Does Processing Really Make Food Unhealthy? (SNP47)

Hello, and welcome to Sigma Nutrition Radio. My name is Danny Lennon. You are very welcome to the podcast. Today, we're gonna bring you a discussion about one of the most topical issues within nutrition and health science at the moment, and that is ultra-processed foods, and taking a look at some of the best evidence we might have to try and explain what exactly is going on, and how can we make sense of some of the narratives that are commonly heard, and do the actually match-up with the best evidence we have. So recently, Dr. Alan Flanagan and I were invited along to an event titled Processing the Evidence, which took place in bargaining and university in the Netherlands, and this was a behind closed doors workshop with the aim of discussing the latest scientific evidence on the role of processed foods within human health. It was an event organized by professors Kiran Ford and Vicenza Faleano of bargaining and university, and it ended up being a really, really successful event, which we took a lot from, which we'll maybe mention in a moment. It was a workshop attended by a whole range of prominent researchers across a wide range of domains related to food processing, food technology, nutrition science, public health, and others. It had sessions that included open discussions on the current evidence, looking at some of the knowledge gaps we might have, some of the challenges within the UPF debate and the area of research. And there were a number of several structured sessions that looked at different sub-topics of this issue, things that we're gonna mention in this episode. So things like the interactions between emulsifiers and the gut microbiome, or even in cases of things like Crohn's disease and some of that emerging data, some of the impacts of processing potentially on the food matrix and nutrient biodevailability, how that matches up with various claims we might see impacts around food liking and the hedonic reward of overeating and what that area of research tells us. And then looking at the concept of ultra-process foods by interpreting the nutritional epidemiology we have in the area, the randomized control trials there, including the presentation of several new trials and the data emerging from some trials have just been published, as well as a couple of others that are yet to be finally published but will be soon. So these included the recently-published restructure trial, which we've referenced on the podcast before, the promenade trial coming out of Italy and some other interesting pieces of data. There was a bunch of other stuff, but this was a give you an idea of the range of topics that were covered. And so in this particular episode, what you're gonna hear is a review of sorts of some of the key talking points that Alan and I took from the event overall. Some of the takeaways and learnings we have, things that may have influenced our thinking on some of the conclusions we can take and an insight into some of those key concepts to emerge from the event. So hopefully it'll be really interesting to you. This was recorded in Vagatingen. So you may hear some background noise from time to dime, but hopefully it is worth the listen as we give our immediate kind of feedback on some of the things we took from it while it was fresh in our mind. And no doubt we'll be broaching this topic again in future episodes. Now as this is a premium exclusive episode of the podcast, to listen to it in its entirety, it's about 80 minutes, you will need to be listening over on the premium feed off the podcast as a SIG-minitrition premium subscriber. If you're currently listening on the free public feed of the podcast, then you will hear a preview of this episode to give you a taste of what we might get into, but bear in mind to listen to the full thing you will need to be a premium subscriber. Also as a premium subscriber you will get detailed study notes to accompany this episode as well as a full transcript. So all of that will be linked in the description box where you are currently listening right now. And without further ado, please enjoy this discussion between Alan Flanagan and myself talking about this concept of ultra-processed foods and some of the data based on the event we attended of processing the evidence at bargaining and university. Enjoy. (upbeat music) Hello and welcome to SIG-minitrition radio. My name is Danny Bennett. I'm here with Dr. Alan Flanagan. We are sitting here in Vaguenin in the Netherlands where we've just been at a two day special workshop style conference hosted by Professor Kiran Ford and Professor of Ingenza Faleano where they brought together a whole host of experts from across many disciplines from around the world to talk to the topic of ultra-processed foods. We're gonna try and go through some of the learnings we took from that, some of the interesting insights, some of our own perspectives based on that and give a recap of some of the interesting discussion that went on. But maybe before getting to the specifics, Alan, any insights over the couple of days and first impressions of your thoughts on the event as a whole? I think the intention of the conference as Dr. Ford made clear was not to litigate the validity of the nova classification system. And I think that was a helpful point of departure because it very much focused the content of the conference on data and the specific components of the various aspects that were being discussed such as the food technology component or some of the evidence from intervention trials, factors such as eating, rate, food texture and epidemiological challenges capturing associations at a more granular level than what we've currently got. I thought that focus was quite helpful because it does move us away from just a kind of getting stuck in the mud as to whether category one or category two or category four are useful categories. Inevitably we do return back to that, I think. I think if I had two top line takeaways thinking about this last night afterwards, the first is that I think there's, I would say, quite a clear sentiment, shall we call it that, that the category itself of ultra processed foods is not sufficiently well defined to be kind of operationalized as an exposure with any granularity and encompasses heterogeneous food groups which may themselves have different directions of association or impacts on health. I think I came away very much with a sense that there is much more skepticism for the utility of the category of UPF than you might otherwise think and that the recent Lancet series is a good example of where I think for people in the lay public reading articles in the lay media or indeed people within the field reading some of the kind of methods and editorials that are accompanying strong advocacy for the policing of NOVA and UPF within dietary guidelines. For example, I think my big takeaway and I think it's important for listeners to notice that there's actually far less consensus to that effect. Then you would perhaps otherwise think from some of the wider popular conversation and relation to that. And then the second one, I kind of thought of one of the prevailing hypotheses related to ultra processed foods as this group for category within the NOVA classification system. We have I think two that have emerged from the epidemiology and we have the statements and hypotheses as proposed by the advocates of the NOVA classification system, Carlos Montero and colleagues. One is that processing per se independent of other characteristics may explain the health effects associated with high UPF and the second is that the impacts of a high UPF intake per se are directionally negative. And I came away with a sense that even though we have relatively limited and recently emerging human intervention trials, I think there is a degree of necessary persuasion, I think in terms of the evidence from those trials that allows us to I think at least say that those hypotheses are very difficult to support at this point. The first in relation to the idea that processing per se independent of other characteristics explains their health effects. I think that's demonstrably falsifiable at this point in epidemiology itself when some cohorts have stratified by ultra processed food type, then we might see lower risk directionally with canned based meat alternatives, for example, which are an ultra processed food. Higher risk associated with sugar sweetened beverages and other categories high and saturated fat, for example, that's bringing us back to the realm of knowledge that we already have. And then in the experimental interventions, then clearly there are factors other than processing, such as texture that influence factors like aging rate that may explain over aging. And so I think the first, even though the body of human intervention evidence is limited, I think we can say that that first limb of the hypothesis is certainly unsupported by any persuasive evidence. And the second part, then, in relation to that, brings us back to this idea of knowledge that we already have. Is there explanatory power to the exposure? Let's classify it as that of ultra processed foods over and above what is explained by health effects of foods or nutrients. And again, I don't see much support for that. So I came away slightly more persuaded than perhaps I was at the start, because I came into it at the kind of the skeptic of the utility of the concept of ultra processed foods as a way of defining an exposure in the population and of improving human health at a kind of individual level or in an intervention. And I've come away with that view reinforced by the evidence that I saw over the last couple of days. - Yeah, and I would probably have to echo similar things. And we'll probably save this for maybe later on in the discussion as we get to some concluding remarks. But I think what you've laid out gives us a nice roadmap of things to touch back on, given the context of what we're hopefully going to lay out to people. One, speaking to that popular narrative that you mentioned. Two, thinking about those prevailing hypotheses that are currently out there. And then third of, based on the knowledge we already have, what does this all mean? And I think as you say, as we'll probably talk about through some of the studies that we're discussed yesterday and some of the new work that is just coming out. If we were to think of those main hypotheses, those two that you laid out and we were to think based on those, what are the predictions of those hybrid theories and this that whole set of predictions? Can we then start designing trials to try and falsify the predictions kind of one by one? Much of that work is actually already there, which is maybe not what people would have came across as of yet. So maybe let's start working our way through that and then circle our whole way back to this general consensus or general discussion and the discourse and what that means for us right now. So maybe if we think about one of those early sessions and the first session that had multiple experts speak was in relation to microbiome and additives. And we have touched on some similar stuff in previous podcast read to either additives or sweeteners or emulsifiers. This particular panel of which you shared had some of the leading names in the field discussed. We've talked about some of their papers in some of those specific studies. Can you maybe give us a rundown from those particular talks that were discussed and the things that came from it? For you, when it comes to, again, what we might see in terms of headlines are the two additives right now. What is there on one side versus maybe what was being more discussed in some of those discussions on that first panel? I thought, yeah, that was a particularly interesting panel. In many respects, I think that panel had a slightly more specific focus in a sense than some of the subsequent panels were more focused on UPF per se, obviously, as a kind of category as defining the exposure. Whereas the emphasis that I certainly took from the first session was very much more specific to certain emulsifiers, dietary emulsifiers. And so within that, and we've spoken on the podcast previously that in relation to emulsifiers and risk emulsifiers, are substances that help to stabilize mixtures of two municipal liquids, for example, oil and water. And they are common autodives in the food supply. And there are myriad numbers of dietary emulsifiers that have been approved to say for use on our in various food products. To me, this was less about UPF per se, because emulsifiers have been used far before anyone conceived of the Nova classification system or the very concept of UPF. We do have relatively ubiquitous presence in the food supply. There was a paper by Kevin Whelan and his group and dropped you 23 in public health nutrition, which was looking at prevalence of emulsifiers and common emulsifiers and UK food supply. And you commonly in kind of categories such as galleistries and cakes or milk-based drinks or industrial desserts and confectionery. And you can have a range of emulsifiers within that. I think it would be, and I think this was raised in the context of the discussion around that session, it would be important to clarify for listeners that really to date, there is not a sense of the entire class of emulsifiers being indicted here in this context. The focus is very much on certain specific emulsifiers. Polysorbate 80, caroxymethyl cellulose or CMC. The human evidence is relatively nascent in terms of some of the mechanistic effects, then what Chasseng presented on his fascinating research and one of the first kind of controlled feeding studies in relation to that, they did use a dose of CMC that was for experimental purposes quite high. But essentially they did manage to recreate some of the observations that have been seen in experimental and rodent models, which is that in a certain susceptible host, the distance to between bacteria and the epithelium can be impacted by these kind of emulsifiers. They can reduce the distance, essentially, opening up the epithelial layer to closer proximity to perhaps invasion by pathogens, et cetera, and stimulation, some intestinal inflammation. That's what's been observed in the animal models, telling that to some kind of slightly more interesting outcomes in the context of pathology because one of the associations has been between emulsifiers and IBD. And there is evidence presented from Kevin Whelan's group in relation to the adapt trial, which is the first trial of emulsifier restriction in adults with active Crohn's disease. And there's been an abstract published in relation to that listener's will have to waste with their breast for the publication of the final full paper. But some interesting potential application in that specific context. And I think there's obviously, we would temper how much that would be generalized to otherwise healthy individuals in the population. I think the sense that I got was that, and there was a lot of very interesting discussion on the microbiome and all of this. Obviously, the emphasis of the session was microbiome interactions. And I came away with some kind of new fan perspectives on the role of the microbiome and all of this. And I think when Falony's presentation was very interesting in relation to the essential role of transit time in influencing all of kind of what we end up thinking about as far as the concept of a healthy gut goes. And yet, what interested me was thinking about the kind of direction of effect, so to speak. We know that in a short-term intervention, you can alter composition of a microbiome relative to a given style of dietary intervention. But that tipety returns, so to speak, to the baseline host composition relatively quickly on cessation of whatever that intervention is. So what I came away from that interested in is, is there something. Thanks for listening in to this preview that you can listen to in their entirety over on the Sigmundrition Premium Feed. If you wanna become a Sigmundition Premium subscriber, click the link that is in the description box wherever you're currently listening right now. And in the meantime, have a great week. Stay safe and take care. (upbeat music)