字幕列表 影片播放 列印英文字幕 Hello, you're listening to CrowdScience from the BBC World Service, and this week we're coming to you from a festival in London. A vegan festival. The Sun is out, people are having a good time and feeling great. But is that because of the lively atmosphere or because of their diet? The WHO did find that red meats can put you at risk for cancer, but I just find it a better kind of energy source for me personally for my body. So from Bahrain, so we're an island and there's a lot of fish there, so usually pescetarian is the choice for a lot of people, so it wasn't a hard transition for me to cut out red meat and then all meats. Do you think being vegan is a good thing? Yes, it saves animals from being eaten. Do you think being vegan is healthier or not Do you think being vegan is healthier or not healthier? Healthier, cause you're not eating animals. You can live a healthy life being vegan and actually if you look back through history, a lot of cultures especially like you know African cultures, they consumed a lot of vegan food because meat is quite expensive. The reason why we have headed out to this plant-based party is because this week we've come to meet our listener in person. Hello Sam, how are you? Hello! Very hot. Yeah it's a really sweltering day in London and you brought us to a festival, a vegan festival in east London. The Sun is just going down there's lots of people drinking, having a good time. Why have you brought us here? Because I have a question for you: is being vegan better for your health? So why do you want to know the answer to that question? Are you vegan? No I'm not. I guess that's why I'm asking because I'm, I've been moving towards a vegan diet but haven't quite got there. Answering this question might help me decide. Help you decide okay. So Sam wants to know whether it's healthier to cut out all meat and animal products from her diet. The people at the vegan festival would certainly say it is but what does the evidence say? Does sticking to plants make you live longer? is it better for your heart or your immune system? And are you less likely to get certain diseases? There's a lot of information out there about the health impacts - good and bad - of a vegan diet. So CrowdScience is here to trawl through the facts and figures for you. To start things off with me here in the studio is producer Caroline, hello Caroline! Hello I'm good how are you? I'm very well. So Caroline you are a vegan. I am. Well I'd call myself plant-based. Okay, what's the difference? well it basically gives me wiggle room when I mess up and eat cheese. I can be like, oh I'm only plant-based, I'm not vegan! Okay so most of what you eat comes from plants but occasionally you might eat dairy products or something like that. Yeah, basically I'll eat dairy if i'm at someone's house and they've cooked for me. I don't be annoying and be like, no I won't eat that. Or it if you're a bit sad or happy... ... or I'm feeling a bit down, or want a reason to celebrate.. Or if I'm a bit hungry or a Tuesday (laughing). Okay cool and so are you mostly a vegan then for health reasons? No not for health reasons for environmental reasons and animal welfare reasons. Okay so how long have you been a vegan? For years now, yeah for years. I've been veggie most of my life and basically... So you've grown up as a vegetarian? So I wanted to be vegetarian pretty much as soon as I realised that meat was animals, but my mum was really worried that I wasn't going to get enough protein, so she used to hide meat in my food, so that is how worried she was for my health. Okay and I mean does she still do that if you go round for dinner? I mean I hope not who knows? But no she doesn't. She actually doesn't know that I'm vegan because I know that she'll worry. So when I go around for dinner I just kind of pick out the vegetables and look really rude and like I don't eat much. But like surely your mum would understand now because veganism is really common. I mean you only have to walk out of the office and there's like about three new vegan food chains before we came to the studio. I had a look online - so the number of vegans in America grew from 4 million in 2014 to nearly 20 million in 2017. And here in the UK, nearly half of vegans cite health as one of their reasons for their food choices. So there are obviously lots of other reasons for deciding to be a vegan: environmental reasons animal welfare considerations. We're not going to get into that on this show. We are going to focus on the health impacts. Yes but if any one listening does have questions about any of those other reasons, then do send them in because maybe we can look into it in the future. So Anand - last time we worked together we made a programme about motivation and I signed you up for a 200 metre open water swim. Yeah proudest achievement probably so far clocked up on CrowdScience. So what do you think your challenge is going to be this week? I mean I'm gonna take a punt and say that I have to become vegan for the rest of my life or something ridiculous like that. Not quite the rest of your life, just two weeks. Will you do it? I guess, yeah, I don't really have a choice! Okay so two weeks sounds manageable. I'm a little bit wary because I do enjoy cheese and butter and eggs and honey - all the things that you're not allowed to eat on a vegan diet. I suppose I would be a bit worried about potentially getting enough of everything. Okay well don't worry we're going to get all the information in this programme to make sure you're doing it properly and to make it easy I've arranged for your first meal to be a bit of a treat. So you're going to go for a burger at a vegan restaurant around the corner called Eat By Chloe to meet CrowdScience friend and nutrition expert Dr Giles Yeo who's going to give you some tips on how to adjust to the diet. So I think our food is here. That looks like a burger and that definitely looks like a sub. Giles, can I get you any ketchup? Or aioli? Oh yes, ketchup and aioli. It's terrible, oh my god, if my wife... actually she might be listening. She thinks that I murder food because I like a little bit of food with my ketchup. And aioli. This is a pesto meatball. I'm gonna - I'm gonna take a bite all right. First impressions. Sorry? Haha The thing is I went for the sub because meatballs, pretty much, it's meat that's been completely blitzed up and it's actually quite suitable for for the vegan treatment. It's easy, it is very, it's very easy to get a texture and then when you put it in something like the meatball sub it's all about the sauce, you can cover it up. It's very good! Okay, I'm gonna go in for my "bacon cheeseburger" so there are some little bits of - where's the bacon? - I don't know it's... maybe these little brown shavings? There's pickles which is good. Okay I think for the purposes of radio, I'm gonna need to take another bite. For sure. So in terms of the nutrients that you need to get in a diet and the things that you might be wary of missing out on if you become vegan, you have to watch out when you're being vegan and there are few things you have to replace, okay So let's start with the things you gotta watch out. You have to make sure that you get a full range of the type of protein that you're actually gonna need. The proteins are put together by these things called amino acids and not all proteins have all of the amino acids and so you need to make sure that you actually cover this. Now this is actually relatively easy to do so if you eat something like tofu, that's pretty that's pretty complete. The second thing you've got to worry about probably is iron. Now once again it's... you are gonna be able to do this completely and particularly tofu eaters, okay? I think you're gonna quite a lot of iron in that but if you're particularly a picky vegan, then you need to watch as well, your iron intake and make sure that you actually have enough iron. And then calcium. So obviously if you're going vegan and suddenly all the dairy products disappear, then you're gonna want to make sure that you have enough calcium as well. You're going to be able to get that from really quite a number of different types of vegetables and also from the beans. But you just need to make sure you watch it. Right so a vegan diet can become a bit low on protein, iron and also calcium. But if I'm careful and watch what I eat I should be able to get enough of everything. Are there other nutrients though, that I might need to take supplements for? There are certain things that you will need to replace, the first and most important of (these) is actually vitamin B12. Now the interesting thing about B12 is, B12 tends to come from animal-based products. It's critical for brain development for example and finally iodine, or depending on which part of the world you actually come from. Now why? So famously things like seafood are high in iodine. It's important for our development and also our maintaining our metabolism and so there we go. You've got things like protein, iron and calcium in which you need to watch, but you easily get, as long as you're careful. B12 and iodine are things if you've made the decision to go vegan, you really have to supplement in order to maintain healthy. Okay Caroline so a vegan diet isn't healthy and can actually become quite unhealthy unless you take supplements because you might get deficiencies in B12 or in iodine? So doesn't that technically mean that a vegan diet isn't healthier for you because it doesn't have everything built into it that we need? Yeah I see what you're saying, so I take B12 and iodine every day and that doesn't bother me. I guess some people might say that's not natural but then vaccines and antibiotics aren't natural either and we need them for our health. Yeah, no, okay, I see where you're coming from, yeah that's a good point. Okay well the next step is to start the diet for real. You're not going to be in it alone. You and listener Sam are both going to be sticking to the diet and we're going to do this properly. You're gonna meet a dietician, she's known as the London nutritionist, her name is Jo Travers and she's just around the corner and she's going to help construct a meal plan for both of you. Brilliant, bring on the veganism. So the reason why we're here really Jo is because we are interested about veganism. I mean do you get a lot of people that come to your kind of practice asking about veganism? I do now yeah, so in the last couple of years it's become very very common with the rise of sort of more proprietary products so things that are alternatives. So when you go now into any kind of high street cafe particularly in London where we are, you know, you can get any vegan products you like. Whereas before, people used to have to carry a loaf of bread and a jar of peanut butter around with them, just in case. Okay so I think the idea is that we're gonna have to go on a vegan... well, we want to go on a vegan diet, so I've been keeping a little meal plan, have you Sam? yeah. Why don't you go first? What have you been eating? I was surprised that this week... At this point Sam ran through what she'd eaten over the last week - lots of whole grains and vegetables while my ears burned in shame as I recounted a few late-night fast food trips. But Jo had some words of wisdom about how to approach our new diet in the weeks ahead. Alot of cheese... I have seen people follow a vegan diet and be completely unhealthy and miss all of the main nutrients, but I've also seen people do it really well. So if you're just trying to get through a couple of weeks without eating animal foods, that's one thing, but if you want to do in a healthy way, we have to see where we can make a few changes, does that make sense? Yeah yeah. Two weeks isn't long but you can notice almost immediately when you eat well, how much better you feel. You should measure your energy level and then you can measure your progress and adjust it accordingly. So if you feel tired maybe having a bit more carbohydrate and a little bit more protein or getting some good balance to your meals. If you feel constipated you probably need to drink a bit more water, being aware of how you feel and being really mindful about how you feel is a really good way to learn. Right good luck with it! Any problems just give me a shout. Brilliant thank you so much. Thank you very much. How you feeling Sam? Erm, actually motivated, because I think knowing that Joe's there in the background and I'm doing it for a reason, I'm hoping that will motivate me. I'll admit right now that I am not feeling motivated. Although dietitian Jo says that switching to a vegan diet might make me feel better now, that could be true. But CrowdScience is not about feelings - it's about data. So what do the facts say? Well normally researchers would find a large group of people and study their diet over time while measuring their health. This is called epidemiology. Tt's been done for drinking and smoking in the population but there's actually surprisingly little work done on vegans and it is particularly tricky to study vegans in the wild, as it were, because there are lots of other factors that might also play a role in their health. So for example people who are vegan are likely to be wealthier and so that might have an impact on the things that you're measuring. Someone who's been wrestling with these issues for a while is Professor Tim Key an epidemiologist at the University of Oxford in the UK. He's currently studying a huge group of some 30,000 vegans and vegetarians. On average the vegans have a lower body mass index, meaning they're sort of, not as fat as the meat-eaters, yeah, they're thinner, they have a slightly lower blood pressure but not not a marked difference. But they on average have a quite substantially lower level of cholesterol in their blood. So all those differences you know - thinner, lower cholesterol, slightly lower blood pressure are in the favorable direction and you would expect them to lead to a lower risk of some diseases, particularly heart disease and diabetes. What about cancer? I mean presumably if vegans aren't eating things like sausages or steak are they less likely to get cancer? So these have found a low risk for prostate cancer in vegans which is just statistically significant, so that's interesting but not enough to say it's definitely true, you know, it's in that direction. The studies I mentioned have also looked at the total of all cancers added up and have found the significantly lower risk in vegans than in meat-eaters, but I'm very cautious about it. I don't normally like adding up all cancers because we know some types of cancers have probably got nothing to do with diet or little so yeah lung cancer is mostly caused by smoking and you know, there are other examples. Okay so vegans are thinner, they tend to have lower cholesterol and lower blood pressure which probably means they're less likely to get diabetes and heart disease and there's also some evidence that they may be a lower risk from certain types of cancers.These all seem like pretty big ticks but surely it can't all be good news for the vegans? So far the one disease or condition we found where the risk was higher in vegans than the other diet groups, was the risk of fractures of the bones which suggests you know maybe their bones were just slightly weaker, so you know that's an example of something where there could be a hazard by following a vegan diet, where you're just not quite getting enough of some of the nutrients. But I think there could be other things, because for many conditions we just don't have the data yet. We've talked about about specific diseases but what about like lifespan? I mean do vegans live longer? Well we've looked at overall mortality in our study and people in America did the same and neither found a significant difference. I think the best we can say at the moment is that you can choose a vegan diet that will be good for your health but I don't think you can argue that it would be better than a sensibly chosen non vegan diet. What's your diet? Well yeah I've actually been a vegan since 1976 because I used to be a vet. Oh wow. And I was concerned about the treatment of animals and farming in slaughterhouses. Have you noticed a change in you and your health since you switched or is it kind of just too too messy, you know, a set of factors to try and... I don't think so, no. It's a long time ago. I've got older, but I probably would have got older so...! There you have it Professor Tim Key who has been a vegan for 43 years,is still 43 years older. I'm about one week into my vegan diet and producer Caroline has kindly invited me around to her flat for breakfast. So we're gonna be eating vegan bacon butties. They sort of look like pink worms. Yeah. What's it actually made from? Let's have a look. Okay it's got added iron and B12 so that's good. Charles will be pleased, and it's made from rehydrated soya protein. Tastes delicious. Yeah, okay so while the oil heats up and and you're about a week into your diet, how's it going? It's been pretty difficult actually. So I think in the first week I have just been forgetting that I'm supposed to be vegan so I keep you know making tea and putting milk in it and just kind of not realising. But the last few days I've been much more - determined to actually try and be vegan. I'm always hungry and I know that this is supposed to be breakfast but I've already eaten a breakfast, so this is gonna be my second one. You're going to spoil your appetite! I could eat a horse. Okay. I'm not going to because I'm vegan. And would you like a cup of tea? Oh I definitely would yes, what kind of milk have you got going on in that fridge? I'm afraid there's only oat milk, probably enough for a cup and speaking of milk we are about to do a bit of seamless cross promotion because CrowdScience has literally got milk. We did a show previously, a whole episode on dairy alternatives called which milk is best for me and for the planet? Which actually helped me to decide which milk to buy so you can download that and the whole of our back catalogue wherever you get your podcasts. That was very smooth. Thank you, ooh there's milk. I think the bacon is ready to go on the heat - okay let's stick that in there. Oh that's on fire, okay so we're back at Caroline's and managed to set fire to the packaging. Luckily Anand's here to save the day as per... Shall I do that? You'll be pleased to hear that Caroline successfully managed to put out the fire and that the sandwich of bacon worms was actually pretty tasty. But enough about me. I wanted to hear how Sam was getting on and whether she was holding up her end of the bargain. Hello! hi Sam! How is the vegan diet going? Not bad actually, I've stuck to it. I've probably deviated from the exact meal plan but predominantly you know, I've stayed. vegan. So no slip-ups? I had a glass of wine, and someone said that might not be vegan, and I thought oh I didn't, I didn't think about that. But I think if that's the worst of your slip-ups mate, I think you're doing pretty well. I've maybe gone more simple, maybe really, less like tofu, more like pasta and pesto. Pesto's not vegan! Yeah I know, you can make vegan pesto! Okay good just checking. I'm just trying to kind of catch you out. I haven't felt particularly different in the last week. Okay yeah me neither but then again I haven't really been sticking to the diet that well... All right well yeah, so good luck with the rest of the plan. You're putting me to shame really ,but I've got a new kind of a newfound sense of determination to stick to it. So I think I'm gonna keep going. Good alright bye. So perhaps no surprises that Sam has been sticking to her vegan diet plan better than I have. Now so far we've been looking at veganism from a fairly narrow point of view, mainly my struggles to deal with an existence without cheese. But a big component of veganism and health is the switch from meat to alternative sources of protein things like micro protein, which comes from fungus and tofu which comes from soy. At the start of this year (2019) the World Economic Forum published a report about the future of meat substitutes like this, where they modeled the health impacts of replacing meat with alternatives. I spoke to Susan Jebb from the University of Oxford in the UK about what health effects the model considered. So we were basically looking at the effects on blood cholesterol levels, so that's largely down to how much saturated fat there is in the product. We were looking at the effects on blood pressure and then we were looking at the health effects which we know were attributable to two dietary fibre or things like potassium which is rich in in plant-based products. And yeah, what did you find broadly? Broadly we found that anything's better than beef but if you look at everything else there, the health improvements are all you know really quite quite considerable. Susan's model found that overall, alternative proteins lowered cholesterol blood pressure, increased fibre intake and decreased intake of saturated fats. And by adding up the effects of all of these individual components was able to measure the combined impact on health. Well in the end you know it all ends in death and so we used that as our kind of final, you know, overarching outcome. And what you see for some products is because they are perhaps quite high in, say cholesterol it may be that you get slightly adverse effects but overall the meat alternatives were better than meat when you integrate all the different effects of sodium and and cholesterol and fat and so forth. Did you look at how they would apply to people depending on where they live in the world? Yes we did and that's a really important thing to consider because if we look at meat consumption at present it's incredibly variable. We've got some countries which are almost entirely vegetarian whereas we've got countries like the UK, the US, Australia some parts of Latin America with very very high meat intakes and whilst it's not absolutely true, in general, high income countries consume a lot of meat and lower-income countries consume less meat. But what's absolutely clear is that High income, high meat-eating countries would benefit their health if they ate considerably less meat whereas there may be some countries, mostly low income countries, who are really developing quickly now, where it may actually be good for their health if they were able to eat a little bit more meat, because it is such a good source of of important nutrients, which shows that it's important to have a global outlook on this issue/ Because for many people in the West veganism is a choice. But of course not everyone has that choice. This World Economic Forum report modeled the health impacts of alternative meats but are there any real experiments done on actual people? Well luckily for Crowd Science Andrew Salter from the University of Nottingham has just done a study which is the first of its kind to intervene in participants' diets rather than just measuring what people eat and it confirmed Susan's predictions. And you've got a group of meat-eaters to halve their meat intake and increase their consumption of meat substitutes - things like vegetarian burgers and vegetarian sausages for three months. And just like Susan's model predicted Andrew found a decrease in the group's cholesterol by about ten percent which lowers their risk of heart disease. But that's not all they found. There was also a rather unexpected result which didn't appear in the World Economic Forum model. There was just one thing that we found which surprised us, which we haven't really been able to explain in terms of the changes in their diet, but it seems to be quite consistent, and that was in the level of white blood cells in their blood. Now white blood cells were involved in protecting us from infection and there was a significant drop in the number of white blood cells. It still remained within what we'd call a normal range but it went down and in one or two it actually dipped just below the normal range and that was a complete surprise to us and it really needs exploring a little bit more, but it was one potential adverse effect so the people in the study they reduced the amount of meat they were eating and then they kind of replaced it with these meat alternatives and it seemed that you you're able to measure some some positive health outcomes. But how are you able to separate out the fact that they were just eating less meat from the fact that they were eating more of these meat alternatives? That's always very difficult to know whether it's what you've taken out of the diet or what's going into the diet which is having the positive effects. All I would say is that we did, through doing diet diaries, look at their individual nutrient intakes and most of the people involved in the study significantly reduced their intake of saturated fat which is often associated with meat products and we know, we've known for a long time, saturated fat tends to put up LDL cholesterol - the cholesterol which increases your risk of heart disease - so that's one factor I think which probably contributed to the benefits. Whether there's an any additional benefit from physically eating the meat alternatives I think you'd have to probe a little bit deeper and do a slightly different sort of study to be able to assure that so a potential cause for concern a decreased white blood cell count suggests that the participants might be a greater risk of infection although we should say that this is just one study and so more research is needed into this particular issue and you also emphasize that this study was based on meat eaters in the UK and that reducing meat consumption is it necessarily going to be healthier for everyone in the West? We have an almost limitless supply of a whole range of different types of food different types of vegetables, pulses, beans. We import what we need. When you go into poorer parts of the world where they're essentially often still dependent on what they can produce themselves, that maybe one or two crops, and we know there's certain crops which particularly that the protein for example isn't digestible or available, and they are at considerable risk and introducing some meat and/or dairy products into those diets can often take them out of that risk of malnutrition. I think we've just got to be a little bit careful of preaching to these people. Just because we have to change what we're doing it doesn't mean just at this moment we should be eliminating meat from their diets. Thanks Andrew and we'll be putting a link to that research up on the CrowdScience web page. Right so we are getting towards the end of the show but Sam we've got you into the studio - thanks so much for coming in, especially because as I understand it you're leaving tomorrow for your wedding. Yeah flying tomorrow. Wow that is commitment. Well we're really glad we managed to get a hold of you. As a thank you, we've brought some vegan half-eaten treats. So this is a packet of bacon flavored snacks that is now empty because Caroline ate them all on the way to the studio. There are also some cashew nuts, some chewy fruity rainbow flakes wheats and some vegan chocolate. Thank you especially for the eaten crisps. So the one thing we should probably do is talk about the diet and maybe check in with Jo and see how it's gone. Sure sounds good hmm Why don't you go first then? It's gone quite well actually, surprisingly and that I've stuck to the whole vegan diet but maybe not the meal plan as such and I'm still struggling with having a breakfast in the morning. Yeah what about you Anand, have you... go on yeah. So the first week wasn't great I'm gonna admit I've kind of kept forgetting I was supposed to be vegan and I'm making tea and putting milk in there and stuff. Okay but then the second week actually has been really good. So I think for the last week I have been maybe 99% vegan so, it's just I'm hungry all the time, like I went, I was driving the other day I had to pull over it's like a petrol station, just buy some nuts and I was just shoveling nuts, it's just so... today, I've just been eating non-stop. Yeah. What about your energy levels? They've been yeah like it's hard to tell, like pretty pretty good, I think, while I was gonna say it's meant that I've eaten less junk food but actually we just before we came into the studio, actually, we were just all gorging ourselves on dark chocolate and sweets, which is all technically vegan, yeah, so unless it's been sort of either super healthy or super unhealthy. So after doing it for a couple of weeks what do you think do you think you're gonna continue doing it? Are you gonna sort of be a bit more flexitarian, what do you think? I think I like the idea of being flexitarian so predominantly vegan, but I have to say, I think I kept to it because I thought well it's just two weeks and then I can have, like you know, yeah I can not worry too much if that packet of crisps is not vega.n I think I like the concept of flexitarian a bit more. Yeah I think that's interesting. What about you? And yeah I think I again I was just thinking of it like I've just got to do this get it out of the way for a week. But I think actually, more for environmental reasons, I have thought about becoming a bit more vegan. And so yeah just things like you know I've never bought oat milk before but actually I might just keep doing that and just cut down on animal stuff you know, a little bit here and there. Yeah oh that's good that's interesting well keep me updated, let me know how you get on and if you've got any questions you can just give me a shout. Brilliant thanks so much. Sure Okay and Caroline what are your thoughts on this? I don't think you really thought I was going to be able to stick to this diet but are you proud of what I managed? I mean you didn't, you weren't vegan for two weeks but you tried, and I'm proud of you for trying and towards the end you improved, so I'll give you a medal for most improved vegan. That's all I want - medals. But yeah I am pleased you're gonna make some vegan swaps and if you ever persuade me to make you a cup of tea I will be making it with oat milk. So last question Sam, have we answered your question, are you satisfied with the services that CrowdScience has provided? Yeah I think you have I think. What's been encouraging for me is it's not black and white - you must be vegan or you know you must follow this diet. It's more about having a varied diet and you know, not always constraining yourself If you do want to have a bit of a treat do that but if you're predominantly plant-based then that's going to be better for your health which i think is more attainable than just saying I must be vegan. That's it for this week's show and I'm going to hand over to Sam to read out the credits but before I do that I just wanted to ask you listeners a favour - if you liked our show please can you consider leaving us a review wherever you get your podcast. It really does make a difference - it helps more people to find out about CrowdScience and it means that we can make more programs and also that Caroline can set increasingly zany challenges for me to take part in. So Sam over to you. That's it for this week's CrowdScience on the BBC World Service. Rhe question this week was from me Sam Dawood. Today's episode was produced by Caroline Steel and presented by Anand Jagatia. If you have your own question you'd like to send in, like I did, you can email CrowdScience@bbc.co.uk Thanks for listening. Bye!
B1 中級 美國腔 素食(Is a vegan diet better for your health? - BBC World Service, CrowdScience podcast) 29 2 joey joey 發佈於 2022 年 01 月 01 日 更多分享 分享 收藏 回報 影片單字