Trans fats: How worried should you be?

[Music] hello and welcome to Zoe shorts the bite-sized podcast where we discuss one topic around science and nutrition I'm Jonathan wolf and today I'm joined by Dr Sarah Berry and today's subject is trans fats so Jonathan we often talk about The Good the Bad and the Ugly when it comes to fats and I think when people consider bad fats trans fats are often a major area of concern for a lot of people due to its reputation and to Sarah what is a trans fat and should we all be worried about them in our diet well there's a really clear answer to this Jonathan and I think our listeners may be quite surprised by it fantastic let's get into it [Music] Etc so for those of us who haven't been studying fats for the last 25 years what is a trans fat so interestingly Jonathan trans fats are actually a type of unsaturated fat however there's two different types of trans fats one is produced industrially and the other is found naturally in products associated with rumen and animals like cows and sheeps who ferment their feed in the digestion process okay and so what purpose uh do these trans fats provide what trans fats this is what will come to mind and these trans fats were originally used as a low-cost way to harden vegetable oils and thereby produce hard fats that firstly had a lower saturated fat content so were perceived at the time to be healthier and secondly they had the advantage of being cheaper than other hard fats such as butter or Tropical Oil like cocoa butter for example now Sarah hard fat what does that mean so when I talk about hard fats I will talk about a fat that is solid at room temperature so this will include tropical fats like palm oil cocoa butter and also butter and lard and these hard fats are used often because they have suitable melting points for lots of applications in foods and Industry produced transfers were also incredibly versatile and this is because what we can do is we can blend these hard trans fats with other fats and oils to produce fats with really diverse melting properties which makes them suitable for whole wide range of food applications and particularly in processed foods which is why in the 1950s for example where their intake and use really soared was with the increase as well in all of these kind of processed foods such as biscuits cakes margarines and some also stable deep frying oils so what you're saying basically is they're great for food manufacturers to make all sorts of different products like very efficiently and and cheaply absolutely and also at the time that they were first used they were considered to be potentially a healthier alternative because they were like I said unsaturated fats and therefore reduce saturated fat intake and without getting too technical on us please Sarah how do you make these trans fats do you sort of like boil up some regular fats they're they're actually produced from unsaturated vegetable oils uh using a process called partial hydrogenation and this involves reacting the oil with hydrogen in the presence of a catalyst such as nickel so what it does is it changes the format of this unsaturated double bond so the fat has a more rigid structure and this is what causes it to have a higher melting point and therefore become a solid fat and so this process of partial hydrogenation typically creates a fat with around 15 trans fatty acids although it can actually be as high as 55 depending on the manufacturing process used and Sarah I appreciate that although I think we need to talk about what not too technical means so if I if I if I explain what I've taken away like that's some pretty serious chemistry right like there is no hydrogen in my kitchen I'm not even sure what a nickel Catalyst would look like I feel like it's something that might be in my car um and it therefore sounds quite worrying right but you mentioned that actually they can be naturally occurring in some products too yeah that's right trans fats can also be found in butter in cheese and the meat if we've learned animals so for example in beef however these trans fats are different to the ones that are produced industrially and that's really important to remember well Sarah we did a bit of research on the history of trans fats so apparently the process of this partially hydrogenating vegetable oil was created as a cheaper alternative to butter around 1910 so a long time ago and as you said at first they were believed to be a healthy alternative to saturated fats because they were unsaturated and in the U.S they used oil from soybeans while in the UK they use rapeseed or canola oil as it's known and it's as you mentioned in the 1950s that margarine became one of the products and that that really Rose to prominence yeah Jonathan so it was a cheap alternative to butter and also many people had fridges for the first time and margarine was spreadable right out of the fridge unlike butter so it was considered something of a Wonder product especially throughout Europe and North America but margarine at this time was reliant on trans fats and it wasn't wonderful for the health of our customer which is funny because I I grew up with margarine um first in the states and then in the UK um you know as I've mentioned a number of times my dad was diagnosed with high cholesterol when he was very young so all the butter was banned from the house right but margarine well that didn't have saturated fat so that was sort of okay and you had to have something to spread uh on your toes and this was you know when my memory of this is in the in the 80s um so while I've read that actually there were already some concerns about trans fat in the 70s you know this certainly hadn't reached my house and I know that you know my mom and my dad were choosing this very much as sort of trying to make the best health decision about what to eat yeah that's not surprising Jonathan and the consensus on trans fats really changed in the 1990s and there was really good evidence coming out to show that trans fats increased bad LDL cholesterol and reduced good HDL cholesterol which leads to an increased risk of heart disease and also impacted other unfavorable Health outcomes such as inflammation so much of this research was produced and presented to the wealth Health Organization who recommended the removal of industrial trans fats from Foods in 1994. in fact just to illustrate how unfavorable trans fats are on our health the accumulated evidence now shows that for every two percent of energy from transfers and this is about four grams of trans fats for someone eating let's say 2 000 calories a day there's about a 25 increase in cardiovascular disease risk and this is huge I mean Sarah that's terrifying right like what you're saying I think is even just this very small amount of these industrial trans fat was leading to a massive rise in in heart attacks and strokes that's correct okay so if the World Health Organization advised that trans fat should be banned back in the 90s why are we still talking about them today so we're still talking about them because in fact in the west we've seen a real change in the food industry's approach to transfatty acids and there are now no trans fats in any of the foods in the UK and the US now except for either these naturally produced trans fats found in dairy or certain imported foods but Jonathan with the removal of trans fats comes the problem of what do we replace them with ultimately we still need fats with variable melting profiles and varying levels of hardness so the question is do we return to the use of unhealthy animal fats or do we use often expensive and unhealthy tropical oils or do we find alternative industrial processes to create new hot fats and actually that last question is what the topic of my PhD was so I'd be happy to sit here now for the next six hours and discuss that that if you'd like to we'll maybe do that as a supplemental podcast for people who would like to listen to Sarah's PhD thesis for six hours and we'll report back on the appetite for that one so Sarah just to confirm are you saying that trans fats are actually illegal now in the US and the UK so in the US the grass status was removed a number of years ago so they are no longer allowed to be included in the US in food products in the UK there's voluntary removal and use alternative facts and alternative processes so I I find it reassuring that it's not in the food but I'm also a little shocked that it isn't actually outright banned in the UK in the way that it is in in the US is this like surprising to you Sarah well in contrast I find it incredibly reassuring that the food industry took responsibility in the UK without legislation and so Sarah what have they replaced these trans fats with so the food industry now uses a combination of techniques and it differs between the US and the UK so typically in the US they use a process called Full hydrogenation and what this does is it starts with a oil like soybean oil and it turns it into a really hard fat so even harder than a trans fat this is then blended with a liquid oil such as an unhydrogenated so the original soybean oil again or maybe a rapeseed oil and what they do is they blend it in varying ratios to produce a fat that has suitable melting points depending on the final product for example whether it's used for a pastry or a biscuit or a spread or requires slightly different levels of hardness so slightly different melting points now in Europe and the UK we don't use fully hydrogenated fats and instead we typically blend together liquid oils so we blend together oil such as rapesoid oil with tropical oils such as palm oil and coconut oil and we use a very special process called intracerification and that was what the topic of my PhD was so for once I'm glad to get that word into one of our podcasts well done Sarah and so why do we use different fats you know between the UK and and the US the End Food seems quite similar so I think this is really interesting because Jonathan Jonathan is a really great example of the power of the consumer because this is all down to Consumer perception so in the UK the consumer perception of fully hydrogenated fats is that they're bad for us so they see the word hydrogenation and they can't distinguish between that it's full hydrogenation or partial hydrogenation it's got the word hydrogenation oh my gosh it's going to kill us it's bad for us so the UK food industry responded to Consumer demand consumer perception and therefore found alternative processes that would be considered acceptable to the consumer so are you saying that in this particular case these partially hydrogenated fats are bad they produce trans fats but actually you know if you see fully hydrogenated fats they're not bad for us at all and you shouldn't worry so not exactly it's a little bit more graded than this so what's really clear is that the process of partial hydrogenation that produces these harmful trans fats are bad for us that's uh clear that's conclusive full hydrogenation there is a different process and in this process it changes a liquid unsaturated oil to a saturated fat and it typically changes it to a saturated fat called stearic acid that seems to have a neutral effect on our blood cholesterol it doesn't produce trans fats however because it does form a saturated fat we know that it may have some unfavorable health effects but certainly nowhere in the region that a trans fats would so don't don't rush out and stuff your mouth full of this but it's not it's it's not gonna have these terrible effects that I think you were describing with the trans fat is that how I should understand it absolutely it's just creating a saturated fat from an unsaturated fat and if we were to compare it with a natural saturated fat it would be no worse for us than a natural saturated fat what about what about the rest of the world yeah so cost is a huge factor most countries have now eliminated trans fats some countries were quite slow to eliminate them probably due to cost such as many Eastern European countries but now data would suggest that they have stopped using them the one country that we know is still a big user of trans fats is Russia but that's one of the few countries that I'm aware of that produces foods with these Trends and countries with regulations against industrial produced trans fats have triple just in the last three years um alone it's the wealth organization pursues their Global goal to eliminate it totally from Foods throughout the world by 2023. all right Sarah so so what's the conclusion should our listeners be concerned about trans fats no and the reason we shouldn't be concerned about trans fats in the UK or the US is because they are simply not in our food anymore from industrial sources simple as those which are naturally occurring also don't seem to have the negative effects that these industrially produced trans fats have using this process of partial hydrogenation so what about the replacements for these trans fats so um how should our listeners think about you know these Replacements um for fats that are in it sounds like you know a very large part of the the foods that we would eat if we're buying them from the um from the supermarket so I think Jonathan we first have to separate out the health effects of fats versus the functionality of fats and I think people blur the two and I think this is where we're going wrong that there's very clearly very healthy oils such as olive oil can you make a biscuit with straight olive oil can you make a spreadable spread with olive oil no you can't yes it's without doubt one of the healthiest fats that you can use but we have to think about the ingredients functioning for the food that we're eating and so for many applications for pastries for spreads you need to have fat that has that suitable Mel profile and this is why we either need to have quite unhealthy saturated fats such as coconut oil or butter or lard or we use these other alternative processes that we talked about and so we need to compare within groups of fats that are functionally equivalent learn their health effects to make the right choices so by that let's say compare margarine spread and compare that with butter they are used as functional equivalents they are used interchangeably now the fair comparison is to say which of those is healthier rather than is that spread more or less healthy than olive oil because you wouldn't use it for the same function so if we use that as an example in my opinion the sum of the evidence is very clear that the margarines that are currently sold so margarines that are trans free so don't contain partial hydrogenated fats are healthier for us than butter I think that's quite clear and I think it's quite clear that a lot of these commercially produce seed oils dare I say it are actually more healthy for us than many of the animal-based functional equivalents and Sarah I guess that's really helpful to understand and helps to understand how I think as an individual then you have to recognize there's some conflict between the convenience uh of the particular product that you might want to buy and potentially the health impact from it and I guess we have to recognize that if we're not willing to do anything about those trade-offs it does push us towards these these types of food that are pretty heavily implicated I think in um and really bad long-term impact on on the health of everyone in the society yeah I think you're correct but I also think you're making a little bit of an unfair comparison there because what I think is really important and is this whole aspect of functionality you could not for example make a pastry with olive oil you could not do chocolate with olive oil chocolate the reason it's so special is because it has cocoa butter cocoa butter is so special because it melts at 37 degrees which is body temperature that's why you get the wonderful mouth feel of cocoa butter because it's melting at your body temperature would you get that same mouth feel with olive oil no what is it that makes chocolate so special it isn't just the taste I.E the the flavonoids the the dark chocolate taste it's also that mouth feel so you have to also remember that ingredients have functional properties and roles to play with our food it's brilliant Sarah thank you so much for sort of sharing with us some of those um those complexities if after today you've stopped worrying about trans fats but you do want to add more of the right good fats into your diet then you may want to try Zoe's personalized nutrition program to improve your health you can get 10 off by going to join zoe.com podcast I'm Jonathan wolf and I'm Sarah Berry join us next week for another Zoe podcast thank you [Music]

Channel: ZOE

Views: 22,830

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Id: qiY2ybtYiuI

Length: 18min 29sec (1109 seconds)

Published: Mon Apr 10 2023