The truth about vitamin supplements | Professor JoAnn Manson and Dr Sarah Berry

my three-year-old it's incredibly hard to get her to eat anything that isn't beige and we do give her vitamins and I was curious what your take would be on that Jonathan that's the same for my 10 year old as well not not just your three-year-old so what should we do Joanne for older children such as your own I think it depends on really the quality of their diet most children do not really require multivitamins or dietary supplements welcome to Zoe science and nutrition where World leading scientists explain how their research can improve your health foreign thank you for joining me today why don't we start with a quick fire round of questions from our listeners and the first one very simple should we all take vitamins every day it's not essential if you have a healthy and balanced diet and vitamins and mineral supplements will never be a substitute for a healthy diet brilliant in that case our vitamins and supplements just a scam by manufacturers to make us pay for something that we don't need no I don't think it's a total scam however it has to be targeted and appropriate use which we'll get into in more detail brilliant I think we'll talk about that that a lot um next question should I take vitamin D in the winter months yes it would be very reasonable to take one thousand to two thousand IUS a day and I should note that Joanne does not like being forced to say yes or no in quite such a short period on such a complex topic so we're going to come back to that in a bit more detail are collagen supplements a waste of money maybe um okay I don't know how well studied the collagen supplements are most of my work has focused on vitamin mineral and supplements as well as some bioactives such as Omega-3s wonderful and may I just say that I'm incredibly excited to have you join us and part of that is because Sarah has been telling me for months how excited she was that you were going to to join us and Sarah why is that gosh well Joanne's been a real inspiration I think you know to us female scientists and I think Joanne your work in the area of nutritional research has been really um you know foundational for a lot of the work that we've gone on to do and I'm especially excited by your Cosmos and your vital child that hopefully we can go on to talk about which are huge randomized control trials Jonathan that just haven't been done before in the way that Joanne's done these recently thank you so much Sarah it's very kind of you and I'm really honored to hear that Joanne we had a huge number of listeners saying that they were incredibly confused about supplements what's caused this level of confusion there have been so many mixed messages about dietary supplements over the years there are findings from observational studies just looking at what people do what people consume and they're reporting certain findings and then the randomized trials are done which are experimental studies for example giving vitamin D giving vitamin E or beta-carotene to a group of participants and half of them will get Placebo a flip of a coin assignment to treatment and the results are often very different so there is a different message that comes out a year later and it's completely understandable that the public is confused brilliant which supplement would the majority of the population benefit from taking and why I think at this point the evidence is really mounting that a multivitamin may be worth seriously considering just as a form of insurance and to hedge your bets I would say second would be a vitamin D supplement uh 1000 to 2000 IU's a day a small to moderate dose no mega dosing not taking doses of six thousand ten thousand I use a day for small to moderate dose so why don't we start at the very beginning Joanne like what are dietary supplements and vitamins so think of vitamins as organic compounds or substances that we our bodies usually do not make but are essential for our metabolism and for good health in fact we do synthesize vitamin D through the skin when exposed to ultraviolet B light but otherwise vitamins and minerals are not made by the body they're essential to function and we need to get them from food or from supplements I think that Joanne a lot of people use the word supplements not just for for essential components so the out on the market at the moment there's so many supplements out there that might be you know beta glucans so a kind of fiber or polyphenols for example that actually they're not essential and so I think this is something really important to clarify the difference between essential supplements versus these emerging new supplements that aren't essentially in the way vitamins are that is absolutely correct there are more than 90 000 dietary supplements on the market 90 000. that's crazy a dizzying array of supplements on the market in the US and I imagine it's not too different in the UK and most of these dietary supplements have not been well studied my my comments were limited to the essential vitamins and minerals but even there the supplements are usually not really necessary if you follow a healthy diet and that's what we encourage as the number one guideline not to take supplements for that purpose but certainly for many of the other tens of thousands of dietary supplements there's very little research about efficacy or safety and in fact these supplements can get on the market without testing for either efficacy or safety but if problems are found they can be withdrawn from the market so it's a real problem it's buyer beware consumer beware and many people are spending a lot of money on dietary supplements that are not only of no value to their health but actually can be harmful especially when taken in high doses so we have to be very careful about safety issues and avoiding mega dosing yeah I think that's a huge problem there's so many of these Mega dose Vitamins out there but there's reasonable evidence I think to show that there's certain dose at which um we have the maximal health benefits a dose at which it becomes harmful or a dose at which actually you're just paying it all down the toilet for essential vitamins and minerals The Institute of medicine National Academy of Medicine and professional or organizations in different countries do provide guidelines but for many of the dietary supplements out there there are no guidelines even in terms of the doses that would be appropriate so just to make sure I've got this as a sort of wild west here so there's this small number of essential vitamins maybe you could tell us in a minute what what those are and the key ones and then there's this just this vast mass of things over which you're saying there's really no scientific evidence that at all it should take them and quite a lot of concern that you might just be taking stuff that is is bad for you is that right absolutely true we have very very little research on benefits risk safety issues for the vast majority of the supplements that are on the market and why do you think there is all of this advertising that's suggesting that we should be taking all these supplements and vitamins how have we ended up here I think because it's possible to get them on the market and to promote them and Mark you know sell them and many people are just looking for Magic Bullets for popping a pill that will they think will benefit their their health and I think it's really unfair to the public to mislead them into thinking that there's research and evidence that most of these dietary supplements will be of benefit to their health in fact there's very little evidence for that but there are some vitamins and minerals that are really important for health and it's essentially what's in your multivitamin pills you know if you look at any generic multivitamin it will have you know vitamins a vitamin A and number of B vitamins like folic acid and B6 B12 vitamin C vitamin D vitamin E vitamin k um these are the really essential vitamins and then you will also see calcium magnesium um and a number of selenium a number of minerals as well so that's interesting right so you slowly strike to a much smaller set of things versus your your 90 000 that you've been talking about now you've done just as Sarah was saying before some of the biggest research studies in the world full stop and then specifically into a number of these dietary supplements could you maybe just start by telling us about your own research like why why you did this and and what does it tell us today um and what is still I guess open and uncertain we've been doing large-scale randomized clinical trials these are relatively pragmatic low-cost trials with very large numbers often more than twenty thousand participants Nationwide in the U.S for close to 30 years we started with some of the antioxidant vitamins we studied beta-carotene vitamin C vitamin E and overall we did not see clear benefits of these antioxidant vitamins and over time there were several randomized clinical trials as actually suggesting some risks of beta-carotene especially in smokers and increased risk of lung cancer and in for vitamin E and increased risk of hemorrhagic stroke the bleeding type of stroke and um there are now recommendations at least in the U.S U.S preventive Services Task Force saying do not take beta-carotene or vitamin E supplements so that's we started with some of these what looked like very promising antioxidant supplements we did not see benefits of vitamin C for prevention of cancer cardiovascular disease and then since the year 2009 we've moved into large-scale trials testing vitamin D and the Marine Omega-3s which is basically fish oil and EPA DHA in prevention of cancer cardiovascular disease autoimmune diseases mood depression changes cognition changes very extensive art research on vitamin D and the Marine Omega-3s and then even more recently we have been testing the multivitamins as well as the cocoflavanol supplements now I in the Physicians health study too which began well over 20 years ago we were also testing multivitamins and so we have now two large-scale trials of multivitamins and uh in Physicians health study two we did see a significant reduction in total cancers and eight percent reduction but the trial went on for 11 years it took a very long time to adequately test the multivitamins in terms of cancer prevention so these are long-term effects and in the more recent trial of multivitamins we're seeing a very exciting finding over only three years for slowing cognitive decline or actually seeing a 60 percent reduction over the three years in the rate of uh cognitive decline in the multivitamin group versus the placebo group in some research we're doing in collaboration with Wake Forest School of Medicine and I think you said vitamin C which I think lots of people will still associate with something they should take when they've got a sore throat like me today sounds like I should be throwing that out the window is that right Joanne the the research on its value for shortening upper respiratory and infection duration that has been actually controversial some studies do show a little bit of benefit taking it for short term during an a an upper respiratory infection is still reasonable but for prevention of cancer cardiovascular disease diabetes chronic disease outcomes it has not been shown to be a benefit in the large-scale randomized clinical trials I think you went further than that at least for some of these and said it might actually be harmful so for vitamin C we didn't see clear harm or or risk but we did see for vitamin E in the Physicians health study too we saw an increased risk of hemorrhagic stroke the bleeding type of stroke and we also saw that all cause mortality was a slight bit higher in the vitamin E Group compared to the placebo group we would that cause you to be cautious about very high dosing of anything unless there was like really good evidence for it um or would you say in most cases hey don't worry your body's just going to deal with with any of these things they don't really worry it might be wasted but there's there's no harm because that sounds quite scary that I've always sort of thought of these things as being basically inert if you took more than you needed but here you're seeing real harm that's like a negative impact like a like a drug does that really reset the way we should think about um supplements or vitamins yes I think we should avoid mega dosing because these micronutrients and these dietary supplements are not inert and in fact even among the vitamins you have the fat soluble and the water soluble vitamins so with fat soluble they get stored in the fat tissue some get stored in the liver and you can become toxic with vitamin A vitamin D Vitamin K Vitamin E you know these These are fat soluble vitamins the B vitamins are water soluble you have a little more latitude in terms of dosing but even with mega doses of water soluble vitamins you can get there's some neuropathy symptoms that can occur you can get a problem with masking of you know for example if you take too much certain B vitamins it can mask a problem with B12 which if you have a deficiency of B12 that can be associated with an increased risk of cognitive decline so there are risks also very very high doses of an isolated micronutrient can interfere with the absorption of other similar micronutrients for example it's one of the concerns about beta carotene that if you take it in very high doses it might interfere with the absorption of other carotenoids of which there are hundreds and it may also interfere with the bioavailability of some of the other carotenoids I think the message I'm taking is throw away all of the things I have which are like in mega doses that there's no upside and there might be some real downside well I would look at whether there is a recommended dietary allowance or a daily intake look at the label look for several things on the label if you take any sort of dietary supplement first look at the percent of the dosing in that pill relative to the dietary intake or the recommended dietary allowance sometimes you will see 500 percent a thousand it's like many fold higher than what's needed a generally avoid that unless you've been prescribed it by a clinician and there are some times like with B12 some people with pernicious anemia and other conditions they may need quite high intake of B12 so if you're not under the supervision of a doctor or clinician for the purpose of taking higher doses generally avoid it's a general principle don't take more than the recommended dietary allowance so the daily intake and also look on the label at a seal for quality control assessment because there are many dietary supplements out there that don't undergo adequate quality control testing and they can have contamination with heavy metals contamination with microbes they're just and and often the dose is not that's listed on the label is not what you're getting because it's not really confirmed to have that content I think a lot of people think you know more is better and so often I I look in people's cupboards because I'm nosy and I see the kind of supplements they're taking and it worries me this Miss marketing but it worries me also the mega dosing and often I say oh you know you don't actually need that much but people think oh the more is better and I try and simply explain to them well actually if your body doesn't need it your body then has to just work harder in order to process it or excrete it or get rid of it some way and I think that's a really simple way of explaining to people that actually you know it might not be doing really serious damage but you are actually you know adding to the work that your body has to do and Joanne one thing that I was particularly interested to be able to talk to you about when Jonathan allowed me to Gate Crash his podcast um are the two big trials that I know have just recently come out vital and Cosmos and Jonathan I wonder if we can spend a few minutes going through these because I think they're both covering supplements that even in the field of nutritional research is really contentious so vitamin D which I know you mentioned at the beginning omega-3 and then also the polyphenols from the cosmos and so vitamin D has been a really hot topic it's contested a lot whether we should be taking it as a supplement and I think during covid it really came to a head and and actually I don't think there's clear consensus and so I wonder if you could tell us your perspective on this and also the findings from your vital trial where I know you looked at Vitamin D so the vital trial which is the vitamin D and omega-3 trial was conducted in more than 25 000 U.S men and women across the entire country I don't want to cut across but I just want to emphasize 25 000 is an enormous study right it's like we are used in nutritional science we're looking at studies of 25 people or 30 people for three months is that a fair contrast I just want to make sure that listeners understand before you just glide on it was an enormous study and the reason it was so large was to be able to look at clinical events such as heart attacks Strokes cancer diabetes a wide range of clinical outcomes as opposed to just looking at changes in cholesterol levels or a biomarker or a blood pressure change we wanted to see if there were actual effects on clinical events and it takes a study that large a randomized trial that large over 5.3 years so we reported the results in 2019 that vitamin D and Omega-3s did not neither one of them and we looked at the independent as well as the joint effect of these supplements did not prevent our primary endpoints which were major cardiovascular events a combination of heart attack stroke and death from cardiovascular disease um for the Omega-3s there was a us a moss modest eight percent reduction that was not statistically significant for CBD events and for the Omega-3s we did see a significant reduction in the secondary outcome of heart attack a 28 reduction in heart attack I'll come back to that but our other major primary endpoint was cancer and total invasive cancer we did not see a benefit of either the vitamin D or the Omega-3s in reducing the cancer endpoint over 5.3 years now of course for cancer it may take longer we're continuing to follow the participants we're now at an additional three years of a follow-up four years of follow-up and we hope to follow over at least a decade for uh cancer endpoints as well as cardiovascular endpoints but we did not see for those primary endpoints a um reduction with either supplement with vitamin D however we did see with a secondary endpoint of cancer death that there was a borderline reduction a 17 reduction and then when we accounted for you know there's a latency period for cancer and we had all we had pre-specified that we would look at people who were taking the the vitamin D for at least two years we did see a statistically significant 25 reduction in cancer death and then when we looked at Advanced cancer as an endpoint metastatic or fatal cancer in the overall follow-up period we did see a statistically significant 17 percent production and advanced cancer now there are some other randomized trials that also suggest that vitamin D doesn't prevent first diagnosis of cancer first occurrence of cancer but it may affect tumor biology make tumors less invasive less likely to metastasize and therefore there may be a reduction in cancer death or Advanced such as metastatic cancer this requires further study not ready to make General Public Health recommendations that everyone take vitamin D for this purpose but there's some exciting research in that area another Finding we had for vitamin D was a significant reduction in autoimmune diseases such as rheumatoid rheumatoid arthritis psoriasis and this may be because vitamin D has been shown to have some benefits for the immune system to boost immune function but to Tamp down inflammation both of these would be relevant to reducing risk of autoimmune diseases as well as potentially to reducing severity of covid illness which is why I said during the pandemic it would be reasonable to take one thousand to two thousand eyes a day of vitamin D although not essential can I ask a question John because I think if our listeners will listen to this you're you're listening all of these things when you take vitamin D that are like statistically significant reduction in cancer and I think they're all gonna be like Oh I'm gonna go out and do that tomorrow for certain for every day for the rest of my life like that sounds incredibly important but actually we're sounding quite cautious about your advice on vitamin D can you help everybody listening to understand that I realized that it may not come across clearly whether or not to to take these supplements I think the main point after all these years of testing vitamin D and seeing these results we recently published that vitamin D did not prevent fractures bone fractures and osteoporotic fractures and that was very surprising to people and that's because I've been a lot of people have historically thought that it was really important um against fractures and something that often menopause you should therefore take is that right Joanne it was believed that vitamin D had any role it was for bone health and preventing fractures preventing osteoporosis now the findings don't mean that vitamin D has no role in maintaining bone health what it means is that we need only small to moderate amounts of vitamin D for bone health for cardiovascular disease and for many of these other health outcomes the reason is probably that that evolutionarily because vitamin D is so essential to health we evolve to be able to regulate the metabolism of vitamin D very tightly so that in terms of the biologically active form of vitamin D enough is getting into the tissues is getting to the vitamin D receptor we don't need large amounts the amount we can get from food sources and from incidental sun exposure and as I mentioned we synthesize vitamin D a precursor of vitamin D in the skin from ultraviolet B light exposure so just being outdoors 15 minutes a few times a week you know doing running errands and being taking walks being Physically Active will provide you know some incidental sun exposure not during winter months but you know during uh during let's say six months of the year and some of that vitamin D is then stored and there are food sources of vitamin D John can I jump for a minute from vitamin D over to omega-3 because I know you looked at that in the same study and this is something that I've been interested in in my own research and we know as nutritional scientists that all you know all omega-3 is not the same that there's different types of omega-3 fats and I think this is somewhere again where it'd be really good to be able to inform people on what to look at on the back of the pack of their supplements in relation to omega-3 because there's the kind of Omega-3 that we know which we call EPA and DHA Jonathan I know you don't like me to do long names so I'm not going to give you the long name um which actually comes from fish oil and then there's the more plant-based it's not quite as big an omega-3 fat that I won't again give you the fatty acid name but um it'd be really good Joanne if you could Point listeners in the direction of what to look for and what you think based on your research and what we know in nutritional research has a greater efficacy in health outcomes I think that's a really good point we really should separate and and make clear whether we're talking about the marine fish oil based Omega-3s which are EPA plus DHA we tested the Marine Omega-3s in a dose of 1.2 to 1 of the EPA to DHA so it was a combination a little more EPA than DHA in the vital trial there's also plant-based such as alpha-linolenic acid and some of the plant-based Omega-3s and Three fatty acids do get converted to EPA DHA EPA so you know you do get some of those Marine base Omega-3s from the plant conversion of plant-based but it's at a relatively low level there have been some Trials of plant-based Omega-3s been in consistent in terms of the clear benefits overall for the marine fish based Omega-3s and there's work on an algae-based form of this which may be more environmentally sustainable long term but anyway for the EPA DHA the evidence overall is that there's a small reduction in heart disease but no clear reduction in stroke or in the major cardiovascular events when you're looking at heart disease and stroke it may be only a modest if any reduction because stroke is generally not reduced yeah in summary children when people ask me should I have the fish oil based omega-3 or can I have any old omega-3 I always suggest to people that they had should have the fish oil omega-3 would you agree with that I I would agree that there's much more evidence for the fish-paced Omega-3s in terms of reduction in cardiovascular outcomes especially heart disease and heart attack listening to that it didn't sound like you were pushing very hard that I should be taking omega-3 every day this sounded like these were quite small impacts which after all we know that if you just taught me to improve the quality of my diets I would also probably have a very big impact on all of these things so just it sounded like you're much softer than on vitamin D is that a misunderstanding well I I think that we're not quite ready to make Public Health recommendations that everyone take official supplement what we found in vital was that in people who had low fish consumption in their diet low dietary intake of fish at Baseline fish being the major the primary source of the Marine Omega-3s they benefited more from the one gram a day we tested in fact that group did have a reduction in the primary endpoint of major cardiovascular events close to 20 percent reduction and those who were already getting one and a half servings per week of fish did not benefit so if you have very low fish consumption if you're vegetarian or you don't like fish you may want to talk with your health care provider about whether you should take a fish oil supplement or even a prescription omega-3 because that's where the benefit was we also surprisingly found a very large benefit among African Americans for the heart attack endpoint we saw a 77 percent reduction in heart attack with the Omega-3s and this was not due to low fish consumption at Baseline because consumption was not lower in the African-American participant so we want to look further at this finding to see if it can be replicated and if so it it may actually be important an important approach to reducing Health disparities of course it's only you know one aspect of many Health disparities out there but it may actually make a difference difference in terms of heart disease if it can be replicated and I think that's a really important point that builds on all of the work that we're doing at Zoe which is trying to look at what works uh in terms of food intake for each individual's biology because we know that we all respond differently to food and just in the way that you've said that some people benefited more than other people with the omega-3 is this something that you've looked at because I should imagine that you have huge variability in the effectiveness of the supplements across individuals where it's more useful for some individuals than it is for other individuals yes we've we've looked at these questions in a number of different ways so in our first randomized trial of the physician of the multivitamins the Physicians health study too we looked by age group at whether there were differences across age in benefits for the cancer reduction that was seen overall and we saw that older purchase recipients who were above the age of 70 they tended to have a greater reduction in cancer with the multivitamin assignment compared to the placebo group now this may be because diet for many seniors it will be a little poorer there may be poor absorption of vitamins and minerals um and and so this is a group that seemed to benefit more in 18 reduction in cancer one eight percent reduction in the older age group compared to overall an eight percent reduction and um very little reduction in cancer in the younger age groups so it may be that if you're already getting these vitamins and minerals it's not going to help to take a multivitamin that would be very very plausible and you know rational that it's going to benefit the people who have lower you know intake more than the people who are already any adequate or replete in that micronutrient but another point I want to make is that because a dietary supplements will never be a substitute for a healthy diet if you have a diet that is high in red meat saturated fat processed foods and all of these unhealthy sugar refined carbs very unhealthy foods and you just throw a multivitamin at that and you know start to pop a multivitamin that's not going to make you healthier I mean you're still going to have health problems related to that very unhealthy diet when you are following a healthy diet such as high intake of fruits vegetables whole grains fish unprocessed Whole Foods you are going to your that diet those foods will be replacing unhealthy foods such as the the red meat and you know the processed foods and if you're just taking a dietary supplement you're not going to be replacing anything that's in your usual diet this is another reason why it's so important to be encouraging first the healthy diet which will just naturally you know these foods will be replacing unhealthy foods and also this very complex Matrix of vitamins minerals poly you know the the polyphenols and phytochemicals and we've we've talked about you know the fiber and all the other benefits that you get from fruits vegetables whole grains and a Diet that's healthy like that you just can't replace it can't package that into a pill and you know get those benefits from by popping a pill I know people love to you know think of a pill as a Panacea and Magic you know bullet but it's really not possible and it's it and there is no pill like that and so Joanne what would be one piece of actionable advice that you could give to listeners of the show regarding uh taking supplements um and you can break this down if you want a kind of different subgroups of people that may benefit yes I think that um the focus should be on a healthy diet healthy balanced diet try to get the vitamins minerals and phytochemicals whenever possible from food and again it the vitamins minerals will be better absorbed from food then when taken as a supplement and you get get all these other benefits of you know this Matrix and and you also will replace unhealthful Foods by healthy foods so I think that that's a really important principle try to get it from food now there are there is appropriate targeted use of certain dietary supplements such as pregnant women really or women who are planning a pregnancy it is extremely important to think about taking a multivitamin taking a prenatal vitamin during the pregnancy um and even prior to conception because that is really essential to healthy pregnancy preventing you know the neural tube defects uh that's been well demonstrated but also a recent uh study in China just suggested that congenital heart defects are reduced through the folic acid as well um so I think that is really important in that high-risk group there are some recommendations by pediatric societies and organizations about the infants who are breastfedged maybe take vitamin D take iron you know I won't go into a lot of details about that but of course if you have an infant discuss that with your pediatrician can I can I put just very high level actually because I'm very interested in this like let's say for kids under five just broadly do you think actually we should be giving them vitamins and I think about this with my own three-year-old like I I push quite hard trying to get good food my 14 year old actually eats pretty well now my three-year-old it's incredibly hard to get her to eat anything that isn't beige and uh we do give her vitamins and I was curious what your take would be on that Jonathan that's the same for my 10 year old as well not not just your three year olds so what should we do Joanne um yes the American Academy of Pediatrics does have certain recommendations that are more for the infant um especially in Incident That's breastfed because the uh formulas do have vitamin D and some have iron and so you know you get uh some of those micronutrients uh there in the formula but of course we encourage breastfeeding but taking certain um you're taking vitamin D supplemental vitamin D and I earned there are recommendations from the academy for older children such as your own um I I think it depends on really the quality of their diet most children do not really require multivitamins or dietary supplements if you can get them to have some fruits vegetables and fish and some you know eat poultry even a reasonably healthy diet is probably enough and if they can be physically active and spending time Outdoors being physically active they probably will be able to do quite well so I generally haven't recommended that routinely parents should give their children multivitamins or any dietary supplements after that infancy period that the Pediatrics societies do have recommendations for um then when you talk about other high-risk groups people with macular degeneration there is some evidence that they will benefit from a formula relation that is antioxidant vitamins and copper and zinc that was shown in the arids trial the arids II trial and there are formulations I don't want to get into specific brand names but you know certainly if you have macular degeneration discuss this with your clinician and there are some products of vitamins minerals that have been found to be a benefit in slowing progression of macular degeneration so that's a high risk group then there are older adults who are in nursing homes or have osteoporosis bone health problems probably should be taking calcium vitamin D supplementation our findings in vital were not targeted to high-risk groups we already have osteoporosis it was a usual risk generally healthy midlife older adult population who don't seem to need um the supplement for bone health purposes but older adults May and then there are people as I mentioned the malabsorption conditions you know if you uh if you have Crohn's disease all sort of colitis celiac disease is another one like severe lactose intolerance it may be a benefit to take these vitamin mineral supplements and um I think that there are some some other groups that would benefit who take a medication locations like metformin proton pump inhibitors these medications that could interfere with absorption of some of these vitamins and minerals um so Joanne you you've highlighted all of these different people that for different reasons would benefit from supplements and obviously you know some of these only apply to maybe one percent of people or even less than that and so my take home from listening to you talk through all of that is that given that there's no harmful effect of taking a standard dose multivitamin maybe the outcome is is that actually we should all um or if we want to we would all benefit from taking a standard dose multivitamin you know again I don't want to make a public health recommendation that everyone take multivitamins the U.S preventive Services Task Force just weighed in on this and made the recommendation that it was not indicated you know that everyone take multivitamins however at the same time their meta-analysis showed a seven percent statistically significant reduction in cancer taking all of the trials of multivitamins including the physician's health study too and um some a European trial as well they they looked at all of the trials that had been done of multivitamins and said there was a significant reduction but they're still not recommending it so I think I'm going to leave those guidelines to professional organizations and societies because generally I think as a researcher I'm trying to provide evidence and data that can be used by the you know these professional societies and organizations synthesize the evidence and come to Public Health recommendations when you asked me what I thought was reasonable I do think especially during this pandemic period taking the vitamin D 1000 to 2000 I use a day and to just hedge your bets and also a multivitamin is quite reasonable if you have concerns about having this really healthy well-balanced diet I think it's very reasonable because these specific supplements have been so well tested and they have been shown to have some benefits and they're also very importantly safe with long-term use and I think that can't be said about so many of the other dietary supplements on the market the more than the 90 000 plus supplements out there most have not been well tested at all and don't have clear efficacy for any outcome and also haven't been clearly shown to be safe and some of them haven't been shown at all to be safe even with short-term use amazing Joanna I'm going to try and do something we always try to do at the end of this podcast which is for me to try and summarize you know what we've just uh covered and this time both you and Sarah can can keep me honest so I I think we started by saying that most people can probably get all the vitamins and nutrients they need from a healthy varied diet we also said that actually taking too much of these vitamins can be toxic so these sort of Mega doses aren't just neutral they could really be a problem then we talked about multivitamins and there's this new really exciting evidence from from your latest study of vitamin D I think on balance the evidence suggests there is some impact on our health and that many of us may get enough from our food and sun and then I think the final thing we talked about again was sort of specific groups so for example omega-3 you've seen this impact but it looks like it's really impacting if you're not eating these fish if your fish consumption is there it probably doesn't have much much impact and then I think picking out some specific groups so interestingly with children you were saying after infancy probably doesn't require it but in pregnancy or prior to conception incredibly important and this is where you were we're strongest in the entire discussion as we get towards older adults there's potentially a lot more value and we may see more of this and I think this is again this this General view there's not just one feedback for everybody your own personal situation is very important uh and and so it sounds like particularly as we're thinking about ourselves or other people we know who may be a bit older really thinking there might be some value there superb summary Jonathan oh wow that that's my one one point in doing this Joanne thank you so much I I would say just at the end of this that the other big area of research that you've been covering is is about everything to do with Women's Health and I do hope that we can tempt you back for a whole podcast just on this topic absolutely would love to do wonderful thank you so much and thank you Sarah for helping to to keep this podcast on track thank you thank you for letting me get Chris and great to chat to you Joanne yes thank you so much Jonathan Sarah I actually really enjoyed it wonderful thank you to Joanne and Sarah for joining me on Zoe science and nutrition today we hope you enjoyed today's episode if you did please be sure to subscribe and leave us a review if this episode left you with questions please send them in on Instagram or Facebook and we'll try to answer them in a future episode if you'd like to understand more about how to forget the vitamins you need from whole foods that are right for you then you can try Zoe's personalized nutrition program at Zoe we want to improve the health of millions to prove our health manage our weight each member starts with an at-home test comparing them with participants in the world's largest nutrition science study if you're interested in learning more about Zoe you can head to join zoe.com podcast and get 10 off your personalized nutrition program as always I'm your host Jonathan wolf Zoe science and nutrition is produced by Fascinate Productions with support from Sharon Fedder yellow humans Martin and Alex Jones here at Zoe see you next time [Music]

Channel: ZOE

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Length: 48min 10sec (2890 seconds)

Published: Mon Nov 28 2022