Dr. Tim Spector: Why these supplements don't work with Dr. Federica Amati

is vitamin D a vitamin no we call a vitamin but is actually closer to a steroid than it is to a vitamin it's had fantastic PR for the last 100 years just because it's called a vitamin wrongly our vitamin D intake is a tight rope walk on one side deficiency and on the other side intoxication today we're joined by two o zo's best scientists to steady US during this Balancing Act Tim Spectre is one of the world's top 100 most cited scientists a professor of epidemiology and my scientific co-founder at zui definition of a vitamin

is something that the body cannot produce itself but if you think about it vitamin D as we call it the body synthesizes itself via sunlight can vitamin D supplements be bad for your health sadly yes you'll be prescribed a supplement and be told oh this should help tness depression muscle aches but we now have scores of Trials showing that it doesn't work I'm also joined by Dr feder amarti Federica is the head nutritionist here at Zoe an author of the bestselling book everybody should know this when you look at the reports there's between a 10

to 14% adults lacking vitamin D in the UK and in the us it's up to 30% from a public health perspective there is little harm in recommending that certain patient groups take vitamin D there's quite a lot of controversy whether a large fraction of the population is really deficient and so where does this leave the two of you on supplementation welcome to Zoe science and nutrition where World leading scientists explain how their research can improve your health Tim and fed thank you for joining me today thanks for having us so you know the drill I

don't need to tell you the rules we're going to jump straight into the quickfire questions are we ready to go for it ready Tim is vitamin D a vitamin no that's going to be a big surprise for many people it's a good start fed can vitamin D deficiency increase your risk of developing cancer possibly can you be vitamin D deficient without experiencing any symptoms unlikely Tim can vitamin D supplements be bad for your health sadly yes and then finally maybe for both of you what's the biggest misconception about vitamin D in your opinion in my

opinion the biggest misconception is that it's a Panacea for all ills it's not I would say that taking more of it is going to give you great benefits and there's no evidence for that as someone running a company that does a lot of data science here's something that fascinates me YouTube tells me that 69.3% of you who watch this channel frequently ly haven't yet hit the Subscribe button so I want to ask you a quick favor your choosing to subscribe helps us a lot it helps us make the show better access World leading experts and

ultimately make more progress on our mission to improve the health of millions so if you enjoy this show all I ask is that you hit the Subscribe button and in return I promise we'll continue to make the show better and better each week I think that's going to already shock a lot of people all this feedback I mean I'm already still reeling from vitamin D is not a vitamin so that's already like quite confusing and I know there is a lot of Buzz about vitamin D in the media and I've noticed sort of more and

more Vitamin D supplements and fortified Foods you know the grocery aisles but I've never really understood what it was and I thought I at least understood it was a vitamin and apparently it's not even that so you know I definitely want to start at the beginning but before I do that I just want to sort of tell our listeners I think they're in for a bit of a treat because because uh you know Federica and Tim have slightly different views about what the scientific evidence tells you about vitamin D and this is sort of I

think a window for a lot of our listeners into what it's like to be at Zoe and try and take the latest cutting age science and turn it into real advice because one of the things I've learned is if you ever meet someone who is like absolutely categorically convinced about what the science says about something they're not probably a leading researcher because it's always they're always telling me well it's a bit nuanced and there's this other study and so I think today will be quite fun to understand like what does the science really tell us

and understand how you know World leading scientists like Tim try and pass the latest evidence to understand what might that mean for you know regular people like me trying to figure out what to do so if vitamin D is not a vitamin what is it it was misnamed a long time ago and a v definition of a vitamin is something that that the body cannot produce itself and you only need minute quantities in order for it to be effective and keep your body going and so real vitamins are things like the B vitamins that are

key for chemical reactions in the body in our cells that basically Keep Us Alive and that we can't generate them themselves and so we have to get them from our food and that's why the vitamin D as we call it doesn't meet those CR is Cu uh it's actually in huge amounts compared to the small amounts you need for vitamins already in its natural form and the body synthesizes itself via sunlight so uh Under the Skin you can convert sunlight mixed with various lipids and fats into this compound which we call a vitamin but is

actually more like a pro hormone or a form of a steroid so it's closer to a steroid than it is to a vitamin and I think our reactions to to it if we're calling it a steroid would be very different it's been had fantastic PR for the last 100 years just because it's called a vitamin wrongly and so I understand now it's not a vitamin I have no idea what a steroid is so could you help me to understand what it does do well we got to call it vitamin D I can't I'm not going

to rename it now just just par hormone D par there you go parah hormone D is key to many many functions in the body that's why uh we evolved to be able to synthesize it and as we moved out of Africa our skin got lighter so that we could uh get more of sunlight in and convert it into Vitamin D so we know it's very important for our bodily function and it's crucial for our immune Health primarily that seems to be the main driver of it but it's it's involved in all kinds of reactions just

like in a way the other the other vitamins are it's not different in that it's just it's coming in it from a different angle so we know that for it's involved in many immune reactions and our response to the environment is fairly crucial and when we talking about immune reactions we're talking about inflammation we're talking about the response to allergies we're talking uh about response to aging and and Cancers and it has a very general uh plan of action as well as specific effects on things things like bone health and growth so that's where it

s comes into its more specific roles in that you can't create bone properly if you don't have um some vitamin D on board you absolutely need it it's like I feel like quite a lot of things we end up talking about on the show is like involved in lots of different things you can't live without it absolutely but you're saying the key difference between this and generally the vitamins that we talk about is that generally those are vitamins that the body can't create at all so you've got to ingest them like very low levels but

You' got to have it whereas here we can actually make it ourselves so fed is sunlight the only way we can get vitamin D so no it's not we can get it in food I think what's important as well to note is that actually now we've discovered that for example Vitamin K is made by gut microbes so it's not the only vitamin that isn't made by some part of our body but Tim's writing that it's the vitamin that our body is very well adapted to make plenty of for us if we just get enough sunlight

exposure we can also get it in food but uh the generally speaking we can't get enough of it in food compared to what we need for our health so we do need to get some sunlight exposure onto our skin to create vitamin D what's the recommended daily intake of vitamin D and I'm sitting here feeling that I know I haven't got enough of it that no one I know has got enough of it because I'm surrounded by all this advertising telling me that I need to take more so Jonathan this is really complicated actually because

we have receptors for vitamin D all over our body every single tissue right and that causes this a Cascade of reactions including different Gene Expressions it's hard to even measure how much vitamin D we have in our bodies let alone how much of it we're actually converting to other things because that depends on how many receptors you are so it's not a simple answer and it goes back to what Tim was saying this is a parah hormone it's a bit like if I said what's the recommended amount of estrogen that every woman should have there

isn't a recommended amount uh but the UK and the US differ quite a lot in what they consider to be healthy amounts in the blood and what people should supplement through not food but supplementation and it's really interesting because when you look at the recommendations they clearly state that these recommended amounts to take a supplements excludes any exposure to sunlight and any food intake so already these recommendations are aiming at helping people who have very little sunlight exposure and maybe don't have the right Foods in their diet to include vitamin D and these numbers are

28 nanog in the US as the recommended blood level whereas in the UK we recommend 12 nanograms and in the UK we recommend 400 international units per day for adults and for the us we recommend 800 international units per day so very different numbers um which we'll get to why that is or why we think that is because it's a very interesting story as a supplement just to make clear that you're talking about that's exactly excluding sunlight exposure and food so it's interesting because in my career I obviously started studying vitamin D as a rheumatologist

in the late 1980s and when I started there weren't many Labs measuring vitamin D and the only cases you saw were these rickets and osteomalacia these are when the bones go all bendy and soft and you might remember those pictures from the 50s and 60s where um many poor children had bow legs and stunted growth and there's an adult form of this called osteomalacia these were serious diseases and and people had no vitamin D to grow their bones at all and slowly the level of what was seen as the normal level of vitamin D in

The Blood Rose from actually having quite minimal levels where you saw these diseases to every 10 years like doubling up to the point where many organizations around the world or in the US are claiming very you need very high blood levels to be seen as having sufficient vitamin D now as fed explain it's very difficult to know what that level is because you're actually trying to measure things in the cell not not actually directly from the blood and I think that's been directed more by the vitamin D companies and the pressure the commercial pressures than

from science and many people who are experts in vitamin D agree with me that it's just been pushed up and up and up without really any scientific evidence to say that uh 28 nanog is better than 14 nogs uh and that there is any universal amount and it's confused by the fact that we did a very large twin study to show that the the blood levels you have is not so much dictated by how much you eat or once you go in the sunshine but it there has a genetic basis so about half of that

difference between people is actually genetic so everyone has their own personal uh vitamin D blood level that suits them which makes it even less likely that you can sort of give everyone the same level across the world and say that's what they need so it's extremely problematic and I think it's been driven more by commercial concerns uh than by real clinical evidence and can I ask a bit more about the conse quences of deficiency so I think you would um painting this picture of what happened with um you know children with absolutely no vitamin D

which sounds pretty terrible are there levels of deficiency still below that and like what percentage of people are classify that and what happens to you if you're in this sort of low level of vitamin D but not like the complete absence that you were sort of describing so that's the difference between deficiency and insufficiency and that's where the lines get a bit blurred because with deficiency as Tim described you see a real change in the in bone structure in children and in the quality of bone even in adult so it's quite easy to see measure

what do you mean is they can fracture with very painful fractures that look really obvious on the X-ray it's just not and they don't heal up well and so if you're in the US or in Western Europe like what fraction of people have that level of vitamin D deficiency tiny it's a tiny tiny amount that have deficiency luckily rickets is really rare there is a strange increase in numbers in the UK and the us but we think that's mostly related to Lifestyle and diet actually but really vanishingly rare to see somebody with rickets or AUST

Malaysia however when you look at the reports countries will report that there's between a 10 to 14% in the UK deficiency and in the us it's up to 30% some other papers have suggested that deficiency and insufficiency might be as much as half of the population but these are based on numbers from surveys and they are with these inflated numbers that we're expected to reach um and you see this across the randomized control trials as well where some participants in the randomized control trials will go into Vitamin D trials with very high blood levels already

and then they're given extra to reach even higher levels so it's I think when you look at clinical reports of ostala or rets they're still incredibly low very rare um but sometimes the reporting of how many adults are missing vitamin D or lacking vitamin D in the US and UK can seem alarmingly high but just to clarify because I I used to treat people with osto Malaya which is the adult form of rickets and you'd often see this in uh immigrant populations who changing their diet had come to a place where there had a lot

of sunshine to to know sunshine and their diet wasn't adequate and they may have been lacking it as children anyway and so they would come with very painful uh muscles aching in their body very tired and they'd have these rather weird fractures for little reason at all so that's the classical picture of the adult form of rickets which we call osteomalacia and it tells you that's what the symptoms of real vitamin D deficiency are they're they're painful joints painful muscles and the consequences with with these fractures everything else we're talking about is like theoretical risks

or theoretical problems this is where we get into this difficult territory and Tim can I ask you about the health consequences of what you're talking about the theoretical deficiencies you're saying like there's this people it's really clear they're getting these awful fractures but that's with extreme deficiency and then we're hearing there's maybe 30% of the population that's deficient what are the symptoms depression tness all kinds of mental illness um there were these conditions like fibromyalgia which were were supposed to be associated with it everything that couldn't be explained by Medical Science was in the last

of several decades been linked to vitamin D deficiency and and in general uh if you take super healthy people and you compare them with generally unhealthy people there will be a difference in their blood vitamin D levels and the healthier people will have higher vitamin D on average it's a sort of marker of Health yeah and I think this is this is why the whole literature is rather confused but if you think about it someone on a healthy diet who's going outdoors and uh doing sports and things is going to have a higher vitamin D

level than someone who is unwell and sitting inside and on a poor diet so this is where the whole literature has got very confused and people have Associated the fact that it's a health marker with the fact that ah we just have to give you more of that Health marker and you can be even better and healthy that's really interesting so it sounds like everyone agrees you need some vitamin D or that's a huge problem there's quite a lot of controversy about whether a large fraction of the population is really defici and this is really

causing them symptoms or whether actually it's a much smaller fraction who are truly having symptoms from lack of vitamin D yeah well it's not a controversy in my eyes but yeah that's uh and it's not a controversy in your eyes because because I I believe that you don't need that much vitamin D and everything above that you you're fine I've seen so many patients for example with extremely low levels uh you know that sort of nearly off the charts including one who was a colleague of mine who was an expert in vitamin D and and

and calcium he came from Sri Lanka and he'd been walking around for years with you know virtually no levels and felt completely fine so I think the idea that it's this amazing thing that you know we is like a thermostat of our health and we just have to top it up every now and again uh is very misleading but at the same time I've seen vitamin D cure some of my patients and if you give vitamin D to someone with these painful fractures their pain goes away nearly immediately so you know it's it's this ground

where I think the industry has made a disease where none really existed and Federica I'd love to get your perspective I think because it's such a marker of Health I can see how there's lots of studies that show how individuals who suffer with certain conditions including depression multiple sclerosis um Crohn's disease cancer they to have lower vitamin D levels so I understand how you know when you have these patients giving them vitamin D could be one of the tools that you use to help improve what's known to be a marker of health and so I

I know what Tim is saying in terms of the the deficiencies are pretty hardcore and easy to spot clinically but there's this insufficiency range which lends itself to giving your patient or your client an intervention that might be helpful and Jonathan we've just SP about the fact that vitamin D receptors are all over the body and they impact all tissues and there's a lot we still don't understand about vitamin D so from a public health perspective there is little harm in recommending that certain patient groups take vitamin D to help them Reach that healthy marker

level that we feel would be good for them basically now it's true that the markers are so different between the UK and the US I feel that the US has been conflated and inflated because of Industry intervention and there's been uh Lots written about this but if we take the sort of medical cut offs I think it can be very helpful to give people vitamin D to get them above that critical deficiency line and it could be something that helps them without harming them and that's really important how would someone know if they're low in

in vitamin D there's a blood test you can have uh 25 hydroxy D which is one of the metabolites of vitamin D so as we I've said earlier it's really hard to actually measure vitamin D status and this is the best proxy measure and so a proxy measure means that it gives us an idea of how your body is breaking this down but it doesn't necessarily tell us how it's being used or what effects it's having so again very hard to know how useful and some countries and other places have a an alternative test called

the parathyroid hormone which goes up if you're deficient and uh that might be a better way of seeing that so they go in opposite directions so if your body needs vitamin D in a way your parathyroid hormone goes up and therefore it it it starts to get nutrients from the bone and I feel this is something that I have been told about by doctors in both the US and the UK so it's this quite a typical sort of clinicians test absolutely yes but it's been a problem because we don't know what the normal levels are

and that also goes for parathyroid hormone it goes for um these vitamin D levels and so I think you know medicine likes to play safe so what we've done every 10 years just keep raising this level the bar so that half the population are now seen to be deficient whereas it perhaps should be you know 1% of the population uh you've now got 50% nervous and worried that they've got some deficiency or problem so this is this is the risk of of of taking this route and and treating it like okay let's G give everyone

this it's all harmless um that that'll be fine and it's you know absolutely not the case and I think by focusing on these things you're then neglecting many other things you could be doing for their health care you could be looking much more at their diet you could be the look at their lifestyle their exercise levels or some other disease that they've got so at the moment we're very focused on this as the Cure R and uh the evidence simply doesn't back it up so can we talk a bit about supplementation and the experience I

guess that people are having and then you know I think we're already exposing definitely a spread of view about what to do and we said there's quite a big difference between you know the US and the UK which is actually very surprising because it's been very unusual across these podcasts that we ever have that and I think that itself is interesting it sounds like you're saying like 30 to 50% of people might be low on this number what happens when that's the case well if you see your family doctor and they they do a blood

screen for you and show you're below that level they would probably prescribe a vitamin D supplement with or without calcium and that I think is fairly common around um the world uh depending on each country's cut off levels and what their lab is telling them all of which are very different and even in the US depending on whether you take you know the bone health colleges the the gynecologists the cardiologist we know they all got slightly different levels interestingly um so there's no real consensus for where that level is but once you've made that St

and you've taken it then generally you'll be prescribed a supplement and be told oh this should help X Y or Zed whether it's your tness whether it's your depression whether it's your muscle aches or it's going to be a general preventive for fractures and that's still commonly practiced although we now have scores of Trials showing that doesn't work I would love to discuss okay what does the science say so presumably there have been real clinical trials to try and answer this question so there there's two types of study there was the the ones that led

to this which were the epidemiology studies which compared 100 different diseases to controls and as we discussed they found vitamin D levels were generally lower in the disease group than compared to the control group for the reasons we've discussed virtually all likely be lifestyle and self- selection of people because of their disease it's not before there after they have the disease these are called observational studies they're a useful starting point in epidemiology and that's how you know lung cancer and smoking came about that's a starting point but it doesn't ABS prove anything because there are

all these other factors particularly with something that's involved in lifestyle diet and General Health a disease could lure it the fact that you're sick you stay indoors the fact you're sick you're not eating well all those three things can lower your vitamin D so that's probably the explanation for why it was associated with 100 different diseases um all erroneously then you've got the clinical trials and they're seen as the gold standard of of this and I actually did one about 20 years ago in twins uh we gave calcium vitamin D to one twin and we

gave dummy to the other one and measured their bone densities Etc and found no differences and we thought this is strange because everyone was saying this should be a miracle cure and um at the time there were a few studies dating back to I think the late 80s when they did some big studies in France in nursing homes yeah and they basically randomized nursing homes to be given Vitamin D supplements or not and found a difference in fracture within two years of of doing this and people said oh wow and from that point really everyone

was told vitamin D can prevent fractures and uh is really important in in old age and but bit by bit there have been another 20 studies or so including a massive us study called the vital trial that have shown no difference at all in fracture rates I will come in on that though and say that the study that was done in the old people's home was looking at people over the age of 65 the vital trial the average age was about 50 so actually when we look at the evidence there is some suggestion that older

people especially women that are in a care home setting May benefit from vitamin D supplementation so I think within these trials there's subgroups of people who do seem to benefit but they are the minority and Tim was talking about family physician and prescribing but actually the public health recommendation in the UK is that everyone supplements with Vitamin D from October through March that's 400 international units of 10 micrograms so the question becomes that whether everyone supplementing is helpful or whether we should really be focusing on the groups in the randomized control trials that did show

an improvement in their outcomes yes but a lot of people have discredited that very early French study the guys who were running the study ended up um you know having their own companies selling vitamin D that doesn't help um and it was never been replicated so there have been other subsequent studies in old people so that haven't found the same effect so I'm not saying we can prove definitely and yes these are very high risk individuals and very high risk of hip fractures in in old age homes they don't go out much the diet not

not good I think it's still reasonable to do that but I think we have to be a bit cautious about how great the evidence is did you say there was a third type of study that you were going to talk about as well yes there's there's another study based on gentics yeah which is called very complicated Jonathan I'm sorry about this it's called mendelian randomization well it's got a fantastic name I've heard the name before and I don't have any idea what it means what is melan randomization well you might remember this monk Gregor mendal

who did this PE experiment and Al they he probably faked a bit of the results he he basically sorted out the idea that you you inherit these these genes from your parents and they get passed down and they sort of they're mixed up and then they get separated so the idea is that once you've discovered the genes for something for say vitamin D and I actually led a study of this about 10 years ago showing that Not only was vitamin D genetic but that you could determine what genes controlled it so there are about 10

Gene variants that we've all got that can make your vitamin D Li higher or lower this is the thing you were saying before that actually amongst different people like my wife and I might be making very different levels of vitamin D even though we're eating the same food and we're having the same amount of sunlight MH exactly and it might be perfectly healthy for you to have lower levels than your wife because your genes have decided that's what they want to do we're not sure uh we don't know which way around it works but you

would expect that if you've got the genes for low vitamin D then it doesn't matter what stage you are at life you're going to have had lower vitamin D levels than your wife so it's like doing randomized trial lifelong because you can't change your genes they can't be influenced by your disease they can't be influenced by whether you're you live in Spain or or Iceland um it's the same so this was supposed to show that people with these low vitamin D traits these low genes should have higher fracture levels and they've done this in over

a million people now and there's absolutely no difference there's no difference whatsoever if your genes are making more vitamin D than someone else V absolutely none so if you combine that with the metaanalyses of all these randomized trials really the evidence that vitamin D supplementation has any role in bone health once you're out of that rare deficiency range it doesn't exist and there's some evidence that from about three trials where they get quite high levels of vitamin D that you make it worse and actually there was one trial that showed that actually more than one

trial that showed that if you have the vitamin D Plus calcium in some populations older people can increase risk of cardiovascular disease so that's where the vitamin D calcium supplementation issue comes up and you know I'm always quite wary if people are taking large amounts of calcium supplements because again the thinking there is that it could help with your bone bone health well there's even less evidence that calcium supplements work compared to vitamin D and there's even better evidence that it's really harmful for you so I don't think anyone listening uh unless they've been given

specific advice by their doctor uh should be taking calcium and supplementation because there's quite a lot of evidence both in animals and in humans that it can uh lead to atherosclerosis or clogging up of the arteries because you think about getting calcium naturally from plants or dairy or whatever form it is you're getting small tiny amounts all the time regularly which your body is used to to take a big one gr tablet of this once a day that your body's got to deal with we're not meant to do and it's not surprising that it ends

up in the wrong place you are saying that unless a doctor has specifically prescribed calcium supplementation Tim you think people should not be taking it because you think it's not just that it's neutral it's positively harmful and you know and can H your health absolutely in particular your heart and particular your heart because I think it's rather terrifying right because you can't buy it you know at the store anywhere it doesn't have great big labels on it saying warning have we known this forever or is this different from what we understood 20 or 30 years

ago we've known it for the last 10 years but such is the difficulty of changing medical mindsets and the power of the supplement industry that uh really hasn't still got mainstream and so most family doctors are still prescribing it although many of the Specialists now now are not people who suffer with osteoporosis or bone disease sometimes are prescribed both and the randomized control trials even in the groups who have you know a higher chance of uh problems like osteoporosis the trials clearly show that the vitamin D Plus calcium combination is not helpful and it's not

helpful for the bones and actually could be dangerous for your heart so it's it's interesting that it's it's very clear in the research but as Tim said people still take it and I've seen it as well where people come to me and they say this is what I'm taking I'm like let's not take the calcium and what about the vitamin D alone so I think you're saying very clearly like if a combination with calcium is like definitely out is there any downside of taking um these Vitamin D supplements you know is there any risk can

I take too much absolutely we didn't think there was but in the last 10 years there have been several trials where they've given people larger than 400 units up to 5,000 units um a day and many people are self-medicating and in these these trials they've shown that the group that were having say vitamin D by injections or large amounts by mouth had increased fractures and increased Falls you know these are well-controlled trials and they weren't expecting that result so the researchers in those in those trials are really change their minds about it so you can

overdose on these and increasingly in clinics we're seeing people who have self-medicating from the internet you can get very high dose tablets from the internet you know which seems very strange and these are very very dangerous because you you do accumulate the vitamin D in your body it doesn't uh just get peed out like some other B vitamins so you will get more and more levels and that can cause real problems and nerve problems muscle problems and uh I think it's it's an increasing you know area because because it's called a vitamin people think it's

harmless it's not just getting passed straight out if I don't need it correct that's right it does depend on the form you're taking it but in general that that's correct because uh it it does build up and it is dangerous so again it comes back to this idea of taking a supplement in a chemical form is often different to you know can't get too much from sunlight or from food mhm I think that's really it's more like a drug right like I could take paracetamol that's great it you know helps with my headache but I

know that if have loads of there it you know it could really hurt me or kill me and so you're saying that I should think about vitamin D a bit more like that like it's it's not a sort of there's no downside to taking um too much which I I feel is how I've understood most Vitamins because when you look on the stores these days they have all these different levels right and you just get to choose yourself whether you have one level the super level and it always seems like well you should get the

super duper level right why wouldn't you get the most yeah so where do you go and buy Tylen oil you're not allowed to buy you know 500 uh of those uh tablets but you can buy unlimited amounts of vitamin D and and self-medicate and I think it's it's just wrong and if it was called a a steroid you wouldn't have this it would be more more controlled so I think and that's why you know our body is well set I can go in the sun as much as I like and as may have noticed I've

been in the Sun but my vitamin D isn't going to keep going up it my body knows when I've got enough we have a system for controlling it when it comes from food or sun we don't have any system to control it when we're having it as a pharmaceutical getting older I've realized that what I eat makes a massive difference to my health now I'm eating the things that help my body feel great with Zoe I've got actual science to guide me and my test results help tailor my advice I'm making smarter choices every day

like what to add to my plate it's like having a nutritionist in my pocket it's changed everything I'm living my best life I mean I'm going to be clubbing with the grandkids join me and over 100,000 people transforming their health with Zoe everything we've talked about has really been around um bone health um and the impact on fractures is that the whole role of vitamin D cuz I feel like lots of people are taking it because they think it's going to help with General Health and does that also mean that if I'm not worried about

fractures then I can keep taking lots of it because I don't think that's a very big risk for me no there's so much more to the research and there's so much more to how we think vitamin D works so we spoke at the beginning Jonathan about its role in immune function immune system function and I think that's where research has been more promising for the use of vitamin D even as supplements um because for example with groups of patients who have for example Crohn's disease which is a inflammatory disease we see that those individuals benefit

from vitamin D supplementation in randomized control trials they have a reduced risk of hospitalization and complications now if we think about this as a steroid that helps immune system function in individuals who have complicated inflammatory diseases it makes sense that supplementing with vitamin D could help to mitigate some of these problems um another group that has seen some good outcomes in the vital trial is patients who have cancer now not to prevent cancer but if you already have cancer taking vitamin D could actually help to reduce mortality risk um now again this is in a

subset of patients so patients who don't have obesity whereas patients who do don't seem to benefit and that probably comes back to how the vitamin D is stored in tissues so again try to understand how this works in our bodies is really important and so where I stand is like there is exciting evidence that this could be helpful in certain groups of people and really make a difference on the outcomes for those people and so where does this leave the two of you on supplementation I'm living in uh a Northerly climb which is dark all

winter um and that is going to be true for you know quite a few of our listeners and I think they're getting this message that you're just not going to get enough from the sunshine during the winter so you should supplement that is outside should there be supplementing and if so how much there is reams of evidence that getting outside all year is helpful for our health for lots of reasons not just vitamin D now if you get outside all year round including in the summer months being mindful of your skin tone so some people

listening to this like myself and definitely like Tim can get outside and not wear a strong Sun sunscreen and not get sunburned right other listeners listening know that if they go outside for more than 5 minutes they will get sunburn sunburn is always a risk factor but if you can go in the sun and enjoy 15 to 20 minutes out side without sunscreen without getting burnt so with no redness then doing that every day is recommended remembering that we accumulate vitamin d means that if we get enough sunlight exposure in the months when there is

sunlight right um then we'll probably have enough to carry us through the winter months but if you're somebody who can't get outside if you're somebody who has perhaps a really sensitive skin tone and finds it difficult to go outside or if you're somebody who already has compromised health so maybe you're an older person living in a care home maybe you have Crohn's disease or maybe you've just been diagnosed with cancer then it may be worth speaking to your healthc care professional and getting some vitamin D supplementation because it could be helpful but I will really

again come back to this vitamin D toxicity I've seen vitamin D toxicity and it's really not fun there is a lot of influences online that are promoting very high levels of vitamin D so the takeaway for me with vitamin D is if you're one of these groups who could benefit make sure you're getting the 400 international units in the UK that's 10 micrograms in the US they recommend up to 800 international units which is 20 micrograms but really if you're taking 400 international units a day in one of these groups you could see a benefit

so I don't completely disagree with but I I don't want to give the impression that everyone living in northern Europe or northern northern parts of Northern America and Canada you know should be so dependent on on vitamin D I think we've evolved for tens of thousands of years to have the right conditions for our body so we mustn't forget that and if we have a diverse diet then you know that's also going to help us there are some conditions that interestingly I'm fully convinced vitamin D can prevent and one of those is something called multiple

sclerosis which many listeners may know about my mom actually suffered from and there's a link between people getting uh multiple sclerosis who live actually in Northern Hemisphere and uh in cold climates and it gets less as you go towards the equator and this is one where this mendan randomization studies actually showed a difference in the likelihood of of getting multiple sclerosis so there are some U rarer diseases where this can be useful and I think it it makes sense so if you've got any family history or risk then making sure your vitamin D level is

is adequate could be fine now if I did my blood you know my mother's got it so I've got high risk but I I know my vitamin D level is high so because I go in the sun I have a a good diet so I'm not going to take supplements but someone else might if they're living in Alaska or living in Scotland then it'd be quite reasonable in the in the winter months to take those supplements but I think we got to realize that you know I would say sunlight and food are a much better

option for the vast majority of people that's really clear and we've gone a little bit but I do want to make sure I touch a bit these alternate ways of um getting vitamin D and so what are some of the foods that contain vitamin D well most people know that it's contained in dairy products which a lot of people are already eating so milk cheese cfir yogurts Etc then uh it's in oily fish and it's in mushrooms and they're the the key ones and many people not incorporating those in their diets and that's why I

think it's been quite interesting this this journey with Zoe and the nutrition program that we're seeing we're getting people to eat these kind of foods incorporate them more regularly into their diets and that's just one example of how we can sort of shift people's attitudes to Foods so that they don't need supplements just by thinking intelligently about what they're eating if we think about it in proportions I think up to about 30% of our requirements can come from the food weed it could really make a difference at that absolute minimum level of vitamin D you're

getting compared to the sort of people living in these terrible conditions 100 years ago you're talking about yes but compared to the sort of numbers that the government is talking about this now pushes you over to sunlight is that right as the much bigger thing that would drive your vitamin D levels being outside yeah and that's interesting because a lot of the place countries suffering from the most vitamin D deficiency are places like Australia where they're now avoiding the Sun and living in air conditioned you know the inside for six months or more of the

year so as we're changing our environment away from nature we are sort of developing some of these new problems it's about how we you know live with our Evolution and our nature and and everyone has to decide you know what those special examples are that brings up a good point though Jonathan as well if you're some if you're a person of color and you have darker skin and you live in the like like cold climates then you are at higher risk because that sunlight that will actually penetrate your skin and create the vitamin D you

won't get that in London right very rare or maybe like a couple of weeks a year so to Tim's Point we' revolved to adapt to our environment but now we're such an International Community all over the world we have to be aware of what we need for ourselves and our backgrounds to make sure we don't lack but also another important point we talk about sunlight I want to be super clear here that sunlight does not there's no hack for sunlight you so having a suned so that you create vitamin D is not the way to

do it right there's this fine line between getting enough sunlight exposure but not increasing your risk of cancer of skin cancer well I was going to say Federica so both Tim and I are married to dermatologists so I happen to know that Tim created a storm in dermatology circles uh earlier this year um because the idea of going out um in the sun without sort of you know fact 50 sunscreen is very controversial because quite reasonably dermatologists spend a lot of time dealing with people with skin cancer and people who end up dying from skin

cancer right so they see that and therefore there's been these very big campaigns right across the states and uh Europe Australia about the extent to which whenever you go outside you should make sure that you have a really high sunscreen and I have to say that since I met Justine I've wear way more sunscreen than uh I had done before so young Jonathan well well thank you and I am totally convinced that this is great for anti-aging so I'm sold on that but I think Tim um you know this conversation brings around this question about

what the impact might be on vitamin D and health and I think you had what I thought was a fairly nuanced position but was interestingly very controversial so would you tell us how you think about sun exposure and and sunscreen given this conversation of of Vitamin D it was it was triggered both by research article I read which was actually on mice which normally I don't pay much attention to but it it was showing that how Vitamin D was really important in helping the immune system deal with Cancers and the other thing was going in

the tube and seeing posters by uh UK skin charity but basically sponsored by a uh sunscreen uh manufacturer to say that we need sunscreen all year round in order to stay young and beautiful and to protect us from the harmful rays and O of the sun and the idea that has permeated that we need 365 days of protection with a chemical a pharmaceutical on our skin has permeated everywhere so there are some schools um in the US and the UK that won't let their children go unless they've got sunscreen every day and this is quite

ridiculous in in Northern climbs uh where there's you need every little bit of sunshine just to get enough vitamin D you're not going to get any harmful radiation in that time it's not going to make a significant difference to your aging and we're seeing more and more dermatologists are seeing more and more problems of particularly young girls with major skin problems because they're applying so much uh chemicals to their face and this just seemed to to be totally driven by the sunscreen industry uh who are going through Charities and making it sound like it's all

scientific when I looked into it and when I asked melanoma experts like my wife there was ABS no evidence and and after about two million people had seen this tweet and I got lots of you know nearly death threats for sort of insinuating that Sunshine might be good uh including from you know doctors and celebrities and various other people um it turns out the British Dermatological um Association came up and said actually you know he's right there's no rationale for year round uh use of this and you know the risks are worse than you know

you need you need every bit of sunshine you can get in winter so you're basically suggesting sunscreen in the in the summer when the sunshine is high and you got this risk of burning all the rest of it but actually um you know if you're not lucky enough to be in Florida or in the winter or whatever it is actually your view is you're better off not having the sunscreen because you're going to increase the vit D and that is much better than what you're saying like not really real risks that they're worrying about to

do with skin cancer correct more like to do harm than good and definitely your skin health will probably be better if you don't have all these layers on every single day of your life fed too too radical in your opinion well tell that to women who wear lots of layers but anyway um I think the main thing there though is we have to be mindful of sunburn again so I with children especially we know it's the evidence is really clear sunburn in childhood increases the risk your risk of melanoma later in life and so when

it comes to protecting children's skin or again if you're somebody who's got extremely fair skin I think we know that you only need about 10 to 20 minutes of sunlight exposure between 10:00 a.m. and 2: p.m. to produce enough vitamin D so it's you don't necessarily have to have prolonged exposure with no sunscreen it's just about getting enough in every day and I do with him 100% though that we don't need to be wearing SPF 50 throughout the winter months it does just seem like a complete waste of money and a a waste of a

layer on our skin but try buying a foundation cream for women that doesn't have uh SPF you know 30 or 50 in it is really hard so women are not given the choice really actually that's the other thing that's is quite interesting I'd like to talk about covid actually briefly and the immune system because I think that was a another big area that when I I I was talking about vitamin D and preventing Co you might remember that there was a huge thing about taking it and this was absolutely crucial to it was like 5,000

international units a day to prevent people people everything sold out as usual in in this area in a bid to prevent it and we did our own study with Zoe looking at supplements and people what they were taking and we did find interestingly we looked about a million people and saw the severity of covid we saw a slight effect of vitamin D but only in women this was a self-report support observational study and the fact that it wasn't consistent in men we said it's probably just selection bias and that um women were buying it and

they believed in it for the family and the men were just you know being given it and therefore it didn't help them so it was a placebo effect but other Studies have shown no benefit in uh in covid for for vitamin D and um there were some big studies about injecting it for people with the disease that didn't share it unless they were very deficient so so people again in this sort of really deficient category will benefit from vitamin D and it's again this nuanced argument that it's really hard to convey to the public that

if you're severely deficient in vitamin D giving it can be life-saving it but if you've already got reasonable levels having anything extra is really unlikely to to help you at all and I think the same goes you know these studies of cancer and all the things related to immune system autoimmune diseases Etc so I think that's where we just need to think are you really deficient or not and um only if you're really deficient should be really worried about this otherwise I think sunshine and and a diverse diet is going to um be all you

really need and we should be worrying about other things and spending our money on other things and that's why I think Zoe members who are getting all this education are uh in a much better position to think about the things that are really important in their health that they can make changes to rather than just spending huge amounts of money on uh supplements that are proven not to work so it feels like you're basically saying for most people they could save all the money they're spending on this vitamin D supplementation and spend it on something

else that they're going to eat that is going to have a much bigger impact on their health is that spending more on their on real food getting mushrooms for example that have been suntanning the oily fish occasionally you know just a more diverse diet and realizing that yeah just putting their arms in the in in the sunshine and walking in in the woods in the garden regularly is is is good for you I think moving away from this miracle fix of the vitamin is really important for these other aspects of this more holistic view of

life I mean I mean and I'm personally about this about the vitamin D supplementation for the last three years as Tim knows but I'm coming away from this podcast pretty clear that as long as I'm able to get some sunshine it's out it's out the window and I should be thinking about um you know what am I doing really to feed the good bugs good man you got it finally and I think for those people who have caring responsibilities maybe you have children maybe you're helping with a an elderly parent having it in the home

and maybe occasionally giving your child some or giving your elderly mother some isn't going to do them harm but there's other things that we can do for our health which are going to have a much bigger impact and actually measurable improvements um to to to our health so if if you've got some in your cupboard you don't have to throw it in the bin but definitely don't worry if you skip a few days um unless as we said you're in one of these minority groups of people who do have a specific condition that could benefit

brilliant well federick and Tim thank you very much and I think for the listener I hope that was fun because you can definitely see that although there there's there's agreement on what the studies are and what they say that you can have two scientists looking at this and still have some some some spread of opinion and we've had a lot of conversations like this uh over the last um seven years and I imagine we will have many more I'm going to try and do a quick summary if that's right so my biggest takeway from all

of this is do not take calcium supplements like if I think anyone listening if there's one thing to take away is don't take calcium supplements and if you have unless they've been prescribed yeah unless they've been prescribed and if you have friends or family who are taking calcium supplements again ask them like has the doctor actually told you to take this and if not you should stop so I think that's actually probably the most valuable thing I've taken away secondly V D is not even a vitamin that does matter a bit because it means that

for example you really can overdose on vitamin D and end up with something that's toxic because you're saying if it was really a vitamin you just sort of pee it out but actually it sort of builds up and so that really should shift the way that um I think about it and everyone else would think about it and then the other bit is there's this huge gap between what the government is saying in terms of saying maybe 30% or more of the population is deficient in vitamin D D and what you can really tell from

people getting you know rickets or some of these other diseases which is a tiny tiny fraction and so there is a big debate about really are so many people deficient or is it actually just a product of the fact that we're all different and our genes are um different and that the evidence on this has really shifted over the last 20 years where previously you know Tim was saying he also thought vitamin D was really good and prescribe it because it was going to reduce fractures and basically the data the studies one after another have

been drip feeding and saying actually there is no evidence that if you take this vitamin D it's going to reduce um your risk of fractures which was the original idea for taking it and there is real evidence that you can overdose on it so if you are taking really high levels of vitamin D unless your doctor has told you to do it like stop again and then I think critically um while there may be some groups and Federica is pointing out some groups where supplementation could work and interesting it's you're tending to talk about groups

that might actually be living with some sort of disease maybe there's a role for people who are very old and in Care Homes I think Tim you said that's also possible but you know it's these are relatively small groups what we should all be doing is rethinking our attitude to um the sun particularly in the winter for people who are living in uh you know very Northerly or southerly climbed or people who are living in a place where it's hot and they're putting on so much sunscreen like Australia or Florida all year round that they're

getting none and that actually we need to rethink this balance between yes you want to avoid cancer you don't want to burn but on the other hand you do want to get some vitamin D from your skin and that for a lot of people um that means that you could probably go out in the winter months without having to have um sunscreen and just to wrap up I would say I have had a personal dis compensation from my wife that you know in the winter 6 months I'm allowed to not wear sunscreen so and I

think that her view has changed since I've known her so I think what I see there I think Tim is it's obviously you know a shift also you know in medical views from dermatologists and others as this evidence is changing right that the vitamin D is seen as something that matters if you can get it through something like the sun whereas this supplementation has come under much more more question yeah and I think Tim's been saying this for a while actually have to say Jonathan he's been very skeptical of vitamin D supplementation for General Health

and prevention of all disease and the newer evidence is proving that Tim's approach has been right and I think quite satisfying for you I guess but it's really it's important to always keep an open mind because the status quo on what recommendations are doesn't always hold I don't want to puff up Tim's head anymore since you know that uh we wouldn't want to recommend that could be another study next year that proves me wrong so you know um you're open to that and but you you know and I open to you know if there's another

way of giving vitamin D that actually works uh because it's so important in the body it just so happens that the trials that have all been done so far apart from saying multiple sclerosis and a few other rare diseases you know have not been effective but I'm open to supplements working but let's look at the evidence clearly and uh come into it with our eyes open and not be driven by the industry into take spending all our money on things that are proven to work and if I were going to wrap up I just say

I think this reminds me of the conversations we have around food and nutrition all the time where you know the latest science is very often completely different from what I was told 30 years ago is the right answer that it's complex you have to work it through and it's part of the reason we we spent so much time trying to figure out how we use sort of the membership in the app to guide people to understand what to change because this is just vitamin D right like it's just one little part of how you think

about improving your health it is complex and I think what's interesting is just how many areas scientists are now saying actually you know what the view that we had 30 years ago with a lot less data we've really changed a lot and that there has been an enormous amount of research that's going on uh around the world in so many of these areas I think you know Tim is generally saying well actually you know what this has really changed you know My Views and our views about what we should do but I do think that

though the science is complex I think the advice remains quite simple and Jonathan we obviously know this in the app and in the way we speak to our members but eating a whole food based diet where you have a lot of plants on your plate and being active throughout the day preferably outside is quite simple in terms of the messaging so I think we mustn't lose sight of the fact that these are all things people can do and it's quite easy to make that change obviously it's easier when you have the help of something someone

like Zoe to do it yeah so it's a holistic approach it's not about one little chemical it's all about the the thousands of chemicals the whole complexity of our body that we need to embrace and that's why yeah I this whole idea of diversity is absolutely crucial brilliant thank you both very much thank you pleasure I loved having Tim and Federica on the podcast today I hope you learned something new and enjoyed watching them disagree a little bit my biggest takeaway is that if possible we should try to get our vitamin D from natural sources

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