ZOE Science & Nutrition - The truth about vitamin supplements

Episode Date: November 24, 2022

Good information about vitamins is hard to find. With over 70% of Americans and 40% of Brits using them, it's a hugely lucrative market, which means numerous voices in the media and online pusing a pro-vitamin agenda. All without the scientific evidence to support their claims.  So do we need vitamins to lead a healthy life? Or could these supplements actually cause serious health complications? In this episode, Jonathan speaks with Prof. JoAnn Manson and Dr. Sarah Berry to better understand how vitamin supplements affect our health. JoAnn Manson is a professor of epidemiology at the Harvard School of Public Health and one of the world's most cited researchers. She’s run multiple enormous studies with over 20,000 participants to uncover the real effects of vitamin supplementation on our health. Dr. Sarah Berry is one of the world's leading experts on human nutrition, who has personally run over 20 randomized clinical trials looking at how humans respond to different fats. Download our FREE guide — Top 10 Tips to Live Healthier: https://zoe.com/freeguide Timecodes: 00:00 - Introduction 02:29 - Quickfire questions 04:27 - Why are people confused about supplements? 05:17 - Which supplement does the majority of the population benefit from taking and why? 05:51 - What are dietary supplements and vitamins? 09:33 - Why is there so much advertising suggesting supplements? 10:54 - JoAnn’s research 14:07 - About vitamin C 15:15 - Megadosing 19:51 - VITAL and COSMOS trials 25:13 - Should we take vitamin D 27:37 - Omega-3 32:48 - Variation & personalization 36:51 - Actionable advice on supplements 38:45 - Should children take supplements? 42:13 - Should we all take a standard dose multivitamin? 44:54 - Summary 46:25 - Goodbyes 46:57 - Outro Episode transcripts are available here. Check the trials mentioned in today’s episode: AREDS 2, COSMOS, Physicians' Health Study II, VITAL Follow Sarah: https://twitter.com/saraheeberry Follow ZOE on Instagram: https://www.instagram.com/zoe/ This podcast was produced by Fascinate Productions.

Welcome to ZOE Science and Nutrition, where world-leading scientists explain how their research can improve your health. Let's talk about vitamins, shall we? Good information about vitamins is hard to find, and there's a reason. With over 70% of Americans and 40% of Brits using them, it's a hugely lucrative market. Numerous voices push a pro-vitamin agenda in the media and online without having the scientific evidence to support their claims. Have you heard the one about vitamin C curing colds?

This theory spread across the Western world in the 1970s. Decades later, it's utterly debunked, but many still hold this belief. Cash incentives may explain the pro-vitamin argument. But what about those who think the vitamin supplements should be avoided? Can supplementing naturally occurring micronutrients really be dangerous? Sure, supplements markets lack regulation, especially in the US. No one really knows what's inside those pills they're popping. Sure, supplements markets lack regulation, especially in the US.

No one really knows what's inside those pills they're popping. Products containing many times the daily recommended doses are widely available. Could overdosing on these supplements actually lead to serious health complications? Amidst the scare stories and the miracle cures, legitimate scientific research has been taking place, trying to uncover the real cost and benefit of vitamin supplementation on our health and our wallet. Our guest today is behind a lot of that research. Joanne Manson is a professor of epidemiology at the Harvard School of Public Health and

one of the world's most cited researchers. Her achievements, spanning more than 40 years, are too many to list. We often talk on this podcast about how tiny most nutrition studies are. Joanne's are the exception. Joanne has run multiple enormous studies with over 20,000 participants to find out how vitamins and supplements affect major health conditions. Talking of health conditions, I have to apologize for my sore throat when recording today's episode. Luckily, Sarah Berry joins me as a co-host. For those of you who aren't sure of how much of a big deal Joanne is, you can judge it from Sarah's excitement. Joanne, 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, are 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 a lot. Next question. Should I take vitamin D in the winter months? Yes, it would be very reasonable to take 1,000 to 2,000 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. 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 nutritional research has been really 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 trial that hopefully we can go on to talk about, which are huge randomized controlled 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's 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, 1,000 to 2,000 I use a day, a small to moderate dose, no mega dosing, not taking doses of 6,000, 10,000. I use a day, but a small to moderate dose.

So why don't we start at the very beginning, Joanne? What are dietary supplements and vitamins? So think of vitamins as organic compounds or substances that 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 though, Joanne, a lot of people use the word supplements, not just for essential components. So out on the market at the moment, there's so many supplements out there that might be 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 essential 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 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 we have the maximal health benefits, a dose at which it becomes harmful or a dose at which actually you're just peeing it all down the toilet. For essential vitamins and minerals, the Institute of Medicine, National Academy of Medicine, and professional 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, there's a sort of wild west here. So there's this small number of essential vitamins.

Maybe you could tell us in a minute what those are and the key ones. And then there's just this vast mass of things over which you're saying there's really no scientific evidence at all that you should take them and quite a lot of concern that you might just be taking stuff that is bad for you. Is that right? Absolutely true. We have very, very little research on benefits, risks, 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 suggesting that we should be taking all these supplements and vitamins? How have we ended up here? them on the market and to promote them and sell them. And many people are just looking for magic

bullets for popping a pill that they think will benefit 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. If you look at any generic multivitamin, it will have vitamin A, a number of B vitamins like folic acid and B6, B12, vitamin C, vitamin D, vitamin E, vitamin K. These are the really essential vitamins. And then you will also see calcium, magnesium, selenium, a number of minerals as well.

So that's interesting, right? So you suddenly shrunk to a much smaller set of things versus 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 you did this and what does it tell us today? 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 20,000 participants nationwide in the US 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 actually suggesting some risks of beta carotene,

especially in smokers, an increased risk of lung cancer, and for vitamin E, an increased risk of hemorrhagic stroke, the bleeding type of stroke. And 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. 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 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. In the Physician's Health Study 2, which began well over 20 years ago, we were also testing multivitamins. And so we have

now two large-scale trials of multivitamins. And in physician's health study two, we did see a significant reduction in total cancers, an 8% 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,'re actually seeing a 60% reduction over the three years in the rate of 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 research on its value for shortening upper respiratory infection duration, that has been actually controversial. Some studies do show a little bit of benefit. Taking it for a short term during 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 risk, but we did see for vitamin E in the physician's 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. Would that cause you to be cautious about very high dosing of anything unless there was like really good evidence for it? Or would you say in most cases, hey, don't worry, your body's just going to deal with any of these things. So don't really worry.

It might be wasted, but there's no harm. Because that sounds quite scary. 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 drug. Does that really reset the way we should think about supplements and vitamins? Yes, I think we should avoid megadosing 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. 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 are some neuropathy symptoms that can occur. You can get a problem with masking of, for example, if you take too much of 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. 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%. It's like many fold higher than what's needed. 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, this general principle, don't take more than the recommended dietary allowance or 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. And often the dose that's listed on the label is not what you're getting because it's not really confirmed to have that content. I think that a lot of people think more is better. And so often 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 mismarketing, 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 to talk to you about when Jonathan allowed me to gatecrash his podcast 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 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 US 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? 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, 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. For the omega-3s, there was a modest 8% 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 follow-up, four years of follow-up, and we hope to follow over at least a decade for cancer endpoints as well as cardiovascular endpoints. But we did not see for those primary endpoints a 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 pre-specified that we would look at people who were taking 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% reduction in 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 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 1,000 to 2,000 IUs a day of vitamin D although not essential. Can I ask a question Joanne because I think if our listeners were listening 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 going to be like oh I'm going to 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 realize that it may not come across clearly whether or not 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 there have been a lot of people have historically thought that it

was really important against fractures and something that after menopause you should therefore take. Is that right, Joanne? It was believed that if 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 evolutionarily, because vitamin D is so essential to health, we evolved 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. 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, few times a week, you know, running errands, taking walks, being physically active will provide some incidental sun exposure, not during winter months, but 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. Joanne, 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 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 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 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 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 3-feti acid do get converted to EPA, DHA EPA. So, you know, you do get some of those marine-based 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 inconsistent 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, Joanne, 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 should have the fish oil omega-3. Would you agree with that? I would agree that there's much more evidence for the fish-based 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 told me to improve the quality of my diet, I would also probably have a very big impact on all of these things. So it sounded like you were much softer than on vitamin D. Is that a misunderstanding? Well, I think that we're not quite ready to make public health recommendations that everyone take a fish oil 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 a 20% 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 a vegetarian or you don't like fish, you may want to talk with your healthcare 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% 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 participants. So we want to look further at this finding to see if it can be replicated. And if so, it may actually be important approach to reducing health disparities. Of course, it's only one aspect of many health disparities out there, but it may actually make a 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 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 looked at these questions in a number of different ways. So in our first randomized trial of the multivitamins, the Physician's Health Study 2, 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 participants 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. And so this is a group that seemed to benefit more, an 18%

reduction in cancer, one 8% reduction in the older age group compared to overall an 8% reduction and 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 rational that it's going to benefit the people who have lower intake more than the people who are already adequate or replete in that micronutrient. But another point I want to make is that 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 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, that diet, those foods will be replacing unhealthy foods, such as 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 polyphenols and phytochemicals. And 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. You can't package that into a pill and, you know, get those benefits by popping a pill. I know people love to, you know, think of a pill as a panacea and a magic, you know, bullet, but it's really not possible. 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 taking supplements? And you can break this down if you want to kind of different subgroups of people that may benefit? Yes, I think that 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 than when taken as a supplement and you get all these other benefits of this matrix. 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 is appropriate targeted use of certain dietary supplements, such as pregnant women or women who are planning a pregnancy. It is extremely important to think about taking a multivitamin, taking a prenatal vitamin during the pregnancy and even prior to conception, because that is really essential to healthy pregnancy, preventing the neural tube defects. That's been well demonstrated. But also a recent study in China just suggested that congenital heart defects are reduced through

the folic acid as well. So I think that is really important in that high-risk group. At high risk group, there are some recommendations by pediatric societies and organizations about the infants who are breastfed, 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. But just very high level, actually, because I'm very interested in this. 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 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 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 just your three-year-old. So what should we do, Joanne? Yes. The American Academy of Pediatrics does have certain recommendations that are more for the infant, especially an infant that's breastfed, because the formulas

do have vitamin D and some have iron. And so, you know, you get some of those micronutrients there in the formula. But of course, we encourage breastfeeding, but taking vitamin D, supplemental vitamin D and iron, there are recommendations from the academy. 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 if you can get them to have some fruits, vegetables, and fish, and some, you know, 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. Then when you talk about other high-risk groups, people with macular degeneration, there is some evidence that they will benefit from a formulation that is antioxidant vitamins and copper and zinc. That was shown in the ARIDS trial, the ARIDS 2 trial. And there are formulations. I don't want to get into specific brand names, but 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 who already have osteoporosis. It was a usual risk, generally healthy, midlife, older adult population who don't seem to need 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 have Crohn's disease, ulcerative colitis, celiac disease is another one, severe lactose intolerance, it may be a benefit to take these vitamin mineral supplements. And I think that there are

some other groups that would benefit who take medications like metformin, proton pump inhibitors, these medications that could interfere with absorption of some of these vitamins and minerals. So Joanne, you've highlighted all of these different people that for different reasons would benefit from supplements. Obviously, some of these only apply to maybe 1% 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 that actually 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 7% statistically significant reduction in cancer, taking all of the trials of multivitamins, including the Physician's Health Study 2. And 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 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, 1,000 to 2,000 I use a day, 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 90,000 plus supplements out there,

most have not been well tested at all and don't have a 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. Joanne, I'm going to try and do something we always try and do at the end of this podcast, which is for me to try and summarize what we've just covered. And this time, both you and Sarah can keep me honest. So 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 your latest study on 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 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 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 general view, there's not just one feedback for everybody. Your own personal situation is very important. 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, that's my one point in doing this. Joanne, thank you so much. I would say just at the end of this that the other big area of research that you've been covering 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. Yes, absolutely. I'd love to do that. Wonderful. Thank you so much. And thank you, Sarah, for helping to keep this podcast on track. Thank you. Thank you for letting me gatecrash.

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 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 get 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 and 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 joinzoe.com slash podcast and get 10% off your personalized nutrition program. As always, I'm your host,

Jonathan Wolfe. Zoe Science and Nutrition is produced by Fascinate Productions, with support from Sharon Fedder, Yela Huynes-Martin and Alex Jones here at Zoe. See you next time.