Welcome to Zoe, Science and Nutrition, where world-leading scientists explain how their research can improve your health. Today, we reveal how selecting the right coffee could improve your health. Espresso, instant, aeropress, cold brew, decaf, the list of coffee options is endless. But Which chemical compounds hold the secret to coffee's health benefits? And how many are in your cup of coffee? Today, we're joined by world-renowned coffee expert, James Hoffmann, who set up a mini laboratory right here in our studio to help us invest game. Alongside James is my scientific co founder at Zoe, Professor Tim Specter. Tim is going to share ground-breaking findings from his brand-new scientific study on coffee's impact on our health. James Hoffmann is the best-selling author of How to Make the Best Coffee at Home. Tim is one of the world's top 100 most-cited scientists and a professor of epidemiology at King's College, London. James and Tim, thank you for joining me today.

Happy to be here.

I think that you probably know that we like to start with a quick fire round of questions. Just to remind you, we're going to have the same rules, a yes or a no, or if you absolutely have to, a one sentence. You up for it? Yes. Tim, you ready? All right, I'm going to start with you, Tim. As you know, I don't actually drink coffee, but if I started to drink coffee, could that reduce my risk of heart disease?

Absolutely.

James, is instant coffee unhealthy?

No.

Tim, if I want to improve my gut microbiome, could drinking coffee help? Yes. James, is it true that the darker the roast, the more caffeine in the coffee?

This is disagreement.

Okay. And finally, Tim, are you going to share the results of a brand new research study on coffee with us today?

Maybe, if you're nice to me.

If I'm really nice? We'll see.

Brilliant.

Okay, very interesting to get into that. And look, James and Tim, it's fantastic to have you back on the podcast, and this time in person. And a few of our listeners who have been with Zoe on the podcast from the very beginning will know that this is actually the second time you've come on the show. But the vast majority of listeners will not have heard you before because it was at the very, very beginning. But for those who have been listening before, don't worry, because this time we are in for a treat because James has brought in some amazing technology, and we're actually going to be doing some science here in the studio and therefore understand some more about what's really going on inside a cup of coffee. We also have a second really fun thing, which is that I know that Tim has been working on a brand new peer-reviewed paper about the health benefits of coffee. I'm really excited to hear about this. But before we get into either of those things, can we actually just start right at the beginning with James? Why are we all so obsessed with coffee?

That's a good question. It's delicious. Caffeine plays a massive role. Inevitably, it's the world's most popular psychoactive drug. But I think coffee's woven its way into our cultures all around the world in different ways. The US is a very different coffee culture to the UK, to Italy, to Australia or Scandinavia. I think we enjoy the feeling of drinking coffee, but I think we enjoy the act, the sociability or the ritual or the break or all of those things of drinking coffee. And hopefully it's good for us.

And Tim, what are the health benefits that these people might be receiving? What are the things, what are the key things in coffee that could be How are you affecting this?

Well, for many years, we thought coffee was bad for us because short term, it increases your heart rate, increases your blood pressure. For decades, people said this is a rather dangerous thing to be having. Don't do too much of it. You're going to have a heart attack. Then they started doing some proper studies and have shown that you actually, based on over 25 studies, you can now see a reduction of about 25 % in your risk of a heart attack or heart disease. So then you're saying, why would that be? Something that's short term, slightly stressing your system is actually long term good for you. And I think it's seeing as coffee as this hole, coffee as this fermented plant that has microbes acting on it, has hundreds, not thousands of chemicals produced from it. And it's a combination of all those things that gives it this health benefit, such as the fiber in it. And we used to not think of coffee as a fibre-rich drink, but we now know that broadly, you can get about 1.5 grams of fiber out of a cup, which means if you're having three cups a day, that's 4.5 to 5 grams of fiber, which it's a quarter of your daily fiber intake in the UK and the US.

I always find extraordinary because I always somehow in my mind think about fiber has been like This roughage that you can't brand exactly or the stuff that my grandmother might stir into a glass of water. Yeah.

And two cups of coffee is more than a banana in terms of fiber.

But the point is it's a drink. So where Where's all the solid bits of fiber? And this is because my understanding of fiber isn't quite right.

Well, that's right. Well, fiber can be in drinks and can be small particles that are still going to have a similar effect when they reach the lower part of your intestine, where all the gut microbes are. And there are soluble fibers and there are insoluble fibers. And they may be, some of them might be invisible.

So I think that's the way- It's actually dissolved into the drink. So there can be fiber in something you can't even see, which is- We always think about it's just like eating spinach or something.

But actually, It's not like that. And there are lots of different ways that we can get fiber into our body. And until recently, we didn't appreciate this. And it's not in most nutrition textbooks as a health drink. But There's more fiber, generally in coffee than an equivalent amount of orange juice, for example. So it's not sufficient. I'm not saying you can live just on coffee and have a good diet. But given that in the West, we're very fibre-deprived, it's actually perhaps the thing that's just keeping us going on this very low fiber diet and making up perhaps a quarter of a third of our fiber amounts. So it's the fiber, but it's also these individual chemicals that we're still just getting to understand. And there's a range of polyphenols that are in the coffee beans. Some of them are enhanced by the microbes as they ferment it, and those are released, and those have direct effects on our body. And some of them can reduce blood sugar and reduce stress and actually reduce blood pressure and things like this. So it's It's a complex area, but I think we're suddenly putting it together from a drink that was demonized as being very harmful to us to something that actually could be beneficial.

And the other interesting thing is we always thought it was about the caffeine. And the studies have now clearly shown that you get nearly as much benefit on the heart with decaffenated coffee. And again, it comes back to this idea of how we see foods. We was thinking there's one thing, coffee is It's all about caffeine and, you know. Lemons is about vitamin C, and we forget everything else. But it clears all these other stuff going on in that food that can give us these huge benefits. And we all react very differently to caffeine. And that's a whole other series of events, men, women, whether you're on the contraceptive pill, whether you're drinking alcohol, whether you're having broccoli at the same time as it, all kinds of things can influence how the caffeine in the coffee is having an effect on you.

People are sleep experts, tend not to be as keen on coffee as the two of you, because what they see is the impact of caffeine on sleep and the poor sleep has these terrible health intakes. So they vary, in my experience, between you should never, ever drink coffee whatsoever because that's terrible, to, okay, you can have coffee, but you need to cut it off at midday or something, depending on your sleep. So what you're saying is that- I got it wrong around. Have you?

So the things that It's a perfect coffee metabolism, so the speed at which coffee is broken down, therefore it doesn't hang around and keeping you awake or has this effect on your body, it's reduced by alcohol. So coffee metabolism is reduced by alcohol, so it lasts longer, but it's sped up by vegetables like broccoli.

But it's something like broccoli Sprouts, which are even higher in s efirophene. Polyphenols. Yeah, that would be even better? Yes.

In general, if You're having a lot of vegetables that's going to have that effect.

So if I'm overwired and can't go to sleep, I eat a big plate of broccoli. Just a lot of chrysophrase. Yeah, and then suddenly I'm going to fall asleep. That's right. And if any listeners feel it doesn't work, they can write in.

And have a cigarette. You can also have a cigarette. That is also good. That's why cigarettes actually need more coffee to get that same caffeine hit.

To be clear, we are not in fact promoting that you should have a cigarette, but you are saying that people- I'm just demonstrating how chemicals and all food and things we eat and are all chemical. But what you are saying actually is that if you are a smoker, the coffee doesn't work as well. Is this why you need more coffee in order to get the coffee to work?

Yeah, you're going to probably have twice as much coffee to have the same caffeine hit than if you're a nonsmoker. And that's in males. Actually, if you're females, the metabolism is generally lower. So caffeine has a longer effect on the body. And also if on the contraceptive pill, it also increases it further. So metabolism has decreased, so it lasts even longer. So females on the contraceptive pill, even a small amount of caffeine can really have a last a long time, can be counteracted by smoking and broccoli. So just showing you how everyone is different. Again, it comes back to this personalization, and not only in taste, but also the effects of these chemicals. And that's just one of the chemicals calls we're talking about.

I think it's the great frustration of coffee conversation is the substitution of coffee and caffeine. It's this incredibly well-studded drug. We know a lot about caffeine, but it's not all that coffee is, but it ends up being all that we talk about most of the time when people want to talk about coffee and health.

Do we understand why coffee is full of not only caffeine, but all of these other polyphenols? What's it? Most of us think about coffee as being either something ground that we buy from our grocery or maybe we think about it as this blackened thing that looks a bit like a bean, but we definitely don't think about it as a plant or anything else. What's the...

The caffeine is easier to understand the presence of. It's primarily produced in the coffee fruit. So coffee beans grow in a cherry. It's about the size of a small grape with two peanuts seeds in the middle. So if you look at a coffee bean, it's two flat size. They would typically face each other. As a defense mechanism, the plant produces caffeine to act as an insect repellent, for want of a better term, to discourage insect attacks on the fruit. That's really why it's there in the quantities that it is. Therefore, you tend to see species of coffee that are hardier and more robust, one of which is robuster, grows lower, more insects are present, twice the caffeine levels of something like Caffeia arabica, which grows higher up and obviously has less challenge, and so it needs less defense. But yeah, that's the primary The reason caffeine exists. Caffeine is produced by other plants.

Yeah, tea leaves as well. So I mean, not green, more the black tea ones for the same reasons.

Yeah. And there's another argument that some flowers produce caffeine, and it's one of those situations where everything becomes crab in that different plants through different pathways have ended up producing caffeine almost for different purposes. There was one study that showed caffeine improved bee memory. And so things like orange flowers produce caffeine, and that's the speculation in that it improves the quality of pollination as a result.

So the bees can find their way back to the flower.

That's the theory, which I think is amazing. Or they got addicted to the caffeine and came back to get more. Either way, it worked.

I love that. And polyphenols themselves are all So what I understand defense chemicals is how I've heard you and others describe them, Tim.

Yeah, this is, again, it's an incredibly broad family. But in general, these are chemicals produced by plants to defend themselves not only against insects, but it might also be against high winds, or it could be cold, or it could be strong sunshine, or it could be to change the way predators, the taste and things for predators. But generally, it's a defense mechanism for plants that ends up having a side effect of being beneficial for our gut microbes. That's how nature has come in this full circle.

Now, I know, Tim, you teased us a little bit, but you have got a really exciting new paper. Can you tell us a bit about it?

Okay. I'll give you a little teaser anyway. So it's still under peer review. It hasn't come out yet, but this is work I've been doing with a fantastic Nicolas Sagata in Trento and his team there, plus with the 40,000 plus the Zoe samples. So people have been giving their stool samples, and we've been comparing them with their drinking habits and their food habits. And now we've got this huge sample, both in the US and the UK. We've actually looked at other populations around the world. We found that of all the food and Drink Associations that we linked up from our questionnaire to the microbes, the one that comes top of the list that pops up every single time was a microbe that is associated with coffee.

Hi. I have a small All favor to ask. We want this podcast to reach as many people as possible as we continue our mission to improve the health of millions. And watching this show grow is what motivates the whole team at Zoe to keep up the really hard work of creating new episodes each week. So right now, if you could share a link to the show with one friend who would benefit from today's information, it would mean a great deal to me. Thank you. It's amazing. So literally, the thing that we could most clearly have a one one relationship between bacteria and food was actually a drink.

Exactly. It's like a forensic test. Rather than doing questionnaires, you just take a bit of that stool sample, you extract the DNA, and you find this microbe called lorsinobacter, named after Dr. Lorson, and it is inevitably linked to the consumption of coffee. And that was so strong. We had this list of all these other ones, and many of the foods are all mixed up and you don't get a clear signal of any one microbes. It seems very specific. It doesn't seem to eat anything else. So it's been hanging around for us humans to produce coffee, imagine. And this microbe is pretty much in everybody in the US and the UK. Even if, like you, you're not a coffee drinker, you would still have low levels of this microbe. And you say, why How is that possible? I haven't had coffee for 20 years. Well, it's all around us, this microbe, because we've all got it, because half the population now are coffee drinkers, it's in people's breath, their saliva, We swap microbes with the people we share houses with. So nearly everyone has low levels of it except young children. So when you're born, infants don't have it.

So they're acquiring it from around the place, and then it stays dormant until it starts being fed coffee. And then it grows up and gets these enormous levels. And what's really interesting, then it feeds off the coffee. And then we found that it then produces these chemicals that through the fermentation process, that turn out to be really healthy for us and have been shown to reduce blood pressure and reduce blood sugar and things. So all this is going to come out in this paper, but it is absolutely fascinating fascinating because other countries that don't have a history of eating coffee don't have this bacteria at all.

It's like a panda, and the panda only eats one thing. We all know that it only eats bamboo. And you're saying that maybe it's not quite as extreme as that, but basically this horse anabacter lives on the fiber that comes off coffee. Is that what you're saying?

Yeah, that's right. But it seems to be able to survive without it in a very suspended animation form.

So it can get by a little bit enough, but it's a very small fraction of your microbiome.

It won't be happy until it finally gets that shot of its first cup of coffee, and then it takes off, and then it It reduces all these healthy chemicals that we know from the epidemiology are actually reducing our risk of heart disease and generally helping our metabolic health and perhaps helping our blood sugar levels.

This is a bit like a, don't they say a dog can be vegetarian, so it could live on it, but it's pretty miserable. That's not really what it is. But then finally, you give it a steak and it's like, Okay, I'm off. I'm stretching the analogy a little bit, but somehow they're managing to survive a bit because if there was no food it could live on, it wouldn't be there. But basically this is the thing that it has the ability to really thrive on and presumably better. Therefore, it can break down the coffee stuff better than all the other bacteria in your gut. And so you often talk about this idea that it's like an ecosystem, like in the jungle or in a coral reef with everything specialized. And so here you've actually found this bacteria with this really clear one to one relationship.

Yeah. And it's the strongest signal we've got in all the foods and drinks.

And has anyone done that before? I mean, is Is now, are there many examples already of where people have been able to find these links?

No, I think we're not the first to find this microbe. It's been shown in some small studies, but they didn't really know its global full epidemiology patterns and I think showing how it affects normal people and the idea of people who don't drink coffee still having low levels, I think is really cool. And also the other thing we found is that It still likes decaf as well. So it's not as fussy.

I think there are many listeners who might be quite fussy about their decath versus caffeine. But this is an example of where you're saying it's not the caffeine in the coffee that this bacteria cares about.

No. And again, it's not the caffeine that has the... Seems to have the health benefits either. So it's all these other chemicals that are produced once the microbes are dialing into, we don't know, one of the many fibers in coffee. And we don't know exactly which bit it's particularly targeting, but it then thrives on that and uses that as an energy source and produces lots of other really fascinating chemicals that help our body.

I could just for a I'm going to take a minute because I think for somebody listening to this, I think they'd be like, okay, I understand that I've got this bacteria inside my gut that eats coffee. Help me to understand, though, why that then creates any health for me as the human being. I can see it's good for the bacteria, but why is that good for me with the bacteria inside me?

At some global level, you're having something as a source of fiber, which means in general, lots of microbes are benefiting and general gut health is improved. But in this specific one, which we got a nice example here, it's showing that eating the coffee, the bits that get to the lower intestine have been mashed up a bit, but they're still mainly intact. And this lorsanobacter is attaching to it, breaking down some of those sugars in the fiber. And as a byproduct is producing these key chemicals. There are probably many of them, but we've isolated a couple of them. One of them is quinnic acid, which is well known constituent of coffee, but it's producing in large amounts. So it's perhaps liberating it and sending that into the blood. And we know that that chemical, when you take it out of the system, you put it into animals and things. And some human studies will do things like increase insulin levels and reduce blood sugar levels.

That's a good thing.

Which is a good thing. So these chemicals are generally having good effects on the body. And all these chemicals used to be called antioxidants.

And sorry, that was quinnic acid. Is that what you said? Yes. So that's a specific example, something you can measure that is really being created by this.

It's just one example. I mean, again, Our technology allows us to get small microscope on one bit of it. There's probably lots of other things happening there. But that's a really nice example of high levels of this quinnic acid are related to the presence of the lorsonabacter. So it's not just the presence of coffee, it's when you've got high levels of that microbe, microbe plus the coffee equals this other chemical, which is something that normally you wouldn't get in your body. And that chemical, just like taking, going to the chemist, and if I went to the chemist and then got some quinnic acid and said, okay, that's going to be good. That's going to be good for my blood sugar, my metabolism. And there might be other ones that are also good for you, reducing your blood pressure long term, who knows, reducing other stresses in the body, anti-inflammatory effects. So it's one of the first examples we've got of a constituent of food that reacts with a very specific bacteria to produce these chemicals. And this is really giving us this whole picture of how our food interacts with our gut microbes to produce...

They are basically these mini pharmacies, and each of them is producing an incredible little drug that we couldn't dream of producing yourself. They know exactly the right dose. They know what to give it. And evolution and everything has done this to us. And it's a way that we can now, well, there's a glib term that food is medicine. You can clearly see, yeah, a coffee bean is a way of delivering something like quinnic acid in exactly the right doses for your body if you have three to four cups a day.

Can I get into the weeds just slightly here? Is that okay?

You probably know much more about quinnic acid than I do.

I don't know that much. I'm vaguely familiar with quinnic acid, but I want to split out into coffee. I want to, just as a question, separate the fibers, which would be very different compounds to the polyphenols. Because when we come to doing a little bit of science later on, I can look at one of these things, I can't look at the other. And so talking about quinnic acid specifically makes me feel like polyphenols are a key constituent of the diet of this thing, because I know that when you roast coffee, you degrade some of the polyphenols in the roasting process. And one of the byproducts actually of roasting coffee is quinnic acid. And so there's a curve and relationship there. I'm wondering if it is the polyphenols in coffee that the locinobacter is interested in or the specific fibers present in coffee that I think are reasonably distinct to coffee. I think they've got slightly... I don't know enough about fiber. I know the names of some of the coffee fibers, but I don't know that much about them. But to me, they're separate things. If you at measuring the presence of either in coffee, they don't necessarily correlate and that you can have lower fiber levels, but quite high levels of chlorogenic acid, specifically are the polyphenols most commonly found in coffee.

Which is a precursor of quinic acid, right?

Yeah. So that's the bit where I'm like, if I'm trying to theoretically optimize to feed this thing as much as possible, I would think differently if I'm thinking about how do I get it the maximum polyphenols versus the maximum fiber. And so that's why I'm interested in in its specific diet, whether it's, we're not sure. It could be a little of both or it's more one than the other. That's what I'm interested in as a bit of a nerd right now.

Well, I don't think anyone knows the exact proportions. My understanding of this is it's a bit of both. That polyphenols are used as a direct energy source for microbes to allow them to reproduce and do their thing. And one of their things is to drill into the fibers and extract, again, nutrients from that and then produce other ones as a byproduct. So It's probably a bit of both. It's going to be a while, I think, before we work out-Exactly what it is.those proportions. And also, generally, most of these work in combinations in teams and guilds. So it's very hard to work out who's doing what. This is quite a rare example where you've got what seems to be nearly a one-to-one type system here. But of course, coffee isn't one thing.

So I have a simpler question. We're getting into the weeds. No, it's great. But my simpler question is, does this mean I have to start drinking coffee?

No. I think there's other ways you can improve your health. But I think for those people who don't like the caffeine, decaff coffee really should be more of an option. And I think we ought to be exploring other foods and drinks that do contain some of these good things so that your body can still produce this substance like this quinnic acid. And I think that's where a lot of these new science takes us. There could well be a way of making a blend of coffee, for example, that you liked, that we changed its taste profile so it was less bitter for you.

What's interesting, I don't think we've discussed this before, but I gave up coffee more than 20 years ago, and it was part of dealing with a lot of food intolerances that I got. So I was definitely drinking lots of coffee at 21. I got these food intolerances after I was very sick with mononucleosis glandular fever. And a few years after this, as part of trying to deal with this, I gave up coffee. And one of the things I found was that coffee was definitely triggering a whole bunch of digestive problems. And apparently, it's quite common. I remember it's one of the things the doctor had talked about trying, and it's not necessarily the caffeine, actually, because same impact, really, with decaf. And so this is part of what I gave up along with this whole process of giving up this vast amount of food and ending up on this really miserable, very processed diet. But interestingly, what What I did find was I ended up just drinking more tea. That pulled up my level of caffeine. And I think I found a happy meeting, which is there's a lot of caffeine in a coffee, and I actually found that tea was a lower spike.

So It's not that I gave it up because I hated the taste, but I am curious. I think a lot of people are listening and saying, do I have to drink coffee for health, or is this more saying, actually, you should think about this as a healthy drink as opposed to the way that people have thought about it before as unhealthy? But it's not saying you have to drink it if you don't want to, but it is definitely contributing to the way we get fiber and all these positive things, or is this like, wow, there's like a silver bullet. If you're not drinking coffee, you should really try quite hard because of how good you think it is?

I think it's nuanced. I think I wouldn't want anyone to regularly eat or drink things they didn't like. Food is to be enjoyed and savored, and that is the most important thing. And everyone has Food preferences. And we've done our twin studies to show that some people have a sensitive palate. They don't like those bitter flavors at all. And genetically, their threshold is very different to someone else. So realize we're all different, don't start forcing people to do things. But at the same time, this is a health drink. The evidence is really clear that if you can have... You can reduce heart attacks by 25 %. That's pretty cool if you can do that. And there's not many other ways, something so simple, you can actually achieve that. So I would say to people, I haven't had it like you for 15, 20 in a year's, try it again occasionally or try different ways of having it. Or think of all these vitamins, supplements, multivitamins that people take. They don't really like taking them, but they do it because they think they're doing them good and there's no evidence whatsoever. However, here you have, you could take a shot of Espresso and it's easier to take the most vitamins, and a couple of those a day, and you're getting huge health benefits.

So I think just revisit it and realize that you can overcome these thresholds, these bitterness thresholds by constant use. It'd be hard if you now because you've been off it, but there might be other ways of doing it, perhaps. And that spoonful of sugar where the balance would still be positive. Maybe not with six sugars, but...

Modern coffee, in particular, has focused on reducing bitterness and improving flavor as a outcome. And I think we see lighter-roasted coffees that have less bitterness to them. The way that we prepare coffee, I think really well-made coffee is not that bitter compared to badly-made coffee. I think the thing that's notable about humans is that we're pretty blank slates and our preferences are learned. And while we have different perceptions of things like bitterness, When it comes to flavor, if you want to learn to like something, well, you can just choose to learn to like it. You can acquire a taste if you want to. We do it all the time. No one enjoyed their first lager. No one enjoyed their first lager. No one enjoyed their first coffee. But we go back and we choose to acquire tastes.

So genetic studies have shown the threshold is there for bitter taste. So if you don't like coffee, you don't often like red wine as much as white wine, you might find broccoli and Brussels Sprouts, hard to have. And this is more common in females and also dark beers. So they tend to go together, these free profiles. But as James saying, you can get used to it very easily, and most of us do that as students.

We have basically the world's foremost expert on coffee, and we're going to do something fun. Now, just before we do it, could you explain, does the way in which you make your coffee have a big impact on both the taste, but also tying into what Tim is talking about? Does it impact, therefore, the health of these things, the fiber and the polyphenols we've been talking about?

Yes, a lot. I mean, taste is the most important thing for someone like me. But yes, if you take some ground coffee and you brew it, you are dissolving things from it. And a good percentage of coffee is not soluble. You could brew it forever, keep running water through it in a little drip machine. It would still be there afterwards. It's simply not soluble.

Aboutit's soluble means it dissolves in the water.

It will dissolve in the water. It's like wood, what is left over in a simplified way.

It just- Good bits are in the bitty bits.

Yeah. So you can wash out and dissolve into your brew water about 30% of the grounds. And so if you took 100 grams of ground coffee, brewed it for ages, dried it out afterwards, you'd have 70 grams left. Okay. And the 30 grams max would end up in a cup. Ideally, you don't want 30% of the coffee. Some things you just want to leave behind, actually, that don't taste great. Generally, we between probably 20 and 23, 24% of the coffee dissolved in the cup below.

So you want all of it dissolved in. You want to get somehow the good bits, but leave some of the not nice tasting bits. Generally.

And there are some very bitter compounds that tend to come out at higher extractions that people don't enjoy. However, if you don't get enough out of the coffee, you tend to get a lot of the acids and not a lot else. It's a bit like lemon juice rather than lemonade. Good coffee should have some balanced acidity. You give it a freshness to it, add some flavor. But badly brewed coffee will just be sour, unpleasant, and to be avoided. And so, firstly, you want to get the extraction right for the taste perspective. And that's how finally you grind the coffee. Obviously, the more surface area you expose, the easier it is for the water to get in and pull out the things that you want. Because there's a correlation between what you're extracting in terms of taste and what you're extracting in terms of the soluble fibers and things like the chlorogenic acids, a well brewed cup of coffee will have more of everything good. More taste, more chlorogenic acids, more polyphenols, therefore, and theoretically, a little bit more fiber, too. So all in all, you want to get your money's worth. You've bought some nice coffee, there's good stuff in it.

You want to make sure you're getting it all out. So that's the goal of good coffee brewing.

Hi. I want to take a quick break here and tell you about something new we've created, a free guide that will kickstart your journey to better gut health. We feed our gut microbiome through the variety of foods we eat, and in return, our microbes give us a wealth of health benefits. They're responsible for so much as we've been learning, from digestion to immune support and even our mental well-being. So how can you nurture your gut in the best way? Which food swaps can you try to nourish those good bacteria? What does a high fiber shopping list really look like? Our free Gut Health Guide shares it all. Emails and actionable tips that are designed to put you in control of your gut health. To get yours for free, simply go to zoe. Com/gutguide. You'll also find the link in the show notes. Okay, back to the show. I understand you have brought along a mini laboratory to show us how Both professional, we test for these compounds, but they can also talk through for us to understand, and we are going to have a tasting and science experiment at the same time.

Yeah, I think it's interesting. I have a little portable caffeine meter that has the benefit of also giving me an output of chlorogenic acids present in the brew as well. It'll be in milligrams per deciliter, so per 100 milliliters. We can scale it up to a normal cup of coffee for people in a minute. But yeah, it'll give you an idea of something like instant coffee versus fresh brewed. What are the differences there? Then we can have a look at instant as well, which is a lot of people's choice, and talk about some of the theoretical benefits that instant might have or might not have.

Got it. We're going to try. Let's just run through. What are the different things that you're going to-I'll make you some regular, fresh, well-grown arabica coffee.

I've then got some good decaff coffee, and I can talk about decaffination because I think it's something people want to know more about and fear a little bit because they see chemistry and get a little bit nervous. And then I've got some instant, too. And instant's super interesting on a technical level. However you feel about the taste, I'm going to try and stay away from the politics of taste of that. But we can actually look at some of the chemistry of what you get in there or what you don't get in there.

Got it. And I think we might have a coffee kombucha as well. Is that right? Oh, good. All right, James. So we've got the equipment out, which now looks very impressive. Can you tell me what you've got? Sure.

This is called an Aeropress. It was invented by the guy that invented the Aerobe, and it's a bit like a French press and a paper-filtered brewer all in one. I'll put ground coffee in, hot water, let them steep together. It's a paper filter at the bottom here, and at some point I'll press it, and so it'll separate the grounds from the liquid. I will add some coffee, which I ground just before I got in a cab to come here, so it's nice and fresh.

You're just throwing in a random amount of coffee?

I would use, as a ratio, 60 grams of coffee per liter of water that I want to brew. So I'm going to brew 20 grams of coffee to 330 milliliters.

The answer is you very carefully measure the amount of coffee, and you're going to put in just the right amount of water is what you're saying. Yeah.

I like using weighing scales because most of the time I'm making coffee before I've had coffee, and I don't want to guess or have to think. And I like a weighing scale for telling me what I have to do, and I just make the number happen. So that's why I'm Big on scales.

This is for an americano?

This will brew like a filter strength brew, yes. So americano tend to be fractionally stronger, but like a drip coffee strength seem to be the easiest thing.

While you're pouring, tell me about the water, because one thing that did entertain me is that James arrived with his own water.

I don't know how much you want to know about water because it's a miserable subject. But the minerals in water play a big role in extracting the flavor. So they are involved in essentially dissolving some of the stuff that we want. But then there's also something called alkalinity, or a buffer, if you want to get into the chemistry, which will affect your perceived acidity. And too much buffer makes everything taste a bit brown and dull. No buffer makes things taste very sour and unpleasant. So I brought water that had an ideal amount of minerals in terms of calcium and an ideal amount of buffer so that we get some acidity, but not too much.

So you won't take the water out of the tap. You have to get your own specially modified water to make the coffee the way you want it to taste.

London water It tastes good, but it has a lot of calcium and a lot of buffer in it, too. So it tends to make all coffee taste a bit the same, which is a bit of a shame. And so I've paid for the good stuff. I want it out and I want to enjoy it as much as possible. Making your own water is a little bit extreme. I agree.

I'm glad you're still at the point where you can see a little bit, at least, the entertainment that I'm taking from the fact that you not only brought your own coffee, which seems very reasonable, but brought your own water, which I think is acceptable, but verging on the slightly.

What about adding salt, you mentioned?

So yeah, salt's interesting. Salt's a great little hack in that for the majority of people, it's not everyone, table salt acts as a bitterness suppressor. It's one of the reasons you obviously salt and dark chocolate together, actually. It makes them more palatable as well as enhancing flavor, too. But if you are served miserably bitter coffee, the real filth in a hotel breakfast coffee, a tiny sprinkle of salt. And I mean a tiny, don't... Just a little tiny sprinkle of it, stir it in, you'll shocked. It mutes the bitterness quite impressively and increases, let's say, palatability. When you just need the caffeine, I want to help get you there. This shouldn't need salt, I would hope.

And so talk me through. The hot water has been sitting there right now, and you described before about how the fact that the ground coffee has a lot of things inside it which are going to start to dissolve. So is that what is going on right now?

That's what's going on right now. So essentially the water is pulling these things out of the cells that we've exposed through grinding the coffee bean.

And so the longer you You believe it, the more is being dissolved out.

Is that what's going on? Yes. And there's a point at which you have diminishing returns, and it's not worth waiting much more. So I'm just giving a quick mix before I press it down, and then we'll press it through and we'll have a brew. Now, this is paper-filtered. From a health perspective, the data seems to suggest that actually paper-filtered is healthier for you than unfiltered. I think it was a big Scandinavian study that showed that the peak health, heart health benefits came with filtered coffee. I think there's a couple of lipids in coffee that were filtered by paper that show a correlation to an increased rate, a level of serum cholesterol. I just enjoy it more, if I'm honest. I enjoy the clarity of.

I'm not sure it's that convincing, though, because these are intermediate effects on lipids. And as we're saying, lipids are complicated. So short term change in lipids doesn't mean necessarily long term health. So I stick with the one you prefer, I think.

Now, what I'm going to do is just do a little caffeine test on this, and then I can dispense to you.

That looks quite weak to me.

It's a light roast. So this This is actually from a Scandinavian coffee company, and Scandinavian are famous for their light roasts, but it should have a little bit more fruitiness to it, lower levels of bitterness from being a lighter roast. So for the I don't like coffee, you could approach this more as a strange fruit tea, mentally, and see how you get on with that.

I'm very excited. I'm definitely drinking the coffee that has been made in this exquisite fashion.

So I'll just give it a quick stir just to get a better sample.

And James, you brought a piece of technology here. Do you want to talk us through for those people who are just listening listening on audio, what are you doing?

It's a little Bluetooth connected caffeine and chlorogenic acids analyzer. What I'll do is I'll pull a very specific quantity of coffee with a little pipette here, and I'll add it to a small solution that I'll shake together for a while. Then there's a chip that I insert into a machine. I cover a little sensor with the liquid, the reagent in the coffee. Then within about 15 seconds, it'll tell me the caffeine content and the chlorogenic acid content.

Which is a polyphenol.

About, I think 90% of the polyphenols in coffee are counted as chlorogenic acids. I think there are some others in there, but there's a very strong correlation between the quantity.

Basically, it's giving you a measure of the amount of polyphenols.

One of the major classes of polyphenols.

There's loads of individual variants within that, but that's like a big category. How cool.

I have to shake this for 10 seconds.

Do you do this every time you go to a coffee shop?

No, because they're like five or a test. It's very quickly. I mean, it's interesting. We did it. We took it to different I need to look at the variants in. If you ordered an Espresso, what's the caffeine dose going to be and how much is it going to vary? And the answer is massively. And caffeine is one of those things. And as much as it isn't all that coffee is, it is a big part of it, where it's the most popular drug and we consume in a completely unregulated way. If you order a coffee out, you have no idea how much caffeine you're about to consume. I'm not sure that's good. As much as I like coffee, I'm just not sure that that's a brilliant idea.

It's like going to a pub and not knowing what percentage of alcohol is in that beer, isn't it? Absolutely. Any of these coffee shop chains, even in the same machine, same trained staff will produce a different There's a high degree of variation.

It's not like when you're just drinking a beer or something that every glass of beer has the same level of alcohol.

No, it's regulated. You got to show on it how much alcohol is in that bottle. But the amount of caffeine will change a lot. No, there's no testing in terms of caffeine.

Can I send this along to you if you want to have a little taste?

Yes, I would love to have a taste. Tell me how I'm supposed to taste my coffee.

If you have a glass that is oval-shaped, so to speak, yes, swirling will give you a nice head space of aromas that you can smell if you want to do that. You don't have to do that. If you sip it, if you slurp when you sip, you will generally have a more intense flavor experience as you spray the coffee around and send more stuff volatile.

Like olive oil tasting?

Wine tasting, whiskey, everyone likes a slurp.

What I would say as someone who hasn't drunk for a really long time is it smells really nice, much less strong than I would normally expect from a coffee. And the color also, Tim already mentioned this, actually looks like it could be a tea. It's really not that dark. Yeah.

So as a brew, this is on the very light, very fruity end. And you might think, oh, there's no caffeine in this then. No. So the caffeine level, we'll start there, that's the easiest thing, because that's understandable to most people. So that's 72 milligrams per deciliter. So if you drank, let's say, a small, which would be 200 milliliters, that would be 140-ish, 145 milligrams of caffeine. The daily recommended dosage for adult males is about up to 300 to 400 milligrams.

That's almost half your amount just in one small cup of coffee.

So three smalls over the course of the day would exceed your recommended caffeine dose. So it's actually surprisingly caffinated, I would say.

So I'm going to drink this, but my caffeine is about to go through the roof. So if later I'm talking very, very fast at the end of the podcast, you'll know why.

You've got a small amount there. It's not a lot. But yes, that's a decent whack of caffeine. Chlorogenic acids, this will only be useful as we look at other things in comparison, I suspect. 166 milligrams per deciliter of chlorogenic acids here. So a decent dose, I would say, of chlorogenic acids, which is good news because that's good for l'ocinobacter. It's going to be happy down there. Or it's going to be happy.

So you're measuring all It's all these polyphenols, and so this is what's going to be feeding these bacteria in the paper you were talking about earlier, Tim.

But the fiber content of this would be relatively low compared to something like a darker roast. I think there is more breakdown of certain compounds in darker roasts that make them soluble and easier to extract.

Take us to the next coffee.

Well, I brought some decaf next, which I thought would be interesting because I'm curious to see how it stacks up. If you skip the caffeine, what are the polyphenol benefits like in a decaf? So this is a coffee from Brazil. It's a decaf coffee. So you decafinate coffee before you roast it. So you take the raw coffee seeds and you decafinate those. There's a bunch of ways to do it that have various nice-sounding names. All of them are safe. And I think a lot of people hear certain chemical names and inevitably freak out at the idea of ethylacetate, which is often known as the sugarcane process because no one likes the name ethylacetate. So yeah, I think decaff historically has been underrated. I think people don't think of decaf as delicious. I think people see it decaf as a compromise, which is a terrible shame. It's harder to roast as a coffee roasting company. It's harder to make it taste good, but it's actually very possible to make good tasting decaf. I think for a long time, decaf drinkers have been undervalued. They are the true coffee lovers because they're not even getting the chemical hit out of it.

They're just drinking it for the taste, and yet they are not well looked after. By the time I made you a flat white, most people would have no idea if it was a good, well-produced decaf, well-roasted, well-brewed. Delicious. Absolutely delicious. I drink a lot of decaf now because I'm I'm quite caffeine sensitive and I value my sleep quite highly. And so my afternoons are full of decaf because I still like-So this would be a way basically to reduce a lot of, I guess, the main health risk about the coffee, which is that it impacts your sleep and we know how important sleep is.

Right.

I'm precious about that.

And you said, Tim, most of the health benefits?

Yes, that's correct. You still get the heart benefits from decaf.

And you're making it exactly the same way, and it looked to me exactly the same as the ground.

It doesn't need special treatment. Just get my dose in there. Right. And I'll give you a little mix and a share.

Excellent. And before we get to the answer, I'm going to ask Tim, so what is your guess in terms of looking at this on the fiber content and the polyphenols? How do you think it's going to compare with the first one?

Well, fiber should be higher. We know that decaff coffee has the same fiber as regular. As a general rule, if things are more bitter and more tannic and more astringent on your tongue and less smooth, they're more likely to be higher in polyphenol count.

It smells stronger to me, less soft than the last one.

There's a lot of reasons for that. It's a different roast level. It's a different country of origin. I would still say low bitterness. It's quite gentle, friendly in that perspective. The polyphenols came in at about 58 milligrams per deciliter. So I would say not a statistically significant variation. The previous one was? About 170, I think. So high. Plenty of those things are available there. I think the interesting thing for me about instant, as a contrast coming into this, is that instant cheats in an interesting way. The manufacturer of instant is motivated by price more than anything else. And so what they need to do to keep this as cheap as possible is to yield as much as it's humanly possible from the coffee beans that they start with. And so through a variety of processes that are only used by instant coffee manufacturers, they can get their extractions up past 30%. They can get it all the way up to about 55% cent, which means that they can get almost twice as much out of a coffee bean compared to normal people brewing at home. They do that by breaking down some of the insoluble stuff.

They hydrolyze it, and then it effectively acts as a bulking agent. And so you would therefore see technically higher fiber contents in instant coffee than you would see in filter coffee. But there's a trade-off. That's come from less coffee beans in the first place. And so what I'll do is I'll brew this at a matching strength to these here, and that'll give you a matching strength. And then we can have a little look at the caffeine as well as the polyphenols. Interestingly, they recommend you brew instant quite weak. They recommend a one % strength. I'll say one gram per 100 milliliter, which is surprisingly weak, especially as it's. That's why when I try a strong one, it's virtually undrinkable, isn't it? It's designed to beIt's designed to be weak. To be produced quite weak.

Now, just as you're making the instant, there'll be a There'll be people listening to this who have no idea what instant coffee is. Could you just explain for a minute? It's sitting in a packet. It's lots of these little granules.

So instant coffee, the way you make it is basically you make a very large, very strong cup of coffee, and then you freeze dry, ideally, all of the moisture out of it. And what you end up with is a solid, clumped, powdered thing. And what they then do is turn it into a shape that mimics ground coffee to most people to remind you of ground coffee. But you could sell this as a pure powder. You could sell it as large, chunky flakes.

So really, it's like dried coffee, and then you rehydrate it. Is that what you were saying?

It's like a stock powder. You know what I mean? And you were going to reconstitute it into water.

And when I was growing up, this was the primary way that people drank coffee in the UK, but I know that in the States, where I also grew up, this was never really the primary way that people had coffee, and they used to have a filter coffee in the house. Was the benefit of this really convenience? Is that where this comes from?

That's primarily it. You need a cattle, and you can just scale it very easily. You need to make 10 mugs of it, one mug of it. It's just 10 spoonfuls or one It's very easy, but with all convenience comes compromise. And so as we suppress the price of this, the qualities of raw materials inside instant coffee will inevitably much lower. And then that doesn't start you in a good place. And then it's manufactured to maximum yield, not about maximum flavor. They do some clever stuff in that when you buy a jar, they will have injected just under the gold foil lid on the top, some aromas. They do an oil extraction, and then they capture some of the aromas of fresh coffee and inject them under the foil lid so that when you pocket open, there's a release of aroma that reminds you of fresh coffee, even though those flavors were never present in the soluble material underneath.

This is like selling a house and you're told you should bake bread. It's like a bread bread. People are like, Oh, I'll buy that house. It always smells of baked bread, but they don't realize. It doesn't come with the house. This is the coffee equivalent, is it?

Pretty much. Give it a quick stir. We've made coffee, which is obviously much faster than me messing around with a coffee brewer. But let's have a look at what we get as a result. So this is technically the same strength as the last thing I gave you.

Okay, well, it is really dark compared to the previous ones when my hand was underneath it, it was just like a little brown. This is so dark, I can't see my hand at all. So it's a completely different color, and yet you're saying it's the same. It's still the 1% of this water is made of coffee.

But 1.3..

It doesn't smell anything like the other two at all. It doesn't smell very much of anything, actually.

No, because the process of brewing and freeze-drying, and you lose a lot inevitably in that process, especially the aromatic stuff. This is huge used half the amount of coffee to make it, essentially.

So it's half the amount of coffee, and they've just extracted more like a squeezing an olive, crushing a whole olive.

Absolutely. And yield, 38.8 milligrams of caffeine. So about half the caffeine of the It's the first thing you tasted. It's surprising.

Half the caffeine.

Half the caffeine. 33.55 milligrams per deciliter of chlorogenic acid.

So only 20% of the polyphenols that we had in the- But lots of fiber. In the previous, but lots of Fiber. So interestingly- So that's a strange one.

So if you're just chasing fiber in coffee, this actually is pretty good. Whether those are the right fibers that are preferred by your gut microbiome, I couldn't say. But It's definitely lower in things like polyphenols.

What are your thoughts, Tim?

I haven't had actually instant coffee for a long, long time. But actually, it's not that bad. If you get the concentration right, it's perfectly drinkable. It's just not complex. It doesn't have any the other interesting aromas or flavors.

This is what I think of as coffee tasting like. It's the thing you might have served at the end of some dinner.

This is a premium end of it, an instant, I would say.

Yeah, it gets much worse. This is as good as it gets.

But I would say if you're chasing the health benefits of coffee, it seems to me that good quality coffee brewed fresh is the best of all worlds because you get lots of what you want and it tastes really good. And for me, that encourages both delight and more consumption. It's easier to drink a good quantity of this stuff if you really enjoy it.

So I think that was fascinating. And we have one left to go, don't we? Which is not really a coffee at all.

We were exploring other ways of having coffee if you don't like it, the taste in the original beverage form. And so as people know, I like fermented foods and drinks, and you can have coffee kombucha. And there's two ways of doing this. So kombucha is basically a a fermented tea where you use a scobi, which is this blob-like composite of a fungium and microbes together in a look like a bit of a jellyfish floating around And they basically like eating tea and sugar. And once you've got a nice big healthy one, you can put it in a mixture of tea and coffee. And it will produce, it will transform that coffee into something new and original that's got a tiny bit of alcohol in it. You can't generally taste it, one %, but of CO2 and all these extra chemicals that make it healthy for you. And it's a probiotic coffee. Could be the ultimate. It doesn't grow as well. It prefers tea to coffee. So you don't get as much and they're harder to grow, so they're harder to find. And you have to then put it back into tea after it's done a bit of its coffee stint.

You Can't keep it going in coffee. And then there's another way of doing it, which is what I do, is make it in tea the normal way. And then for a second fermentation, you pour it off and you add a little bit of coffee flavoring with a little bit of extra sugar, and that gives you all the coffee aromas. And you've got a coffee beverage there that's got the combination of both the tea and the coffee, and it's really different, but I find it delicious.

James, have you had this before?

I haven't had this. I've had various coffee kombuchas over the years.

And so are you appalled by this idea or excited? Can we pour a bit and maybe try it?

Yeah, I can't actually measure it yet because I need something that's not fizzy because the gas messes with the pipette measurement. I'll come back to it in a little bit. The challenge, typically, with coffee and kombucha is that a good cup of coffee has quite a complex acid profile. A bunch of different acids in there contributing to that. And synergies between different acids can get quite complex. And so once you throw an acetic acid, that vinegar, you can really produce a very strange outcome. It's mixing different vinegars. It doesn't always work out. And so I've mostly tasted pure coffee kombuchas with a sweetened brewed coffee, and the scoby has gone to work just on that, and the acid outcome has been challenging. I'm very curious about this one, though.

All right, let's try it.

Cheers. Cheers.

Well, that's pretty weird. What do you think?

Well, I've had these ones before. So the first time you drink it, you're not expecting it. So it's a coffee pop, isn't it?

Yeah, it's like a weird combination between a fizzy... I almost had apple juice in my mind and coffee at the same time, which is a very strange combination. So they've done this?

This is the second fermentation one. So it's basically a of kombucha, then done a second ferment.

For me, I like my ferments to go a little longer. I feel like this is quite a gentle-It's a bit like.

It's a beginner's-I want more acid.

I want more pain.

But I think it's a beginner's one. And for someone who doesn't like coffee, could you drink that?

Yeah, I could. Essentially, it's quite It's interesting. It was weird the first time, but could I drink that glass of that? Definitely. While we're waiting to measure it, because you said it's too fizzy to get the-Yeah, I need to find a way. Polyphenol answers, I had a couple of final questions I'd love to. First is, you've given us all of these different types of coffees. I think lots of people were listening to this and saying, Imagine that I'm going into a coffee shop rather than making this at home. What is James's top tip for picking the best coffee in that situation?

First and foremost, I'm going to be pro-independent coffee shops. They have a different motivation. They're trying to win you over with the quality of the product, not with convenience and familiarity, which is how chains tend to work. So it's worth the gamble to find a good independent coffee shop. They'll care more about the coffee. It'll be fresher. It'll probably be of higher quality. It'll probably be theoretically higher in things like polyphenols, which that's a broad statement, and I'm very nervous making it, but you would hope that would be the case. And so that would be the first thing. And then I think as long as coffee is well brewed, which again, independents these days tend to do well, whether it is a flat white, or it is a filter coffee, or it is a straight Espresso. It's actually a matching extraction of the raw material across all of those things. And so you should see the benefits regardless of your a preferred drink. But people or independent businesses are excited to talk to you about what you like and help you find something that you like. And it's always worth a conversation and finding your local place.

I think we don't have that feeling as much anymore of your local coffee shop. And that's a shame. The thing independents offer over chains, too, is community space, experience. So, yeah, all those things is why I'm pro-independent business.

And one question that we were asked a lot from from our listeners was what about people with high blood pressure? So, Tim, you've been talking about all the great health benefits of coffee, but you also mentioned, I think, that historically people were told not to drink coffee because it raised blood pressure. If you have high blood pressure, what's your advice?

I think if your blood pressure is not under good control, then you have to be very careful with coffee and caffeine. But all the studies suggest that if you're just starting to drink coffee, it's only the first few weeks that your blood pressure will go up and then it stabilizes. So I wouldn't advise anyone to completely change their diet or anything they're doing if they don't have stable blood pressure. Get it stable and then start to slowly introduce coffee into your diet. It's not, as far as I'm aware, a contraindication if your blood pressure is well-controlled. I monitor my blood pressure and coffee has no effect on that. And there's some evidence that long term it might actually reduce your blood pressure.

Got it. So you're saying if someone's listening to this and they have high blood pressure, but it's under high control and they like coffee, you're not saying It's not, don't worry about it. You need to give up and... No.

There were old studies, they're out of date. They showed that people who hadn't been exposed to coffee, if you give them large doses, short term, your blood pressure can go up. So obviously, if If you have a problem, short term, you don't want to have that problem. But if it's well-controlled, then no real problem long term. And long term, we know from all the epidemiology that for the average person, they will get derived benefit in terms of their heart health. But the caveat, as always, is everyone is an individual, and all our responses are going to be different. We can't give advice that is going to apply to absolutely everybody. We're talking at this point, averages.

And there's always decaf.

Yes. So there's always decaf. And I think the blood pressure story was mainly about the caffeine side of it. So as we've heard, decatheter coffee is safe. The chemical processes are now considered very sophisticated and safe. There's plenty on the market. Find one that you like. No need to have caffeine. I think everyone's got to work out. There are lots of factors that affect your your caffeine metabolism, work out what suits you, experiment, find out. But for many people, it does get them going in the day and gives them a clarity of thought in their thought processes and other things that are important. And that's why I have coffee in the morning, but I don't have it at night.

All right, let's see what we got. All right, what have we got?

Let me just get you going. Andthank you. Okay, interesting. So caffeine first. This came out at about 33 milligrams, so actually comparable to, slightly less than the instant, but comparable to actually a normal strength instant. Chlorogenic acids came out at 55 0.87, so 55 to 60, probably, realistically, which is, I thought, decent, actually, like better than instant and certainly more enjoyable and fun to drink. So yeah, interesting.

Okay, so more polyphenols than instant coffee in that.

There's still a lot less than the coffee, which is how high the coffee levels were.

But there may be, I assume, some polyphenols from the tea in there as well, which may not be picked up by this if they're not specifically chlorogenic acid. Probably a broader profile.

But suggesting it's a healthy drink as well.

I would like to do a quick summary, and today has been really fun because we got to do a science experiment while we were doing this. I think the key takeaway is that coffee has been really reassessed from something that we were being told was really unhealthy to something that we now understand is actually healthy, and that how we understand that is very much about the way it has the impact on our microbiome and how our microbiome then affects us. There are two different components in the coffee that are really important. One is the fiber and one is the polyphenols. Interestingly, there's lots of fiber that is soluble, which is not how I have ever really thought about fiber. We heard James making the coffee, and you could see the hot water going in, sucking all of this fiber polyphenols out of this ground-up bean from a plant. Interestingly, there's this great new paper, which we will share as soon as it's peer-reviewed and published, which shows that this is then feeding one particular bug that we've now discovered, which I think lorsonabacter, did I just about manage to pronounce that, Tim? Which we can see basically is like a test for whether or not you drink coffee.

I will get my microbiome retested tomorrow and we'll see whether it's fine. I think it takes a bit longer than that, probably, right, Tim? Which then creates these chemicals as a result of eating this coffee, which we understand. I think you mentioned this thing, quinnic acid is just one example of something that we know then has this positive impact in our body because it passes through into our blood. That's very exciting. This does not mean you have to drink coffee. There are other ways that you can get fiber and polyphenols, but it means that if you do like coffee, you should be feeling good about this. And that interestingly for a lot of people in the US or the UK, the amount of fiber from your coffee, if you're drinking three or four cups, you take it be very significant because our total fiber intake is so low. And then we did this wonderful test where we tried a variety of coffee. So one of the things that was really striking to me is that the decaffenated coffee scored just as highly on this polyphenols count as the caffynated coffee, which is not at all how I would think about it.

I put it in my mind as a bit like instant coffee, not really very good for you. Instant coffee, on the other hand, was much lower on the polyphenols, so you've really lost a lot. Then we tried this fun coffee kombucha, which is definitely not something I suspect most of our listeners are regularly taking. And interesting, there were really polyphenols in there. I think that's really fun to see some real, like that scientific measurement right now, that there are some of these good things in that drink. And so the net result, I think, is don't drink the instant coffee. Do go to an independent coffee shop. And after that, it's a lot about your taste choices. And don't at all feel scared about taking the decaf because in a way, you avoid the caffeine and you're still getting most of these health benefits.

Very good.

And I look forward. There will be more papers to come as we understand more about caffeine and as the number of participants in Zoe grows.

Yeah, we'll be able to do one on tea, hopefully soon.

I would. I'm all up for that one. Wonderful. Thank you so much, James. Thanks for having me back. And thank you, Tim.

Thank you.

Thank you for joining me on Zoe Science and Nutrition Today. It's been really fun to learn about the different types of coffee, their beneficial compounds, and Tim's new research on coffee and the gut microbiome. It's even tempting me to drink coffee myself a little bit. Now, if you're interested in finding out more about your own gut microbiome, something that I do regularly, then you can learn more about becoming a Zoe member, getting your gut microbiome tested, and receiving personalized advice on how to eat the best foods to support a healthy gut. You can also get 10% off your membership. Simply go to zoe. Com/podcast. As always, I'm your host, Jonathan Wolf. Zoe Science and Nutrition is produced by Yellow Hewings Martin, Richard Willen, and Tilly Fulford. See you next time..