Gut Expert: Eating these 3 foods could improve your mental health | Tim Spector: Full Interview
Big Think
0:00 My name is Tim Spector.
0:02 I'm an MD.
0:03 I'm a professor of epidemiology at King's College in London
0:07 and I'm also co-founder of the nutrition and gut health company, ZOE.
0:12 Today on Big Think, I'm going to talk about the connection between what's going
0:17 on in your gut and your gut microbes
0:20 and how that affects your brain and your mental health.
0:22 I'll also be giving you tips about how you
0:25 can improve your gut health to improve your overall health.
0:35 Chapter one, how the gut microbiome works.
0:38 The gut microbiome I like to think of as as it's
0:42 like a virtual organ in our bodies that we've only recently discovered.
0:46 Something like discovering we had a liver.
0:49 And essentially, it's made up of trillions of little
0:53 tiny microbes that you need a microscope to see.
0:58 bacteria, fungi, parasites, viruses,
1:00 and other things we still don't exactly know about.
1:05 This collection forms a community mainly inside the lower part of our colon,
1:12 the large intestine.
1:13 They essentially need to be thought of as mini pharmacies.
1:18 They convert the food that we eat into chemicals,
1:22 into hundreds and thousands of different chemicals.
1:25 And those chemicals have this amazing impact
1:28 on our body that we're only just beginning to realize.
1:31 This collection of microbes has something like 200 times
1:34 more genes than we have in our own human cells.
1:38 That means they're much more versatile.
1:40 They're more flexible in what they can produce in terms
1:44 of chemicals and they're actually more numerous than our uh human cells.
1:49 This is important because we evolved from these bacteria and the very
1:56 first mammals and then humans were built because they contained
2:02 these colonies of microbes that could interact with them and without
2:06 these microbes we really wouldn't function
2:09 and particularly our brains don't develop normally.
2:12 So, one way to think about our gut microbiome is either
2:16 as a the environment of a jungle or an amazing natural zoo where
2:22 you've got these thousands of different species of microbes that have taken
2:28 over a little niche inside our gut that is very specialized to them.
2:33 They're not all fighting for the same food.
2:36 They've evolved just like animals have to get have very specific tastes.
2:41 The example I like comes from our own research where we
2:46 found there is one bug that only really eats or drinks coffee.
2:52 It is so fussy it hangs around maybe for years just waiting for that first
2:57 cup of coffee before it will replicate and really start to be noticeable.
3:02 If we start thinking of coffee as a great example,
3:05 then you think about all the other bugs that we might have lying
3:10 dormant in our guts that are waiting for us to eat something unusual,
3:15 say a bit of baobob or some beetroot or um
3:19 some particular type of of nut or herb or spice.
3:23 And so that's a really important concept because we
3:27 now know that the more diverse your gut microbes are, the healthier you are.
3:33 So that's why uh we need to be thinking
3:37 how can I best feed these very different gut microbes.
3:41 Some of which might like coffee,
3:44 others will only like uh the leaf of a bit of cabbage,
3:48 others uh might like seeds or nuts and others will
3:52 like the leftovers from what the other microbes have eaten.
3:55 And this is also a really
3:56 interesting concept because they they're working together.
3:59 They make sure there's no waste.
4:01 they are these perfect ecological beings.
4:04 So that the concept of waste doesn't really exist.
4:08 And what they've shown in some mouse studies is that um if you
4:13 uh have a really strong colony of gut microbes that are very diverse,
4:19 then you eat your standard diet, you have no waste left over.
4:24 But if you only have a few microbes,
4:27 rather poor uh colony, they're not very well diversified, you get leftovers.
4:31 And when you get the leftovers, then you get what we call the bad bugs
4:35 will eat those uh because they've got something to eat.
4:39 So a really good healthy colony of microbes, like a zoo,
4:43 is one where all the animals have a role, they've got something to eat.
4:47 Uh there's no real waste, and everything is used up.
4:51 It's really a marvelous model that we all love, a sustainable gut society.
4:56 Although we all have thousands of species
4:59 of these trillions of bugs inside our guts,
5:03 we're actually really different one to another.
5:07 And this is because as as kids uh when we're born, we're born sterile.
5:14 So, it's slightly random which microbes end up colonizing our own uh colons.
5:20 And it turns out that the average person only
5:24 shares about 20% of their gut microbes with another.
5:28 And even in identical twins, they don't share many more than that.
5:34 So it's a process that's part random uh
5:38 part uh designed that way and not very genetic.
5:42 This means that we all have a different
5:46 set of microbes producing slightly different functions.
5:48 Until recently, we didn't really know how
5:52 good bugs and bad bugs were interacting.
5:56 And it turns out they're fighting for resources.
6:00 The good bugs, these are ones that eat your, for example,
6:04 plants and change those plants into healthy
6:07 chemicals that your body can then use.
6:09 And that has a a health effect.
6:12 If they do well, they leave no food left over for the bad bugs,
6:18 by which we mean bugs that increase when you have a bad,
6:23 you know, an average American diet with fast foods and burgers,
6:26 etc., lots of fat, those ones will increase and cause bad outcomes.
6:31 So, it turns out that if you're only having a a a good diverse diet,
6:37 there's very little waste to supply the bad bugs.
6:40 This concept has changed quite recently because we used to be thinking
6:44 okay how do we get rid of the bad bugs that are
6:48 causing inflammation irritation in there but now we know it's focusing
6:53 on on the good it's increasing uh those guys as much as possible
6:58 essentially giving them a greater diversity of food so that everybody
7:03 gets something to eat and we can really use the full armory
7:07 of all those good microbes to produce the biggest possible possible array
7:12 of chemicals that the body can then use in the best way.
7:17 Chapter two, an unhealthy gut leads to an unhealthy brain.
7:21 When I started this research, we thought that the gut microbiome was really
7:26 just involved in things like obesity and metabolism.
7:30 And it's only recently we've realized that it does so much more.
7:33 I like to think of it really interacting in sort of three key parts of the body.
7:41 Yes, it does influence metabolism, energy levels.
7:44 It uh sends signals to the brain
7:48 about appetite and body weight and distribution etc.
7:52 and is probably important in things like type 2 diabetes.
7:55 But one of its key roles is acting on the immune system.
8:00 Our immune system is pretty crucial for virtually
8:03 every common disease that we're encountering at the moment.
8:07 From autoimmune diseases,
8:09 food allergies to things like preventing cancer by these our immune
8:14 cells killing off early cancers and the aging process itself.
8:18 So the immune system is a huge part of what the gut microbiome does.
8:23 And without a really good microbiome, you can't have a good immune system.
8:28 The third key thing that the microbiome
8:30 does is interact with our nervous system.
8:34 And it does this through a huge network
8:37 of nerves that are sometimes called our second brain.
8:41 They're as big as a cat's brain.
8:43 And they probably evolved around our intestine before even
8:46 our brain was formed as when we were in the womb.
8:51 And this network of of nerves connects
8:54 to the brain primarily through the vagus nerve.
8:57 This is like a fast internet cable that picks up what's going on in our gut
9:04 microbes through the gut lining picking up
9:06 signals in every single layer of the gut.
9:09 So right through to the the tiny connections right
9:12 on the inside of the mucosa through every layer.
9:16 So they are actively sensing everything that's going on there.
9:20 All these neurons interconnect.
9:22 They're picking up signals from the gut microbes that are sending chemicals such
9:29 as short- chain fatty acids which they make when they break down fiber.
9:35 They might be getting them directly from the microbes
9:37 or from the the cell wall of the microbes.
9:39 They might be getting it from uh some hormones that the microbes are making.
9:46 these endocrine hormone sensing uh cells in the gut lining
9:51 like GLP1 that's uh people now know is how ampic works.
9:56 They're picking up uh you know hostile chemicals, good chemicals.
10:00 Everything is is going through to these little
10:03 little tiny neuron endings and they're being fed
10:07 into this vagus nerve through this incredible cable
10:10 to our brain where it tells the brain what's going on.
10:15 This discovery has really changed our whole idea of the the gut brain axis
10:19 because we used to think the brain was telling the gut what to do.
10:24 Turns out most of the traffic is from the gut to the brain.
10:29 People conceptually thought the brain uh was separate to the body.
10:34 And this is the carteesian view really that has penetrated
10:39 and been very persistent in medicine for centuries and still
10:44 means the reason that psychiatrists and uh medical doctors don't
10:48 really mix and that we have separate hospitals and separate training.
10:52 And yet now the latest science is
10:55 showing that there really is very little difference.
10:58 The brain is just another organ.
11:00 It is not the brain controlling the rest of the body.
11:04 It is just another organ and it relies on the gut for most of its information.
11:11 Many people have vaguely heard about inflammation.
11:14 I was unusual because as a kid uh I heard about it
11:18 a lot because my father was a professor who focused on inflammation.
11:22 Before it was trendy and well it was trendy briefly then it went out of fashion.
11:26 Now it's definitely back and everyone needs to know what it means.
11:30 It's a normal response we all have to a threat in in our bodies
11:35 whether it's uh stress or it's an infection or something alien to us.
11:41 Our body responds.
11:43 It sends all these white cells from our body
11:47 to that site and triggers a whole careful
11:50 reaction that gets rid of that threat as quickly
11:54 as it can and goes back to normal.
11:57 Now, we currently have uh problem of what's called chronic inflammation,
12:01 which means it lasts too long.
12:04 So instead of getting a brief brief spike of uh
12:09 inflammation in response to a threat say some bad food uh
12:15 that returns to normal our bodies uh have become in some
12:21 way uh changed so that that threat level stays up.
12:26 So we are suddenly going through life
12:29 at a a a threat level that isn't our baseline.
12:33 That may be due to our environment of terrible food.
12:37 Uh it could be due to pollution, pesticides, all kinds of things.
12:43 But or it could be due to our stressful lives and social media.
12:48 Whatever the cause, it's true that in the west
12:51 we have stress levels based on the levels of inflammation
12:55 or our immune system that are higher than you would find
12:59 in Africa or India or uh where our ancestors came from.
13:02 I also learned a lot of it because I was a rheatologist originally
13:07 in my one of my early careers before I I changed several times and saw
13:13 patients with rheumatoid arthritis um autoimmune disease
13:17 who suffered a lot and they were constantly tired because of the inflammation
13:23 in their joints which spread to their bloods.
13:26 I didn't think much about it because we thought
13:30 they were tired and depressed because their joints hurt.
13:33 And that's really what we were told.
13:35 Oh, it's normal.
13:37 They are uh tired and depressed.
13:39 They've got quite bad crippling arthritis.
13:41 But it turns out it was just the reaction in the brain
13:46 to what was going on in the rest of the body.
13:50 We now know that many mental health problems,
13:53 virtually all of them have been studied so far,
13:57 have above average levels of inflammation
14:00 and they also have abnormal gut microbes.
14:04 So there's a link between uh mental health disorders which nearly
14:11 all of them have reduced energy and reduced mood to some extent.
14:18 even in forms like psychosis and schizophrenia or even in uh ones
14:24 you don't regard as mental health but brain problems like epilepsy or migraine.
14:30 This is also true.
14:31 So there's a general increase in inflammation in the blood.
14:35 There's also a general uh abnormality of the gut microbes
14:40 compared to uh people who don't have any mental health problems.
14:46 So we're seeing this picture developing whereby we are getting uh
14:52 much more common ground to explain this explosion in mental health problems.
14:57 That's that's based not on the old theory of uh
15:01 a deficiency in certain brain chemicals or an excess of brain
15:07 chemicals but due to this underlying inflammation which probably starts
15:11 in the gut and then sends those signals to the brain.
15:17 So an obvious question is where does this inflammation come from?
15:22 What's triggering the body to in a way overreact
15:27 and keep overreacting to stimuli rather than dealing with the problem,
15:32 getting rid of it, going back to the base state
15:35 which is what we know that our healthy ancestors had.
15:38 Inflammation is both a cause and a consequence
15:42 of many things we're talking about.
15:44 The most obvious cause in the west of this uh pandemic
15:49 of mental health problems is the fact that since the 1970s,
15:54 we've been eating uh an increasingly bad diet.
15:57 The standard American diet, the SAD diet, which is denuded of fiber,
16:03 it's plenty of saturated fats and it's full of ultrarocessed food.
16:09 All of which have been shown
16:12 in uh particularly mouse models to cause inflammation
16:16 in the gut of those mice leads to many more bad bugs compared to good bugs.
16:22 There's not much for the good bugs to eat.
16:24 The bad bugs take over.
16:26 They like an inflammatory environment
16:28 and they actually produce chemicals that will
16:31 stir up uh the gut lining and that environment to in a way
16:37 be more toxic and raise the levels of the immune cells in the body
16:42 that think in a way they're infected or diseased in some way.
16:47 So I think that's the unifying idea of how uh bad food on a long-term
16:53 basis causes this increase in the imu
16:56 the immune cells which you've got to remember
16:59 that the gut microbes probably by evolution are
17:02 there to pick up signals from the environment
17:05 tell the brain who that can't really
17:07 see outside the little skull what's going on.
17:10 Gives it an idea of what's going on.
17:13 It's this consciousness and it's picking up
17:16 these signals and if those signals are bad food,
17:20 inflammation, heightened you, fear, it's like,
17:23 gosh, there's something bad going on here.
17:27 Let's signal that back to the brain.
17:29 What does the brain do?
17:30 It goes into some sort of lockdown mode,
17:33 a sickness behavior, some people call it, which is quite natural.
17:37 It it's getting a signal from its main communicator,
17:40 the gut, along the vagus nerve.
17:42 It tells it all kinds of[ __] is happening down here.
17:46 This is not good.
17:48 We're getting really bad signals.
17:50 How do we react in evolution?
17:52 We'd say it's like an infection.
17:54 We lower our mood.
17:56 We lower our sociability.
17:57 We lower activity.
17:59 We tell the body we're tired, so we rest.
18:02 And that's what you get fatigue,
18:04 mood change, and all the other associated factors,
18:07 and you end up with what we're calling depression.
18:11 That's my way of thinking about this problem for perhaps the commonest
18:16 factor that's changed in our lives in the last 50 years.
18:20 And particularly why in kids, we're seeing this this pandemic at the moment.
18:24 kids that have had mothers that were had terrible diets that passed
18:30 that on to the kids and then basically they've had ultrarocessed
18:34 foods for the the whole of their lives uh without ever having
18:40 any real food to nourish any the few good microbes there are.
18:44 Only the bad ones have been surviving in that jungle uh just
18:48 on the fats and the scraps and the artificial sweeteners and the chemicals etc.
18:53 So I think that for me is the the key model.
18:59 You can also uh think of other ways that you might
19:04 get inflammation and my research in this area is not that I've
19:08 done it myself but looking at the the literature is that many
19:12 of the risk factors for mental health disorders are all the same.
19:16 So it doesn't matter which of these so-called 300
19:19 different disorders you have the risk factors are the same.
19:23 childhood stress, trauma, poor diets and um living in urban environments.
19:28 All of these things increase stress and they now know that that stress
19:34 you can see as an increase in inflammation in the in the immune system.
19:40 So just psychological stress can also cause this as well as uh
19:45 in a way dietary or gut stress end up with the same common pathway.
19:51 After a bad night's sleep or some stress,
19:54 your body seems to crave fatty and sugary things that are unhealthy.
19:59 And we've all experienced that after a a poor
20:02 night's sleep or a hangover or whatever it is.
20:05 You reach for the the one thing that you think you you need,
20:09 but it turns out you're wrong.
20:11 Your brain's given you the wrong directions,
20:13 and this is going to make you probably feel worse.
20:16 So this sort of explains this loop people
20:19 get in particularly uh with depression or anxiety.
20:23 The brain is telling them to do one thing that actually is making it worse.
20:28 And so it really explains why people with low mood and depression end
20:32 up eating badly and can't get out of it and it's making them worse.
20:37 hadn't really thought about the gut brain connection quite as much.
20:41 But about nine years ago, my mother uh suffered a stroke.
20:45 She ended up uh in a care home with uh dementia.
20:50 Each time I visit her, you know, I am reminded of the fact that so many
20:57 of us now are potentially facing this fate in old age.
21:02 And it's not something that anyone really wants.
21:06 dementia is probably the the worst way to go.
21:09 So, it's made me think about this more and start
21:14 to look how my own research could potentially have
21:19 an impact or help not only myself but other
21:24 people prevent dementia or at least delay it uh considerably.
21:28 It turned out my mother with her stroke
21:33 and subsequent acceleration of dementia probably had what's called
21:37 vascular dementia which is a fairly general term
21:40 that affects about one in three people who get dementia.
21:45 It's the second commonest form and it tends
21:49 to occur in phases so that the blood supply
21:53 to the brain is getting progressively diminished and knocked off
21:58 probably by atherosclerosis in the arteries uh supplying the brain.
22:04 The other type of uh dementia that many
22:07 people hear about is Alzheimer's which is
22:10 probably the commonest form of dementia perhaps affecting
22:13 uh 60% of all cases and it can start in a similar way with uh loss
22:21 of memory or cognitive function and then progresses
22:25 uh at a m usually a more sustained
22:29 pace um that doesn't have these separate phases.
22:33 is and that's caused slightly differently it being distinguished by having
22:38 these protein folds in the brain these amaloid and these towel
22:42 proteins that have led to some of the damage in the brain
22:46 as the brain has been shrinking now we don't know
22:49 they are causal it could be that these proteins just are
22:54 part of the damage after it's occurred but we believe that there
22:58 are some common causes of both these types of dementia
23:03 that the risk factors seem to be quite similar in both cases.
23:07 We can link this back to gut poor gut health.
23:11 the picture of gut health that uh where you
23:14 have a low ratio of good to bad bugs,
23:18 you've got poor diversity of species and you got an inflammatory
23:22 component going on there is a major risk for both types
23:26 of dementia as is things like type 2 diabetes which probably
23:31 is involves the energy supply to the brain which affects both.
23:36 So for practical purposes,
23:38 you should be trying to prevent both kinds of uh dementia because they have
23:43 a big overlap in the causes although they can look very different at the end.
23:49 So we have gut microbes all through our intestinal tract and that re means
23:55 from our mouth to our anus and some bits are harder to access than others.
24:01 It's very hard to know what's going on in the middle bit,
24:06 the small intestine, because it's very hard to reach.
24:09 And so we rely generally on what's happening in stool samples,
24:12 but we also can look at what's happening in our mouths and our saliva
24:17 where which is teeming with microbes that are there basically to protect us,
24:22 but also start the first bit of digestion of food.
24:26 And just like in our colon,
24:29 there's a little colony of microbes there that uh interact with each
24:33 other and you have good ones and you have bad ones.
24:38 And if you provide an environment that uh doesn't clear away your food,
24:45 leaves food waste, the bad bugs will
24:47 accumulate and they can lead to inflammation.
24:50 And this tends to happen um at the interface between your teeth and your gums.
24:55 And we know that gum disease is very prevalent in in the west.
25:01 Perodontitis and specific bugs absolutely love the environment there.
25:06 You get slight redness and swelling which is a sign
25:10 of inflammation and you can generally see it there.
25:13 Your gums might be slightly tender, might be swollen, might be red.
25:17 And in certain cases, they will bleed if you uh floss them or brush them hard.
25:22 That's a sign that you've got inflammation
25:25 there that they're bad bugs living there, eating the bits of food.
25:31 They form plarkes.
25:32 And a plaque is a a complicated structure that's made
25:37 by these microbes that builds up like a protective shield.
25:41 So that in a way they can keep uh digging away,
25:46 eating things uh and they're protected from you uh brushing them away.
25:51 So our teeth, it turns out, are a really good place to look for inflammation.
25:57 And remarkably, we we we learned about 10 or even
26:02 15 years ago that dental decay was related to heart disease.
26:06 And there were certain microbes they found very early on.
26:10 I think it was strep mutans is
26:12 associated with uh increased risk of heart attacks.
26:15 This was very strange when that first came out.
26:18 I remember now we were able to look much more broadly at all the microbes.
26:22 We know that poor uh mouth uh hygiene means
26:26 high rates of bad microbes compared to good ones.
26:31 These are pro-inflammatory.
26:32 And if you're not brushing and flossing your teeth,
26:36 you have roughly a 25% increase in heart disease.
26:41 And some studies are showing anything between 20
26:44 and 50% uh increase in uh dementia and cognitive decline.
26:50 So suddenly we've got a really good example
26:55 of how um uncontrolled inflammation in our bodies
26:59 can have a direct effect on areas we
27:03 hadn't really thought linked at all like our brain.
27:07 I think this gives people the idea uh of how important it is
27:12 and how preventive action can work because
27:15 if you then brush your teeth regularly, you'll reduce that risk perhaps by half.
27:20 So rather than 50%, you're down to 25%.
27:23 But if you then floss um which is gives you an extra
27:27 say 30 or 40% of cleaning you do that really well
27:32 and you can get rid of the plaque and get rid
27:35 of the bleeding and the the inflammation you can get right back to zero.
27:38 So I think this is a marvelous example of how we need
27:42 to battle inflammation in our bodies really to save our brain health.
27:45 Well it's hard for the average person to know what their gut health is like.
27:50 Basically, it means that your uh your trips to the toilet are regular.
27:56 You look at your stool and you see, is it fairly soft?
28:00 You don't want to be a cowpat.
28:02 You don't want to be a sheep dropping.
28:05 You want something in between and you are going once or twice a day.
28:10 If that's the case and you're not getting any bloating
28:14 and you're not having constipation or diarrhea or, you know,
28:18 a lack of regularity, then you're probably pretty healthy.
28:21 If the opposite is true and you're having any of these problems,
28:25 your stools look rather strange, they're, you know, they're varying,
28:29 you're only going once or twice a week, then it's highly likely you have uh gut
28:35 problems and uh you need some dietary help.
28:38 We talked earlier about thinking about your mood and energy.
28:42 Are you fatigued?
28:43 Is your mood lower than it should be?
28:46 Are you getting uh some bloating?
28:48 These are signs you do have gut health issues and you should address them.
28:54 Improving your plant intake will improve your fiber.
28:56 You know, do a bit of exercise, have some more water, etc.
28:59 Having done that, if you want to test your gut microbiome,
29:02 which I think will be standard of care in five years time,
29:06 it's very difficult at now to know who to go to.
29:10 Your general family physician may or may not be able to help.
29:14 A functional uh medicine doctor probably will,
29:16 and we're seeing more of those more holistic type of uh doctors appearing,
29:22 but uh it's not something that's very easy to do.
29:26 But I think a good gut microbiome test is much more
29:30 useful to you than getting your your genes tested or your DNA.
29:35 It's really your metabolic blood pressure.
29:38 Um, if your gut health is good,
29:39 most of the rest of you is going to be pretty good.
29:42 And if it's bad, you're going to have problems.
29:45 Chapter 3.
29:46 Eight tips for maintaining a healthy gut ecosystem.
29:51 The old way of thinking about nutrition is the way I was taught and doctors are
29:59 still being taught is that essentially there's only
30:02 four things you need to know about nutrition.
30:06 It's calories, how much fat there is,
30:08 how much protein there is, and how much sugar there is.
30:10 If you get those four things right, everything else will follow.
30:14 We've been following that advice for the last
30:18 40 years and it's been a complete disaster.
30:22 It doesn't make sense scientifically anymore.
30:25 Uh it's only really helped the food companies uh sell us more crappy products
30:31 and it's led to a disaster uh of unbelievable scale for the public health.
30:37 Real food, unlike fake food that is made just from a few ingredients,
30:42 contains thousands of chemicals.
30:44 And all of these uh play a role
30:47 in our body because they then nourish the trillions
30:51 of microbes inside our gut to produce thousands
30:54 of other chemicals that our body can't produce.
30:58 It's only by focusing nutritional health guidelines
31:02 on this new organ in our body, our gut microbes, that it all makes sense.
31:06 We have to have a seismic shift in our idea
31:10 about nutrition in order to make healthy progress and focus
31:14 on gut health and what are the key principles
31:18 to improve all of our gut microbes which will help us.
31:21 As I've been studying the gut microbiome, I've been obviously thinking of how I
31:27 can translate that science into progress and practical
31:30 tips for people in various ages and states
31:33 of how they can improve their gut health.
31:36 The first one is what we call mindfulness.
31:39 And this seems a bit strange.
31:41 What what's he talking about mindfulness for?
31:43 Well, I remember when I uh started to change my diet, I decided to be vegan.
31:49 It was an easy way to change your diet.
31:52 as a a temporary fix if you like because
31:55 it meant that when I was going to medical
31:58 conferences I would stop and think before I
32:00 just took something from that tray from that buffet
32:04 I would say what's in it uh was there meat in it or is there dairy in it
32:10 and we don't need to be that extreme all you need to do is to think about what
32:16 you're eating just for a second before you grab it or you put it in your mouth
32:22 So mindfulness in this context means just stop
32:25 and think am I hungry do I need this what's in it you know and what what are
32:32 those contents are they going to uh have an effect
32:35 on me and then what effect is that going to have on me if I do eat them.
32:40 So these sort of three steps that I think are important in mindfulness
32:44 is an important realization that food is much more than just calories.
32:48 uh is it going to affect my mood?
32:51 How am I going to feel in three hours time?
32:54 Uh what what are the long-term consequences?
32:56 But also, is it going to be really tasty?
32:59 Am I going to really enjoy it or am I just being forced
33:03 by marketing by big food to eat this rubbish that I don't really want?
33:08 So there three uh steps in this this concept of mindfulness.
33:13 We just want people to stop and think.
33:16 That's number one.
33:18 So the second principle, probably the most important that we've found
33:23 scientifically is to eat a diversity of plants.
33:27 It's not about eating the same plant many times a week.
33:32 We think that the science is pointing us to is something
33:37 around 30 different plants a week gives you optimum gut health.
33:40 This is a study that I took part
33:42 in with the British gut and the American gut about 10 years
33:45 ago where we saw that the sweet spot for gut
33:49 health was people eating around 30 different plants a week.
33:53 It looks like it might be slightly more than
33:55 that, but certainly 30 is a really good target.
33:57 It turns out it doesn't matter if you're vegan or vegetarian or an omnivore.
34:04 It's the people that eat the most plants have the healthiest gut,
34:07 which I think is is really interesting.
34:09 30 plants to many people say that sounds way too much.
34:13 The average American probably has between 10 and 12 plants a week.
34:17 How do I get, you know, how do I get over double that?
34:21 Well, you got to remember what a plant is.
34:24 It's a it's not only a fruit and a vegetable, but it's also a nut.
34:28 It's every different type of seed.
34:31 It's an herb.
34:32 It's a spice.
34:33 It's even things like coffee, which is a fermented bean.
34:38 So when you just change your mind a bit about what plants are,
34:43 then it becomes easier and fun to add them to your plate.
34:47 Think about more rather than less.
34:50 Most diets are all about excluding things.
34:52 And what we're trying to do for our gut health is to in include more things.
34:57 We've got little microbes just waiting around for that bit
35:02 of baobob or that particular nut or seed or berry.
35:06 uh the chemical that comes from it.
35:09 So the more you can give your gut microbes, the better.
35:14 My third guideline is to eat three fermented foods daily.
35:20 So I've spent the last three years researching
35:24 fermented foods and have a book on that subject.
35:27 And what was really interesting is I I didn't think it was a topic
35:31 worth discussing three years ago because the science wasn't really up to it.
35:36 But I've been convinced by a couple of studies.
35:39 The first was from my colleague Christopher Gardner at Stamford,
35:43 a very detailed but small study of adults
35:47 who were told to eat five fermentss a day,
35:50 comparing that group to a high-fiber group.
35:53 And what they showed was that not only
35:56 did the gut health improve in the fermented
35:59 group particularly the immune system was impacted
36:03 and they had around 25% less inflammation.
36:07 So suddenly moving from anecdote and lots of small not very good studies
36:12 in the literature uh that were all
36:14 pointing the same way that fermented foods were
36:16 good for you to suddenly a mechanism that this can really impact your immune
36:20 health in different ways to just rather
36:22 than just eating lots of fiber and plants.
36:25 People think what is a ferment?
36:26 A fermented food is something that's
36:28 been transformed by microbes into something better.
36:31 So you transform milk into cheese much more interesting than milk.
36:35 You transform grapes into wine.
36:38 Uh you're transforming cabbage into sauerkraut.
36:42 So think the 4Ks.
36:44 Keir, uh kimchi, kraut, kombucha.
36:47 Kombucha is uh fermented tea, which is all really good for you.
36:53 Most cheeses, if they're not, uh made artificially in in in factories, are good.
37:00 Yogurt is great.
37:02 All the soy products that you see in[ __] Japan, miso paste,
37:06 all these krauts and pickles that are fermented in salt are really good for you.
37:12 So variety is important.
37:14 They've all got plenty of different
37:16 microbial species and they're probably better
37:18 for you than just taking probiotics from the pharmacy or the drugstore.
37:22 So my recommendation is to build up to three fermentss a day
37:26 as an extra boost for your immune system and your gut microbes.
37:30 a big fan of fermented foods now because the science has finally caught up.
37:36 The fourth guideline is to diversify your protein.
37:40 We're going through a protein craze at the moment
37:44 where every product has added protein in it.
37:48 Every uh American thinks they're deficient in protein.
37:52 And um there's nothing wrong with protein.
37:56 It's not particularly harmful.
37:57 But if you don't uh need it, you lose it.
38:01 You can't store it.
38:03 So you pee it out or it gets converted to fat.
38:06 If you are trying to get more protein and perhaps
38:10 10% of people are lacking in protein because they're unwell,
38:14 they might be elderly.
38:16 They're uh trying to uh build body mass or try and not
38:20 lose it too much as they're on the these um weight loss drugs.
38:24 Then my view is you should be trying to think
38:28 about other protein sources rather than just uh red meat.
38:32 The one that comes to mind are beans and lentils uh things
38:37 that have really high protein content but also contain lots of fiber.
38:41 This means your microbes can actually use
38:44 that at the same time as your body's getting that protein.
38:48 So that's a real reason why we should be switching
38:51 eating many more beans and pulses than we are currently.
38:55 They're very cheap, they're accessible,
38:57 they're good for the planet, and our microbes love them.
39:02 Guideline number five is focus on quality, not calories.
39:07 For decades, we've been obsessed with the calorie as the main
39:12 source of describing food and nutrition about whether it's healthy or not.
39:18 There are hardly any uh nutrition scientists who
39:22 now believe in the dominance of the calorie.
39:24 It's only a tool for the food companies to make rubbish food
39:29 uh seem more healthy because it is lower in this magic term.
39:35 The science tells us that these uh in the vast majority of people fail.
39:41 It's really impossible for most people to follow
39:44 a calorierestricted diet for more than a few weeks.
39:48 And even if they do lose weight, as most people do,
39:52 uh virtually everybody regains it because
39:55 your body's appetite signal is turned up.
39:58 The brain has finally tuned to know if you're uh not getting enough
40:04 energy and it switches up its thermostat to ramp up your hunger signals.
40:10 Your body is designed by evolution to overcome that pure uh calorie signal.
40:15 The other problem with calories, not only the fact that it's it's virtually
40:20 impossible to calorie count and and lose weight,
40:24 is that it disguises the food in ways that gets
40:28 us to stop thinking about the quality of what we're eating.
40:31 And that's what the food companies have been
40:34 doing for the last uh 40 or 50 years,
40:38 trying to switch our thought away from the fact that they are just
40:43 making this uh crap food out
40:45 of a few ingredients that have government surpluses,
40:48 away from the food we should be eating, which are whole foods,
40:52 which is what our gut microbes want to eat.
40:55 They want to eat a variety of foods that are in their original
40:59 state that have the the casing uh that contains most of the fiber.
41:04 They want the skin on it.
41:06 This is where most of the nutrients and ingredients are
41:10 that uh we need for our bodies to work really well.
41:13 This is a really important step as people
41:17 um try to disregard the calorie which effectively
41:21 doesn't have a major role in our any
41:25 of our plans and we ignore the calorie completely.
41:28 So tell people it doesn't matter.
41:31 It's all about the quality of the food,
41:33 how it's going to impact your gut microbes.
41:35 And once you do that, it's very liberating for people
41:38 to think I don't have to worry about this.
41:40 And generally, if something's got low calorie on it, it's a poor quality food.
41:45 You should be avoiding it.
41:47 Number six, avoid high-risk processed foods or high-risisk ultrarocessed foods.
41:53 These are the foods that make up 50 to 70% of the American diet hire in kids.
42:01 And most those foods are really harmful for us.
42:05 There isn't a universal definition of an ultrarocessed food.
42:09 We think that ultrarocessed food itself is is too broad a term because
42:13 it most people use as anything that has got an additive in it.
42:17 Some of those additives can be like vitamin C,
42:20 therefore not particularly bad for you, whereas others are are dreadful.
42:24 And the worst ones, the ones we categorized that make up 25% of uh
42:30 the American diet have a number
42:33 of components that make them particularly harmful.
42:36 Remember, these are foods that are mainly
42:39 made from cheap ingredients that are government
42:43 subsidized like uh like maze uh like uh soy and uh wheat and sugar.
42:52 These are things that are plentiful and taxpayers are paying
42:56 for them to be cheap and they have surplus of it.
43:00 So they've got to make create foods
43:03 with them and they do that really effectively.
43:05 and they try and upsell them by adding additives to them that change
43:10 their color and they change their texture and they change their taste.
43:16 And some of these additives are not too bad.
43:20 Others are quite unhealthy and others are really unhealthy for us.
43:24 Some of them are associated with cancer.
43:27 Some of associated with mental health problems in kids.
43:30 You have emulsifiers which glue them together
43:33 which are bad for our gut microbes.
43:36 You've got artificial sweeteners which uh many of them
43:39 develop from the petrochemical industry which our bodies are
43:43 not used to that cause our microbes to produce
43:47 funny strange chemicals in response and are generally harmful.
43:51 You've got others that we still don't know how bad they are.
43:56 That that's the additives.
43:58 Then you've got uh the hyper palatability
44:01 that the companies use a mixture of salt,
44:04 sugar, and fat in those combinations to make
44:07 that food override your normal fullness signal.
44:11 So they do this very deliberately.
44:14 We all know we've eaten a big bag of chips or whatever
44:18 it is in front of the TV and it's it's got potato, which is starch in it.
44:24 It's got um salt.
44:26 It's got usually um some some uh fats in there and it's that sugar, salt,
44:33 fat in the perfect combination that these brilliant
44:36 food scientists have created that will tickle
44:38 our brains into uh thinking we can keep eating them and we just don't get full.
44:44 So hyper palatability is a component of 70% of these foods.
44:48 The other component that you need to be looking out
44:52 for is is it something that you can eat super quickly.
44:56 Uh its structure has been taken away.
44:58 So you strip off all those bits of plants that make it
45:02 necessary to chew it and you've just got the inside uh bits.
45:05 So we end up eating baby food.
45:08 They melt in your mouth, dissolve away.
45:10 You can keep eating them without even noticing it, without exercising your jaw.
45:16 And then finally, the best from the food company's point of view are
45:20 foods that you can get lots of energy in really quickly without noticing it.
45:25 And this is called calorie density.
45:28 The worst offending foods have those.
45:30 So these are the the four categories.
45:31 The ones to look out for are the ones that have all of those components.
45:36 And that makes up 25% of the American diet.
45:39 breakfast cereals uh for kids, uh most children's yogurts,
45:44 um most savory snacks, most cookies,
45:48 uh most ready meals, most u sodas and drinks, even if they are low calorie.
45:55 So, not only is it bad for your gut microbes,
45:59 it's also going to make you uh keep eating
46:02 and become obese and have all those problems of diabetes, etc.
46:06 I don't think it's realistic to cut them all out completely.
46:10 And my view is that yeah, you can still have the odd uh treat,
46:16 but don't have any of these as a regular part of your diet.
46:21 Number seven, try and eat the rainbow.
46:23 You may have heard that before, certainly been around a while,
46:27 but we now know why it's good to eat the rainbow.
46:31 Rainbow plants and uh especially fruits and vegetables have rich colors.
46:36 And that's what we're looking for when we trying to select something
46:39 to put on your plate is to try and get as bright
46:43 and as varied as possible because plants that have these bright colors
46:47 tend to also have high levels of a defense chemical called polyphenols.
46:53 Plants like humans, you know,
46:55 have a defense mechanism and this is their defense mechanism.
46:59 They are fighting off insects and sunlight and d dr dr
47:01 dr dr dr dr dr dr dr dr dr dr dr
47:02 dr dr dr dr dr dr dr drought etc with these chemicals
47:04 that turn out to be actually very good for us.
47:07 They used to be called antioxidants which is a rather vague scientific term.
47:12 We now know that our microbes can use these polyphenols as a form of fuel.
47:18 If they're getting this, it's like they're getting extra gasoline.
47:23 And so this engages all our microbes to be healthier.
47:27 So as well as breaking down the fiber in the these plants,
47:31 they're also getting these extra chemicals which is acting
47:34 as a fuel which makes them even more productive.
47:37 So nature's given us these clothes, bright colors.
47:41 For example, you got a store uh you got
47:44 an iceberg lettuce there and you've got a rosolo,
47:48 an Italian one with lots of purple uh leaves on it.
47:51 always go for the brightly colored one
47:54 that will have a thousand times more uh polyphenols
47:59 than the uh ubiquitous iceberg lettuce whose only
48:04 advantage is that it stays forever in your fridge.
48:07 It has no nutritional value other than that it
48:10 will come still be there after your vacation.
48:12 The other clue in nature is they can be bitter as well.
48:16 So, slightly bitter tasting plants like your broccololis,
48:20 the cruciferous vegetables.
48:22 Uh, nuts and seeds.
48:23 You've got uh extra virgin olive oil,
48:26 which is my oil of choice, is really high in polyphenols.
48:30 The best ones will make you slightly cough,
48:33 and you want them to be really nice and young.
48:36 You've got dark chocolate.
48:38 over 70% is generally healthy because that cacao bean has really been
48:43 um fermented and is uh really strong in polyphenols as is coffee.
48:49 If you like a drink uh the the the only one I'd recommend for your gut
48:54 health is probably red wine which has
48:56 high levels of polyphenols uh again in moderation.
49:00 So they're the tips that nature's given us uh to identify
49:05 why eating the rainbow and bitter foods are actually good for us.
49:11 The final tip is try and give your gut a rest.
49:16 And by that I mean timerestricted eating.
49:19 20 years ago and certainly when I was at medical school
49:23 was the idea that we should be uh grazing not feasting.
49:27 Things have now changed and we now realize that constant
49:32 grazing is what your gut microbiome doesn't like at all.
49:36 We know how important sleep is for our health.
49:39 Uh getting eight hours a night can really extend your lifespan,
49:43 improve your immune system.
49:44 Well, the same is true for our gut microbes.
49:47 They have a circadian rhythm.
49:48 They actually go to sleep and they need this time to repair the gut.
49:54 So if it's eating all the time
49:57 and you're having late night snacks, early breakfast,
50:00 they're not getting the natural time they need that our ancestors
50:04 had for millions of years to clean up our gut,
50:07 particularly the lining of the gut where the mucosa is.
50:11 This is really important as an immune barrier and the healthier that is,
50:16 the healthier generally our immune responses are.
50:19 So give your gut 12 to 14 hours to recover
50:22 overnight and this is the basis of timerestricted eating.
50:26 The way timerestricted eating seems to work is through a number of mechanisms.
50:31 The first is by leaving that gap uh in time your microbes are not
50:37 focusing on eating and you have a a defense team that comes out at night.
50:42 A bit like in American football you
50:44 have a different teams for offense and defense.
50:47 defense comes out.
50:48 It cleans up the lining of your mucosa.
50:51 That tidies up the gut lining, makes it more efficient, helps the immune system.
50:56 You're also getting metabolic advantages so that uh your gut health is
51:00 generally better the next day because it's all been tidied up for you.
51:03 There isn't that much debris lying around
51:06 and you get less unhealthy bugs over time.
51:09 It also seems to be uh better for your mental health.
51:13 A lot of this is uh anecdotal, but we did do a large study in ZOE
51:20 of 140,000 people asked them to do timerestricted eating.
51:23 A third of people hated it.
51:26 They were snackers and they just found it really difficult.
51:30 A third loved it.
51:31 They're still doing it years later.
51:33 And what we we learned was the people
51:36 that that were adhering to it had improved mood,
51:40 energy, and less hunger from doing it.
51:42 So there do seem to be other benefits that we still uh are looking at.
51:47 And it also helps you avoid snacking and we know that uh mindless snacking
51:52 accounts about 25% of calories in in in the United States and the UK.
51:58 So it just makes you a bit more thoughtful about what
52:01 you're eating if you're trying to give your gut microbes a rest.
52:05 Timerestricted eating is a form of intermittent fasting,
52:08 but you're not restricting calories.
52:09 you're just eating the same food you would normally eat,
52:13 but in a more limited time frame.
52:15 So, for people wanting to give it a go,
52:17 I would say the easiest thing is to start
52:20 with a little rule like leave at least 2 hours
52:23 before going to bed where you're not eating anything
52:26 else except maybe some black tea or or or water.
52:29 That way, your gut will have a chance to recover
52:33 and hopefully you'll notice the difference the next morning.
52:36 And if that works, then you can extend it and maybe say, "Okay,
52:40 I can try this uh for a 12-hour overnight
52:43 fast as well." We are moving to the idea
52:46 that many people can do very well just having two
52:49 main meals a day or maybe combining breakfast and lunch.
52:53 The concept of brunch many people are enjoying around the world and see
52:57 actually I feel quite good at the weekend when I do that.
53:00 I don't necessarily need to eat first thing in the morning.
53:03 And I think we're realizing that this this idea of three big meals
53:08 and maybe three snacks events has been forced on us by the food industry.
53:13 Mr.
53:13 Kellogg was probably the first one to say that everyone had
53:17 to have a breakfast before doing anything otherwise you'd be unable to work.
53:22 It's Kelloggs for breakfast [music] and a happy happy day.
53:27 I personally find, you know,
53:29 I'm doing this interview now and I decide not to have breakfast
53:35 because I'm actually sharper uh when I haven't eaten just before it.
53:40 So, for me, uh two or three meals,
53:43 no major snacking events, eating relatively late.
53:46 I eat until [snorts] say finish eating maybe 8:30 at night and then
53:51 will try and not have anything to eat before about 10:30 the next morning.
53:56 That suits me.
53:57 When we asked the 140,000 ZOE members what they preferred,
54:01 they found two-thirds preferred that same rhythm.
54:05 One-third uh couldn't miss breakfast.
54:07 They said, "I really like my breakfast.
54:09 I'm hungry when I get up.
54:10 I want to have my breakfast but then I'll finish eating around
54:14 uh 6 6:30 and so people have different rhythms as we discovered.
54:20 I think there is a bit of personalization to this and you have to find the one
54:24 that suits you but my advice would be don't
54:27 follow what the big food companies want you to do.
54:31 Uh do experiment find out what works for you and follow that.
54:35 So there you go.
54:37 There are my eight guidelines.
54:39 The key message is you got to eat for your gut microbes.
54:44 If they're happy, you're going to be happy.
54:47 Chapter four.
54:48 Why the internet gets dieting all wrong.
54:51 I think it's very hard at the moment
54:54 for the average public who's not a scientist,
54:57 not a doctor to know what to do for their health.
55:00 Reports, you know, one day that coffee is bad for you,
55:04 another day coffee is good for you.
55:06 Uh eggs are good for you.
55:08 one day and eggs are bad for you.
55:11 Public has to realize that the media
55:14 thrive on these stories on these scare stories.
55:17 Uh they love food stories.
55:19 So you know our newspapers and social media are full of all this stuff.
55:24 So the the key is to not overreact
55:27 and to realize that your core diet is the most essential
55:31 and that if you are looking after your gut microbes
55:35 and you're doing most of those those eight things we discussed,
55:40 it doesn't really matter what else you do or don't do because the majority
55:45 of your plate every day is going to be full of good stuff.
55:48 Whether you have eggs, whether you have coffee,
55:50 whether it's good or bad is not going to be crucial to your health.
55:54 What is crucial is that majority of the time you're doing the right thing.
55:59 80% rule is what I love is you 80%
56:02 of the time you're doing uh things right and you
56:05 don't worry about the odd time the you may
56:08 have the odd trip to McDonald's once a month.
56:11 If your gut health is good, it will cope with the rest.
56:15 All good scientists should change their minds when the data changes.
56:20 And I've made lots of mistakes in my career.
56:23 Most of it not my necessarily my fault.
56:26 There was some data on margarine being healthier than butter.
56:29 So I changed our fridge back, this is 20 years ago,
56:34 to having these low-fat spreads and kicked out the butter.
56:39 My wife objected.
56:41 She's she's uh French speakaking so she wouldn't have any of it.
56:44 She kept the butter so we had separate compartments.
56:46 And I realized that I I got it wrong
56:50 and now there's no low-fat artificial ultrarocessed spreads in my fridge.
56:54 So I'm constantly changing my view on many of these things.
56:59 I'm much more open-minded than I think I was before.
57:02 So it's an exciting time uh to be a scientist.
57:06 I think what is important to realize is that science is moving on at a pace.
57:12 It takes on average 20 years for doctors to change their practice
57:17 from the time that uh a new uh scientific discovery has been uh proven.
57:23 So there's a big lag between what the latest science is delivering and what
57:29 the latest practice is or what your insurance is going to pay for etc etc.
57:34 the public is stuck in the middle here.
57:37 And I think what's important is to see when there's a consensus,
57:41 when there have been a number of studies that are all pointing
57:44 in the same direction and they've got
57:45 someone they trust that is telling them yes,
57:49 the summary of this data convincingly is saying you need to do this.
57:53 I think the lesson here is that the public needs to up their game a bit to be
57:58 a bit more educated to know that I can create any outcome I want in a test tube.
58:03 You need to disregard that.
58:05 I can do the same thing in mice.
58:07 That would probably be pretty irrelevant.
58:09 Getting people to think, has this been tested in humans?
58:13 Was there a placebo arm?
58:15 Is this really going to change the practice of most people without
58:19 just jumping on every bandwagon that people want you to to jump on?
58:23 At the same time, realize that the guidelines
58:25 that are out there from government, etc.
58:27 are very behind the times.
58:29 and realize that uh a lot of the stuff people might be
58:32 seeing on social media is probably too far ahead of the time just
58:36 so someone can talk about a test tube study or a mouse
58:40 study that sounds exciting or wacky or uh accounts for some weird theory.
58:45 There's lots of people on to looking at paleo diets or keto diets,
58:49 people who only eat meat or people who only have really
58:53 high levels of fat above 70% that claim miraculous benefits from it.
58:58 Most of these diets work shortterm
59:01 because if it's away from ultrarocessed foods,
59:03 then generally it's going to be healthy uh to that extent.
59:07 And so people who go on a carnivore diet,
59:10 which is a an idea of what our ancestors ate, uh,
59:14 a very selected idea of what our ancestors ate,
59:17 they will feel benefits for a few weeks, might lose usually lose weight.
59:22 Those people will then tell everyone about it.
59:25 Isn't it amazing?
59:26 People who go on very strict gluten-free diets, keto diets,
59:30 carnivore diets, seed oil free diets like the idea of excluding things.
59:34 So that suddenly you're belonging to this club
59:37 of people that are excluders and that's perhaps
59:40 the attraction and that's why most religions have
59:43 some food based ideas that keeps that community together.
59:47 So they they become a little group,
59:49 they feel better for the first six weeks and that's when the problems start.
59:55 So, a they might be very hard to sustain like a keto
59:59 diet is really hard to sustain those high levels of fat.
1:00:03 Most people feel rather sick.
1:00:04 And long-term your gut is suffering.
1:00:06 Any restriction to the amount of plants that are going into your gut
1:00:11 will start to have an effect of killing off the good
1:00:15 ones and making the uh overgrowth of the bad ones that are
1:00:20 just uh eating the scraps of what of what you're eating.
1:00:24 And so long-term you have immune problems uh and gut health problems,
1:00:28 mental problems down the line.
1:00:31 So I think uh exclusion diets will work short term and people
1:00:37 might want to do that as an experiment to see how they feel,
1:00:40 but then they've got to long-term
1:00:42 start looking after their long-term gut health,
1:00:44 which is the thing that's going to keep
1:00:46 them alive and keep them free of diseases.
1:00:49 What I like about our message is that it's not about exclusion.
1:00:53 It's about inclusion at the very best level.
1:00:56 All that mattered was you're getting that big variety.
1:00:59 There's those those u 30 plus plants.
1:01:02 I get a lot of questions about uh organic food, for example.
1:01:07 Should we only be eating organic food?
1:01:10 How bad are these pesticides and these herbicides for us?
1:01:15 These are great questions that don't have simple answers.
1:01:20 It's always better, I think,
1:01:23 to eat non-organic vegetables than not to eat them at all.
1:01:27 Yes, our fruits and vegetables are sprayed with pesticides
1:01:32 and herbicides that are probably slightly negative for our health,
1:01:37 particularly if you're uh pregnant or you're a young
1:01:41 child or you're have some immune problems or you're sick.
1:01:45 For most of us, it's a low-level harm.
1:01:47 You want to avoid it, but it's not life and death.
1:01:51 And that's the way I I see about these things.
1:01:53 We should also be try and supporting farming that's
1:01:56 moving towards organic because we'd all prefer to live
1:02:00 in a world that didn't have these chemicals
1:02:03 sprayed to kill every kill all kinds of life.
1:02:07 And we do know that these pesticides harm our gut microbes.
1:02:11 So, they've been shown to be relatively safe for our genes.
1:02:14 They don't alter our genes,
1:02:15 but they do interfere with the genes of our microbes.
1:02:18 So, in theory, I don't want to eat pesticides uh at all.
1:02:22 The reality is it's tough.
1:02:24 I don't like paying twice as much for my food.
1:02:27 At home, what I do is I uh yeah,
1:02:30 I get organic food delivered on a weight a basis, but when I'm out and about,
1:02:36 I'm not that worried about it because it's better
1:02:39 to eat vegetables that have some uh chemicals on them,
1:02:42 wash them off than not to eat them,
1:02:46 and deprive your your gut microbes of a meal.
1:02:50 Now, some foods I would worry more about
1:02:52 than others because they're not all the same.
1:02:54 Uh if you look at oats, oats have a terrible record because
1:02:59 they're sprayed multiple times before harvesting.
1:03:02 So they can have um many times the levels of other crops.
1:03:07 So I'd always go for organic oats and you can find those in stores now.
1:03:12 It's worth paying a little bit more for those.
1:03:15 Similarly with berries,
1:03:16 if you can get uh organic strawberries that aren't sprayed,
1:03:20 they'll be much healthier.
1:03:21 But if you're talking about things like oranges or avocados,
1:03:25 I'm less worried because you don't not eating the skin
1:03:28 and a lot of the pesticide is is in that skin.
1:03:32 So, it's a it's a slightly nuanced question, but personally,
1:03:36 I'm not obsessed so that uh I get stressed every time I go out
1:03:41 to a store or a restaurant about not finding uh the exact product I want.
1:03:46 It's about not exposing yourself to things over long periods of time,
1:03:51 not the occasional uh event.
1:03:53 That's really important.
1:03:54 Another thing people ask me about is mercury content of large fish.
1:03:59 If I'm a fish fanatic and I'm I'm having fish two or three times a week,
1:04:04 I wouldn't want want to having the those same large
1:04:07 fish because I would be building up high mercury levels.
1:04:10 You might want to have your fish checked.
1:04:12 And there are places you can buy
1:04:14 fish from that have guaranteed low mercury levels,
1:04:17 but I'd be going for smaller fish
1:04:19 which are also more sustainable for the oceans.
1:04:22 My own personal choices of food are I'm
1:04:25 thinking about uh the health consequences of the food,
1:04:29 some ethical considerations about it, uh but also the effect on the planet.
1:04:34 Fish is particularly pertinent to that because most of the fish
1:04:37 we get is is uh grown in fish farms.
1:04:40 um some which are good, some of which are bad.
1:04:43 So, it's good to be thoughtful, but in general,
1:04:46 go for small fish that are more likely to be sustainable and also
1:04:50 have very high levels of the omega-3s that are really good for your brain.
1:04:55 I'm often going to people in restaurants
1:04:57 and the they're very worried about the salt
1:05:00 content and they're asking uh for no salt to be added to their food.
1:05:05 This is a subject that I was interested in because
1:05:08 I had high blood pressure diagnosed came on suddenly about 15
1:05:12 years ago and I tried salt restricting for a couple
1:05:16 of weeks and see if it would change my blood pressure.
1:05:19 I didn't notice the difference.
1:05:21 So, I started researching this and it it turns
1:05:25 out that um for the the average normal uh 50-year-old,
1:05:29 cutting out salt virtually completely from your diet
1:05:33 improves your blood pressure by about 1 to 2%.
1:05:37 If you have a problem with uh hypertension,
1:05:40 blood pressure, it might increase to about 4%.
1:05:42 And when I looked in detail, it turns out that there's only about one
1:05:47 in five people that are really sensitive to salt.
1:05:49 Four out of five of us are not that sensitive.
1:05:52 So it has an exaggerated effect that most people aren't aware of.
1:05:57 So I tell people that if you're worried about salt, do a proper test.
1:06:03 Take your blood pressure three times a day
1:06:06 for two weeks having no salt salt at all,
1:06:09 which is horrible, and see what effect it has on your blood pressure.
1:06:14 What I also found out is that eating just something like beetroot
1:06:19 can increase can reduce your blood
1:06:21 pressure three times more than salt restriction.
1:06:24 Similarly, just changing your salt to a potassium salt
1:06:26 can have three times the effect of salt restriction.
1:06:29 So most people don't have to worry nearly as much as they are.
1:06:32 And I think it destroys a lot of the pleasure of eating and stops them maybe
1:06:37 enjoying vegetables as much or fermented foods
1:06:40 as much because they're worried about the salt content.
1:06:42 That's why it doesn't come into my guidelines.
1:06:44 And if you're avoiding most of the ultrarocessed food,
1:06:47 you're going to be avoiding the salt.
1:06:49 There's really good data showing the salt
1:06:51 you add at your table is negligible effect
1:06:53 on your health compared to all the rubbish
1:06:56 you're getting consuming too much ultrarocessed food.
1:06:58 When I was researching fermentation,
1:07:00 I looked at kimchi eaters and then anyone who's had kimchi
1:07:04 knows it's really tastes really salty and when you make fermented foods,
1:07:07 you have to add a lot of salt.
1:07:09 They looked at um over 10,000 kimchi eaters in in in South Korea,
1:07:15 compared them to non-kimch eaters of the same age,
1:07:19 and they actually had lower blood pressure than uh the non-kimchas.
1:07:23 So, the benefits of having fermented foods and plants,
1:07:27 and plants contain potassium, outweighs any effect of the salt.
1:07:32 That's a great example of a nice simple solution being exaggerated because
1:07:38 of rather outdated research that stayed in the in our in our minds.
1:07:43 Yes, salt has a role.
1:07:45 Most of it's an ultrarocessed food.
1:07:47 Eating plants would have a much better effect
1:07:49 on your blood pressure than worrying too much about salt.
1:07:52 A lot of people also think that diet isn't
1:07:56 that important if you've got a rich supply of supplements
1:08:00 and there's a lot of marketing directed at people like
1:08:04 that to say you don't have to worry about your diet.
1:08:08 You just got this green powder you take
1:08:10 every morning with 80 different uh chemicals and vitamins.
1:08:13 That's all you ever need.
1:08:15 Again, that falls into this idea of reductionism.
1:08:19 a nice simple solution to a complex problem that usually by definition is wrong.
1:08:27 And all the studies suggest that eating the food is always better
1:08:34 than eating the chemical that uh has been derived from that food.
1:08:39 because there are other things in the food that aren't represented
1:08:42 in that highly purified chemical that's made
1:08:45 often made artificially by yeast in factories.
1:08:48 Most of them are in China uh with all kinds of additives etc.
1:08:53 that make it very different to just having that from uh a natural plant.
1:08:58 The example I like is for for years I
1:09:02 was giving calcium replacement tablets to my patients in rheumatology
1:09:07 uh thinking I was helping their bones and they'd
1:09:11 be taking you know maybe a gram a day.
1:09:15 It turns out that taking something like that, your body doesn't deal with it.
1:09:21 And it's now been associated over uh six studies uh showing that it's associated
1:09:28 with increased risk of heart disease
1:09:30 and atherosclerosis with a hardening of the arteries.
1:09:32 So the calcium is being deposited in places that you don't necessarily want
1:09:37 it because it's given in a form that the body's not used to.
1:09:41 We normally break down calcium in tiny amounts from all the foods we're eating
1:09:45 or from mineral waters and things like
1:09:48 this and it's gradually gets incorporated into our body.
1:09:51 So taking one big dose of it uh can have very different effects on our body.
1:09:56 So that's why I'm always wary about supplements.
1:09:59 They can also interact with each other.
1:10:02 So they don't work.
1:10:02 you know, if you have zinc and you have iron at the same time,
1:10:05 they they stop each other working and you don't know the quality of them at all.
1:10:12 And things like vitamin D, vitamin D is called the sunshine vitamin.
1:10:17 The body converts sunshine uh into vitamin D,
1:10:22 and that's how we get most of it in our in our bodies.
1:10:26 And that's how we've evolved.
1:10:28 But taking vitamin D is not a replacement for sunshine, for example,
1:10:32 because there's many other things in sunshine that we still don't
1:10:36 know about that provide our bodies with a lot of benefits.
1:10:40 And there's a lot of epidemiology comparing people who go in the sun
1:10:44 and out of the sun uh showing that even after having a melanoma for example,
1:10:48 people who go in the sun have a better immune system and a a better
1:10:53 uh outcome than people who are maybe just taking vitamin D tablets.
1:10:58 So often we mistake a subset of of a food for being
1:11:03 better than the whole food or the whole um environment like like sun.
1:11:08 And there many other examples like that where you know we just take one
1:11:13 thing from a carrot and call it keratene and say that's going to be good.
1:11:17 We know carrots are good for you but if
1:11:19 you have too much kerotene it's probably bad for you.
1:11:22 We love to reduce um foods to one thing.
1:11:25 we we can manufacture that in huge quantities.
1:11:29 Marketing does the rest and what seemed like a good idea is
1:11:33 often really a pretty poor one and can often be harmful for you.
1:11:37 If someone's offering you a single solution to a nutrition or a gut problem,
1:11:43 it's probably rubbish.
1:11:44 They're probably just trying to sell you something.
1:11:47 But we all as humans are suckers for the the simple solution.
1:11:52 The science of nutrition as I've you know got into it really without
1:11:58 biases 15 years ago is one of the most complex sciences we have.
1:12:03 It's we were told it was the simplest all calories and macronutrients.
1:12:07 Turns out it's really complicated.
1:12:09 That means there isn't one single product or solution to it to it.
1:12:13 There isn't one vitamin that's going to cure you.
1:12:16 We need to take a more holistic view of it.
1:12:19 And that's that's a really important message.
1:12:21 We need to be doing things that aren't just for a six- week diet,
1:12:24 aren't just to lose weight.
1:12:26 It's how do you change all your habits
1:12:28 that you've you've accumulated all these bad habits.
1:12:31 How do you change them in this direction going forward?
1:12:35 Uh and do this for years so that your body is much healthier,
1:12:39 your brain is much healthier.
1:12:41 We make hundreds of food choices every day.
1:12:45 And the food choices we make are the most
1:12:50 important choices we can make for our health.
1:12:55 So make them wisely.
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