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Busting Myths about Olive Oil with Dr Joanna McMillan

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Busting Myths about Olive Oil with Dr Joanna McMillan

Should we be avoiding cooking with olive oil because of its’ low smoke point? How can you tell if an oil has gone rancid? 

In this episode Dietician, Nutrition Scientist, and olive oil aficionado Dr Joanna McMillan busts the various myths around olive oil, along with the benefits of incorporating it into your diet, the differences between extra virgin and other olive oils, and her guidelines on finding a good quality one and how to store it properly. 

Covered in this episode

[00:58] Welcoming Dr Joanna McMillan
[01:58] Joanna’s background
[03:11] The true Mediterranean diet and Blue Zones
[06:07] Extra-virgin olive oil and olive oil are not the same
[09:31] Rancidity and olive oil freshness
[12:23] Beneficial pytochemicals are created during the cold press process
[15:01] Food should taste good
[17:31] Biophenols in olive oil
[21:44] Benefits of olive oil
[24:23] Can you cook with olive oil?
[27:36] Finding a quality olive oil and proper storage
[37:29] Thanking Joanna and final remarks

Andrew: This is FX Medicine. I'm Andrew Whitfield-Cook. Joining us on the line today is Dr Joanna McMillan, doctor of nutritional science, dietitian and health advocate. A PhD qualified nutrition scientist and accredited practising dietitian, Dr Joanna McMillan is one of Australia's favourite and most trusted health and well-being experts. 

She's a regular on television, and she's most recently hosted Gut Revolution, a three-part series on ABC's Catalyst Program. But she's also regularly appeared on Channels 9 Today Show, 7NEWS and 9NEWS and Studio 10, as well as across a variety of radio networks, online and print publications. She's the founder of Get Lean, an online lifestyle change program, and she has authored six books, including her latest Get Lean, Stay Lean

Dr Joanna McMillan, welcome so warmly to FX Medicine. How are you?

Joanna: I'm well, thank you. Thank you for having me on Andrew.

Andrew: Jo, we're going to be discussing olive oil today and some myth-busting of olive oil. And I've got to say, I am one of those that was hoodwinked. But first of all, I'd really like you to take us through your history, first studying nutrition, and moving to Australia indeed becoming a TV celebrity. What happened? How?

Joanna: Oh, gosh, I've got no idea. People always ask me about this, whether I had in my mind where I wanted to end up? And I know that some people really are that sort of goal orientated. But really, I wasn't. I came to Australia knowing that there was really great research going on at Sydney University. And I was wanting to do my PhD, I was working in London. And so that was the sort of decision to move here. I've always had a contact with Australia. I have Australian cousins over in Perth, WA. 

Andrew: Right.

Joanna: So I've always had an Australian connection. My aunt's married to an Australian. So, I came here as a backpacker when I was 17, always wanted to come back and then found myself here doing my PhD, and I've been here ever since. So, despite the way my accent sounds, I have now been here 19 years.

Andrew: Yeah.

Joanna: So yeah, so that was my history. And for the last at least 10 years, I've had a real interest in the Australian olive oil industry, and the research behind olive oil in general. So really, that's what's brought me to today.

Andrew: And you've always been an advocate of healthy food and healthy eating practices. Mediterranean diet with its olive oil central, is central to the evidence of olive oils health benefits. Can you take us through a little bit, though, about what is a true Mediterranean diet?

Joanna: You know, when we look at dietary research, the mistake that we've made in the past is that we do tend to point the finger of blame or indeed the finger of...

Andrew: Benefit. Yeah.

Joanna: …saying this is the be-all and end-all. It's quinoa, it's this, it's that, you know, we pick out superfoods, but really what research shows us is that dietary patterns are important. And the Mediterranean diet is one of those dietary patterns that's been picked out. It's not the only one. But it's one of those that's been picked out worldwide as being associated with longevity and good health. So not just a longer life, but a healthier life right into those later years. And so it's the pattern that's important, rather than it being a prescriptive diet. 

So of course, if you move around the Mediterranean region, there are differences. Some areas tend to have more bread and others more pasta. Others more different aspects to the diet. But the key core component of it is that they eat lots of plant food, they don't eat a lot of junk food, they have whole grains and legumes, lots of fruits and veggies, nuts and seeds, they have smaller amounts of meat, they do have fish and seafood and some poultry, depending on the areas that you go to. 

And then right at the centre is their use every day, the ubiquitous use of extra virgin olive oil. And that, you know, the whole dietary pattern is what's important. But the oil does seem to have a really key role in exerting some of the health benefits that we see.

Andrew: Just before moving on to olive oil, I'd sort of noted in the Blue Zones, that really important book that one of the important factors was movement, it wasn't exercise. It was movement.

Joanna: Yeah.

Andrew: An importance and this sort of respect for elders and this function to life, a meaning to life. There were all of these esoteric aspects that aren't taken into account normally when we discuss things.

Joanna: Absolutely. And the Mediterranean diet is just one of those Blue Zones. So we also have Okinawa, which is one of the Japanese prefectures. There are other areas around the world. And so that's an important point to make. So it's actually not just about the dietary pattern, but it's also about their way of life. And again, there's commonalities between all of these zones, including as you say this activity. 

So the Okinawans for example, do Tai Chi, and dancing, and gardening, really late, even as very, very elderly people. We see their sense of community, they have a lot of social contact, they manage their stress levels very, very well. And they have that sort of sense of community. And I think that's also something that we often tend to lose in urban life. 

So I think it's very important before we talk about one specific food that we do recognise that that's just one aspect of a whole load of interconnecting factors, both dietary and lifestyle-wise, that really give us the best shot at having a long, healthy life.

Andrew: And so to olive oil on the face value, one would think of the monounsaturated fraction of the oil being the major, or the only part, of olive oil that's of benefit. And indeed, I remember a program where Michael Mosley, Dr Michael Mosley spoke of work that was done, I think it was in Scotland. And he was basically saying that 20 mils of olive oil will change positive aspects of cardiovascular indices. And what he said was that you don't need the extra virgin olive oil, that any olive oil will do. So where do we sit with this?

Joanna: Well, I'm afraid I'm going to contradict Michael Mosley there. I have enormous respect for Dr Mosley's work, he's done some really great work. But he's not a nutrition scientist. And so I'm afraid he doesn't know all of the aspects of the olive oil research, and that's what he's missing in this story. 

So what is certainly the difference, if I can explain first is that extra virgin olive oil is the cold-pressed oil from the olive fruit. So it's essentially olive juice. And it's a very, very simple process, although the technology in doing it has improved vastly so that it's more efficient today. Effectively, the pressing and the extracting of the oil is the same technique that has been used for thousands of years. And so that's what's really important.

This is a very traditional food that's been a part of the human diet for a very long time. Now, in the last 50 or so years, we've got techniques to refine oils. And if olives go rancid, and then they're processed to get the juice, you've already got some of those products of the rancid nature going on.

Andrew: Yeah, rancidity. Yeah.

Joanna: Yeah, and that's going to turn the oil “off” for want of a better way of explaining. So the oil then has to be refined in some way. And the same is true if you get seed oils or the oil was extracted from other foods like rice bran and so on, canola. All of these oils are refined in some way to make them fit for human consumption. So that's an attempt to get out the products that gives either a nasty taste or actually toxic products. But in doing that, you have to use high heat, or pressure, or chemicals, in order to refine that oil. So olive oil is a refined oil. The only oil that's not refined is extra virgin. And so the refined olive oil, although it has the same types of fat, and that's what I suspect, Dr. Moseley found was that there were still benefits on some cardiovascular mass markers, things like your blood cholesterol profile, for example, will still be improved by swapping out saturated fats for these monounsaturated fats. That's a known improvement that we see in lots of...that's just backing up lots and lots of nutrition studies that show us when we replace saturated fats with unsaturated fats, we get improvements in blood lipids.

But what you miss out on with olive oil, the vast array of what we call in science, phytochemicals, and phyto just means plant. So these are plant chemicals or plant compounds, things like antioxidants that are present in very high quantities in the extra virgin olive oil. And that's really what makes it stand out. Compared to every single other oil on the supermarket shelf, that's what makes it unique. And when you refine the oil and make it into just pure olive oil, or light olive oil, it's those kinds of labels. They're either blended with other oils, or they're refined in some way to make them edible. So you're getting the good fats, but you're missing out on these wonderful phytochemicals that give us the additional benefits.

Andrew: You made a really good point earlier on, one which I have never thought of, and yet, it's an obvious one. We would think about it, let's say for milk. You wouldn't leave milk to go rancid before you took it for processing and packaging, right? You wouldn't do that. You wouldn't think of it. You wouldn't think of leaving meat to rot before you then process it for packaging.

Joanna: No.

Andrew: And yet, what you're saying is that we often do this with the seeds, that they're left in silos, not necessarily with olives, but they're left after being picked. And they're awaiting processing and that period before processing is critical in what you're going to get out of that oil.

Joanna: It absolutely is. You want oil to be really, really fresh. So when it comes to extra virgin olive oil, I mean, that's one of the most extraordinary things. When you look at a really good producer, it's less than four hours from picking the olives off the trees to actually getting the end product of the beautiful extra virgin olive oil. And oil is not like wine, it doesn't get better with time. You want it as fresh as possible. And so that's what's really, really important. 

We want that really good technique so that the olives are processed very, very quickly. And here in Australia, where we have a pretty extraordinary industry. More than 95% of our oils are actually extra virgin. And that's because it's a relatively young new industry. So they have the modern technology and they've set up their plants and processing plants, using all that modern technology so that can be done most efficiently.

Andrew: So I think here's a big catch cry, “Buy Australian.” But it goes further than that, doesn't it? That we really need to be more questioning, more discerning about how our oils are processed and what benchmarks they adhere to, with regards to that, is that right?

Joanna: We do. Absolutely. I mean, I think one of the things that has shocked me most, although this research was now a few years ago, it continues to shock me. This was research that looked at oil being sold as extra virgin in our supermarkets. And when they were tested, there's a German lab test that you can do to test if the oil truly is extra virgin.

Andrew: Yeah.

Joanna: And they find that a vast majority, I can't remember the exact figure off the top of my head, but it was well over 70% of the imported extra virgin olive oils were not, in fact, extra virgin. So they weren't passing this very good lab test. So in other words we're being hoodwinked, we're getting oils that have been refined, or that are older oils. They're not Europe, of course, I mean, places like Spain, and Italy, and Greece, produce some incredibly wonderful oils. But unless you're paying very top dollar in a grocer or a deli, those are not the oils that are being sold in Australian supermarkets. So, my message to Australians is in this country, let's support our local industry A, to support our own country, but B, because we are producing the best oils that are available in this country.

Andrew: You know, I think there's a big lesson there with olives and wine. I have to ask you there, though, when you're talking about the freshness of the oil about an extra virgin olive oil being cold-pressed from the fruit, am I right? I mean, I've tasted an olive fresh off the tree, it was not something I would go back to.

Joanna: It would be yuck. No, no, no. It was very, very bitter.

Andrew: I have done it. I know. So we don't tend to get that bitterness when we are talking about the oil.

Joanna: No.

Andrew: What's missing there? Like what's the processing there? What's happened?

Joanna: Well, you're losing...of course, the pulp of the olive is being picked out. But that bitterness that's in the fruit is actually the phytochemicals that are present. But the process of extracting the oil and then pulling out the pulp so that we're left just with the oil actually creates one or two new phytochemicals that happen, but you're then effectively concentrating and getting all the oil out of a whole load of different fruit to create the oil. So it's actually a very, very different product, but you will still taste those phytochemicals. So if you have a very, very fresh oil and you know, that you get that kind of peppery taste right or back of your throat.

Andrew: It's a peppery nuttiness. I know it. Yeah.

Joanna: Yeah, yeah. Well, that is some of the phytochemicals, one in particular called oleocanthal. And oleocanthal actually acts a bit like ibuprofen, it's an anti-inflammatory. And it has very much of the same effect as a mild dose of ibuprofen. So that's the peppery kick you're getting in the back of your throat. So when you have the pure olive, and we have to remember that well, in fact, it's a different variety that's used to make table olives, but even table olives, we don't actually eat them directly off the tree, they tend to be soaked in brine and...

Andrew: Yes.

Joanna: ...they're left for a long period of time before they've actually got that lovely taste. So it's not a fruit that we pick direct from the tree. We do something with it before it's tasty for us to eat.

Andrew: And so the benefits of that will obviously be changed if you're thinking about olives themselves. You've obviously got many different sorts, the Sicilian olives and the Kalamata olives, and blah, blah, blah, but you're not going to get those same benefits, because you've been soaking them, changing them in brine and other things to change their makeup.

Joanna: Well, that's right. I mean, the thing is, it's not just about the soaking, it's also if you think about it, you only eat maybe half a dozen or so olives at the most in one sitting.

Andrew: Of course.

Joanna: So you're not getting the same concentration of that oil and the same amounts therefore of the different phytochemicals. And as I say, things like oleocanthal are actually produced during the process of pressing the fruit and extracting the oil.

Andrew: This is something that really interests me. Humans, over millennia, have worked out how to process in some instances, not this one, but in some instances, an extremely toxic food and made a food out of it, something that's quite safe to eat. Here we're creating oleocanthal by making the oil. So it's something that the Mediterranean peoples have figured out, that they're actually making a health benefit by creating...oh, sorry. Creating a health benefit by making the oil.

Joanna: Yeah, and of course they are unaware of what it is and what the chemicals are.

Andrew: Yeah.

Joanna: They didn't measure these things back then. And there are numerous examples of that all around the world. Our ancestors have been very, very clever at understanding the impacts of food and our health. And in that region, I mean, go right back to ancient Roman and Greek times, olive oil, extra virgin olive oil was thought of as a medicinal food as well as it being a flavoursome food. Way back then, I mean salad is called salad from the word sal, which is for salt. And then where they used to consume their vegetable is with salt and a drizzle of extra virgin olive oil.

Andrew: Right.

Joanna: So unbeknown to them, they were actually improving the absorption and getting the benefits, not just for the oil, but extra virgin oil actually improves the absorption of the antioxidants in the vegetables, too. So there was this sort of ancient wisdom around foods that they couldn't explain, but they just knew that it tasted good, it made them eat more vegetables, but they just recognised that there was a medicinal effect from eating these certain foods, and we're just…science is just catching up with them.

Andrew: Yeah, that's right. And this is something that really, it always gets me like, just to have...you don't need to drown it. But just as you say, the drizzle.

Joanna: Well, you know, it's one of the things I feel really strongly about is that we've forgotten in our striving for the optimal diet, and how our diet impacts on our health, and our weight control in particular, we sometimes lose sight of pleasure you know?

Andrew: Yeah.

Joanna: And I feel very strongly that food should be a pleasurable part of life.

Andrew: That's right.

Joanna: Not something we battle with, and we're forced to eat this and not eat this and whatever. Food should be enormously pleasurable. And that's what the Mediterraneans have done right as well. They take time out to have meal, they make food taste really, really good. And that's what extra virgin olive oil does to a meal, it lifts the flavour. Plus, it gives a big nutrition boost, and they are sociable with their eating. So they eat together, they give mealtime a priority in the day. And I often feel that that's what we've kind of lost...

Andrew: Yes.

Joanna: ... in our sort of modern striving for whatever that optimal diet is.

Andrew: Now, you've mentioned oleocanthal. Can you please go into a little bit more about what the actual characteristics are of this polyphenol? Indeed, I understand the correct term now is biophenols, is that right?

Joanna: Yeah, well, there are different terms. It depends how you group these chemicals together. But if you think about them as “bio” is just really standing for these are biologically active ingredients...

Andrew: Phenols.

Joanna: ...and “phenols” are the chemical category. So biophenols are present in really high quantities in extra virgin olive oil in particular, and also in lots of different plant foods. So what we know is that when you have a diet very, very high in these different biophenols, A, there's very good effects within the gut. So we know that some of them are utilised by the gut microbiome, which is another big area of interest of mine. So we know that it's involved there. And there's a knock-on effect, not just for gut health, but on physical immune, your immune system, even your mental health is affected by the health of your microbiome. These are the new links that we're starting to uncover. 

But we've long known that a high intake of these bisphenols is associated with all sorts of beneficial outcomes. They have anti-inflammatory effects in the body and antioxidant effects. So they're sort of...think of them as protectors. They're protectors of cells all over the body, particularly as we age. So this is the benefit. And oleocanthal in particular is a very anti-inflammatory action. So I mentioned it acts in the same way as ibuprofen. So you might pop a couple of ibuprofen if you've got arthritis, and your joints are sore, or you're just feeling you've got inflamed muscles from your workout. A good dose of extra virgin olive oil is like a mild dose of ibuprofen, it has that anti-inflammatory effect. 

So for people who've got things like an inflammatory condition, whether that's a gut condition or something like osteoarthritis, then actually taking a regular dose, a daily dose of extra virgin olive oil, just might be beneficial.

Andrew: I just need to ask a safety question here. So when you're talking about anti-inflammatory actions, with the NSAIDs, you're talking about COX-1, COX-2, and obviously, the age-old issue with NSAIDs is bleeding with overuse of them. You don't have that issue with olive oil, and certainly...well, maybe not the oleocanthal on its own. I don't know, but you certainly don't have it with olive oil isn't it? In its entirety.

Joanna: No. Well, this is the real difference between eating whole foods and then trying to take extracts and take really high doses of particular chemicals. And when we look at nutritional research, everyone got very excited about antioxidants way back over two decades ago when I was first studying as a dietitian. And everyone was very excited about antioxidants. There were all these trials trying to extract the antioxidants that we'd learned about back then, put them into supplements and then suddenly give them in really high doses. That whole, “Some is good, more must be better," idea. And effectively, that's what drugs are. 

Drugs are much more controlled doses and very high doses. Sometimes the things that are present in nature are sometimes things that have been produced synthetically. So if you take the chemical compounds that are naturally present in foods, then you concentrate them into supplements, and then you run a trial, often you get into trouble. And instead of getting the desired benefits, you can get a bad effect or you can get side effects. And in some cases very detrimental effects. It doesn't have the same effect as eating the whole food. 

And so that's what we'll see here, you know, you're not going to get the same risks as taking something like a non-steroidal anti-inflammatory drug, you're not going to get the same effect from having a whole food like extra virgin olive oil, because you simply don't have that really high dose.

Andrew: I think the biggest lesson that I've learnt is you cannot outrun a diet based on fast foods, you can't you just can't outpace it, asking a supplement to do that.

Joanna: You can't.

Andrew: I guess I will differ from you on that adding to a well-balanced diet with some exercise, good sleep, can have some dramatic effects. But that's tying off loose ends.

Joanna: Oh, absolutely, 100% agree.

Andrew: Yeah.

Joanna: And there are places for supplements. I should make that clear. But I completely agree with you. Supplements should be used with great care and consideration as to are there any side effects, are there any risks, and do I really need it? And is it likely to be of benefit to me? So you know, there are certain supplements that are very useful in certain situations.

Andrew: Perfectly said. Thank you. I got to say that we often think about the benefits of olive oil, and indeed other oils, in these broad health benefits. Like, it's good for your heart. It might be good for your joints or well being. Are there any specific areas of research where olive oil, particularly extra virgin olive oil has been done, and indeed, what's it shown?

Joanna: Yeah, well, I guess two of the most exciting areas for me are, I've just finished writing a brain food book and I uncovered some really great research on extra virgin olive oil and brain health. So in fact, it's probably down to those biophenols we were talking about earlier. But these chemicals that are present in extra virgin olive oil seem to be helping to protect the neurons in the brain. So that's pretty exciting research. 
And the other area that's of interest to me is skin health. I'm an ambassador for the Skin Cancer Foundation. And so I'm also always keeping my eye on research to do with nutrition and skin. And there's another compound we haven't mentioned in olive oil yet called squalene and squalene seems to concentrate in the skin and migrate to the skin. And it's thought — and certainly in the lab it's shown — to protect cells from UV light from becoming cancerous. And we know that there's a lower incidence of skin cancer in the Mediterranean region where they have lots of extra virgin olive oil. 

So now the research is continuing in that area to see whether, "Okay, is it the squalene in the oil that seems to be protecting and lowering the risk of skin cancer?" So obviously, that's a really good one and a key one for Australians where we have such a high incidence of skin cancer here. 

Andrew: This is something that confuses me, squalene. Squalene is along the same pathway as HMG coenzyme A reductase. So the same pathway to which statins work on. And it's really confounded me that squalene was historically used to reduce cholesterol, and I'm like, "Huh? How the hell does that happen?" Any ideas? What was it? A saturation of a biochemical pathway or what?

Joanna: I don't think we know, I don't think we totally understand. I mean, even statins now are not totally understood. Originally, we thought — when I say “we," I mean, the scientific community — thought that statins were acting via lowering cholesterol. But now it's thought that regardless of any effects in cholesterol, it may be working in a totally different capacity.

Andrew: Yeah.

Joanna: So the same may be true and this is what's difficult with biochemistry is that there's never just one thing going on, and trying to identify the different pathways and understand the interactions that go on between different chemicals that are in our food and the biochemical pathways that are going on in the body is a long, difficult process to try to source out.

Andrew: Now, what about cooking and heating olive oil? I've always learnt that the monounsaturates are more resistant to oxidation, and heating processes. Help me with this one. I always used to... I was told, and I have always done this, to add a little bit of garlic and oil right at the beginning in the hope that the sulfhydryl groups in the garlic and oil will protect the oil to some degree. Is this needed? Should I just be using extra virgin olive oil? Which one's best?

Joanna: Well, we have very clear answers on this now. And we've had some good Australian research coming out of our laboratories here. Because this has been a myth that's been standing for years, and years, and years, and years, where people have just been told to keep your extra virgin olive oil for good just for drizzling on your salad and then you use some sort of a different oil. And we've been hoodwinked quite honestly by the seed oil industry who have marketed their oils as being much, much safer. And it's not true at all.

And the hoodwinking has come about in part from being told that the smoke point was the be-all and end-all. But the smoke point is the only measure of telling us whether an oil is safe or not. Now, the recent studies are showing us that the smoke point is actually only one very small factor contributing to how an oil behaves overtime when it's heated. And in fact, you're quite right in understanding that monounsaturated fats are already much more stable. The mono refers to one, which of course is just one double bond in a big long chain of carbon atoms, which makes up a fat, a fatty acid. And poly of course means lots. And so polyunsaturated fats have lots of double bonds, it's the double bond that is the site of oxidation, the site of the potential damage, if you like.

Andrew: Yeah.

Joanna: So monounsaturated fat, and of course, saturated fat don't have any double bonds. So they are also very stable in cooking. And it's the polyunsaturated fats that are not. And then additionally, in extra virgin olive oil, what has been shown is that not only can you cook with it and it's safe to cook with, in fact, in those recent studies, it was the safest. So it's...

Andrew: Wow.

Joanna: And the most unsafe, the ones that were producing the most toxic compounds over both with high heat and over time, regardless of smoke point, where the oils that are sold to us in the supermarket being safe, and that included rice bran oil, canola oil, and grapeseed oil. So these are three very common, you know, the oils that people are using in Australia. So that concerns me greatly. 
Extra virgin olive oil, it seems to be the vitamin E presence, and the biophenols that we're talking about actually help to protect the fat. So they had very small numbers of these toxic compounds being produced over a much longer period of time and a higher heat than most of us would be cooking with at home.

Andrew: Yeah.

Joanna: So you could even deep fry with oil and safely deep fry with extra virgin olive oil.

Andrew: Not that I would ever do it.

Joanna: No, I don't often see a need to deep fry, to be quite frank. But it's just worth noting that this is the safest. It really is the only oil that you need to use. I would not use a refined oil. You will not find a refined oil of any variety in my pantry.

Andrew: No, nor mine. I'm very proud to say that olive oil is the only oil that I put on my barbie.

Joanna: Nice.

Andrew: Apart from beautiful grass-fed steak and some nice salmon.

Joanna: Lovely, yes.

Andrew: But we've spoken about these quality issues but what exactly do we look for on a product? We look for Australian made. Obviously, that's a time issue.

Joanna: Yes.

Andrew: But can I also ask Joanna, what about the time that an oil spends on the shelf?

Joanna: That matters too. You're absolutely right. So remember we said that fresher was best.

Andrew: Yeah.

Joanna: So one of the best things to look for on the bottle is actually the date of harvest. So you know good oils will state on there what harvest. And olive oils are produced...there's only one harvest a year, it lasts for six to eight weeks, depending on the — I was going to call them a vineyard — on the olive groves. It's just a natural association isn't it?

Andrew: Yes, that's Mediterranean.

Joanna: The Mediterranean diet. My mind goes to wine and olives and fruit veggies, anyway. So the harvest only goes once a year. So you can see, and you'll see on the cover in bottles, they often have a neck tag, which will tell you this is the 2018 new harvest, this is the 2017 harvest. And so while the oils will last if they're looked after, they're kept in a nice cool, dark pantry, they'll actually last up to a couple of years. But by the next year, you've already got the next harvest. So you want to be using your oils up in the year from being harvested.

Andrew: I've never had to use that much oil that I go through these tins though. We just don't do it.

Joanna: Yeah, well, I wouldn't buy the tins because of course immediately you open the container the oils are very carefully bottled and packaged up by the oil producers. And so they make sure that there's minimal contact with air, and that these bottles and so on are all sealed. So you can store sealed tins and bottles for a reasonably long period of time. But as soon as you've opened the tin, or the bottle, of course air is getting in. The more the bottle becomes empty the more air, of course, is then coming in contact with the oil.

Andrew: Yeah. Yeah, surface air. Yeah.

Joanna: And so once a bottle is open, you want to be finishing it relatively quickly. So the tins are really for restaurants or for very large families who are going through gallons and gallons of oil. But if you're at home as a couple or a single person with a couple of kids, you're probably not going to get that same level of turnover. 

Having said that if you're having the good PREDIMED Study which is one of the major Mediterranean diet studies, they were giving people about 40 mils of oil a day. So if you think about everyone in the family having their 40 mils, you're going to go through quite a few bottles of extra virgin olive oil, which is a good thing.

Andrew: Yeah, we have a joke in our family like, “Andrew, just because it's on special doesn't mean you need to buy another bottle." So we’re all finders. I have to ask...

Joanna: You need to see my kitchen. I've just put in a new kitchen and my husband laughs at me because I have a whole cupboard that is dedicated to my extra virgin olive oil.

Andrew: Oh, I could imagine your pantry though, it would be the shiniest, cleanest thing, you know? We'd would be glowing with health. 

I have to ask about other ways, what other ways can we help in, even if it's not majorly, but how can we help to stabilise the olive oil? What about refrigeration? What about maybe putting a sprig of rosemary in there? Or some other sort of way? What do you advise?

Joanna: I don't think it's necessary. Don't put it in the fridge because it will also start to solidify in the fridge.

Andrew: Yeah. Yeah.

Joanna: So you don't really want to keep it in the fridge. As long as it's in a cool dark pantry and the bottles that you buy, you want to make sure you're buying those in a dark bottle. There are some I know that Cobram Estate first harvest is in a clear bottle, but the intention that really is the first pressing of the oil of the very first harvest of the year. And so you use that up extremely quickly. 

So my only advice is all you need to do is keep it in a cool, dark pantry is really all that needs to be done. And buy your oil regularly rather than keeping a stock. I have a stock simply because I'm always creating recipes with it, and I'm using quite a lot of it. So only store how much you use and go through those bottles and buy fresh. And then you're using it. And if you use your oil in your cooking, in your salad dressing. I also bake with it. I mean, I try to use extra virgin olive oil wherever I can. So I've just been doing some recipe development for some other clients and I've made lovely healthier cookies, I've made muffins, I've made cakes, I've made some lovely oat cookies with the oil and it works really, really well. So once you start experimenting, then you'll be amazed how many applications you can really use the oil in.

Andrew: Now I'm going to start salivating here because in my mind, I've got this very clear picture. But I use olive oil all the time, and only when I'm having olive oil with some balsamic vinegar in there with some beautiful bread.

Joanna: Gorgeous.

Andrew: But I've got to say like the taste, sometimes I find interferes with say, salmon or something like that. Is it that I'm using too much? How do you get around the taste issue? You spoke about baking? How do you make sure that the taste is okay?

Joanna: Yes. And this is where...don't get confused between a bottle that is labelled as light olive oil is a refined oil, but if it's an extra virgin olive oil, and then it says light flavoured. So depending on the variety of the oil, with the olives that the oil comes from, you'll get either a much more robust, those really peppery...the olive oil that we said sort of gives you that kick in the back of your throat. And then you'll get more light flavoured ones that are much more mild and they don't have as much of that but they still smell very fresh. When you sniff the oil, it'll remind you of summer and grass, freshly cut grass, something like that.

Andrew: Yeah.

Joanna: Those oils are much much lighter in flavour. They do have lower levels of the phytochemicals. But they're still there, you're still getting much, much more than in another oils.

Andrew: Yeah.

Joanna: So that's what I tend to do is when I'm baking or if I'm doing a dish that I don't really want that much of the flavour coming through because I've got another strong flavour like the salmon that you mentioned, then I would use a light flavoured extra virgin olive oil. But just don't get confused with something that says light olive oil. It's something totally different.

Andrew: No. So the main message is Australian.

Joanna: Buy Australian.

Andrew: Buy Australia.

Joanna: Yeah.

Andrew: Make sure that you've got an oil that has the harvest date if you can, so that you can then make an informed decision on how far away from picking it is. Make sure that it's extra virgin whether it's heavy flavour for your breads and that Italian sort of social eating and dipping, versus the lighter flavour ones for when you're cooking with it with other meats and other purposes. 

What else? Do they actually measure the polyphenols or do you only get with the Australian FSANZ labelling, do you only get the type of oils that are available?

Joanna: Yeah, most of them won't give you a measure of the phytochemicals that are in there. But just be aware that the more robust flavoured ones. Since I've been working with the industry and I've done so many of these olive oil tastings now, I have learned to recognise, when they put that bowl of oil out in a restaurant for you to dip your bread in. Start actually putting it up to your nose and having a sniff and taste the oil before you even put it onto your bread and you'll start recognising when it's a good oil, and when you get that lovely...you know a really good oil will not feel greasy in your mouth. It won't leave an oily taste, it won't leave you with feeling like you want to wipe your lips.

And the higher the levels of the polyphenols, the more you're going to feel that sort of peppery kind of aftertaste in your mouth. So if the oil smells fresh, it probably is and if it doesn't leave that oily film in your mouth, then you know you've got a good oil. So try to get used to...and the more that you use oil, actually, I think the more you also adjust to the taste, and you start really loving that flavour.

Andrew: Yeah. Yeah.

Joanna: And the last tip I can get you, as I was thinking it when you were saying that you love dipping your bread in it. The other amazing thing about doing that sort of oil and vinegar dip with the bread is that you, in fact, you also slow the absorption of the carbohydrates from the bread. So you lower the glycemic response by doing that, and that's really the role of the vinegar. But the oil, there's something in the olive oil that actually gives a satiety release. It's a particular hormone from the gut that goes to the brain telling you there's food coming in and slows down your appetite. And that seems to kick in as well. 

So it's a really great idea to do that because you'll slow the response, you won't need to eat so much in that meal to feel satiated and feel like you don't need to eat so much. And that feeling of satiation will continue for much, much longer

Andrew: Joanna, I can't thank you enough for educating me on the true values of olive oil. I do want to make mention though, that Australians, just like how our wine industry has developed outside of the normal Barossa, and Rutherglen, and Hunter Valley regions, you've now got a lot of these olive oil manufacturers like around Mudgee…

Joanna: Absolutely.

Andrew: The Hunter Valley, you've got certainly Melbourne, certainly Adelaide. So there's a lot more of these beautiful boutique olive oil manufacturers coming up, and they're making really, really good products.

Joanna: Oh, they are.

Andrew: I think the issue is to say though, that you really need somebody who knows what they're doing, and how they're preparing the oil.

Joanna: You do. And I'll just finish by saying I commend the whole industry. You know, I've had a relationship with the Australian olive oil industry for several years. So I've met and chatted with lots of these small producers and I've spoken at things like the industry events. And you're absolutely right, we make a staggering amount of really great oil here. 

And so that's the key message for me, let's support them. Let's really help them because, you know, it is a small industry. It's a relatively new industry that is just doing exceptionally well and they're winning awards the world over. So I commend them for that. And let's talk with our wallets and really support them.

Andrew: Dr Joanna McMillan, thank you so much for myth-busting so many issues which I believed to be true and aren't and for taking us all through the health benefits of olive oil, I did want to segue into the microbiota. But that was just a question that would explode into another hour of podcast. So we'll have to get together again and podcast on that issue.

Joanna: If you get me started, we'll be here all day, Andrew. So yes, let's talk again.

Andrew: But I do thank you so much for taking us through the virtues of olive oil in the construct of a healthy diet. Thank you so much for joining us Dr Joanna McMillan.

Joanna: My pleasure.

Andrew: This is FX Medicine. I'm Andrew Whitfield-Cook.


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