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Episode 249:
Show Notes
Episode 249:
Transcript
Dr Mary Barson (0:04) Hello, my lovely friends. I am Dr Mary Barson.
Dr Lucy Burns (0:09) And I'm Dr Lucy Burns. We are doctors and weight management and metabolic health experts.
Both (0:12) And this is the Real Health and Weight Loss podcast!
Dr Lucy Burns (0:21) Good morning, my lovely friends. How are you today? I am joined by the wonderful, beautiful, gorgeous and brightly coloured Dr Mary. How are you this morning, gorgeous woman?
Dr Mary Barson (00:32) I'm pretty good. I'm pretty good. I've had no running water for the last five days. And it's back on now. I live off the grid on tank water. And through a series of unfortunate events, a few possums died in my tank, poor little loves. The way they got in there was part of the ongoing trial of errors and misfortunes. So yes, we're in the middle of a drought and it took a while for the water delivery people to be able to come back and fill my tanks up and after they were cleaned out. And it was just a whole process and I'm feeling renewed gratitude to modern convenience that is running water.
Dr Lucy Burns (01:11) Indeed, indeed. And it's a great example, isn't it? If you don't appreciate something till it's gone. That's right. Yeah, we just turn on the tap. Turn on the washing machine, there's your clothes being washed.
Dr Mary Barson (01:28) So I'm feeling fabulous and particularly clean today.
Dr Lucy Burns (01:32) Oh, very good. Very good. Well, today, we are putting our scientific hats on because it's interesting, we get quite a few emails asking us to review certain journal articles or media articles. And certainly, you know, sometimes we don't have time to do them. But if we do, it's always one of my favourite things to do because at the end of the day, as medical professionals, we like to rely on evidence for our recommendations. But as we know, not all evidence is created equally.
Dr Mary Barson (02:08) No, indeed. This is a key point. This is the crux of the whole thing. And indeed, being able to decipher what is sound evidence and what is not is a key skill that most laypeople wouldn't have. Just like I, you know, don't have the skills to fix my plumbing. A lot of people wouldn't have the skills to be able to read and understand scientific papers. But also, unfortunately, is that the scientific rigour or just the journalistic rigour actually on media reporting of scientific articles has also significantly fallen away in the last few years, making it even harder.
Dr Lucy Burns (02:49) Absolutely. And I think this is what we're going to sort of break down today, using a recent study on mangoes with the very alluring title of Mango Consumption is Associated with Increased Insulin Sensitivity in Participants with Overweight/Obesity and Chronic Low Grade Inflammation. It's a bit of a mouthful. But at the end of the day, I mean, we are in the business of helping people, particularly with their metabolic health, the majority of whom are insulin resistant or want to avoid becoming insulin resistant. So this article speaks, if you like, to our people. So, you know, we want to, I guess, untangle some of the facts from the fiction, if you like.
Dr Mary Barson (03:35) That's it. And this article made a real splash. So the journal that is called Nutrients is the journal in which it was published, set off press releases as they do. And then these press releases have been released globally across all media, The Herald Sun, The India Times, just absolutely everywhere. Just with this catchy little title that mangoes, making people believe that eating mangoes every day will make your insulin resistance go away. I mean, it sounds amazing, sounds fantastic. So people are asking, hey, is this true? And I think that's what we need to dive into a little bit now.
Dr Lucy Burns (04:12) Absolutely. And in fact, paraphrase to sound even more alluring, things like mangoes prevent type two diabetes.
Dr Mary Barson (04:22) That's a wide bow for having read the article. The whole thing is a I think I don't know how anyone can actually even string this bow, but that's a particularly wide one.
Dr Lucy Burns (04:31) Yeah, it is. There's a few things that we can sort of go into background information on, you know, scientific articles, how and why they're published and our criteria for reviewing them. Bearing in mind, again, that for me, and I've spoken a lot about this, I find reading scientific articles quite hard. They're long, they're laborious, they're a tiny bit boring. And there are a lot of words surrounding what we like to call, you know, the little pearls that are in there. So it's no wonder that the general population and often the medical population don't actually review them. They read the start and they read the finish.
Dr Mary Barson (05:16) Yeah. Read the abstract, read the conclusion, maybe look at the tables and yep, that's it. I did science before I did medicine and scientific writing is a very specific type of writing. It has a very specific format that you have to follow. And yeah, it doesn't make for riveting reading. It's true. But it's designed to sort of precisely communicate what you're trying to say. But yeah, it is. It's not beautiful prose. It really isn't. And if it was beautiful prose, it wouldn't get published.
Dr Lucy Burns (05:48) No, no. So I guess the first thing is that let's talk about scientific research. Like how does it get funded?
Dr Mary Barson (05:56) Yes. So multiple ways, there are multiple ways in which scientific research can get funded. I think that a concerning trend over the last decade or so is the rise of the pay to publish journal articles. That is that the authors of the article pay money to have their journal article published. And this has the potential to result in low rigorous studies because the editors of these journals are going to be incentivised to publish the articles that are sent to them. The more they publish, the more money they get. And particularly in online formats, we're not talking about having to have sort of a specific number of bound journal articles that are posted out or put in the library. Online journal articles, you know, it's infinite how many articles they can publish. So this has created some problems that in the scientific community, by and large, these pay to publish journals are considered lower tier, less prestigious. But that's a bit discipline specific, but does create quite a lot of problems. That's one way in which scientific research can be published. But where the actual money comes from is another question entirely.
Dr Lucy Burns (07:21) Yeah, absolutely. So at the end of the day, research is expensive. It's expensive because, you know, it's not an afternoon job. It's months, often months and months of data collection, looking at interventions, creating an intervention. And somebody needs to pay for this. So there's multiple ways in which researchers can get funding. Often it's applying for grants from either government organisations or philanthropic organisations. But to write a grant, honestly, that's exhausting. That is a process in itself. And once upon a time, I was on the board of directors for FSHD Global, which is a scientific organisation to look at research for muscular dystrophy. And so I was sometimes tasked with reading these grant applications because, again, you know, they're asking for lots of money, you know, tens of thousands, sometimes hundreds of thousands of dollars. But gosh, to write the application for this, it is arduous, as it needs to be. But you can see that that is a process in itself and there's always deadlines and whatnot. Or sometimes research is funded when an interested party, like the Mango Company, I'm trying to think of what that might be called, the Board of Mangoes. But, you know, it might be the Dairy Association, the Meat Association, a company, a drug company, a supplement company, a company. Sugar Science Association. Yeah, yeah. A lobby group. They can approach a bunch of scientists with a proposal and ask them to research it on their behalf. I mean, how much more tempting would that be than having to write a 400 page dossier on why your research should be funded?
Dr Mary Barson (09:17) Absolutely. This particular paper is about mangoes being associated with improvements in insulin resistance it was funded by the National Mango Board and received research grants. Yep.
Dr Lucy Burns (09:31) I'm presuming an American board?
Dr Mary Barson (09:33) I don't know the basis of this, but all authors have no potential commercial interest to declare other than the research itself. They got grants from the National Mango Board. Yeah. And the funds for the literature review received by the National Mango Board. So definitely some vested interest in their wanting, hoping to paint mangoes in a positive light.
Dr Lucy Burns (09:57) Yeah, absolutely. So, yeah, so we've got some research funding things to consider. The other thing to consider for the researchers themselves is that many researchers are tied to academic institutions and the basis of their employment is on the number of either grants they can obtain or research that they can have published.
Dr Mary Barson (10:25) Yeah. Publish or perish was our mantra when I was in my honours year at the Walter and Eliza Hall Institute, very prestigious medical research institute in Australia. Publish or perish. They did have a little side mantra, which was patent or perish. So if you could get a patent for some really, really amazing drug vaccine or some scientific equipment technique, then that was really good. That generated a fair bit of money. Publish or perish, patent or perish.
Dr Lucy Burns (10:51) Yes, absolutely. So, yeah, so for researchers, there is an incentive to publish. And then, as you alluded to earlier, Miss, then you've got these journal companies. So this mango article was published in the MDPI. Well, sorry, no, it was published in Nutrients, which is the name of the journal. But the journal is owned by MDPI. And MDPI, which sounds sort of fancy, stands for Multidisciplinary Digital Publishing Institute. So it's a publishing house. Their job is to publish stuff. And as you mentioned, Miss, the authors or the researchers or the owners of this research pay this publishing house to publish their journal.
Dr Mary Barson (11:46) Usually like thousands of dollars. So it adds up to a significant amount of money. I feel like I'm sort of sounding like a tin hat person here.
Dr Lucy Burns (11:52) This is actually like it's mind blowing when you think about it, because not only do lay people not know this, most doctors don't know this. There is a huge difference between something like the BMJ, the British Medical Journal, the JAMA, the Journal from the American Medical Association. Their journals make money, too. That's not beating around the bush, but you can't pay your way in to that. Their articles are received based on, I guess, I don't know. And again, when I say I don't know, it's because I don't know. So it might be a merit. It could be nepotism. It could actually be anything.
Dr Mary Barson (12:31) It can also be tied to fashion as well. Some things, science is not immune to that. Some things were more fashionable at the time. They're more likely to publish them.
Dr Lucy Burns (12:38) Yeah. But this particular one, the Nutrients and the MDPI, you pay your way in.
Dr Mary Barson (12:45) And it's been publicly criticised for its editorial practices. In 2018, 10 senior editors resigned from the Nutrients Journal, reportedly because the publisher, MDPI, was pressuring them to accept manuscripts of mediocre quality and to publish research of mediocre quality.
Dr Lucy Burns (13:05) Yeah, yeah. So huge conflict of interest there. So, we've already got our spidey senses up with this, with this publication. And again, both you and I, Miss, before we came on air today, identified our own bias here. So our own bias is that we are, you know, we are proponents of a low carbohydrate way of eating to improve insulin resistance. And this research contradicts that. And so there is this phenomenon, you know, with something called cognitive dissonance, which is where you see evidence and because it doesn't marry up with what you believe, your brain and you, you just dismiss it. So we're highly aware of that. So we looked at it. And again, in my mind, there's a secret little part of my mind going, well, it would be great if mangoes helped because honestly, who doesn't love a mango? Mangoes are delicious. Amazing. And, you know, but in our world, they're in the tropical fruit section, which is, you know, again, they're not harmful. They're not going to give you, they're not like arsenic, but lots of consumption of mango and particularly lots of consumption of something like mango juice is probably not going to help your metabolic health. And for us, we've got a mechanism for that. Like it increases, you know, triglycerides, there's both fruit, sugar, fructose and glucose, sugar, glucose in it. So, you know, we've got a mechanism, they all make sense to us. So therefore then our brain's going, well, hang on. How can mangoes, how can mangoes help type 2 diabetes? We need to look at this. So we did. So the first thing I guess, to know about this is what you referred to earlier, Miss, as an intervention study. It's not an epidemiological study. So what does that actually mean?
Dr Mary Barson (14:54) So it means that they've taken, you know, in this case, two groups of people and devised an intervention and a kind of placebo. And rather than epidemiological studies is when you just get a whole lot of groups of people and study what they're already doing, study what's already happening for them, and then try and look at differences in their health outcomes. If we're looking at health related epidemiology, this one is getting a whole lot of group of people, hopefully with similar health stats to begin with, at least the health stats that you are looking at, and then you randomly assign one group to get a man, in this case, a mango intervention and the other group to get an ice intervention, which is what they designed as their placebo, and then measure their health stats at the start and then measure their health sort of statistics at the end of the intervention, which this one was a very short four weeks. It's very, very helpful if it can be blinded. So people don't know whether they're getting the intervention or the placebo, because the placebo effect is a very strongly documented confounder. You give people a red pill and say, this will make you feel better. And sometimes it doesn't even really matter what's inside the red pill, people feel better. It's amazing. It's the power of our brains. It astounds me, but it's true. And this wasn't blinded, not effectively. You can't, people knew whether or not they were having mango or ice. I don't think you can be really blind to this.
Dr Lucy Burns (16:21) No, I think they referred to it as single blinded. So the people collecting the data didn't know which intervention the participants had. But yeah, you're right. I mean, you know, mango versus ice. That's right.
Dr Mary Barson (16:33) Double blinded is the people in the study who don't know what they're getting. And the people collecting the data don't know what they've had. And that's sort of best practice. You can't always do that though. Single blinded is just, yeah, the people collecting the data didn't know, which is good because we don't want their judgment to be confounded
Dr Lucy Burns (16:50) No. And I think in, and look in nutritional studies, it is, it is really hard, almost impossible to have a double blinded because food is food, you know.
Dr Mary Barson (17:58) It's not, it's not a pill that you can just disguise whatever active ingredients you want. Yeah.
Dr Lucy Burns (17:02) Often what will happen in nutritional studies is they'll have the two groups. They'll have the one with the intervention, the one without the intervention, and then they'll swap them over and repeat the study, but reverse the groups. They didn't in this one.
Dr Mary Barson (17:16) No, I didn't do a crossover.
Dr Lucy Burns (17:17) Yeah. It was just a four week intervention. So, um, the results were somewhat underwhelming. Yes. If we could call it that. So there's a few things that came out. So initially they had a hypothesis that the, uh, mango would help improve insulin sensitivity based on the immune mediated pathways through something called TNF, which is related to polyphenols in food. So we know, you know, we've talked about this before that food is not just the sum of the macronutrients. There are lots of other things that come in it and yeah, mangoes and many, many fruits and many vegetables are high in polyphenols, which are helpful, helpful. So that was their theory, but what did they find?
Dr Mary Barson (18:09) So they found that there was actually no difference in inflammatory markers before or after. And reported that, which is great. You've got to love people who report their negative data. That's really important, but it didn't make any difference on inflammatory markers for weeks before and after. In fact, there were only two statistically significant changes. And I say, I use the word statistically significant and not the words clinically significant after the four weeks intervention of people having the mango versus people having the ice.And that was a very small reduction in insulin resistance as seen by the HOMA-IR, which is a marker of insulin resistance and the disposition index, which is not something we talk about very much, but the disposition index is a measure of how well the pancreas is functioning. The beta cells are making insulin. And these results were statistically significant. They just clicked over P values of less than 0.5, 0.05. You don't really need to, you know, memorise that. There won't be a quiz at the end of this podcast about that, but it just essentially means that when you've got that level, looking at the maths of it, all the statistics, it shows that it was unlikely to be caused by something else, but the actual change was tiny. So not clinically significant, but it did just, just sort of ping over to being something statistically significant that they would be able to report on.
Dr Lucy Burns (19:40) Yeah. I have a couple of issues with the data and the way the data has been presented to us. So again, you know, if you're inclined, you can go and look at the paper and what you'll find in the paper is a graph. Now, interestingly, they've done my favorite thing, which is a glucose tolerance test with corresponding insulin levels. And I love this because it shows you exactly how hard the pancreas is working to maintain a steady glucose state. And so for me, it's like, wow, if your pancreas is having to work really hard, like you're getting really high insulin levels, but your glucose is perfect. Well, on the surface level, again, it's like a duck, the duck looks calm. The glucose is normal, but the pancreas is working like the clappers. The little legs on the dock are going nuts. So I'm always happy when they do that. But two things have happened. They've published this graph, the intervention graph. They've changed the look of the Y axis, if you like. So the Y axis is the vertical axis. It gives you the scale of the insulin levels, which are measured at 0, 20, 40, 60, 80, 100. And in the study that shows that there is an improvement, they've elongated the axis to visually make the improvement look more.
Dr Mary Barson (21:10) Yes, it is sneaky. So if you look at the graph, you say, oh, yeah, I can see that's quite a big jump, isn't it, compared to the placebo effect? Yeah, absolutely. I can see that's come down a fair bit more, but it's actually just the way that the data's been printed on the page. So it makes it look bigger than it is. It's just a bit sneaky. Yeah. We didn't also talk about how small this study is as well. So 48 people. So it's a tiny study, which is pretty going to be. You only just have to have one or two people on each side that just happen to be healthier or less healthy. And you're going to have significant confounders that you can't necessarily account for. So that's another reason why I'm pretty cynical about this particular study. Yeah.
Dr Lucy Burns (21:54) And interestingly, in the study, I couldn't find so there's the graph and the graph. Interestingly, the graph, when you look at the fasting insulin levels, which is the thing they've reported to be statistically different, significant on the graph, they look the same. So I'm thinking, oh, so how's that working? Like the graph is the graph, not right. Where does this other data come from? How come your graph and what you're saying, they don't actually match up. So they've published the fasting insulin levels before and after the intervention, the average, but there's nowhere on the the highs and the lows, like as you mentioned, because it's such a small study sample, if you've got, say, two or three people who have had profoundly improved results and everyone else is the same, well, that's going to completely change it. And there's no data spread of the results anywhere listed, so I think that's not helpful.
Dr Mary Barson (22:51) No, it is. It is. It's pretty difficult to draw conclusions from this study. I would say that the results aren't clinically significant. The study size is small. And to say that mangoes then go on to prevent type two diabetes is, I think, irresponsible journalism.
Dr Lucy Burns (23:15) Absolutely. Oh, and then I guess the final thing we mentioned earlier was that they didn't cross over the studies. They didn't take one group and then give them the intervention and check so that it's not reproducible within two groups. They haven't even bothered to do that. So honestly, it's like, wow, it's almost the lowest brow research that you could probably get published.
Dr Mary Barson (23:36) Certainly, certainly among the lowest. Yes.
Dr Lucy Burns (23:41) So, Lovelies, I think that we need to always be thinking scientific evidence based information is still at the heart of what we recommend. Honestly, it is because without that, you've just got people with the loudest voice to make all the rules, if you like. So it's not that we do not value scientific expertise. We absolutely do. But it's interesting to note why and how scientific rigor has kind of gone down the drain a bit.
Dr Mary Barson (24:12) Yes, yes. Sad but true. And we just need to remain vigilant, sceptical, but balancing that with open mindedness. Open minded sceptics are what we must remain.
Dr Lucy Burns (24:24) Yes, absolutely. So, yeah, because again, you know, it's easy to fall into the conspiracy trap that everything is a conspiracy, that everybody is out to make money, that everybody is, you know, just, you know, there to bow to the gods of capitalism. And yeah, there are most definitely financial incentives for things. But at the same token, there are still good journalists out there. They're few and far between. But to all the good journalists, we really value your opinion. We really value your scientific rigor. And, you know, if only there were more of you to all the people out there that the lay people just beware of clickbait. Again, healthy scepticism. Not everything you read is true, but not everything you read is untrue.
Dr Mary Barson (25:11) So I know that's it. Balance, balance. Yep. You don't want to believe everything and you don't want to disbelieve everything either.
Dr Lucy Burns (25:18) No, no. The final thing I just forgot to mention in all of this was that at one stage in the discussion in this one, they then start referencing another study on mangoes that promoted the benefit of it. And the other study was comparing a mango to a low fat cookie.
Dr Mary Barson (25:38) Now, I'd probably pick the mango out of those. Yep.
Dr Lucy Burns (25:41) Yep. I know. I don't think you need to publish. Like, honestly, that doesn't need a bloody scientific trial to prove that a mango is going to have more healthful effects than an ultra processed low fat cookie. But honestly, that's the level to which we've stooped to. So, you know, I guess we just finished my love with, you know, whole food is the most helpful. Reduce your processed food. Definitely protein is good, but ultra processed protein is not so helpful. So get your protein from real food if you can. Vegetables, choose vegetables over fruit. But again, fruits are not the enemy. If you have a mango every now and then nothing's going to happen. But again, lots of mango probably is not going to save you from type two diabetes and may worsen fatty liver disease if you've already got it. And so I know it's hard. Humans love rigidity on some levels. They love listening to it. They love going, all right, so these are the rules. We like the rules. But as humans, we are complex and our rules are often, you know, in real life medicine, our rules often start with, well, it depends. Yeah. So, you know, I'd love to say, yes, no one should eat a mango or everyone should meet a mango. But at the end of the day, it depends.
Dr Mary Barson (26:58) So somewhere in between highly individualised.
Dr Lucy Burns (27:00) Indeed. All right, lovelies, we will catch you all next week. Oh, and if you want to go back and look at any of our other episodes where we have debunked some science and gone through some particularly outrageous claims, then go back and have a look at our supplement series. They are episodes 231, 232 and 233. Then we had a little break. Then we did 238 and 239. And then we've even discussed our own evolution on the way we've changed our thoughts and I guess view just a couple of weeks ago on episode 247. So there you go. Plenty of listening for your ears.
Dr Mary Barson (27:44) Bye bye, gorgeous ones.
Dr Lucy Burns (27:45) See you then. Bye now.
Dr Lucy Burns (27:49) The information shared on the Real Health and Weight Loss Podcast, including show notes and links, provides general information only. It is not a substitute, nor is it intended to provide individualised medical advice, diagnosis or treatment, nor can it be construed as such. Please consult your doctor for any medical concerns.
