The benefits of olive oil, with Elizabeth Berger

Olive oil could transform your health. It regulates blood sugar, helps with weight management, and prevents long-term disease.

That is, if it's the right kind of olive oil.

Distributor of fine olive oils Elizabeth Berger and Prof. Tim Spector discuss the health benefits, debunk myths, and explain how storage and cooking methods affect olive oil’s nutritional value.

Elizabeth Berger is the founder of Frantoi, which works with growers and millers across Italy to harvest exceptional extra virgin olive oils.

Prof. Tim Spector is a true olive oil evangelist, as well as one of the world’s top 100 most-cited scientists and the scientific co-founder of ZOE.

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Episode transcripts are available here.

Transcript

[00:00:00] Jonathan Wolf: Welcome to ZOE Science & Nutrition, where world-leading scientists explain how their research can improve your health.

Olive oil could transform your health. It regulates blood sugar, helps with weight management, and prevents long-term disease. But how it's made matters. It also matters how you store it, cook with it, and how long you've had it.

In today's episode, olive oil expert Elizabeth Berger tells us everything we need to know to get the most from this kitchen staple. Elizabeth Berger is the founder of Frantoi, which works with growers and millers across Italy to harvest exceptional extra virgin olive oils. 

We're also joined by Tim Spector. Tim is an olive oil evangelist, as well as being one of the world's top 100 most cited scientists and my scientific co-founder at ZOE.

Elizabeth and Tim, thank you so much for joining me today. 

[00:01:02] Elizabeth Berger: Thank you for inviting us. 

[00:01:03] Professor Tim Spector: Hello.

[00:01:03] Jonathan Wolf: So Tim knows this, but Elizabeth, we have a tradition here at ZOE where we always start with a quick-fire round of questions from our listeners. Are you ready to give it a go?

[00:01:14] Elizabeth Berger: I'm going to give it a go, yeah. 

[00:01:15] Jonathan Wolf: All right. And so the rules are very strict. You have to say yes or no, or if you absolutely have to, a one-sentence answer. 

We know that for scientists, it's particularly tricky, so I'm going to start with Tim. Could the right olive oil help prevent heart disease? 

[00:01:33] Professor Tim Spector: Absolutely. 

[00:01:34] Jonathan Wolf: Should we be having olive oil every day?

[00:01:39] Professor Tim Spector: Yes, these are easy. 

[00:01:41] Jonathan Wolf: Okay, Elizabeth, is one type of olive oil healthier than the rest? 

[00:01:46] Elizabeth Berger: Yes. 

[00:01:47] Jonathan Wolf: Are there ways we could use olive oil better to give us more of the benefits? 

[00:01:51] Elizabeth Berger: Yes. 

[00:01:53] Jonathan Wolf: Does storing our olive oil in a tin compared to a bottle make a difference? 

[00:01:57] Elizabeth Berger: Yes, it does. 

[00:01:59] Jonathan Wolf: Ah see, it's quite easy. And then final question, and you can have a whole sentence here. What is the most surprising thing that you've learned about olive oil? 

[00:02:08] Elizabeth Berger: Potentially its seasonality. So, olives are harvested at a certain point of the year and the olive oil changes through the season as it evolves. 

[00:02:19] Jonathan Wolf: Olive oil is definitely a staple in my kitchen. I think it's increasingly a staple in many people's kitchens, certainly for people who are more affluent.

And I use it basically every day because I've been listening to Tim for a long time, and I often heat it up on the stove as the basis for cooking food. And although I've been told often that this is okay by scientists I respect and trust at ZOE. There continues always to be this little nagging thing at the back of my head about if I see it smoke, is this really okay? 

And I'm not alone because when we asked listeners for questions for this episode, this was the number one question that came back about. Is it really okay to cook with olive oil, and what are the restrictions? And I know that you have great answers for us on that question, along with a lot of others.

Before I jump into these sets of questions for the listeners though, I think we should maybe just start right at the beginning, as we often do on this podcast. Elizabeth, what is olive oil? How is it made? 

[00:03:22] Elizabeth Berger: Olive oil is rather unusual in the sense, when you look at commercially produced cooking oils, because it's naturally extracted, naturally pressed from the fruit of the olive.

It's the only commercially available oil that is actually totally just freshly pressed juice. So it's got its own set of natural preservatives in it. Nothing's added in. And rather like, perhaps something like freshly pressed orange juice, the benefit of that is that you're getting a very, very fresh product, but it's got high polyphenols and antioxidants that protect it through the lifespan of about 18 months.

So the shelf life of extra virgin olive oil is around about 18 months. 

[00:04:01] Jonathan Wolf: And is all the olive oil in the grocery aisle the same or made in that same way? 

[00:04:06] Elizabeth Berger: Extra virgin olive oil is made in that way, yeah. So it's very important that you look for extra virgin olive oil if you're looking for the highest quality of olive oil.

[00:04:16] Professor Tim Spector: Yes, well then it doesn't say a blend of extra virgin olive oil with virgin olive oil. 

[00:04:21] Elizabeth Berger: Which it may not even say, regrettably. 

[00:04:24] Jonathan Wolf: So can I just for a second get a bit of clarity here because we've jumped from olive oil to extra virgin olive oil. Could you unpack that for me? 

[00:04:34] Elizabeth Berger: Yeah, so there are actually four classic grades of olive oil that you can find.

So there's extra virgin olive oil, which is the highest quality grade, and that is deemed to have the lowest level of free acidity, which must be below 0.8%. 

You then have virgin olive oil, which is a slightly lower quality grade. And that should be written on the label, so you should be able to see that it's virgin olive oil. That has a free acidity of 1.5%. 

And then you have further lower grades of olive oil as you go down, ending with just simple olive oil, which will have a very small percentage probably of extra virgin olive oil blended into it just to enhance the flavor. But it's quite a different product. 

[00:05:18] Jonathan Wolf: Just to help me to understand, because you mentioned these technical terms between them, are they made in exactly the same way, of olives in exactly the same way, and this is some sort of test to decide whether this is high enough quality to be an extra virgin olive oil?

[00:05:29] Elizabeth Berger: They're extracted in a slightly different way, so extra virgin olive oil is just either using a centrifuge or a normal press in order to extract the olive juice. 

Whereas with lower quality grades, there may be a little bit more of a process involved in terms of extracting it. They're trying to get more out of the olive basically.

[00:05:47] Professor Tim Spector: So the more you squeeze out of it, you're getting the dregs, the bits that aren't normally part of the fruit, the sort of fatty bits of the fruit. You're getting these extra components that aren't really the healthy bit, so the more you try and do it. 

And I guess the more industrial ones are actually using chemicals as well, aren't they?

[00:06:03] Elizabeth Berger: They are. 

[00:06:03] Professor Tim Spector: Chemical solvents, which get mixed up with the oil as well. So it's this huge range. 

[00:06:09] Elizabeth Berger: There is a massive range and it's a little bit difficult to navigate. And I feel that probably quite a lot of people have found that a challenge and maybe that's why some people think, Oh, I'm going to, you know, maybe I won't try extra virgin olive oil because it is more expensive.

There's a reason why it's more expensive. And even within extra virgin olive oil as a category, you can get quite different grades of quality. And that's all determined really on the harvest point. 

So olives happen to be green and they go black when they mature. Unlike grapes, which are determined to be red or white from the start of their life, all olives are green, and they become black as they mature.

And if you think about the consistency of an olive, so a green olive is quite firm when you touch it, whereas a black olive is actually softer. So a black olive will yield more oil. That's great if you're looking to make a lot of oil, but in terms of the quality of oil that you can get out of it, a green olive will deliver a much higher quality of oil.

So an olive oil, an extra virgin olive oil that comes from green olives, is actually going to be better for you. All of that said, you can't just harvest super early, because it would damage the tree to get the olives off, and also it would be quite difficult to get the oil out of the olives. So you have to find that point when it's exactly about to turn, just starting to blush basically.

[00:07:29] Professor Tim Spector: It takes about seven kilos, doesn't it, of olives to get a liter or maybe it's even more than that for many, many varieties.

[00:07:36] Elizabeth Berger: Yeah, exactly. It depends on the cultivar because it also depends on the size of the pit and all of that sort of thing.  

[00:07:41] Jonathan Wolf: So can I just make sure as a extra virgin olive oil novice that I've understood this? This is a danger I can see with Elizabeth and Tim together. They're already shooting off ahead of me.

So extra virgin olive oil means the olive has just been pressed. Presumably they take the stone out and then they squash it, do they? 

[00:08:00] Elizabeth Berger: Not necessarily, no. I mean, mostly you don't. It doesn't need to be taken out as it happens. You can just crush it with, absolutely everything goes in.

[00:08:07] Jonathan Wolf: Put everything in there, including the stone, and you just squash it with something really…

[00:08:09] Elizabeth Berger: It all gets squashed, exactly. And then from there, the oil is coaxed out with a centrifuge. 

[00:08:15] Jonathan Wolf: So spun round and round and you get the oil out. And you're saying the difference between the extra virgin olive oil and the olive oil is they're doing more than just squeezing it in order to get the oil out.

[00:08:27] Elizabeth Berger: So the quality that you would get out of that paste, you know, you'll get the highest quality from the sort of early part of the press. And then as you go on, you get the sort of the dregs, as Tim was saying. [00:08:38] Jonathan Wolf: So there's some rules therefore in different countries about...

[00:08:44] Elizabeth Berger: Well, there's a European council that sort of determines the level of olive oil that you've produced, and ultimately it ends up in a taste test.

And this is really, really important because, I mean, this is how I came to olive oil is through taste. I've then subsequently discovered all of the additional benefits to it. But I think that, you know, taste is a fundamental part of it. 

And they do judge ultimately whether something is extra virgin or not based finally on the taste of it. So it should have a superior taste. 

[00:09:13] Jonathan Wolf: So my takeaway from this is in a sense, it's less just the process that was used to extract the oil, which we often talk about elsewhere in food, right? We're very focused on the manufacturing. 

Here it's like genuinely sort of the quality of the product that comes out that restricts the process to make it. But extra virgin olive oil is ultimately like a measure of the taste and quality of the oil that comes out. 

[00:09:39] Elizabeth Berger: It is, but the quality is determined throughout the process. So, you know, there are a million little steps here, and that's why it's important that you understand who you're buying your olive oil from.

Because, for example, when olives fall from the tree, they come off the tree, often shaken off, they fall onto the nets, they're collected up, and they're put into baskets, or crates rather and then they're taken to the frantoio, which is the mill. 

Oftentimes this mill is not owned by the person who owns the olive grove. And so there's a little bit of a delay time. If you imagine you're harvesting throughout the day, you get to the end of the day and you've got your olives in a crate, you then can't get them into the mill because the mill's also closing for the day. And so what you might do is you might keep your olives and then take them the next morning to be pressed.

That's completely standard practice, by the way. So that's what, you know, 99.9% of people are doing. What, however, that means is the second that you've taken the olive from the tree and it's detached from the branch, it does start to begin the process of oxidation, you know, exactly in the way that it would with grapes when you harvest them.

And so, you know, the job that is quite important is to be able to get them to the press as quickly as possible to avoid that oxidation. So you're preserving the quality of the oil by getting them into the press as quickly as you can. 

Therefore, if you own your own press, that has a material difference because you can harvest all day and you can say, well, it might happen to be five or six o'clock in the afternoon, no problem. It's my own press, I'll get them straight in there. And so you can control that process better. 

But as I said, 99.9% of producers don't own their own press because it's just not practical. It would be far too expensive. 

[00:11:21] Jonathan Wolf: So I think Elizabeth you’ve done a great job of already helping us to understand that there's a wide variety of ways in which olive oil can be made. And I think there's very clear distinction now between the extra virgin olive oil and these other forms of olive oil. 

I'd really like to switch over to Tim now, because in a way, why on this show about health and nutrition are we spending so long talking about olive oil? And the answer is because of the health benefits that are associated with it. Tim, what are they? Are they real? 

[00:11:53] Professor Tim Spector: They are real, but it's been a slow process of us getting to the point where we can be so confident about it. Because in the 1960s, it was noted that Mediterranean countries had much less heart disease than northern European countries. And people thought it was something in the diet, they thought it was about the wine or the lifestyle or they couldn't really know what it was, but it was the vegetables.

And it turns out that it's been a slow bit of detective work to work out that the amounts of fats consumed in Mediterranean countries is actually quite high, which went against the sort of theories of 20 years ago that fats were bad for you. 

But it turns out the main source of fats in the Mediterranean is olive oil. So huge amounts of fats are consumed in the form of olive oil. So that started people thinking, well, maybe there's something in olive oil that's actually healthy despite the fact that you can get up to 12% of it is saturated fat, which we're all told, you know, in the U.S. and the U.K. is really bad for you.

So, you have these Mediterranean countries drinking a lot of saturated fat in their olive oil, and they have much lower rates of heart disease. So people started then looking at olive oil itself. It wasn't studied much, because it was very low levels in the U.S. and the U.K., where a lot of this epidemiology was being done.

And so, gradually, more and more studies have shown that people who drink olive oil regularly, compared to those in the same country that drink less amounts, have significantly lower rates of heart disease, stroke, and increasingly, evidence that cancer is less. Now, this was all observational. There are at least 30 studies of observational cohorts showing this.

And there are hundreds of smaller studies now showing that if you give, say, the normal diet type study of 20, 30 people, give control groups, you can see changes in their bloods and their blood fats and inflammation going down. 

There hadn't been any large-scale, long-term studies until 2018, when they did something called the PREDIMED study. It was randomized, but not blinded, because it was, they were delivering large amounts of olive oil to 7,000 Spaniards, large amounts of mixed nuts to another group, another group that were just given the standard Mediterranean meals. 

And they followed them up for six years and this was the best study that had been done and clearly showed that the olive oil group had these really significant reductions in heart disease and strokes and breast cancer.

[00:14:36] Jonathan Wolf: So Tim, I just want to be clear, like the drug intervention in this study over six years was literally just got sent bottles of olive oil and the people who got sent bottles of olive oil actually had lower levels of strokes and things like this.  

[00:14:50] Professor Tim Spector: And heart disease. 

[00:14:53] Jonathan Wolf: It sounds crazy, right?

[00:14:54] Professor Tim Spector: Yes, and breast cancer and some signs that are getting, you know, less brain dysfunction leading to dementia.

So it was an amazing study because it was huge logistic exercise to keep people stocked up with this. And they were giving them the equivalent of about four to five tablespoons a day. Which actually is not far off some levels you'd have in bits of Greece, for example, which would be seen as quite normal, but a hundred times more than you get in the U.K. or the U.S. where, you know, we're only really drinking one bottle of olive oil a year, as opposed to one every two days in many Mediterranean countries.

So this, I think, was a fairly pivotal study, but there've been other ones since in the U.S. showing that it's not just a Spanish thing because they were sponsored by the olive oil industry, and Spain does have a slight interest in promoting it. They're the biggest producer in the world. 

But in the U.S., the cohort studies comparing olive oil drinkers against non olive oil have found virtually the same results. So I think we're now very confident that drinking extra amounts of olive oil, and particularly extra virgin olive oil has these major benefits. 

It seems to be that that is quite important, that the quality is important and the few studies that have looked and compared extra virgin against virgin or basic industrial level olive oil have shown clear differences.

So I think it suggests it's the extra ingredients in the extra virgin olive oil rather than necessarily just the fats themselves, perhaps a combination of both. 

[00:16:35] Jonathan Wolf: So it sounds like the evidence looking at what happens to human health is quite compelling. 

Do we understand what's going on? Do we understand what it is inside this extra virgin olive oil that is creating this really rather remarkable, I think, health benefits? Completely the opposite to how I was brought up with this idea that oil is a fat, fat is really dangerous. 

I often talk about my father having this high cholesterol. The idea that he should be adding olive oil to his food, I think, would have literally made his doctor explode with anxiety. 

[00:17:14] Professor Tim Spector: Yeah, absolutely. That's how we were all taught. That this is a fatty oil, it's got saturated fat, which we're told in meat is terrible for us, it gives you heart disease. And yet this thing is not working like that. 

So, olive oil is complicated, so there's a lot of components to it. It's not one single fat, it's not one single chemical. But as well as the saturated fat, there's a lot of these monounsaturated fats, which are smaller, simpler types of fat called the good fats.

And one of the key ones is called oleic acid, just comes from olea, the Latin for olive. And that seems to be one of the most important healthy fats that have this effect on the body. 

So some of the studies have tried to separate out the different components and see what it is, suggest that, yes, it's these types of fats, like the oleic acid, that are beneficial to the body, as we've discussed on other podcasts, you know, there are good and bad fats, it's this ratio that's important.

[00:18:17] Jonathan Wolf: And we've actually recorded recently a podcast on seed oils with Dr. Sarah Berry, who Tim and I know well. Which is the best explanation I've had to help me get my head around these different types of fats. So if this is something you are interested in, I definitely think that's an interesting follow-up.

[00:18:36] Professor Tim Spector: So, but it's not just the fats. So the epidemiology study, which has measured things like fat levels changing suggest that it's actually the polyphenols. We've mentioned these before on a number of podcasts, these defense chemicals in the plant and this time in the olive fruit that are conveying the benefits to the body. 

Because they are the key antioxidants. They are the ones that nourish our gut microbes, and they're in huge numbers in olive oil compared to other foods. You can sort of see how, if anyone's had, you know, olives or olive oil, there's some similarity, and it's because of those defense chemicals in your mouth that are, as well as defending the plant, end up nourishing our gut microbes and perhaps helping our immune systems to then fight disease and aging and all the stresses of life in the cells.

[00:19:33] Jonathan Wolf: And is the level of polyphenols in olive oil, you know, very high compared both to other oils, but I guess also to other plants that I might eat? 

[00:19:44] Elizabeth Berger: There are 36 known polyphenols in extra virgin olive oil, and I guess if you would compare that to coconut oil, for example, there are six. So it's a much more complex mix of polyphenols in extra virgin olive oil.

And for example, one of those polyphenols is oleocanthal. It's the polyphenol that gives a slight burn in your throat when you're tasting really, really decisive extra virgin olive oil, so peppery olive oil. 

And oleocanthal exists naturally in olives. It's one of the components in ibuprofen, for example. So it shows us that it's an incredible natural anti-inflammatory. 

[00:20:25] Professor Tim Spector: Extra virgin olive oil is probably one of the best sources of polyphenols you can get. Certainly in any oil that we drink normally. But it's also related to the quality. 

So the higher the quality, the greater the concentration and diversity of polyphenols in it, which I think is a really important message. And the lower your quality, it gets diluted, and you don't get nearly the same benefit. 

[00:20:49] Jonathan Wolf: So one of the big differences between that extra virgin olive oil and the regular olive oil is the amount of these polyphenols that you're describing, which you're saying is so important for the health properties.

[00:21:00] Professor Tim Spector: Yeah, we think they are critical for giving these benefits to the heart, et cetera. 

[00:21:05] Jonathan Wolf: And there'll be a lot of people listening who haven't heard of polyphenols before, or very briefly, Tim, could you help us understand a little bit more why they matter? Do we understand what's going on?

[00:21:20] Professor Tim Spector: Polyphenols is an umbrella term for all kinds of chemicals you find in all kinds of plants that are exposed to the elements. They're perhaps, there are thousands of them, and we don't have names for them all yet. We're still discovering some of them. 

And it turns out that these chemicals in the plant are there to protect the plant against sunlight, against wind, against fungal infections, against pests, insects, all kinds of traumas. And allow it to survive and function, and that's why a lot of the best wines and the best olive oils are perhaps in extreme temperatures as well, because the harsher the environment, the more polyphenols are produced. 

Now, we know now that polyphenols act mainly via our gut microbes. So when we drink olive oil, these polyphenols are released into our guts, into our colon, and our microbes will feed off them, and that gives them energy to reproduce.

They then interact with the cells in our gut and our immune system, sending signals that help our heart reduce inflammation, critically sort of calming down the whole system and meaning that our vessels are in a much better healthy state than they would be if we didn't have these calming defense chemicals.

So that's the sort of simple way to think about these, is like they're rocket fuel for your gut microbes and up to now we've had not nearly enough of them because we've not thought about it. Because we've had this rather reductionist view that everything's about fats and sugars and proteins, which of course we now know is really facile.

[00:23:07] Jonathan Wolf: And how many polyphenols are there? 

[00:23:10] Professor Tim Spector: Thousands. 

[00:23:12] Jonathan Wolf: Okay. Thousands. So just to get everyone to reset, because I think we're used to, you know, there's 10 vitamins or a hundred. I mean, there's like thousands of these. 

[00:23:22] Professor Tim Spector: I mean, that's right. I mean, nobody can reel off the list of the known polyphenols, they have very long names. You know, they're in a group. 

The polyphenolic compounds and the anthocyanins, they give the color also to the grapes or the olives. They'll make it change, you know, those greens and those purples and those things. They're really important, they're signs that any plant is packed with these polyphenols, and you see this in lettuces and tomatoes as well.

So, we're still at a very early stage of understanding them. We can give a rough idea of how many polyphenols there are, but we can't yet identify all of them by a long way. 

[00:24:01] Jonathan Wolf: And so presumably some are probably more healthful than others, and we just don't yet know that. But we do know that in olive oil, not only it's really rich, but you have like these real randomized control trials that you're describing that really show health benefits.

[00:24:16] Professor Tim Spector: Yes. And show differences between very basic olive oil, which has low levels of polyphenols compared to very high quality ones with high polyphenols showing differences in changes in your blood and changes in inflammation, et cetera. So I think the data is really pretty good now. 

[00:24:33] Jonathan Wolf: And so those studies, just to confirm, it's not just Elizabeth saying like this olive oil tastes so much better. And we're going to talk about that later, which I'm very excited about.

But genuinely, you know, there's health benefits. Benefits because of course it becomes more expensive, doesn't it? As you go from olive oil to extra virgin olive oil. But the reality is there are real health benefits as you move to those more expensive olive oils.

[00:24:52] Professor Tim Spector: Absolutely. Yes. So if you're looking for something that could help everything from, prevent dementia, cancer, your immune system, your gut health, your heart, this is something that is worth paying for it. 

As I said, we're in a position where we're drinking hardly any of it in the U.S. and the U.K. and most people are buying one bottle a year and put it in a cupboard somewhere and that amount really isn't going to make any sense any difference to their health. 

So it's trying to change this mentality. And there's a lot of misinformation out there, but I think from the vegetable oil companies, Elizabeth and I were discussing this, that they've got the huge power, the canola companies, the rapeseed oil, to just go in and keep spreading rumors about olive oil being bad for you or, you know, not good, it's not pure, you know, and you can't cook with it, all this other stuff.

So, it's all nonsense. Everyone should be switching to olive oil, you know, it's the simplest thing you can do for your health. 

[00:25:53] Elizabeth Berger: I think as well, if you look at polyphenols, they take a journey. So if you want a deep dive into an understanding of polyphenols, it's possible to do it quite simply. And this was one of the light bulb moments for me when I moved to Italy.

Because what happens, one of the real secrets to me about the Mediterranean diet, is that you eat what's in season. As it turns out, when it comes to olive oil, we don't really think about that. We're very used to just putting a bottle of olive oil in the cart and you move on as if you're perhaps buying washing powder or something like that.

Olive oil should be considered in terms of seasonality because the moment that it's been produced, it has a very high dose of polyphenols and they taper off as the oil evaporates, matures and goes on its lifespan. Because, as I said, it's freshly pressed juice, so it's rather like orange juice.

If you think about buying a freshly pressed orange juice, the next day you wouldn't really be wanting to have it. Well, you know, that's because it's changed and it's oxidized with time. 

So the polyphenols do change in an olive oil as it's going through its lifespan. So having freshly pressed, new-season olive oil is incredibly good for you. What's interesting about that for us is that in the northern hemisphere, for example, the harvest happens in October, perhaps into early November. 

If you are able to get hold of new season olive oil, therefore, it is the time when you need it the most. Those high polyphenols, they protect you through the winter. It's like having a sort of wheatgrass shot or, you know, an intense pomegranate juice or whatever it might be. It's incredibly good for you when it's new season olive oil and that will taper off as time goes on. 

What actually happens as well from a culinary perspective is that during the winter you're perhaps enjoying more base notes. So, I'm thinking root vegetables, grains, pulses, that sort of food. And when you've got a very peppery oil that happens to have very high polyphenols in it, that counterbalances those base notes wonderfully. So it works really, really well with those winter ingredients. 

[00:27:59] Jonathan Wolf: I'd really like to just spend a minute on this sort of thing about the composition of the extra virgin olive oil over time because we had a lot of questions around that.

And I heard Tim mention that there'll be lots of American and British listeners who might have a bottle of extra virgin olive oil that might be sitting, you know, two years. 

Let's say it's been pressed. How stable is this extra virgin olive oil? How does it change in the following months and years?

[00:28:30] Elizabeth Berger: Yes. So the process is that the olive oil is produced and then it then typically naturally decants. So it takes a little bit of time where the sediment falls to the bottom. You then have a choice as a producer, whether you filter or you don't filter in terms of, super high quality, you would wish for a light filtration of your oil.

And there's a reason for that because an unfiltered oil, and I'm sure that this is one of those myths that's out there that, you know, an unfiltered olive oil is really great because you see it in those lovely clear bottles and it's got that lovely cloudiness. It must be the real deal. 

It's actually not. That's actually not great for, for a couple of reasons. One, you shouldn't have your olive oil in clear glass because it will change its quality. So you're looking for dark glass as the very, very best format for extra virgin olive oil. 

But the other thing is, is that that sediment that is in suspension in the olive oil will actually start to oxidize the oil with time. So anything that needs to be shipped, we have to think about these things. If something's being shipped globally, it does need to be stable. And so a light filtration won't change the quality at all. It will actually enhance the quality because it will give it a little bit of stability in terms of shipping.

[00:29:41] Jonathan Wolf: So to confirm, if you see a bottle of olive oil that sort of says it's unfiltered and has some sediment in, which I've definitely seen and always thought that looks pretty cool and very authentic. Actually, that's like a complete no-no, don't buy that because basically that sediment will have been continuing to react with the olive oil and I'm going to lose sort of the health properties we're talking about. 

[00:30:06] Elizabeth Berger: Exactly right. Yeah. 

[00:30:07] Professor Tim Spector: That's even if it's really bright green as well. 

[00:30:10] Elizabeth Berger: Totally. 

[00:30:10] Professor Tim Spector: Which is another marketing thing, isn't it? 

[00:30:12] Elizabeth Berger: Well, that's to do with the cultivar. And when I say cultivar, I mean the variety. So when you start to dig deep, you've got over 3,000 of cultivars in the world. 

In Italy alone, there are over 600, so they are different varieties, and they will give a slightly different flavor of oil and we're going to taste that, and we're going to see what that difference might be. 

But I think as well, heading a little bit back to the polyphenol point, there are certain olive cultivars that have a naturally higher polyphenol level.

[00:30:44] Professor Tim Spector: Each area has got its own, and even within the variety, there are, you know, low lying or high on a hill, you get very different. 

[00:30:53] Elizabeth Berger: Exactly. Provenance makes a real difference. And I think the other thing to consider is whether something's a blend or whether it's a monocultivar. You know, having a pure monocultivar, what you get from that in an olive oil is just definition. So you will be able to taste it's different points. 

Whereas a blend, as with wine, you know, it's not, it doesn't diminish the quality at all of the olive oil, but the blend should be greater than the sum of its parts. So the end result should be better than if those particular oils had been made as monocultivars.

[00:31:24] Jonathan Wolf: So if we imagine that we've now learned to reject the bottles that have all that really nice stuff at the bottom, not clear glass because that's going to damage the olive oil over time. 

[00:31:35] Elizabeth Berger: It will oxidize, yeah. It's much more likely to oxidize because it'll get the light raised that will just damage it and change it.

[00:31:42] Jonathan Wolf: And so does that mean back to the question I asked at the beginning about tin versus bottle? 

[00:31:45] Elizabeth Berger: Yeah. So I mean, in terms of the bottle, the very best is dark glass and you shouldn't keep it next to your stove. So all of the things that I used to do when I was just putting my olive oil in the cart, lovely clear bottle, looked really authentic, sort of Italian sounding perhaps nice and unfiltered, and then keeping it next to the stove. All of those things are wrong. 

So really what you want to do is you want to keep it where the temperature is constant. So away from the stove, away from a window where the temperature will fluctuate quite a lot. So if you can keep it, you could always keep it in a cupboard, perhaps where you keep your salt and pepper and that sort of thing.

[00:32:24] Jonathan Wolf: And is a tin better than a dark glass, therefore, because no light comes through? 

[00:32:27] Elizabeth Berger: So what happens with a tin is that it's a very good container, there's no question about that. But the trouble is, is that as it depletes, as the oil depletes in the tin, that space is filled with oxygen, which is oxidizing the rest of the oil.

There are ways around this. There is now a technology of bag in box and the bag actually closes in around the oil. And that's very clever because then it's reducing the contact with oxygen, which is really important. 

But if you do like to have a tin and if you're buying your oil in quantities, the best thing that you can do is to decant it into dark glass and then put a proper top on it.

[00:33:00] Jonathan Wolf: Imagine that we have now learned also it's in dark glass. Yes, it's been lightly filtered. But you know, I'm in America, right? Presumably it takes a long time for this to eventually arrive, you know, in my grocery store. 

How fast are these amazing chemicals decaying? How many months or years does this olive oil remain good? Does it remain good forever? 

[00:33:26] Elizabeth Berger: Yeah, so it goes on a journey. So you've got very, very high polyphenols, just after the point of harvest. So really, the main point is to be able to get access to that oil as soon as you can, and so finding a way of getting new season olive oil into your life before Christmas is a great thing. That's when it's really going to have the greatest benefits for you. 

And you need to think about distribution, as you've quite rightly said, because of course if you're buying olive oil from a supermarket, it will have been stuck in the distribution chain for an amount of time. There's no question that you would have new-season olive oil in the U.S. before perhaps March or April time. And the polyphenols have taken a journey during that time, so they will have gone down in there. 

[00:34:11] Professor Tim Spector: They go down by about a half every six months or so, is that right? 

[00:34:15] Elizabeth Berger: If you think about the way that the Mediterranean's consume olive oil, they would be consuming that within a year, because of course then there's the next harvest.

[00:34:21] Professor Tim Spector: On the two problems here, one is the amount of polyphenols you might lose with time. And the other is where you're oxidizing the fats and it's slowly going rancid. Could you maybe just sort of tease those apart. 

[00:34:35] Elizabeth Berger: Yeah, absolutely. So the polyphenols take this journey where they're very high at the start just after they've been harvested and then they taper off.

[00:34:44] Professor Tim Spector: And they're protecting not only you, but they're also protecting the oil. 

[00:34:47] Elizabeth Berger: They're protecting the oil and that's the fundamental thing. So as they go down, the oil is getting less protected and it softens. So that pepperiness that you get right at the beginning of the season, many people have actually never tasted because of course, you know, if you're buying your olive oil in a supermarket already, it's been around for probably six months before you take it off the shelf. 

If you look at the back label of any bottle of extra virgin olive oil, it will tell you the harvest date. And it's really, really worth checking because there's no way that you want to be spending, you know, 20, 30 pounds or dollars for that matter, on a really, really good bottle of olive oil and it's, a year old. You know, it's, it would be a shame to do that. You really want to be trying to get it when it's as young as possible. 

So there are a number of faults that you can get in the production process. Perhaps there was some imperfect fruit that went into the press. Perhaps something happened along the way of the production. Perhaps it's been oxidized prematurely. 

[00:35:50] Professor Tim Spector: It’s like a corked bottle is it?

[00:35:51] Elizabeth Berger: Exactly right. Exactly right. It's a fault for acidity and you can definitely smell it. As I said before, the light filtration can avoid anything like that. 

[00:36:02] Jonathan Wolf: If someone's thinking about this, I'm not as sophisticated about the taste as you. Price probably plays into my thinking here as well, because it's expensive. 

I’m taking away from this, that if it's been sitting there for five years, I probably really lost quite a lot of health benefits. 

[00:36:17] Elizabeth Berger: For five years, you wouldn't want to consume it for five years. 

[00:36:19] Jonathan Wolf: Help me to understand. Has all the health benefits disappeared at 12 months from an extra version of olive oil?

[00:36:24] Elizabeth Berger: 18 months is what you're looking at. So after 18 months, then, you know, it's, it's really lost. It's the majority of its health benefit. 

It's still an oil that you could cook with, you know, you could roast your potatoes with it and, and that sort of thing. There wouldn't be, you know, there wouldn't be any issue.

[00:36:39] Jonathan Wolf: And if I went into a grocery store and just picked an extra version of olive oil off the shelf, am I guaranteed that it will have been harvested within the last 18 months? Or could that already be…? 

[00:36:51] Elizabeth Berger: It should have been, but that's why you need to check the label because, you know, distribution is a complex sort of a thing, you know. And it could well be that something could be on the shelf. I've actually seen it a number of times. I recall most recently in New York, seeing a bottle of oil that was $50 on the shelf. I turned it around and it was over 18 months from the harvest date. 

[00:37:14] Jonathan Wolf: Wow, so this is like a very, very premium bottle. And you're saying that if it's not within 18 months, you're gonna tell me that it doesn't taste very nice, but also that the health benefits are really not there. . 

[00:37:27] Elizabeth Berger: Totally different. That works with many, many things, you know, shelf life is an important factor. You know, it's something that would happen, let's say with face moisturizer, it would have a shelf life. And so you would need to know when it had been bottled. 

[00:37:42] Jonathan Wolf: It's really interesting because I think I've tended to think about this as being sort of completely inert. You know, there's sugar and flour in the cupboard. And of course, you know that maybe the flour, a very long time. But I basically thought of it as being like completely inert as long, you know, if it's in the cupboard and there's not sun on it and you're saying it's really not right.

[00:38:02] Elizabeth Berger: It's not the case exactly. When the bottle is open, however, that's an important consideration. Because that is also a slightly different point. 

So once you've opened your bottle of olive oil, it would typically have, between, three to four months, it will be absolutely fine. But of course, the fact of opening, so olive oil, extra virgin olive oil in particular, when it's bottled, they will probably put a little bit of inert gas just at the top, just to protect it. Something like argon or something like that. A heavy gas that will just protect it. That's how olive oil is kept. 

And so once you've opened it, then of course, you know, it does start to go on a little bit of a journey. So the whole thing that you were saying about savoring a bottle because it's your really special bottle of extra virgin olive oil, never do that. Just enjoy it. 

[00:38:48] Jonathan Wolf: It's a bit like a bottle of wine. Like once you've opened it, you know, you can't savor that for weeks because it goes off, but we don't detect this in the same way. 

[00:38:54] Elizabeth Berger: You’ve got longer with olive oil.

[00:38:56] Professor Tim Spector: I used to treat it a bit like a really good bottle of red wine that it might get as a gift, and I'll put that in the back of the cupboard because it's going to get better and I'll be enjoying it with friends who really appreciate it. If you do that olive oil, it's ruined.

[00:39:07] Jonathan Wolf: So I want to ask the question that I asked at the beginning, can you cook with extra virgin olive oil? And Tim, I think this is a lot about health risks. 

[00:39:19] Professor Tim Spector: Yeah, so I think the PREDIMED study that I mentioned was really quite important in this because the Spanish, unlike some other countries in Europe, use it for cooking as opposed to just putting on as a dressing on the finished product. 

So they are heating it up all the time and eating it. And it turned out, although most of the oil was done in the cooking they were using it, they were still getting the health benefits.

And there's various stories about you know, are you destroying it when you heat it up, and is it dangerous when you heat it up?

So dealing with the danger business, and there was this idea that there was a smoke point that you got to with olive oil that made it dangerous or bad for your health or gave you cancer or this stuff. And I think a lot of this stuff, probably propagated by the competition. And it turns out that normal levels of cooking, you don't really get above 180 degrees anyway, when you're frying stuff. It's only if you're doing wok frying that you might get to a point where. You hit its smoke point, which is about 200. So, that's not really a problem. 

It's also very stable because of the saturated fat, and that was the other thing that, I think, Sarah discussed about the stability of these fats, is the other factor rather than the smoke point. And it is very stable because having that saturated fat in there sort of keeps the whole thing together, unlike some of the other vegetable oils. 

So from a purely chemical point of view, it seems okay. Now you do lose some of the polyphenols. And there was a Spanish study that looked at this, that fried up different amounts of olive oil over time at different temperatures, and did show that by heating it on a sort of under regular cooking, you lost about 40% of the polyphenols. But you still had 60%. And at high levels, you did lose 75%, but again, you still had 25%. 

So if you're starting with a good quality olive oil, you're still going to end with something that is stable, not causing problems, it's still got plenty of polyphenols. But if you cook with it, you're not getting the same benefits as you would if you're having it on a salad or you're having it spread, you know, over your fish once you've cooked it.

[00:41:36] Elizabeth Berger: Exactly. And so therefore, if you've got a very high-quality olive oil, you may prefer to keep that as a raw ingredient rather than cooking with it. But the benefit as well, whilst the polyphenols might be dropping down when you heat them in the olive oil, they will improve the nutritional content of the ingredients that you're cooking.

So let's say, for example, that you roasted some carrots with extra virgin olive oil. It will improve the nutritional content of the carrot, not just decrease the level of polyphenols from the olive oil. So there is, there is an upside. So there's no question that you should be using it to cook with.

[00:42:13] Jonathan Wolf: Brilliant. So I would love to move to the next stage of this show, and I'm particularly excited about that, Elizabeth, because you brought a whole bunch of different olive oils with you. And they've been sitting on this table that's hidden on the corner, and I've been eyeing them up throughout the show.

And I'd really love for you to help explain, I have never done an olive oil tasting. I didn't even realize there really was such a thing as an olive oil tasting. 

And then I hope you're going to help us to understand what you might be looking for and experiencing as you're tasting olive oil, and then helping us to understand how you might apply that in your own life, going to your own grocery store to understand what you're doing.

[00:42:55] Elizabeth Berger: Absolutely. 

[00:42:56] Jonathan Wolf: All right. Well, should we start pulling these out? 

[00:42:58] Elizabeth Berger: Yes. Okay, so we're going to have three glasses each, and we're going to taste three oils and they come from three different areas of Italy. The only thing to know is that the olive tree thrives in a warmer climate, particularly a sort of a Mediterranean climate. It can't handle very, very cold weather. 

[00:43:18] Jonathan Wolf: Explain what you've brought. And maybe help us understand a little bit why they would be different. You mentioned the variety. Is it all about the variety or is there anything else? 

[00:43:28] Elizabeth Berger: Well, in this case, it's about origin and variety. So we've got three monocultivars here and they're from three different regions, very distinctly different regions of Italy.

So the first one that we've got is Taggiasca, which comes from Liguria, which is up in the far northwest of Italy, just heading sort of towards the French border. So we can pour a little bit of this in exactly into your left-hand glass so that you keep track of where you are. 

Liguria is a beautiful part of Italy. It's a very sort of slim region that's hugged by the coastline. It's quite a rugged landscape. And you get a patchwork of different olive groves. Many of which are very, very small and on incredibly steep inclines. It's very, very difficult farming. It's actually quite rare now to find an olive oil that's made from Taggiasca.

So this is the north. We're then going to the center of Italy and then to the south of Italy. What I'm hoping that you will see is a distinct difference. 

[00:44:28] Professor Tim Spector: This is the middle of Italy in the middle. 

[00:44:29] Elizabeth Berger: Yes. So then we go to the middle of Italy. Central Italian oils are very different in style.

And this one comes from Umbria. From a gentleman called Marco Viola. And this is a mono cultivar, Moraiolo. So say that after you've been tasting it. Moraiolo. So it's a very distinctive cultivar with incredibly high level of polyphenols. 

[00:44:56] Professor Tim Spector: So the further south, do you get more polyphenols? 

[00:44:58] Elizabeth Berger: Not necessarily. It depends on the cultivar. So this is a Carolea from the Librandi family in Calabria. So you are right in the sort of instep of the boot of Italy. You definitely, the texture changes slightly as you're going further south. But typically you might get an oil that's more aromatic, but this is also influenced by the sea.

[00:45:22] Jonathan Wolf: So I'm looking at the three of them now and it's interesting that the last one definitely looks greener. So it's definitely a different color. The other two look a little bit more like that sort of classic honey sort of color that I think covers olive oil. 

[00:45:35] Elizabeth Berger: So you can see that they've also been on a journey. So these oils were harvested in October.

[00:45:40] Jonathan Wolf: So you're telling me that it's already too late and it's really a terrible time to eat it. 

[00:45:45] Elizabeth Berger: But I'm telling you that they would be more intense in color and the polyphenols would be higher if we were tasting these in November. 

[00:45:51] Jonathan Wolf: So I would really, actually, if I'd poured this out from that bottle six months ago, the color would have been different. You can see a change in color. 

[00:46:00] Elizabeth Berger: You can totally see a difference. Yeah. And actually the thing that's really interesting about that as well, going back to the sort of food angle, is that your food, if you are eating seasonally, as we said, you're eating more robust, sort of wintery base notes throughout the winter months.

And then as you go into the spring, you've got sort of brighter flavors, the oil will have dropped back a little bit in terms of its intensity, so it pairs better. And then as you head into the summer, which is where we are now, and you start to eat tomatoes and mozzarella and things, the oils are more delicate again.

So they pair with the seasonal food that you're eating. 

[00:46:32] Jonathan Wolf: It's amazing. So Elizabeth, tell us what to do. Yeah. 

[00:46:35] Elizabeth Berger: Okay. So we'll take the first glass here. You just cup it like that in your hand and you place a lid on the top with your other hand. 

What we're going to do is we're just going to slightly warm the oil so that it gives off the best of its aromas. So you're going to spin the oil round. Just warming it with your hand. Very, very gently. 

[00:46:54] Jonathan Wolf: Wow, this is all a lot more complicated than I was expecting. 

[00:46:59] Elizabeth Berger: And then, when you're ready and you think you've just taken the coolness out of it, you just lift off the lid and you're going to give it a big smell. 

[00:47:09] Jonathan Wolf: Oh wow, that does, that smells a lot.

[00:47:11] Elizabeth Berger: So that's just livened up some of those aromas so that you can really get what's coming out of the glass there. 

This is a cool climate olive oil. So it's from the north of Italy where it rains a lot, certainly during the winter months and in the spring and the autumn for that matter. And so what you get is aromas such as, and I don't know whether you can get this, but a little bit of green bean, perhaps a little bit of sort of pea and some of those fresher, more delicate herbs that you might be getting.

[00:47:41] Jonathan Wolf: I'm really glad you didn't ask me any of those questions. I was really worried I was going to get asked what you smell. I'm like olive oil. 

[00:47:48] Elizabeth Berger: It does smell like olive oil, but it smells very pure. 

[00:47:51] Jonathan Wolf: It certainly smells a lot better than olive oil I'm regularly drinking. And so do I get to drink it yet? 

[00:47:57] Elizabeth Berger: We're going to drink it now. And so what you do is you just take a small amount into your mouth. And I don't know if you've ever done wine tasting seriously, but you take in a little bit of air because that will just expand the aromas in your mouth. 

What I should also preface to say is that when you're tasting very high polyphenol olive oils, it can give you a little prickle in your throat, and there is a chance that you may feel the need to cough. That is perfectly normal and absolutely fine. 

[00:48:23] Professor Tim Spector: Perfectly respectable. 

[00:48:25] Elizabeth Berger: It's very respectable, and there is some apple here, which is the one thing that will stop you from coughing. 

[00:48:29] Jonathan Wolf: Okay, I'm looking at Tim.

[00:48:32] Professor Tim Spector: So you want me to go first, do you worry it's poisoned? No, it's fine.

[00:48:29] Jonathan Wolf: I'm not worried about that, I just, you know, don't want to embarrass myself. All right, I'm going for it. 

[coughs] I see exactly what you mean. 

[00:48:49] Elizabeth Berger: The prickle in your throat is the oleocanthal, which is one of those polyphenols. And it's extremely good for you. So it's great when you cough. Strangely. 

[00:48:59] Jonathan Wolf: Well, what's interesting is I taste it. I think it's very smooth, has this really nice smell. I'm not getting any cough at all. And then about three seconds later, wow, I feel this burn down the back of my throat.

[00:49:10] Professor Tim Spector: That's a sign of a good oil though, isn't it? 

[00:49:12] Elizabeth Berger: It is. 

[00:49:13] Professor Tim Spector: It's a delayed reaction. 

[00:49:14] Jonathan Wolf: So that's a positive sign. 

[00:49:15] Elizabeth Berger: Absolutely ight. Yeah. That's what you're looking for, but you should always have an apple handy just in case.

So Taggiasca is really, really good with lettuce-based salads, with freshwater fish, a little bit of seafood. It's the almost perfect match for potatoes, so if you're ever making a potato salad, you know, use a Taggiasca olive oil. It's really good if you're making pestos, mayonnaise, or any of those kind of sauces.

There really is a suitability or certain oils to certain dishes. So, we'll move now to Umbria in the center of Italy. 

[00:49:45] Professor Tim Spector: Let's go to Umbria. 

[00:49:46] Elizabeth Berger: And this is the Moraiolo, which is a very decisive cultivar. So it gives a very, very peppery oil. 

[00:49:53] Jonathan Wolf: Just so you know, I'm quite intimidated now if that was my cough on the mild one. The final 10 minutes of the podcast is just me choking in the corner. 

[00:50:03] Professor Tim Spector: Sorry, Jonathan, we got the medical team on standby for you.

[00:50:08] Elizabeth Berger: So yeah, so Moraiolo is much more decisive. And if you put that on lettuce, you would actually find that it overpowered the lettuce. And so, you know, many people particularly in the Northern Hemisphere are still using olive oil just to dress salads. And I'm here to tell you that that's not the only way that you can actually enjoy olive oil.

[00:50:26] Jonathan Wolf: Tim's about to take his hand off it. I want to hear what he's, I want to know what he smells.

[00:50:36] Professor Tim Spector: I'm not getting as much as on the Ligurian one, interestingly. 

[00:50:39] Elizabeth Berger: It's, yeah, so it's a little bit more restrained on the nose. But it has…

[00:50:46] Professor Tim Spector: It’s like straw. 

[00:50:47] Elizabeth Berger: Yeah, and it has more grass. It certainly has more vegetal notes to it. So, a little bit more, perhaps, along the spectrum of artichoke, thistle. 

[00:50:57] Jonathan Wolf: I can very strongly smell the difference between the two. Right, Tim, I'm going to go and have a…

[00:51:02] Professor Tim Spector: Nostrovia.

[00:51:09] Elizabeth Berger: And then on the finish, you get a little bit more black pepper, those kind of really spicy tones. 

[00:51:15] Jonathan Wolf: Tastes really different, interestingly. As I swallow it, it feels much stickier somehow going down the back of my throat. 

[00:51:21] Elizabeth Berger: Exactly. Yeah, it is. It's got a broader character to it. 

[00:51:24] Jonathan Wolf: I didn’t cough in the same way. 

[00:51:25] Elizabeth Berger: Maybe you didn't take quite as much 

[00:51:26] Jonathan Wolf: Probably, I was just much more, I have to admit, I was quite gung ho on the first one. I've been much more cautious on the second. I'm like, ah, a bit more dangerous than I realized, 

[00:51:37] Professor Tim Spector: But it was, yeah, it's more gluey, smoother feel as it went down. 

[00:51:41] Elizabeth Berger: Yes, exactly. So the texture’s a little different. 

[00:51:44] Jonathan Wolf: I was a bit suspicious about whether I could tell any difference between these because I am by no means an olive oil aficionado.

And the two taste very different, you could pick that up very strongly. And Tim, I know you're more, much more of an expert here, but they're very different, aren't they? 

[00:52:03] Professor Tim Spector: Oh yeah, I mean, looking at them, they're not that different, but the smell, just by the smell alone, you can tell, and then as soon as it's in your mouth, it's a different mouthfeel.

[00:52:11] Elizabeth Berger: Yeah. It's got much more of a bitterness to it as well, actually, in terms of what you're left with, I think, on your palate. And so it's very good with grains and pulses, excellent on pasta, and very, very high polyphenols. 

[00:52:24] Jonathan Wolf: So take us to the bottom of Italy now. 

[00:52:27] Elizabeth Berger: And then we're going further south, and this is Carolea, so this is an indigenous cultivar to Calabria.

And here, this is actually on the nose, I think quieter still. So it's, it's a little bit more of a gentle cultivar. It doesn't give a particularly peppery character, but it's more aromatic. So it's more towards the kind of herbal spectrum, which makes it great with seafood, but particularly good as well with vegetables.

I'm just talking about Italy. Northern Italy, you get much more sort of mineral, pure styles, which would probably be better suited to lighter dishes, salads, fish, potatoes, rice, that sort of thing. 

Central Italy, much more peppery, so a decisive characteristics that would be better with grains, pulses, bread, you know, pasta, all of those sorts of things, root vegetables.

And then further south, more aromatic, and they would be better with vegetables. It's a really easy hack, but anybody that's putting butter over their vegetables to glaze them, stop doing that. Just put olive oil instead. You know, it's, it's super easy to do. It takes seconds and it raises the nutritional value of the food and it tastes pretty good. 

[00:53:40] Jonathan Wolf: So Tim, what are we smelling now? 

[00:53:43] Professor Tim Spector: Well, this has gone more aromatic again. Again, I'm getting sort of, well, generally grassy notes. 

[00:53:54] Elizabeth Berger: Yes, very good. 

[00:53:55] Professor Tim Spector: That's the predominant one for me. 

[00:53:58] Jonathan Wolf: I'm gonna try drinking it now. 

[00:54:00] Elizabeth Berger: And you've got a little bit more of the things like oregano and rosemary, those kinds of hedgerow, sage, a little bit of sage. I guess.

[00:54:16] Jonathan Wolf: Definitely much herb- Oh, Tim is coughing. It's good. I thought it's not just me. 

[00:54:21] Professor Tim Spector: It’s got a kick that one. 

[00:54:23] Elizabeth Berger: It's good for you. 

[00:54:23] Jonathan Wolf: Definitely more herby, sort of different tastes. 

[00:54:27] Elizabeth Berger: Yeah. 

[00:54:27] Jonathan Wolf: I say maybe a little sour as I'm swallowing. So like quite distinct across the three. I really wasn't sure I was going to be able to tell the difference. They're very different. 

You're at the very high end of this business. I'm thinking about this as being like very premium wines that we're drinking here, which is very exciting. We're very lucky to have you talk through this and also experience them. 

Presumably, all of these from a health perspective are at the very high end of what you would get.

[00:54:56] Elizabeth Berger: They are. So within each category, so within a Taggiasca monocultivar, this will be the highest polyphenol one that you can find. A and the same with Moraiolo and the same with Carolea. We specifically look for the very best quality in its class. 

[00:55:13] Jonathan Wolf: So imagine, I want to sort of pull this back to sort of the actionable advice from this because I think, you know, listeners are not going to be able to just buy your olive oils, and I know that they would not be able to afford them.

You talked about some of the characteristics of finding good quality olive oil, but you didn't really talk a lot about the place, and I imagine people are trying to figure out for themselves, what else should they be looking for that you haven't already covered? 

[00:55:40] Elizabeth Berger: So I think if you're going into a supermarket to buy your olive oil. And I mean, you know, don't think that I'm saying that you shouldn't do that, because I really think you should. That's how people shop. And that's what we do in life. 

So, you know, you're, you're facing the shelf and you think, gracious, you know, what on earth should I do? How can I navigate this? There are a few things to remember.

So, one, you're looking for dark glass. Two, you're looking for provenance. So where does it come from? Can you tell? Can you see on the label, you know, does it say made in Italy or made in Spain or whatever, or does it just say made in the E.U.? 

[00:56:19] Jonathan Wolf: When you mentioned looking for provenance, does that mean that if it says comes from Italy, that's better than produced in the E.U.? And if it says, made in this particular village, is that better than made in Italy, just to understand from what we're looking for?

[00:56:35] Elizabeth Berger: I would say almost certainly, because at that point, you know that it's been on less of a journey and it's probably, if it's made in Italy, you might have had olives that have been tracked from one side of Italy to the other before they've been pressed.

[00:56:47] Professor Tim Spector: Or even with Greek olives because they're cheaper. 

[00:56:49] Elizabeth Berger: Quite often. 

And also, you know, there are all sorts of even murky things that might happen, such as oils that might be mixed in that a small proportion may not even be olive oil. There are many, many different things to consider. 

When you're looking at a really, really high-quality producer, they will have things like a special top here that is a one-way valve that will allow less oxygen in, but it also means nobody can refill it. So you've got to check all of these things, especially if you're spending a lot of money on olive oil. The last thing you want is to be buying something that you don't know what it is.

So choose carefully, you know, make sure you look at the back label, and make a considered choice for what you're buying. 

[00:57:28] Jonathan Wolf: I think I'm coming away just even more reinforced with this idea that olive oil is really great for my health. And I should be trying to have more of it.

Could both of you maybe share a tip on an unexpected way to incorporate olive oil so that we can get more of it each day?

[00:57:44] Elizabeth Berger: I would replace butter at every step of the way with extra virgin olive oil. Because I think it's an extremely good thing to do for your health, but also for the flavor. 

And so I would start with breakfast. So on your toast, if you like marmalade on toast, try to put a little bit of olive oil underneath your marmalade. It's wonderful. It's uplifting, you know, it makes you feel brighter in the morning.

If you make granola, make it with olive oil. And if you favor sweet things at breakfast time and you perhaps I don't know, make a cake of some sorts, certainly as they do in Italy and the Mediterranean, then make it with olive oil because it will make a moister cake. It'll hold for a few more days and you're just upping the level of olive oil in your diet.

[00:58:36] Professor Tim Spector: Agreeing with most of those, certainly really, I hardly use butter at all. I just reach for the olive oil every, every time. 

The other thing is putting it on as soon as you're serving anything up, a drizzle of olive oil on it. And people often think you have to cook with olive oil for things like fish, but actually cooking it in very little olive oil and then adding the olive oil at the end as you're serving it is often how it's done in Portugal, for example, or southern Spain.

And I find they're really, really useful tips. But I think it's just replacing, you know, what we've been doing for ages, you know, rather neutral health item like butter with olive oil is the way to really boost your health and the amount of olive oil you're, you're getting.

As well as eating healthily, because the healthier you eat, the more salads you're getting, the more olive oil you're going to get. 

[00:59:25] Jonathan Wolf: We've hit time, but Tim, I know you've brought your own special taste thing in for all of us, which I think is new for Elizabeth as well. Could you just very quickly explain this little jar you’ve handed to each of us? 

[00:59:38] Professor Tim Spector: Yeah. This is called OliPhenolia and you're talking about ways of quickly getting olive oil into you. This little jar has about the same polyphenols as a half a bottle of olive oil. So it's got over 240 milligrams polyphenols.

So, this is like concentrated olive oil. 

[01:00:00] Jonathan Wolf: This is like a couple of weeks consumption for that study, the PREDIMED study you were describing. So, what am I supposed to do? Just open the bottle? 

[01:00:07] Professor Tim Spector: Open it, it's a shot. So, you just drink it. 

[01:00:10] Jonathan Wolf: So, I'm now really scared, given my response to the last shot.

[01:00:11] Professor Tim Spector: You don't have to taste it, it's just a shot. It's packed with polyphenols, right? But you got the apple here, so. 

[01:00:18] Jonathan Wolf: Alright, I'm getting an extra apple. 

[01:00:19] Professor Tim Spector: And this comes from a Tuscan farm, and I think we're going to be seeing more of these kind of products. And maybe people will start seeing polyphenols on labels as well, to give them an idea, because there are huge differences.

So, what do you reckon on the, what nose are you getting from this? It's 

[01:00:34] Elizabeth Berger: Very interesting. It smells as if it's got some sort of prune juice or something in it, does it? Can you smell that? 

[01:00:40] Professor Tim Spector: They say it's pure olives. 

[01:00:46] Jonathan Wolf: One, two, three, go. Well, it tasted like medicine.

[01:00:56] Professor Tim Spector: It must be good for you.

There you go. So we might be seeing more polyphenol-rich products because we now finally after all these years, we’ve worked out what is good about the Mediterranean diet and distilling it down into hopefully into many other products that we're going to be seeing. So it's fun.

[01:01:13] Jonathan Wolf: Amazing. Well, I would like to do a quick summary and as always, please keep me honest. 

I think we started off by explaining that extra virgin olive oil is extracted in this very simple way from olives. So it's very close to, you know, the fruit itself and the difference between the extra virgin and regular olive oil is really important.

So the key takeaway really is make sure if you're ever buying olive oil, it's extra virgin olive oil, because otherwise you're not getting any of the benefits, you might as well get something else. 

The health benefits are really real, and Tim, you talked about the fact that it's not just observational, they've now done a number of studies. And I think you particularly talked about this PREDIMED study, where they actually managed for years to get people to take olive oil in one arm versus another. I think you said they were like sending them a bottle of olive oil effectively every couple of weeks. And amazingly, these people had fewer strokes, fewer heart attacks.

So like a profound difference to what we really care about, which is these health outcomes. 

[01:02:11] Professor Tim Spector: Even less cancer as well. 

[01:02:12] Jonathan Wolf: Yeah. even less cancer as well. 

We understand quite a lot about why, and it's partly that the types of fat with, you know, a lot of monounsaturated fat is quite healthy. But the thing that's really important about the olive oil compared to these other oils is really the huge amount of polyphenols in it.

And you said that there's just much more polyphenols in olive oil than in any other oil. And in fact, compared to almost anything else that we have. that we eat, and a wide variety of these different polyphenols. 

And although we don't understand exactly what each one is doing, there is now lots of data that helps to explain through the way they interact with the microbes in our gut, they have all of these health benefits.

Now all of that said, not all extra virgin olive oil is the same. And Elizabeth, I think you gave some great tips actually about how to think about it. 

The first is it's only harvested once a year. So it sounds to me that once you're getting to like September, you've got to be really careful because it's probably already a year. But there should be a date on the back. 

And so if that date is within 18 months, you should feel good about it. If it's beyond 18 months, don't buy it. You will be able to find another one. 

Once you open it, sort of three to four months, you should still be getting the benefits. But if you're keeping it in the back of the cupboard because it's special and you're letting it last for like a year or two, you're actually not getting any of the value.

Cooking is safe. Tim, you explained you can lose some of the polyphenols from it, but there's no danger. And on balance, you're still better off because you're still ending up with this high level of polyphenols, which is why you've convinced me to cook with olive oil. 

You do want the olive oil to be filtered. So I have been a victim for this idea that it looks really natural. That's bad, so you want it to be filtered. You don't want it to be in glass that is clear. So again, that looks really nice, you see the color, but it's going to damage it. So you want this like dark green glass that is meaning you can't really see what the color is.

Don't store it by the stove, ideally you're putting it somewhere where it's not getting sunlight. And anyway, you should be going through this quite fast, ideally, if you want to get the benefits. 

And I think the final thing I took away from this is, you know, most people are not going to be able to buy your olive oil, Elizabeth. But this idea by looking where it's coming from, sort of the narrower, the description of where it comes from, the more confident you can be. And you described like a lot of extra virgin olive oil might say product of the E.U. or something. That's really bad, it's a mix from everywhere. 

But even if it says like produce of Italy or produce of Greece, actually, that will be nothing like as good as something that's saying it comes from this particular sort of small location. It's much more likely to be genuine and therefore higher tasting, but also higher quality for health. 

[01:04:56] Elizabeth Berger: Exactly. And if you can find somebody that owns their own press, then you know that they will have got the olives faster into that press. 

[01:05:06] Professor Tim Spector: Yeah, like in many things in food its pretty crucial knowing that chain. 

[01:05:11] Jonathan Wolf: Which is, I guess, another one of the reasons why if you're listening to this and you're in America or you're in the U.K. and you're very disconnected from because it comes from a whole nother country, is very different than when you go on holiday and the people in Spain or Italy or whatever say, Oh, we only ever buy the olive oil from like, round the corner.

It's a lot easier if you live in a country where they grow it all. 

[01:05:31] Professor Tim Spector: But also trusting your shop and ask, you know, speaking to them like you would a wine merchant. I think it's the same principle, really. We should just have a higher quality the way we're picking our food. Like we do some items, but not others.

[01:05:45] Jonathan Wolf: Wonderful. Elizabeth, Tim, thank you so much for taking us through that. And thank you so much for the amazing taste test. 

[01:05:50] Elizabeth Berger: Thank you very much. 

[01:05:51] Professor Tim Spector: Great fun. 

[01:05:52] Jonathan Wolf: Now, if you listen to the show regularly, you probably already believe that you can transform your health by changing what you eat. But now, there's only so much you can learn from a weekly podcast.

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As always, I'm your host, Jonathan Wolf. This episode of ZOE Science & Nutrition was produced by Julie Panero, Richard Willan, and Sam Durham. The ZOE Science & Nutrition podcast is not medical advice. It's for general informational purposes only.