The shocking damage ultra-processed foods cause to your brain

25:50We've done research to show that it's linked in a dose response manner. The number of oral health conditions are linked in a dose response manner to depression risk. Could you explain dose response? It means that if you had two oral health conditions, your risk or your likelihood of having depression was down here. But if you have eight, it's up here and it goes up like this in a stepwise So it gets higher and steadily as you get more of these oral issues, then your risk of depression is just steadily going up and up and up, like a graph that's sort of like a straight line going up. So the oral microbiome is, of course, directly has access to the brain, but it also makes, there's many pathogens that make their way to the gut, particularly if you're on those PPIs, those proton pump inhibitors, those things that people take for gastric reflux, because that reduces the barrier that stops these microbes making their way to the gut.

26:46So all of our microbes... We actually had a podcast talking about this and some of the downsides of taking these pills. That's correct. And we know that the oral microbes, like everything else, they seem to be influenced by the food that we eat. So this is another link to diet and another way. So again, you're saying it's not that this has always happened with these plaques in your brain. You're saying that the microbes in your mouth are themselves affected by what we eat. and then your inflammation is different. It's highly speculative at this point. But basically diet seems to be able to affect your risk or your mental and brain health via a lot of different pathways.

27:24A lot of this is based on animal evidence at this point, so we really need to do it in humans. We're doing a lot of research at the moment. We've just finished a really, really cool trial where we've looked at the possible impact on the brain of fermented dairy, like, you know, kefir, yogurt. We've also just finished a trial, which is sort of a proxy investigation of ultra-processing. So, you know, when people are living with obesity or sometimes they have to have surgery and they need to lose some weight and they get put on these very low calorie diets, So 800 calories a day, really low. And usually they're put on these shakes and bars, you know, these highly processed foods that say they're nutritionally balanced.

28:11They've got vitamins and minerals added and they've got protein and all the right, they've even got fiber added to them. We worked with a couple of dieticians who've developed a range of pre-cooked and frozen products that are the same very low calorie, but they're based on vegetables. and legumes and things like this. So that people, because they were concerned that people going on these very low calorie diets really weren't doing their health any good. So we randomly assigned 40 women to receive either the shakes and the bars or the whole foods over a period of time. And the primary endpoint was the gut microbes.

28:51So seeing what happened to their bacteria. Yeah. Now I can't give too many results away because this is, we're only just analyzing the results now. But basically, we do see pretty much what we would expect to see. And this, to my mind, reinforces that just because foods have vitamins and minerals added to them, just because they have this nutritional profile that doesn't look like it's too bad, these ultra-processed foods, and here it could be everything from protein shakes and bars to whatever, I don't think that the body and the brain recognize them in the same way that they do, whole foods.

29:29If you think about whole foods, like plant foods, right, it's estimated that there's possibly as many as 150 ,000 different phytochemicals in them. Now, we know about only maybe 20 ,000 if we're lucky, but that includes things like the polyphenols, the flavanols. 150 ,000 of these phytochemicals that interact with each other in highly complex ways interact with every bit of your hugely complex body brain in highly complex ways that we can't even begin to map, not to mention the food matrix, you know, the way a whole food is put together by nature. All of that is lost when you process foods and when you deconstruct them and put them back together.

30:14It's sort of crazy, isn't it? Because I've heard Tim and others talk about this and now it drives me slightly crazy because you see, you know, on some packaged food, something that says high in potassium or whatever. And I'm now thinking, well, that's fine, but apparently there's 150 ,000 other things that I need to get. So, this sort of focus on these individual things sort of shows you how we've ended up in this world where you have this food that's stripped back and then has 15 things in. And then you wonder, I guess, how much we're missing as well as there's been a lot of focus on the bad things in the ultra-processed food.

30:51But clearly there's also this thing about this huge absence of all the things that our bodies are used to having. And when you even just think about fiber, fiber isn't just one thing. There's multiple, multiple, multiple different types of fibers. Everything from non-fermentable to highly fermentable, everything in between, they're all treated by your gut microbes differently. They all have different effects. You can't put that into a processed food and just say, well, it's got fiber and it's okay. Well, what sort of fiber? You know, like where's the complexity of the fiber that your microbes are expecting to come in?

31:28And this is a major issue. And it gets back again to the food system. When do you think about the way the food industry, so our global food system costs the world around$20 trillion a year. $20 trillion? Trillion American dollars. I don't even know how much that is, but it's a big number. Well, an equivalent would be the whole GDP of China is about$16 trillion a year, right? So this is huge. This is coming from the UN Food Summit. Now, about$11 trillion of that is the impact on health, but about$7 trillion is the impact on the environment. And these two things can't be torn apart because biodiversity in the environment influences the biodiversity in us, our microbes in our gut, in probably every part of our body, in our lungs, the microbes we breathe in.

32:20Now the soil, ideally healthy living soil, the way those phytochemicals get into the plants is via this very complex, tight relationship between microbes in the soil and fungi in the soil. So nutrients, phytochemicals make them into the plants from healthy living soil. The way our industrialised food is produced now, soil is dead. There's an estimation that over the next hundred years, we'll actually lose about 30 % of the food producing capacity of the soil across the world because of what we're doing to it with herbicides, pesticides, artificial fertilizers, and also that intense cropping where we just take everything out of the soil, leave it barren, and then go put the same thing back in again.

33:08So we've completely got away from how soil used to help our food to grow. Now, that food is eaten by us. It's also eaten by livestock that we then go on and eat. And don't even get started on the industrialised production of chicken and pork and these things that have huge amounts of antibiotics in them, often to make them fatter. And of course, they make their way into us as well. Now, everything in our industrialised food environment, including the environment we live the advertising, the food that's available to us, the subsidies that make these ultra-processed foods just so much cheaper than whole foods and so much easier to get.

33:49This is what needs to be changed. So, you know, I talk to people and I say, well, we know from the evidence that, for example, the diets that women consume when they're pregnant is linked to their children's emotional health and things like ADHD. We have to change our food environment so that the population is eating in a way that supports the health of the population. You know, there was a really interesting paper just published. It wasn't a scientific study. It's like a report in Norway. Norway has exceptional data because they have these registries that you can actually go and look at and do scientific testing on.

34:30And they basically looked at the introduction of fast food restaurants into the population, which happened in about sort of the 80s in Norway, and then cohorts of children that grew up exposed to fast food restaurants. So it wasn't directly linking consumption of fast food and children. Just the change in the environment. In the environment. So what happened? And you see an increase in body size, of course, but also a decrease in IQ. Wow. And Felice, you're incredibly passionate hearing this. And I think what's striking is, you know, you're a very serious scientist. You're really on the cutting edge of all this research around the brain and food.

35:13And, you know, I heard your answers to the question in the beginning, you know, like many scientists, you're a little cautious about, you know, not wanting to say yes or no, but you sound pretty convinced here. I mean, I think you sound pretty convinced this ultra processed food really is having an impact. This isn't just a hypothesis without a lot of data. You sound like you say, no, like the evidence is quite strong enough in the same way as it might've been with smoking. Maybe that's a good example. How would you compare this? Like we said, wow, that smoking turns out really does have all of this bad impact.

35:43We really need to change things. We need to try and convince ourselves to stop. You know, my grandmother smoked for years. My mother smoked in her froze for years. And then people realized, no, this is really bad. And so people try and shift. And then of course, we try to change the overall environment. I mean, how serious, like how strong is the evidence, I guess? Is this just like, oh, I think this might be the case, but really, you know, who really knows? It's a very interesting analogy because if you look at the global burden of disease study, so the largest health study in the world, it brings together everything we know from health studies across the world involves more than 2 ,000 scientists.

36:20We're doing some work for the Global Burden of Disease study now. Tobacco smoking is up there in the top five risks for illness and early death, but it's up there with the other four factors, which are all diet related. So at the global level, poor diet and smoking are roughly equivalent. The main causes of people dying earlier than they would otherwise. But at an individual level, people vary enormously in terms of their risk. What you have to do is look at converging evidence. So converging evidence from all the epidemiology, where you look at large populations and see these links over and over again.

36:55We did a systematic review and meta-analysis that looked at the link between ultra-processed food intake and a whole host of outcomes. Now, obviously, body weight and size was one of them. All-cause mortality was increased by about 30%. So that's just dying, right? That's just dying, yeah, for anything. For normal language. But also the risk for depression. It was associated with an increased risk of depression of about 24%, I think. Which is a huge increase in the risk of depression. It is, yeah. And then, you know, we've just finished a study in Australia that's looked at this again in a very large sample of, I think, about 20 ,000 people and shown about the same increased risk of a measure of depression over time for people with a higher intake of ultra-processed foods.

37:44What's interesting in that study is that the people with the highest intake of ultra-processed foods were also the most advantaged. So, they weren't the poorest or having the lowest income or the lowest education. It was actually those at the other end of the spectrum. But what was also interesting is that those people were actually having less energy intake, less saturated fat intake. So it looked like these were like diet foods. These were the ultra processed foods with the added sugar, the artificial sweetness and things like that. Yeah. This is one thing that makes me really angry, which is how many people have been trying to do the right thing basically and follow what they think is good and like eat based upon the labels they see in the grocery stores they go into of like, oh, this is good for me.

38:27And it's got this added thing. One of our previous guests said this brilliant thing, which is said basically any food that has a label on it saying that it's good for you isn't. And I thought that I'd never heard that before. And then you realize it's basically, it's all of these ultra process, it's this breakfast cereals for the kids that say, you know, high in these vitamins and whatever. And those are exactly the foods that - had a bit to do with some of these industry players and the nutrition people who work for those big food corporations. They're generally traditionally trained dieticians.

39:01They may have been trained however long ago. And they genuinely think that because food has added vitamins, minerals, whatever, that it is a healthful product because that's based on what we knew back then. What practically, I'd love to switch maybe now to practical advice. So maybe let's start with children and let's think about maybe for our listeners and also maybe also thinking about people as we get really quite old. Any practical tips for us about what we should do? How do we identify this UPS? What should we be worried about? And what could we do about it? The thing with these sorts of foods like ultra-processed foods and these foods that have got a lot of added sugar and salts and fats, they're all designed to interact with the reward system of the brain.

39:43Well, they're probably not explicitly designed for that, but they do. They interact with the reward systems of the brain. And for children and adolescents, those reward systems are particularly sensitive, if you like. And there is some evidence, I believe, that suggests that it is programming the immune system and inflammation and the reward systems of the brain when they're young, if they're exposed to it, so that they will want to keep eating those sorts of foods. They'll make those choices. And is this all or nothing? Or can anyone listen to this say, either for myself or for my family, maybe I can't cut out all of these ultra-processed foods?

40:21Is there a certain amount? Is it better if you reduce it? Definitely. And so what we've seen in our latest study, so this big sample of Australians, is that it's only those in the very top quartile, like that top 25 % of consumers of ultra-processed foods that had the increased risk for depression. Now, you want to normalise healthful foods, but we recognise that so many people have challenges with access, maybe storage, maybe food preparation, education. it's going to take time to overhaul our whole global food system. There's huge pushes on to do this. There's big players and things happening at the level of both industry but also government that I'm hopeful will start to feed into changes in the way we produce foods, changes in the way we market them, all the rest of it.

41:14But governments have to get real about food policy because we're talking about the whole health of the population. But in the meantime, if people are consuming these foods, even just small reductions are going to help. And let's say someone's listening to this now, and we've talked quite a bit about children, but let's say I'm a 48-year-old listening to this, and I would like to cut down on UPF, but I don't even know what UPF I'm... So it's sort of like, oh my God, I suddenly just discovered I've been smoking. I didn't even realize I was. What's the way to start down this path if you're advising someone who's listening to podcast and wants to go and do something.

41:52Yeah, yeah. I believe that there's apps that can help, you know, like swap sort of apps where you can go, okay, I was going to choose that, but actually I'll get that instead. Reading the labels, they're always designed to be very, very difficult to understand. And what would be your simple? Simple would just be if you pick up and it's got a label with lots of different things in it that you don't recognize, then don't choose that. One of the important things that we did with our SMILES trial was we estimated the cost of the diet that we were advocating compared to the cost of the diet people were eating when they came into the trial.

42:25So people coming into the trial had lots of UPFs, lots of discretionary foods, and we estimated the cost very carefully of their baseline diet. And then we looked at what we were advocating for and our diet was actually cheaper because what we were saying was things like frozen vegetables. They're fantastic. They're even superior. You don't get the food wastage. You have them available the whole time. And they're really inexpensive, relatively speaking. Tinned and dried legumes. These are your absolute gold in the food department because they're so cheap. And these are beans and chickpeas and things.

43:05Beans, chickpeas, even green peas, mushy bees, go for it. Because they have so much fiber, So many phytonutrients and they are very cheap and easy to prepare. Tinned fish. I love the pre-cut salads that you get at the supermarket. I live on those during the week. I literally get the pre-cut salads, especially if I can get the ones that have got like, I don't know, kale and beetroot and all sorts of different, like that rainbow, because then I know I'm getting lots of phytochemicals. I stick them in a bowl. I have a tin of chickpeas or something like that on top. Sometimes I'd put in like a small tin of fish or something, mix it all up.

43:44Lots of extra virgin olive oil, which is a really important source of these phytochemicals and some balsamic vinegar. And there's a meal, you know, and if you want to add in like, you know, make it a bit fancier and herbs and things like that, that increases those phytochemicals too. But super easy. It's good for your health and sounds really tasty as well. And really tasty and really quick. So, and I like quick. I think that is brilliant advice. I mean, maybe final question, I think, because we've talked about many stages of life, but you haven't really talked about older age. Is it all too late if you're listening to this and you're already 80?

44:27I think it does matter a lot. So there's been a couple of really important studies done where they've looked at the gut microbes. So we know that in general, a healthy diet means that you have a more diverse gut microbiota. And your gut microbiota diversity is in turn linked to things like frailty, which includes measures of cognitive decline. And they showed that when people moved into nursing homes, the diversity of their microbes really reduced because their food diversity really reduced. And that was associated with increased frailty and more cognitive decline. Now, we don't actually know over what sort of time scale, you know, what we eat.

45:03Just to make sure I understand, you're saying like basically, again, like bad food leads to bad microbes. And when you're older, you get, you know, your cognition, your brain function is getting worse than other people. So actually, it's incredibly important as you're older to think about this. And it's not too late, therefore, to do something positive to support you with the right food. And so what we see is, you know, when we think about those junk food diets that affected the hippocampus and learning and memory in just such a short timeframe, within a week, within four days, we also see that you get improvements in that within a very short timeframe.

45:35And if we look at the literature from the dietary interventions for depression, we can see in as little as three weeks, these really major changes in depressive symptoms. Within three weeks, potentially, if you really change your diet, you could really feel better mentally. Your hippocampus is super plastic. And one of the interesting things I think is that your skeletal muscles, so the muscles that you build if you're going to the gym, lifting weights, whatever, they actually produce the proteins that help to grow your hippocampus. So, when you're going and you're lifting your weights, you're directly increasing the size of your brain.

46:09So, that's really cool. That's amazing. So, I think most of us don't think when we're going to the gym that we're, in fact, we have this bias, right? That people go to the gym all the time. This is only when I was a kid. I think it was like, well, that's not, you know, it's like people not really thinking about their brain. And now you're saying actually they're working out their brain as well as their body. It looks like it, yeah, based on the information we have so far. But it does look like you can affect change in your hippocampus and your ability to learn and remember and potentially your mental health really quickly.

46:36And that makes sense. If you think about, you know, you put in food, if it's high in sugar, it gets absorbed by your short bowel, doesn't even make its way to the large bowel, gets straight into your bloodstream and your blood glucose increases. And that seems to create inflammation. It seems to influence your hippocampus really quickly. If you eat good things, fibre and the polyphenols and the healthy fats that we know that the gut microbes need, once it gets down to the large bowel, all those bacteria get to work and produce all these thousands of molecules really fast. And that influences all these systems in the body, our immune system in particular, our metabolism and our body weight, the way genes are turned on and off, the mitochondria, the way neurotransmitters are produced in our brain, it all happens really quickly.

47:25So that's really exciting because it means you can make changes today and have an impact really fast. And then there's a brilliant place maybe to wrap up because I think quite a lot of this is slightly depressing. And so I think to finish with this idea that actually you could make a change right now if you listen to this, and within three weeks, you could really feel an impact on your brain is rather magical. Even less than three weeks, potentially. Wonderful. I'm going to try and do a little summing up. It was a bit complicated today. So correct me if I get, no, not at all. Correct me if I get anything wrong, I think we started by just saying that we're now starting to understand that ultra processed food is not just something that might be affecting our weight and some of those sort of cardiovascular risks like heart disease and things like this.

48:09It's actually directly affecting our brain and therefore affecting not just our mood, but even our cognition that you think a lot of that is influenced sort of directly through the microbiome and all of these bacteria who apparently make these magic neurotransmitters, which I don't really understand, but they sound like they're very important as one of the ways it sort of links from what we eat through to things that are going on inside our brain, that there's a particular part of our brain called the hippocampus, which although it's very small and Felice, I remember you had your hand like it's very small, but apparently controls almost everything like learning and memory and appetite control.

48:48And amazingly, it's the only part of our brain that can actually grow once we're an adult, which is sort of constantly changing, and that the quality of the diet we have is directly linked to the size of this hippocampus. And so, you can see that basically people with a bad diet and lots of ultra-processed food, you can see in real time the sort of hippocampus shrinking, and that's linked to a lot of bad things as well, like dementia. And on the other hand, there is this possibility to improve your diet. It's not too late. You can actually grow your hippocampus. I love that. It's a bit like going to the gym, but for your brain, that overall the impact of this ultra processed food, it looks like on a global scale is as bad as smoking.

49:27And that is the only other thing that's sort of as bad as this. And then I think we talked a bit about sort of different life stages that you said to me, I was right to be worried about, you know, my little girl, because with children's incredibly important, there's sort of this huge amount of their diet that is ultra processed food today that once again, it's like a tough story for pregnant women because you're saying, well, actually like what you eat does affect your children's mental health. And there's already, I think always so much pressure on pregnant women having seen my wife go through this, but also what, but obviously critically what they're eating afterwards is so important.

50:04And above all, try and get them to eat as much an adult diet rather than thinking that we should have all of these highly processed special foods for children. And at the other end, with older people, actually, again, the positive story is you could potentially really improve your cognition and frailty by eating the right food. And on the reverse, the sort of food that you might be given on a hospital or a care home could actually be leading to really fast decline. And then I think the final thing that you said I thought was brilliant I had heard of is potentially you could exercise to improve your brain and that there is actually this direct link.

50:41So, you know, if you could cut down the ultra-processed food and improve the exercise, you're actually working out on your brain in the same way as you're working out in your body. Yes, I would agree with a lot of that. I would say that a lot of what we know from association studies, which talks about averages across the population. So, we can't say about any individual the degree to which this is going to influence them. A lot of what we know comes from animal study, so we still need a lot more work in humans. But if we bring all the evidence together, it looks like diet really does matter to mental and brain health right across the life course, from the start right to the end.

51:18The degree to which it matters, we don't know yet. In regards to smoking, I think at an individual level, junk food is probably not as bad as smoking, although it might be. At the global level, it's certainly diet and cigarette smoking are pretty much the leading causes of illness and early death. So there's a lot that we still don't know, but if we bring together all the evidence from human and laboratory studies, we see that it's all converging on this idea that what we eat is just as important for our mental and brain health as it is for our physical health right across the life course. And that makes sense because mental and physical health are really just one and the same thing.

51:56We are one highly integrated, highly complex system. I love that story, Felice. And I think in terms of getting more evidence, I hope we're going to be able to announce to our whole ZOE community soon, some new studies allowing us to do some of these interventions and understand more in sort of the large populations, which are normally so hard to do. So lots of people, how what we eat can affect our brain health, our mood, our cognition, because it seems like one of the reasons we don't understand this is just there's been incredibly few studies until very recently. Yeah. What we need to do is push our politicians to help us, help the whole population to have access to better, healthier food through food policy.

52:43We need to have proper food policy. It shouldn't be up to the individual to have to make those really hard decisions every day about what to eat because it's confusing and industry has had a vested interest in making it confusing. Felice, that's a wonderful place to finish. Thank you so much. Really excited by the studies that we have planned together and excited to talk about some of these new studies that will be coming out in the next year. We've got a lot coming out in the next year. So watch the Food and Mood Centre space. We will. And we'll have links on the show for all of this. Thanks, Jonathan.

53:18That was great fun. Thank you, Felice, for joining me on Zoe Science and Nutrition today. If you want to understand how to cut down on ultra-processed foods and support your brain with the best foods for your health, then you may want to try Zoe's Personalized Nutrition Program. You can get 10 % off by going to joinzoe.com slash podcast. As always, I'm your host, Jonathan Wolfe. Zoe Science and Nutrition is produced by Yellow Humans Martin, Richard Willen, and Alex Jones. See you next time.

53:55I'll leave you with one final thought. What if there was one simple habit that when repeated could change how you feel for the better? I'd like to tell you about something that I do daily for my own health. It's called Daily 30, the gut supplement developed by our scientists here at Zoe. Daily 30 is made of over 30 hand-picked plants, including seaweed, fungi, and different types of fiber. It's a source of plant protein, omega-3, and vital minerals. You simply add a scoop to any meal once a day to support your health and increase the plant diversity in your diet. And unlike synthetic supplements, Daily 30 actually tastes great.

54:34It's designed to be enjoyed because when a habit brings you joy, you're far more likely to stick with it. So next time you feel like your plate is missing extra plants, do yourself a favor. Try Daily 30. It's a delicious and healthy habit that you'll feel good about and one that your gut will definitely thank you for. By the way, whenever we talk about Daily 30 as a good source of fiber, we're required to say that it contains four grams of total fat per serving. Obviously, that's all amazing healthy fats from plants. So, order yours today at zoe.com slash daily30. See you next time.