what we're
hoping is that we can start to measure people's
gut microbes in order to predict which foods they
should be preferentially having. So everyone should get
some personal nutrition. We've started this
huge study in the UK in our twins called
the Predict Study. And we've done 300
twins so far doing this kind of two weeks of
logging all their foods, looking at their sugars
with these glucose monitors. I've got one on at the moment. You can now wear
them for two weeks. This shows that one twin
spiked when they drank Prosecco and the other one didn't. And one spiked with rice
and the other one didn't. And these are just small life
choices that you can make. But if you thought
about this regularly, you would know this can make a
big difference over years just by changing what your lunch was
or what your favourite drink was. It's not like cutting
out huge food groups. It's just making small choices
that your microbes prefer. I found out that my average
lunch at the hospital was tuna sandwiches on bread. Thanks for Marks and
Spencer for 10 years. Because that's what
we had in the canteen. And I thought that was healthy. It's got a bit of
sweet corn in it. Turns out that was every single
time it was giving me a glucose spike and probably
responsible for me gaining 10 kilos over 10 years. If I'd known that
now, I would have been in much healthier position now. And so just these subtle
things of changing what that carbohydrate is
can make a huge difference to people's lives. So that's what my
particular research is going for in the next 10 years. Now, if all this has failed
and you can't work out how to improve, these tablets
might be the thing for you. They're frozen poo tablets. And you just have
to about 15 of them and you get a total makeover. The Americans call
them crapsules. They're always very good with
the short, snappy phrases. But they're no longer
a laughing matter. Because they are the number
one treatment for a very severe infection now called
recurrent Clostridium difficile infection. People have too many antibiotics
get recurrent infections and they can die. And people do die. But this has a 90% success. If you have a poo transplant
from someone who's super healthy and you're
very sick, 90% recovery, which is three times better
than the nearest current medical treatment. It also works for
ulcerative colitis to the same extent
as the latest drugs. And it's being tried in a
number of other conditions. And so we know very
little about it. It's a very crude
tool as you can imagine in more ways than one. And everybody's different. So clearly we may have to match
donors and recipients in ways we hadn't thought about. But they're using
it for all kinds of interesting treatments,
including treating diabetes and obesity, et cetera. So watch this space. Finally, just to
recap, I think if you can think of your gut
microbes with this garden analogy you can't go far wrong. It's a key aspect in nutrition. You've got to realise that
food is a series of chemicals. It's not carbohydrates, fat,
and protein and calories. Start thinking of
these as chemicals that react with
other microbes there to produce all this
these chemical reactions which you need. And everyone needs more fibre. There's certain more
polyphenols, more fermented foods. And we need to explore also
the reactions with medicines. Everybody reacts
differently with medicines as they do with
their foods as well. And so none of this is being
tested by modern science yet. We haven't caught up. And, really, there's
huge potential for personalised diets. And the one message I
want to leave you with is diversity,
diversity, diversity. The more you can do
that, the better. And realise with 100
trillion microbes inside you, you'll never truly
dine alone again. Thank you. [APPLAUSE]
