Your Lifestyle Is Your Medicine
“Your Life Style Is Your Medicine” is a podcast that focuses on how a person's lifestyle can be the key to health and happiness. Routed in the principles of lifestyle medicine, Ed Paget, osteopath, and exercise scientist, interviews area-specific experts on how lifestyle impacts well-being, focusing on purpose, physical activity, nutrition, sleep, and stress, which could lead to a longer, happier life. Edward now runs immersive lifestyle medicine retreats, with the purpose of helping others take back control of their lives to live longer and healthier.
Your Lifestyle Is Your Medicine
Unlocking the Health Benefits of Omega Oils with Professor Philip Calder
Unlock the secrets of omega oils with the esteemed Professor Philip Calder as we navigate the world of nutrition and immunology. This episode promises to transform your understanding of omega fatty acids—specifically, omega-3, 6, and 9. Learn about their chemical intricacies, sources, and the profound impact they have on your health. With insights into the roles of EPA and DHA in maintaining cell membrane integrity, you'll gain a deeper appreciation of how these nutrients contribute to longevity and overall well-being.
Discover the pivotal role omega-3 fatty acids play in cognitive and visual development across life stages. DHA, a critical component for brain and eye health, is examined for its potential cognitive benefits in adults, even as evidence remains mixed. Professor Calder sheds light on why most of us need dietary sources of these essential fatty acids and how evolutionary changes might have influenced our ability—or lack thereof—to produce them internally. The historical diet-heart hypothesis is revisited, revealing unexpected insights into the impacts of dietary shifts and the notorious role of trans fats.
In a world where dietary balance is key, learn why the ratio of omega-3 to omega-6 is vital for optimal health. Modern diets often skew this balance, but fear not—we offer practical strategies for recalibrating your intake. From understanding the omega-3 index to choosing effective supplements, this episode equips you with the knowledge needed to make informed lifestyle choices. Reflecting on the overarching theme, we invite you to consider how your lifestyle choices can truly serve as powerful medicine, urging you to embrace a healthier future.
Welcome to the your Lifestyle is your Medicine podcast, where we do deep dives in topics of mind, body and spirit. Through these conversations, you'll hear practical advice and effective strategies to improve your health and ultimately add healthspan to your lifespan. I'm Ed Padgett. I'm an osteopath and exercise physiologist with a special interest in longevity. Now today, we are joined by Philip Calder. He's a professor of nutrition, immunology and head of the School of Human Development and Health in the Faculty of Medicine at the University of Southampton in the UK. He's a world expert on the topic of omega oils.
Speaker 1:In this episode, we're going to do a deep dive into everything you need to know about this essential nutrient what it is, what it does for us, how much do we need, where to get it from and what happens if we don't have enough. This is a true masterclass. Some bits might be a little bit complicated, but that's just because this is a complicated subject and he is an expert in it. I hope you enjoyed this interview as much as I did. Okay, Philip, welcome to the show. Thanks for having me. Great to be here. I'm really excited that I've got you on the show and that I have this opportunity to pick your brain about Omega oils, because you're one of the world's experts on Omega oils. But before we get into that topic, I want you to put this into perspective for my listeners. Like, who are you and why are you talking about omega oils?
Speaker 2:Yeah, so well, I'm Philip Cawler. I'm a professor at the University of Southampton in the UK. I've been researching fatty acid functionality since the late 1980s, so I've been in this area of fatty acids for a long time. I started work on omega-3 fatty acids which is the main topic of our discussion today right back then, and I've really stuck with omega-3s for nearly four decades now because I think they're fascinating fatty acids. I think they're really important for human health and well-being and you know, it's really interesting to me as an academic to find out more about those fatty acids and also to try to put some of those findings into practice for public benefit and for patient help.
Speaker 1:Okay, can you tell people what are omega oils omega-3, 6, and 9s and what do they do in the body?
Speaker 2:Yeah. So omegas, if you like, are just different families of fatty acids. So fatty acids are the main part of the fat that people eat, so of course everyone will be familiar with that, and they are classified based on some of their chemical properties. So one of them is so these are long chains of carbons joined together and one of the properties is how long that chain is, so the number of carbons in the chain. And another one of the properties is whether those carbon chains include what we call double bonds. So these are particular chemical structures within the chain.
Speaker 2:So unsaturated fatty acids have double bonds in the chain. Saturated fatty acids have no double bonds. Now, within the unsaturated fatty acids that is, the ones that have double bonds in the chain, there's the possibility of having one double bond that's called a monounsaturated fatty acid or having two or more double bonds, and those are polyunsaturated fatty acids. So many double bonds, many being two or more. Then, finally, the position of the double bonds in this long chain is important in describing the fatty acids and is also important in determining their functional properties in the body and therefore their impact on health. So omega-3, omega-6 and omega-9 are all families of unsaturated fatty acids, are all families of unsaturated fatty acids and the number the three, six or nine indicates whereabouts in the chain, the carbon chain, the double bond, is found. So those names are just chemical descriptors but actually they are related to the functional properties and the impact on health.
Speaker 1:And what would be a good example of a monounsaturated or polyunsaturated fat?
Speaker 2:Yeah, so a monounsaturated. So we're talking about fatty acids, this is how we have to describe them. So a monounsaturated fatty acid. A good example is oleic acid, and oleic acid is found in high amounts in olive oil and actually you see the link between the name olive oil and oleic acid. So that is a monounsaturated fatty acid. It's an omega-9 fatty acid, polyunsaturated fatty acids. We have two families. These are the omega-6 and the omega-3.
Speaker 2:A good example of an omega-6 fatty acid is the one we call linoleic acid, and there's a lot of linoleic acid in vegetable oils. So oils like corn oil, sunflower oil, for example, canola oil, contains a lot of linoleic acid. And then omega-3 fatty acids can also be found in vegetable oils, so in plant oils. So alpha-linolenic acid that's different from linoleic acid, which is the omega-6. So alpha-linolenic acid is found also in canola oil. It's found a little bit in soybean oil and it's found a lot in flax seeds and flax seed oil. And then there's another even more complex type of omega-3, epa and DHA are good examples. These are found in fish, and I'm sure we're going to talk a little bit more about EPA and DHA today.
Speaker 1:Exactly, where are they found in the body and also why are they used in the body, the body. Why are they used in the body?
Speaker 2:the body is composed of cells and all cells have a membrane and the membrane is sort of the outer layer of the cell. And the cell membrane is partly protein and it's partly lipid. Lipid is another word for fat. So the fatty acids we eat in the diet, some of them end up in our cell membranes. Okay, and cells in different parts of the body have different amounts of different types of these fatty acids in the membrane. So all cells in the body include fatty acids in the membrane that include saturated, monounsaturated, omega-6 polyunsaturated and omega-3 polyunsaturated. So they're found in all cells in the body in the membranes, but different types of cell. So heart cells, liver cells, immune cells they contain different amounts of these different fatty acids. Of course, they're also found stored in our body fat, so what we call adipose tissue, what people commonly will call fat, and so what we don't need for our cell membranes or for energy, because fatty acids are very important energy sources. We need them for energy, but what's left over we store away in our fat tissue.
Speaker 1:What health benefits do essential oils have? So let's let's look at um omega-3, omega-6 and omega-9 and their different roles within the body yeah, yeah.
Speaker 2:So I'll start with um omega-6. So linoleic acid, which I mentioned, is the common omega-6 fatty acid found in vegetable oils like corn oil, sunflower oil, soybean oil. One of its main properties is lowering cholesterol. For promoting linoleic acid intake ever since the 1970s has been its ability to lower blood cholesterol levels. So that's one thing. Linoleic acid is also important in particular lipids we have in the skin. So these are two of the roles of linoleic acid, the omega-6 fatty acid.
Speaker 2:There's another omega-6 fatty acid that we didn't mention so far, which is called arachidonic acid. This is found in meat. That's the major source. Arachidonic acid gets in easily into our cell membranes and it can be converted into chemicals in cells that are involved, for example, in inflammation. So one of the roles of arachidonic acid is actually in promoting inflammation, and inflammation can be a good thing in some contexts, but can be a bad thing in other contexts. So there's a little bit of concern about high levels of arachidonic acid in cell membranes in some situations, because that can promote inflammation in a harmful way.
Speaker 2:If we come on to omega-3s, well, the health-related properties are many. So again, EPA and DHA, these highly complicated omega-3s that we get in our diet from fish or from omega-3 supplements, and maybe we're going to talk a little bit about different sources of EPA and DHA later. They get into our cell membranes very easily and they help many aspects of how cells in our body working. In general, they make our cells work in a more healthful way, if you like. So one of the things they do is they help control inflammation and I already mentioned inflammation can be harmful and omega-3s seem to set up a more helpful type of inflammation.
Speaker 2:They support our immune system to work. They control some levels of blood fats, for example, triglycerides, which are involved in cardiovascular risk. They help with cardiac function, so they help our heart work better. They help our metabolism work better, and so on. So EPA and DHA have quite a range of health-promoting functions. It's also important, I think, to note that our brain contains a lot of one of these omega-3s. It contains a lot of DHA, and that high level of DHA in our brain and also in our eye is linked to better functioning, better cognitive functioning and better visual functioning. And this has been studied very carefully in children, in infants and children, where higher levels of DHA are associated with better cognitive development and better visual development. And we think that as people get older, having more DHA in the brain is also important for maintaining cognitive function and cognitive health. So those fatty acids really have effects right across the life course and right across the body.
Speaker 1:I'm sure there's some people listening to this who think, oh, I should supplement with DHA and maybe that will help my vision or my cognitive abilities. Has that been shown in adults, especially older adults?
Speaker 2:So that's a good question. So some of the things that I mentioned in passing so effects on inflammation, effects on blood triglycerides, there are effects on blood clotting, on heart function that I mentioned All of those things have been demonstrated in studies in adults because those outcomes are relevant to adults. There have been trials of omega-3s looking at cognitive function, so brain function, if you like, in adults and older people and those trials sometimes have actually shown there isn't a benefit. But some of those trials have been done in people who are already showing cognitive decline. So maybe if you're already on an unfortunately downward path, it's hard to bring people back from that.
Speaker 2:There are some studies showing that if you get people really early so what they call that mild cognitive decline there might be benefit from omega-3s in slowing cognitive decline, not in stopping, but in slowing, slowing. There are also interesting studies of omega-3s in other aspects of brain function, if you like. So in depression, for example, there are good studies of omega-3s showing reduced severity of depression and anxiety disorders and so on. I think it's fair to say the studies on brain are lagging a little bit behind some of the studies in other areas like cardiovascular health, but there is a signal that these fatty acids may be important in maintaining cognitive function and normal neural function in adults.
Speaker 1:Now I've heard these been referred to as essential oils, and not the little drops of rose water and all that kind of stuff. As I understand it, essential means something that our body needs but we might not be able to produce ourselves. Can you tell me a little bit about if that's true and then how the body does produce this?
Speaker 2:In classic nutrition, the word essential is used to describe things that the body needs to function properly but which it cannot make itself or cannot make in sufficient quantities. So good examples of essential nutrients include minerals like zinc, copper, iron, for example. We can't make zinc, we have to get zinc in our diet, so zinc is an essential nutrient. Many of the vitamins are also essential, so we can't make those vitamins ourselves, we have to get them in the diet. Some amino acids are essential, so we can't make those vitamins ourselves, we have to get them in the diet. Some amino acids are essential, but of course today we're talking about fatty acids, and there are essential fatty acids. So we already mentioned linoleic acid, the omega-6 fatty acid. We cannot make linoleic acid ourselves. Linoleic acid is an essential fatty acid, likewise the omega-3 fatty acid that I mentioned earlier. On alpha-linolenic acid, we can't make alpha-linolenic acid ourselves, so that's an essential fatty acid. So there's an essential omega-6 and an essential omega-3 fatty acid, and we have to get those in our diet.
Speaker 2:Now I've been talking a lot about EPA and DHA, and there the situation isn't quite so clear, because in our body we have enzymes that, in theory, can make EPA and DHA, so long as we're consuming alpha-linolenic acid. In other words, our body has the potential to convert alpha-linolenic acid that we eat. Remember alpha-linolenic acid is essential to convert alpha-linolenic acid into EPA and then into DHA. But it turns out most people seem not to be very good at that metabolic process and therefore often EPA and DHA are also described as essential Because our body needs them and maybe we can't get enough. We can't make enough of them ourselves, so we have to get them from our diet. So you often hear EPA and DHA also described as essential fatty acids, but that is sort of academically that could be debated, but I think for the consumer actually most people maybe can't make their own and they need to seek dietary sources.
Speaker 1:I'm always interested in the evolutionary origins of certain things. For example, we can't produce vitamin C, and that may be the reason for that. Maybe we didn't have the machinery because we ate it in our foods. Why do you think, evolutionarily speaking, we need these oils and we can't have the machinery because we ate it in our foods? Why do you think, evolutionarily speaking, we need these oils and we can't produce them ourselves?
Speaker 2:I think the idea would be an extension of your description for vitamin C and some of the other vitamins, and that is that we would be able to obtain them from dietary sources.
Speaker 2:So linoleic and alpha-linolenic acids are very abundant in seeds, in seed oils and so on. So you can imagine we've always been able to consume plenty of those fatty acids I mentioned. Our body potentially could make EPA and DHA, but we seem to not be very good at that. But maybe you know, important sources of EPA and DHA are usually things from the sea, particularly certain types of fish. So maybe dietary sources of EPA and DHA have been readily available to us so we sort of lost the ability to make them in high amounts because they were always going to be available. Now I think that's really interesting because of what I mentioned about the importance of DHA in brain and visual development. So this fatty acid is really really important. So the fact that we seem to not be very good at making it would suggest that, you know, through evolution we were in situations where there was sufficient available to us from the diet.
Speaker 1:And there have been some arguments about our discussions, about, you know, human evolution in places near the sea, which would, of course, be a source of preformed EPA and DHA, aiding particularly brain growth, and you know brain cognitive capabilities and you know brain cognitive capabilities, it would make sense, wouldn't it, that historically, humans need a water source, and obviously that's not the sea, but rivers flow into the sea and there's usually some sort of city or habitation that has been in that area since time immemorial. It's interesting. I mean, it's a hypothesis, isn't it? But it's an interesting one.
Speaker 2:It is yes, yeah, but I think there is some evidence about sites in some areas of Africa, for example, where important steps in human evolution took place, and often those sites were near to the sea that makes sense.
Speaker 1:I I recently heard the the stoned ape hypothesis where the? Um, the early hunter-gatherers, would follow the cattle and eat maybe the mushrooms that came out of the, the manure left behind of the cattle and some of those were were magic mushrooms and that opened their brains up.
Speaker 2:That's another oh, I see, okay, that's an alternative hypothesis exactly.
Speaker 1:Okay. I am recently listened to a podcast with mal Gladwell, who's the author. He also has a podcast called Revisionist History and he goes into this deep study of a study that was done in the 1960s where they restricted the intake of saturated fat into certain people who were institutionalized and then they measured the results and they worked out that there was less cholesterol in these people who ate less saturated fat and this was the sort of the genesis of a low cholesterol diet. The guy who did that was called Ivan France or one of them that was involved in it. And then recently that data has been reviewed by a doctor called Christopher Ramson who came up with a similar conclusions. But he also noticed that the increase in the linolenic acid potentially may have affected their longevity outcomes. They didn't live as long even though they had less serum cholesterol. Can you give us some light onto that and maybe a bit of a backstory around those studies?
Speaker 2:Yeah, yeah, thanks very much. So I think we need to go back just a little bit further in history. So in the 1950s and early 1960s, researchers got interested in the relationship between what people were eating, particularly the types of fat they were eating, blood cholesterol concentrations and death from heart disease. And essentially a hypothesis was coined which was called the diet heart hypothesis, and this hypothesis was really that a high saturated fat intake was related with high blood cholesterol and high blood cholesterol was related to higher heart disease. So this immediately, I think, painted high saturated fat diets, or saturated fatty acids in general, and cholesterol as being harmful as far as heart health was concerned. Now I already mentioned that one of the effects of linoleic acid is to lower cholesterol. So if you replace saturated fat in the diet with linoleic acid, people's blood cholesterol levels go down. That's been shown very clearly. People's blood cholesterol levels go down, that's been shown very clearly and therefore you would anticipate that their rate of heart disease would go down. So science is typically done in a sort of stepwise, incremental manner. So it was demonstrated relatively easily in randomized, controlled trials that switching people from saturated fat to linoleic acid lowered cholesterol. So that part was shown to be very clear. Now the next step was to demonstrate that doing that would lower heart disease.
Speaker 2:And um, at about this time in the 1960s into the early 1970s, this was the boom in in the margarine industry. And of course margarines are made from vegetable oils rich in linoleic acid. But those oils are oils at room temperature and margarine is solid at room temperature. So industrially you have to go through a process of converting the oil into a solid fat and this is done by a process which is called hydrogenation and that's how margarine is produced. Hydrogenation and that's how margarine is produced. And what was probably not known or if it was known it was kept secret at the time was this process of hydrogenation introduced trans or formed trans fatty acids in margarines. So I think many of the early margarines had a lot of trans fatty acids in them and people may or may not have been aware of that. By people I mean scientists and people from industry.
Speaker 2:So the study you refer to was one of two now quite well-known studies where researchers set out to prove that replacing saturated fat sources with margarine would not only lower cholesterol but would lower heart disease. And one of them is the study you refer to, which is the Minnesota study which did indeed show that putting I think you mentioned that study was done in people who were institutionalized putting those individuals on a diet with a lot of vegetable oil-based margarine did indeed lower cholesterol. So that was proving that part of the hypothesis cholesterol. So that was proving that part of the hypothesis. But what was never actually published from the study, as far as I remember, was what happened to heart disease, and you mentioned Chris Ramsden. So Chris did an excellent job maybe about 10 years ago now, I can't remember exactly when it was in retrieving the data from the Minnesota study and another study that was done in Australia called the Sydney Heart Study, and looking at the data on heart disease outcomes which had never been published from either of those studies. And what Chris and his colleagues uncovered was that in both of those studies the individuals who were put onto the margarine actually had a higher rate of heart disease, not a lower rate.
Speaker 2:And it's possible that that wasn't published in the first place because first of all, it was not expected but that's not a reason not to publish the results but maybe because it went against the hypothesis. So the researchers selected to publish the, if you like, the positive findings on cholesterol, but not the findings on heart disease. So one explanation could be that, although linoleic acid lowers cholesterol, that doesn't have an effect on heart disease, or it doesn't have an effect on lowering heart disease may even increase it for some other reason. But another explanation could be that the margarines that we used were actually very rich in trans fats, which we know are very harmful to heart health, and that the researchers actually weren't studying linoleic acid. They were studying some random combination of linoleic acid and trans fats. But nevertheless, I think this is really interesting and informative history in our science, interesting and informative history in our science, and hats off to Chris Ramsden and colleagues for their detective work in bringing out the findings from those two studies.
Speaker 1:So this opens the door a little bit to what happens to omega-6s when you heat them, because I've heard that that would damage some of the fats. And let's say we're using vegetable oils in a in a fat, a deep fat fryer. You know, so far, so good. You're putting a vegetable in a fat fryer but you're bringing it out and you're super heating and you're bringing it out. Yeah, are those fat? Vegetable fats? Possibly? Omega-6 is the same as if they weren't heated yeah so.
Speaker 2:So, um, the answer is no what you end up with. So you start with a with a nice clean oil at room temperature which has a lot of linoleic acid, which is cholesterol lowering, in it, and then you um, heat it to high temperature and in doing that you can damage the linoleic acid. You can actually form trans fatty acids, for example, and if you do this at very high temperature and you do it repeatedly, that will make things worse each time you do it. So in some countries there are restrictions. In fast food restaurants, for example, there are restrictions on temperatures that they can use and the number of times they can reuse oil.
Speaker 2:In an effort to mitigate this problem, I think you know a gentle frying in a home setting in vegetable oil once is not a big deal, but really high temperature, repeated cycle frying is not helpful and is not permitted, at least in some jurisdictions. I wouldn't say it's not permitted everywhere on the globe for sure, but certainly in some places. And that's been an effort really to lower trans fat intake which has happened. I mean, that's quite well documented in, certainly in European countries that trans fat intake has been reduced.
Speaker 1:Okay, I think we've built up the case to say that these, the omega oils, are important. The three and three is very important for brain health, and six and nine they all have their roles. So how do we find out whether or not we need to take a supplement or whether we're getting enough in our diets?
Speaker 2:So I think for two of them this is sort of a moot question. So omega-9 fats are extremely common in the diet and we can make oleic acid ourselves. So I don't think there's any question that we need omega-9 as a supplement. Okay, omega-6 fatty acids, linoleic acid is abundant in the food chain because vegetable oils that contain linoleic acid are widespread as vegetable oils, as margarines, as oils within foods that we might eat. So bakery products, for example. That also, you know, present in grains, for example, and we, you know, we eat grains ourselves. We feed grains to cattle in some countries in large amounts. So linoleic acid in fact, some people argue that we have too much linoleic acid in the diet. Okay, maybe we can come back to talk about that. So personally, I don't think we need a linoleic acid supplement at all.
Speaker 2:Omega-3s are harder to get in the diet, particularly EPA and DHA that I mentioned as being the really functionally important omega-3s. They mainly come from fish and particular types of fish are really good sources. So salmon is a very good source. Sardines are a good source. Herring is a good source. Some people don't eat those fish for various reasons. They will have low intakes of epa and dha.
Speaker 2:There's also, I think you know something we might touch on if we have time. You know, ultimately there is an issue with sustainability of fish. Um, some people have concerns about fish, but that is the main source and most people are not getting enough from that source and therefore you could argue that, to get enough, those individuals which, in most countries, most Western countries, you know, are the bulk of the population maybe should consider an omega-3 supplement, by which I mean a supplement of EPA and DHA. Now, mostly those supplements are, you know, what we call fish oil, or are based on fish oil, so they come from fish.
Speaker 2:So, again, I think there's an issue with sustainability in time, so we need to think about alternative sources. So there are algal oils which are available as supplements that people might want to consider, and I think, just in passing it, it's worth mentioning that fish, like us, do not make EPA and DHA very well. They actually get them from their diet, just like we probably need to get them from the diet, and the big producers of EPA and DHA on the planet are algae. So algae are really our omega-3 factories out there in the ecosystem and we can, so companies sort of grow algae that are good producers of EPA and DHA or just DHA alone, and that's what's used for supplements. So you know, algal oils are an alternative to fish oils for supplemental use.
Speaker 1:You mentioned there, though, that algae is a good source of DHA and sometimes EPA. Is there less EPA in algae derived supplements?
Speaker 2:So different algae make different amounts of EPA and DHA, and what's happened, I think, in industry is there's been a focus on algae that produce DHA, is there's been a focus on algae that produce DHA. And part of the reason for this goes back to what we already discussed, which is the importance of DHA for visual and brain development. So, before a baby is born, the mother actually transfers DHA to the fetus across the placenta Okay. And after a baby is born, the mother transfers DHA to the newborn baby in breast milk. So breast milk contains DHA along with other fatty acids, but there's a certain amount of DHA. So breast milk contains DHA along with other fatty acids, but there's a certain amount of DHA.
Speaker 2:Now, unfortunately, sometimes it's not possible for a mother to breastfeed and the infant receives a formula and you know a lot of people will be familiar with with formulas now because dha is in breast milk and dha is important for visual and brain development. Decades ago, there was a lot of interest in seeing whether infant formula should contain dha and if it should, where is that dha going to come from? And for lots of reasons, um, algae that produce dha were seen as the important source for infant formula. So I think dha producing algae came about to support the infant formula industry and and therefore those algae are very well known and you know we're already doing their stuff producing DHA-rich oil, so they can be, you know, a side use if you like would be using those oils and supplements, but there are also algae that make EPA as well as DHA.
Speaker 2:So you know, I think there are also algae that make epa as well as dha, so you know, okay, I think there are supplements with both now, you touched on this earlier that sometimes too much omega-6 can be harmful.
Speaker 1:So is there a ratio of the intake, an optimal ratio of omega-3 to omega-6 that we should be looking for?
Speaker 2:yeah. So people talk about this a lot and it's actually, um, it's quite a complicated question, so I'm gonna um try to uh give my answer in a way that that isn't too too uh confusing. So I've already mentioned linoleic acid and alpha linoleic acid. So these are two plant derived essential omega-6 and omega-linolenic acid. So these are two plant-derived essential omega-6 and omega-3 fatty acids. I mentioned that alpha-linolenic acid can, at least potentially, be made into EPA and DHA, and linoleic acid can be made into arachidonic acid, which I mentioned before. We can actually get that from meat, but our body can do that. Now the conversion, the metabolism of linoleic acid and alpha-linolenic acid uses exactly the same enzymes, okay. So there's competition, there's direct competition, okay. So if you have a lot of linoleic acid relative to alpha-linoleic acid, which is actually the situation we have, linoleic acid is the winner. Alpha-linoleic acid has competed out, and that's actually probably one reason why most people can't make much EPA and DHA because of the abundance of linoleic acid. So what that means is the ratio between linoleic and alpha linoleic acids so the omega-6 and omega-3 fatty acids is really important in determining how well we can make our own EPA and DHA. So, just as an aside in human trials. If you keep people's intake of linoleic acid constant, so you don't change that, but you give them a much higher amount of alpha-linolenic acid, you see, they make some EPA themselves. So that's one way of driving EPA formation. Another way actually is to keep the alpha-linolenic acid constant and lower the amount of linoleic acid. So that's been done in a couple of trials and if you do that you also get more EPA being produced. So those observations tell us that there's something about the relationship, the ratio of linoleic to alpha linolenic acid that's important in determining the metabolism of alpha-linoleic acid to EPA and maybe on to DHA. So that's where I think this idea of ratio is quite important.
Speaker 2:And people have talked about what the ratio is now. Some people say it's 20, some people say it's 10. It's quite high compared to what it used to be, maybe 100 years ago, and it's argued. And what I just mentioned from those human studies supports the argument that the ratio should be reduced, maybe to four, some people say to one, but certainly it should be lower than it is now. So I think that's where the ratio comes into play. If you're thinking about EPA and DHA, I think that sort of ratio is not so helpful because it's telling us something else is not so helpful because it's telling us something else.
Speaker 2:So people have come up with a marker of epa and dha status levels in the body. That um are related both to dietary intake and to the health impact of those fatty acids, and this marker is called omega-3 index. And omega-3 index is simply the amount of EPA plus DHA in our red blood cells. And what we know is if we eat more omega-3, so we eat more fish, for example, or we take omega-3 supplements the omega-3 index goes up. And there are now dozens, maybe hundreds, of studies showing that the omega-3 index is associated with improved health outcomes. So people have even now got to a scale of omega-3 index. So a value less than four is really suboptimal and a value greater than eight is what's desirable, and between four and eight is sort of not as good as it could be and you want to drive it up closer to eight. So there is a scale of omega-3 index and that can be measured in blood samples from people, and there are companies that offer omega-3 index testing.
Speaker 1:So yeah, I did look at that. There was Dr Bill Harris who helped develop that omega-ol index and, as I understand it, the average in the US is low and you mentioned this, that most people would be low. What is the average, do you know? So it depends where you are.
Speaker 2:So I think if you look at the whole US population, I'm guessing the average is probably something like somewhere between four and five. Right, I'm guessing. But you know this will differ. I mean, obviously it's affected by people's diet. So in people who are regularly eating, you know, salmon, you know if you eat salmon once a week, twice a week, you know your index is going to go up. If you're a habitual omega-3 supplement user, your index will be higher. So I think you know supplement user, your index will be higher. So I think you know it's affected by people's diet and you know people's diet is influenced obviously by where they live, by you know their cultural preferences, by their you know socioeconomic status, all of those things. So it will be variable depending on lots, lots of of sort of influences, for sure. But in Western countries, in, you know, where fish consumption isn't high, you know the average is typically around five-ish something like that.
Speaker 1:So it seems to me, with that conversion pathway being blocked by too many omega-6s, that historically speaking perhaps we would have eaten more in our diet and eaten less omega-6, and now we've kind of flipped it with. There was there's vegetable oil everywhere and not so much fish in our diets yeah, yeah, yeah, that's right.
Speaker 2:So I think, um, that's been quite well documented. So again, I I mean you mentioned Chris Ramsden before, so Chris also published a paper, I think in 2016, in American Journal of Clinical Nutrition, but the details don't matter. But again, he and his colleagues did some detective work where they looked at the consumption of different fats and oils in the US over the 20th century and, of course, this is very well documented because, you know, industry and the government keep very good records of commodity sales and commodity use. And they showed quite clearly that linoleic acid intake, because of this increased use of vegetable oils in the food chain and in the food industry well, in the farming and food industry, linoleic acid intakes had gone up very dramatically just in 100 years in the United States and, at the same time, um the omega-3s of great interest to us, epa and dha um, their intake has gone down because, actually, fish consumption nowadays is less um per capita than than it used to be, um for lots of reasons.
Speaker 2:Um, you know, once upon a time, I think you know, fish was a cheap staple food that people ate because it was available. You know, some people ate it for cultural or religious reasons. Very regularly things like that. So EPA and DHA intake has dropped while linoleic acid intake has gone up dropped while linoleic acid intake has gone up. So this change mitigates against our own synthesis of EPA and DHA because of the high linoleic acid, but also alongside that, we're taking in less preformed.
Speaker 2:So, it's a bit of a double whammy, I think.
Speaker 1:Okay. So if we're sitting there and we're like, okay, probably don't eat much fish, uh, my omega-6 is probably quite high. Omega-3 is low. Uh, I could get a test, but I might not need one. Um, what would I? What would I look for in a supplement? Now, how much would I should I be taking and what would be a good, good source?
Speaker 2:so there are are some food related things that people could think about. So there are. I mean, things like flax seeds and chia seeds, for example, contain alpha-linolenic acid. There are some nuts, like walnuts are very good sources of alpha-linolenic acid. Canola oil has a good amount of alpha-linolenic acid, although it also contains linoleic acid. So I think there are some dietary things people could do to try to redress the balance a little bit. There are also um other plant omega-3 fatty acids that we haven't talked about that are further along the pathway, so closer to epa, and maybe are better converted to epa than alpha linoleic acid. So you know those things are also available in supplemental form.
Speaker 2:But if we so I think you know those more fish, particularly the sort of fish I've talked about or look for an omega-3 supplement, and I would look for a supplement that has the most EPA and DHA, as you know, as as possible. So most standard supplements are about 30% EPA and DHA, so there are actually 70% other things that you don't need. So you could look for what we call a concentrate, so that would be. It might contain 60% omega threes or even more. So the industry has worked on concentrating EPA and DHA, so getting rid of the stuff that people don't need. So I would look for a concentrate. Obviously that's going to be a bit more expensive, but you're actually getting, I think, more EPA and DHA, so a better quality product.
Speaker 2:You ask about amount. So the recommendations that are out there so different authorities have different recommendations they're typically several hundred milligrams per day. So you know, 250, 450, 600 milligrams per day, something like that are the recommendations. So if you had a standard one gram supplement, you, you know you might need a couple of those a day, um to meet the recommendations. I think those recommendations are a bit conservative. I think probably people need a bit more than that. So you know you would need um a bit more in the way of supplementation to meet a higher recommendation.
Speaker 2:And you know I would do that daily and you know I think you have to keep doing it. You can't top up and then stop because you know any benefits will go away eventually. And then I think the other thing, ed, is to take supplements with meals. I think that's something that's emerging now from studies that most supplements are much the fatty acids are much better available if you consume the supplements either with a meal or around the time of a meal rather than on, you know, an empty stomach, which you know we've found out. Some people like to do that which you know I think isn't ideal.
Speaker 1:So that's very interesting, because I can see some people buying a supplement, for example, and saying, okay, one gram is one tablet, but that's not actually one gram of omega-3s. It could be 50, 60% or, depending on the quality. Yeah, could be 30 percent.
Speaker 2:25 percent, even if you've got a really cheap one, yeah, so I think this is this is a really important message that that a one gram omega-3 supplement does not necessarily contain one gram of omega-3s. Okay, so you've got to read the label and and if it's less than 300 milligrams in in a gram, you know this is not you know look for something else and actually look for something with 450 milligrams, 600 milligrams, you know there may be. You might be able to get concentrates even with 800 milligrams, and then you're getting a. Really, you know you're getting what you need. Um, you're going to pay a bit more, but you might only need to take one of those a day. So I think this is a message.
Speaker 2:Unfortunately, even in the scientific literature, ed, people make this mistake that you know they're giving a one gram fish oil and the paper says we gave one gram of omega threes, but that isn't the case at all. So you know we're blighted by this confusion, I think. What do you personally take? So at the moment, upstairs, I have an omega-3 concentrate and I have been taking one of those a day. But also in our house, we're regular fish consumers, so we eat fish several times a week. We eat salmon, we eat mackerel, we eat sardines, these are all really good sources of EPA and DHA.
Speaker 1:Okay, I think we're drawing this to a close, but I want to round it out by looking at any potential risk factors here, because it's great saying let's everyone take these things, but potentially there might be some downside to them. Are there any?
Speaker 2:With the sort of doses we're talking about, there are no risks. Okay, people have documented, particularly in early trials using very high doses, some issues with. You know I'm talking several grams a day for prolonged periods of time. So again, I'm going to go back in history a little bit.
Speaker 2:So the whole omega-3 story started with studies in Greenland, inuit, and this was research done by Danish researchers and they were interested in disease incidents in native Greenlanders and they found they had very low rates of and they found they had very low rates of heart disease around about, depending on the study, only 5% to 10% of what was expected based upon the Danish figures at the time. So they had very, very low rates of heart disease. And yet they had what we would call probably quite an unhealthy diet. So they had a very high-fat diet. They didn't have a lot of fruit, a lot of vegetables. They probably didn't have any fruit at all. They might have had some berries and stuff sometimes, but anyway, low fruit and veg, high fat. They used to eat enormous amounts of fat but they had an extremely high omega-3 intake and so this was the first connection between high omega-3 intake and low heart disease and that was the whole start of the story. But what uh was described but has often been overlooked is the native greenlanders also had um problems with uh bleeding, so they had very frequent nose bleeds. They bruised very easily, stuff like that. So these extremely high intakes and I'm talking like over 10 grams per day of epa plus dha, so that's massive, reduced, reduced um blood clotting and people got a bit interested in that because of course, blood clotting is one of the things that kills you after a heart attack or actually causes a heart attack. So one of the early theories was that omega-3s prevent blood clotting and that was actually how they reduced heart disease mortality.
Speaker 2:Now, that might be part of the story, but these doses were very high. But bleeding is often brought up as a problem of omega-3s. But this is really something of extremely high doses and I don't think there are any studies using the sorts of doses that we've talked about that have found any adverse impacts. And in fact there are some studies. You mentioned Bill Harris before, the founder of the omega-3 index. He actually published a trial where they set out to test this hypothesis that omega-3s would increase bleeding by doing a high-dose supplementation trial in people before surgery and they didn't find any effect on blood loss at surgery.
Speaker 2:So I think that's a theoretical consideration. I think it's important to mention because a lot of people have heard about this. But at the doses we're talking about, that is not a problem. So, apart from sometimes the fishy taste that people don't like, I think there's no issue with supplements. I mean, my own preference, of course, is that people would eat fish, so eat food. But I realized that not everyone is going to do that and I realized that, you know, in 20 years time I may not be able to say, eat more fish because there's a problem there.
Speaker 1:Well, thank you very much for coming on the show, and if people want to find out more about your research, where would they go to look for that?
Speaker 2:Yeah, so they could look at the University of Southampton website and just type in University of Southampton and my name and you'll find my website, so you can find out a bit more about my research and my publications there. Of course, you can just Google me and somehow, through the magic internet, you'll be able to find out about our papers and how to connect with me.
Speaker 1:Perfect. This has been an absolute pleasure. Thank you very much for coming on the show.
Speaker 2:Yeah, thanks for having me.
Speaker 1:That's the end of this episode of your Lifestyle is your Medicine. Thank you so much for joining me in my conversation with Dr Calder. Now, if you want to support the show, the best thing you can do is subscribe on Spotify and on Apple Podcasts and that way you'll be notified when the latest episode comes out. And I'd be very grateful if you were to go onto your podcast app and give this a five star review, so that will help me get this information out to more people. Additionally, if you're watching this on YouTube, please leave a review and a comment below. Remember, if you're my direct help, you can go to my website, edpadgettcom. You can subscribe to the newsletter there and drop me a message via the contact us link, and I'll help you make your lifestyle lifestyle your medicine.