Written by Christopher Kelly
May 12, 2016
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Christopher: Hello and welcome to the Nourish Balance Thrive Podcast. My name is Christopher Kelly and today I've got an episode of the podcast that was originally recorded for the Primal Eye Podcast. And I recorded this interview with Dr. Tommy Wood. And I thought you'd find it interesting and I wanted more people to hear it. So I'm going to broadcast it on my podcast. Tommy and I talked about sunlight, vitamin D, sunscreen and skin cancer.
Specifically, we go into what our optimal levels of vitamin D, whether or not it's better to get your vitamin D from a supplement or from food or from the sun, and whether or not you should be avoiding sunscreen and what types of sunscreen are best. And also, finally, we talked about how sunlight can increase and decrease the risk of certain skin cancers. So I hope you find this interesting. And let me know what you think.
Tommy: Hi, guys. Welcome back to the Primal Eye Podcast with myself, Tommy Wood. And this week, we are joined again by Chris Kelly. Hi, Chris.
Christopher: Hi, Tommy.
Tommy: And today, we're going to take a bit of a dive into sunlight, vitamin D and maybe some things about skin cancer and sunscreen because there's a lot of information going around about that at the moment because, obviously, we're kind of getting into the summer months. The sun is starting to come out. It's getting hot. People are wondering whether they should be using sunscreen or not, is it good or not, how much can we use, is it stopping us from producing vitamin D, and all that kind of stuff?
And I know Chris has been thinking about this a lot and has a lot of questions about this and he's done quite a bit of research. So we have been both digging down into various rabbit holes in this huge amount of information out there. I think that finding sort of exact answers is going to be very difficult to do just because of the nature of the data we have. But there's definitely a lot of articles out there, maybe from the Paleo communities, suggesting that we shouldn't be using sunscreen and that some of the ingredients are toxic and we should be avoiding them. And also that we don't want to stop our production of things like vitamin D, which obviously is made in the skin with exposure to sunlight.
Then the more traditional view is that sunlight causes skin cancer, we need to avoid as much sun exposure as possible so that we avoid developing skin cancer or premature aging of the skin and things like that, and that sunscreen is something that we all need to be putting on if we're going to be exposed to the sunlight. And what it seems to be is that probably the answers for different questions sort of lie somewhere between those two. So hopefully, we'll get to cover some of that. But, Chris, did you want to -- Why don't you get started with sort of like the basic questions that you come up with and what you think we need to address?
Christopher: Sure. So, the sun tan cream thing, obviously it's the summer and the weather has been beautiful here. I'm in the UK at the moment. I live in California and there's even more sun there. And even in the UK the weather is beautiful right now. And the obvious thing to do is to slap on the suntan cream. I mean, that's what we've always been told that if we don't do that, we're going to get cancer. Especially for your kids. I've got a daughter who's 18 months old. People look at you like you're abusing them if you don't zinc oxide them to death or whatever the sun tan cream is that you're using.
Also, the sun tan cream thing, it sort of fits into this Paleo or ancestral health philosophy where you kind of -- You look at some of the traditional things that we've been told and maybe it's questionable, that advice. And when you look at the ingredients there in sun tan cream, especially the chemical sun tan creams where the protection from the sun is coming from different chemicals, I don't know what they are at all. I spent quite a lot of time reading scientific papers and I still have absolutely no clue what any of the ingredients in sun tan cream are.
And that doesn't mean they're evil or toxic by any means but I just have gotten good results in the past by following an ancestral health principles or framework, if you like. So if you think about how things would have been in the past, even a few hundred years ago, I guess sun tan cream didn't exist. And did people die of skin cancer? I'm not sure about the answer to that. And then also when you choose your food, I think we all do really well when we choose things with not so many ingredients and certainly not so many ingredients where it's some sort of weird molecule where not many people know what it is.
So, I guess, my first question is how do we become -- So this is vitamin D thing that people have heard so much about. Is there a chance that using sun tan cream could stop me from being sufficient in vitamin D and what is vitamin D sufficiency?
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Tommy: So vitamin D is an incredibly important vitamin, obviously. We talk about it a lot and people are supplementing vitamin D quite a lot. In terms of sufficiency, so how much vitamin D you need, you can make -- So you make vitamin D in the skin, ultraviolet B rays come down and hit the skin and they convert 70 7-dehydrocholesterol to pre-vitamin D3 and then that goes on to be partially activated in the liver and then fully activated in the kidney.
You can take a similar version of the vitamin D that you make in the skin. You can take it as a tablet, take as D3 tablet which a lot of people do. And then the body will kind of do the rest and activate as much of it as needs to, to get the levels right. In terms of what the ideal vitamin D level is, it's actually very controversial. Most people will say that a level below 30 nanograms per mil, so if you had it tested by the doctor, below 30 nanograms per mil is insufficiency and below 20 is a deficiency.
But we're sort of starting to see that maybe a bit more than that is better. I think you're getting toward the optimal range once you get sort of 40 or 50. But then there's definitely a plateau effect and above maybe 90 or 100, there's really diminishing returns. And one thing that's particularly important is that vitamin D, even though it's very important for the immune system, if you take too much, particularly if you just like throw in back loads of vitamin D3 pills, it can actually suppress the immune system.
If you're somebody who's taking vitamin D, it's definitely worth getting your levels checked and that's something you could do with your GP or your doctor and especially if you're taking high doses and you find yourself coming down with the colds or a flu or something. It could be actually that you're overdosing on vitamin D. But if you don't have enough vitamin D, we know it increases your risk of many, many cancers, increase the risk of autoimmune disease, increases bone deformities.
We used to have a problem called rickets in children, which we don't really see as much anymore because our food has supplements of vitamin D. We're much more aware of the need of the need for vitamin D. But things like osteoporosis. If you have low levels of vitamin D, you are at high risk of osteoporosis. And also you need enough vitamin D for the immune system to function properly and also to prevent your risk of cardiovascular disease because vitamin D helps you decide where your calcium goes.
And if you don't have enough vitamin D, then the calcium can end up in the arteries around your heart, which is bad, potential cause for later heart attacks. And if you increase your vitamin D level, then you reduce that risk of later heart disease.
Christopher: Okay. And so the blood chemistry, the marker you're looking for is 25-hydroxy vitamin D, right?
Tommy: Yeah. Otherwise known as calcidiol. People might have heard of that. That's a marker of either how much you're taking in your diet from tablets or how much you're making in the skin.
Christopher: And that's a precursor rather than the active form of vitamin D which is not commonly measured on the blood chemistry, right?
Tommy: No, no, it's not. And the reason they do that is because a lot of the vitamin D you make isn't fully activated to calcitriol, is what they call it. If you're measuring the 25-hydroxy version, the calcidiol version then you get a much better idea of how much total you're getting in and how much you're making. And then your body is usually fairly good at deciding how much activated vitamin D it needs. And then the problem just becomes when you're just not making enough or you're not taking in enough.
Christopher: Okay. And so, I guess, the question is then: Could slathering on the sun tan cream, say factor 20, which is nearly block, could that stop me from producing enough vitamin D?
Tommy: The answer is yes and no. So, no sunscreen provides 100% block from -- So what we're worried about is ultraviolet radiation which is just a small part of the spectrum of the light that we get from the sun. And we talk about UVA and UVB. And UVB is shot slightly shorter and that's what causes vitamin D production. But UVA is sort of the major part of the ultraviolet light from the sun and that is involved in both like skin damage and they both are involved in tanning.
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But most of the ultraviolet light you're getting from the sun is UVA and that's a large part of what you're trying to block out. But no sunscreen is 100% effective. And when you're looking at UVB, so in terms of vitamin D production, no sunscreen will 100% block out all UVB. However, there are some small studies that have been done where they got people to put on sunscreen as directed and then if you expose them to sunlight then they don't really produce much vitamin D compared to, say, a controlled group, which do produce some vitamin D.
But these are small studies that were done very long time ago, back in the 80s. And more recent studies with more people have actually shown that in those people who were just given sunscreen, told to -- Most of them had been done in Australia actually because they have high rate of skin cancer. They just tell them to use sunscreen on all the exposed body parts when they go out in the sun versus, say, a controlled group.
And actually, those people in the sunscreen group don't have a reduced level of vitamin D compared to the controlled group. And actually the people who use sunscreen the most have a trend towards a higher vitamin D level. And that's probably because they're just spending more total time in the sun and that's why they're using more sunscreen. And I think a big part of the reason is because when you're testing a sunscreen, the amount that they put on the skin is two -- They're measured by the sort of the amount there is over certain areas. So it's two milligrams per centimeters squared. So that's just one centimeter by one centimeter and the skin has to have two milligrams of sunscreen on it.
But when people are actually out in the real world and they're putting sunscreen on, they don't want to look extra white and they don't want to have any clumps or anything, then they're probably using about half a milligram per centimeter squared. And once you're using that little, once you're using that little sunscreen, so if you half the amount per centimeter squared, you actually reduce the SPF from what you're told it is. So if it's 20, that should reduce it eight times. So then it's actually SPF2.5. And then you're actually getting some vitamin D production.
So people using sunscreen out in the real world, it doesn't look like the way that we tend to use sunscreen actually reduces vitamin D since there is that much. And part of that is because if you look at how much UV light you need to make vitamin D3 versus the amount of UV light you need to start tanning or maybe even burning, it's about a third. So you need a lot less light to make vitamin D compared to how much you need to start tanning or burning.
Christopher: Okay. So the answer to the question is you probably don't need to worry about becoming deficient in vitamin D if you're using sun tan cream. It's probably not going to happen.
Tommy: No, absolutely. And I think it's -- Hopefully, we'll talk more about the importance of sunlight. And so I think that, I mean, burning is not good. It dramatically increases your risk of all skin cancers. But you definitely don't want to be avoiding sunlight because there's a huge number of benefits of getting your vitamin D from sunlight particularly rather than getting it from a tablet. So I think more sunlight. And if you're going to be exposed to really strong sunlight then I think sunscreen is definitely worth it, if that's going to reduce your risk of burning.
Christopher: Okay. And then since I've got a baby and I'm sure other people listening have babies too, are babies at any particular greater risk? So are they more likely to get burned or can they even synthesize their own vitamin D at all? Or are they different in any way?
Tommy: So they're only different in as much that your -- In children particularly, childhood exposure to sunlight or childhood burning is probably the greatest risk for later skin cancers particularly things like melanoma. So children are more susceptible. But that risk is stretched over the rest of your lifetime. And if you're looked after as a baby but then you burn a lot as an adult then you still have an increased risk of melanoma. But it's just basically starting sun exposure early, I mean, having large sun exposure as a child particularly if you're not adequately protected, that then increases your risk of skin cancer in later life.
Christopher: Okay. That certainly makes sense. A few of the peers, friends I have that do kite boarding and cycling and they've been out in the sun for many, many years, they seem to be with their dermatologist and having suspect lesions or whatever removed from their skin.
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And it seems like, I mean, those people are -- They're the same ancestors as me. They're all English or German or maybe Irish or Scottish. But somehow, there seem to be getting more weird things appearing on their skin. And the only difference I can see between them and me is they just started earlier. They were born in California and have just had more time in the sun.
Tommy: Yeah. So if we're talking about lesions on the skin and skin cancers, maybe it's quickly worth talking about. So there are three main types. There are two types of what we call non-melanoma skin cancer and they are basal cell carcinomas and squamous cell carcinomas. And basically they're just named after which part of the skin they developed in. So the squamous cells are your epithelial cells. So they are the uppermost layers of the skin. And the basal cells are kind of just beneath the squamous cells in terms of layers of skin.
And basal cells carcinomas or BCCs occur, they're about 75% of skin cancers. And squamous cell carcinomas or SCCs are about 20%. And they can be quite distractive. They can cover -- You often see them on the face, around the nose. And they're sort of you just -- 90% of them can be treated with surgery and don't need anything else. And they have a very small rate of metastasis spreading to other parts of the body. And most of it can just be treated surgically.
And the one that we really sort of worry about is melanoma, which is about 5%. It spreads through the body very quickly. It has one of the worst outcomes and treatment prognosis of any cancer. And that's what people are really focusing on if they're trying to reduce skin cancers. And for BCCs and SCCs, particularly I imagine those are the kind of lesions that most of your friends are seeing or at least things are going towards that because they sort of have like precursor lesions or things like actinic keratosis or Bowen's disease, something like that. It's sort of like a pre-cancerous lesion on the skin.
So, BCCs and SCCs basically, your risk of both increases as your total lifetime exposure to the sun increases. And sunscreen is very good at protecting against SCCs but less so against BCCs, for whatever reason. So I imagine it's just because your friends started early and they just spent a lot of time out in the sun and then your risk sort of increases as your total exposure increases.
Christopher: Okay. So we've talked about the risk of different types of skin cancer but how likely are you to get skin cancer in the first place?
Tommy: So that is very dependent on where you live and your skin type, so the people who have the greatest risk are obviously the people, usually people with the fairest skin who then get exposed to very high levels of sunlight or burn a lot. And actually between them, skin cancers are probably the most depending from country to country. They're probably the most common type of cancer. And many people, older people who lived to be 80, 90, 100, most people get some kind of small lesion on their skin that's in the kind of SCC or BCC kind of type.
But your risk of melanoma, say if we're talking about that, compared to your risk of other cancers is fairly small. So you're talking about 1% to 2% of cancer, something like that. So your risk of other cancer be it bowel or breast or prostate or something is much more likely.
Christopher: Okay. So looking at this ancestral health framework, what do you think happened like 500 or 1000 years ago when presumably people were out in the sun a lot? Do you think they died of skin cancer?
Tommy: They might. Absolutely, they might have done. But we sort of know -- We also know that as we kind of migrated from the, let's just say we migrated away from the equator which where we think most of the oldest human evolution occurred, then our skin started to pigment less and less and less because, obviously, the more your skin is pigmented the less vitamin D you make when you're exposed to sunlight. So then in order to survive as you get away from the equator then your skin pigmentation usually drops in order to compensate for that.
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So then, I think, what's happening is that a lot of our risks of skin cancer particularly from exposure to sunlight is the fact that -- I mean, there's a huge number of reasons why this is going on but part of the reason is we're now indoors all the time. So particularly fair skinned people are indoors all the time. And then they go on holiday and they fly to Spain.
Christopher: For two weeks.
Tommy: For two weeks. And they come back a crispy red color. And they do that maybe once, if they're lucky, two or three times a year and it's those cycles of burning and then healing which dramatically increase your risk of skin cancer. So what we didn't get during our evolution is the ability to fly to Benidorm when we got a break from work. So I think that's probably part of it.
Christopher: Yes. So disability to travel. And I guess that could work the other way. If you are a dark skinned person, you can move away from the equator and then maybe have problem synthesizing enough vitamin D and become deficient.
Tommy: No, absolutely. So one of the interesting things is that actually the people who are at the greatest risk of vitamin D deficiencies are the people who are from, say, the ancestors, from Central Africa and they now live in Norway, say, or the northern states of the United States. They are the people that are at the greatest risk because their skin is designed to minimize vitamin D or to minimize damage from the sun. But then they also produce vitamin D from the same sun exposure of somebody with fairer skin and then they're actually at much greater risk of becoming vitamin D deficient.
Christopher: And I think it's interesting to note that this is the step that you remove when you take a supplement. So when you get exposed to the sun your skin becomes darker and that kind of limits the amount of vitamin D that you synthesize. And when you take a supplement, you kind of do away with that step. You can swallow as many pills as you want and your body doesn't really have much choice. It has to deal with it. Whereas normally, there's a right limiting step there.
Tommy: Yeah, absolutely. And there's a huge risk to kind of -- You and I talk a lot about it and we spoke it on your podcast before. We talked about how humans have kind of ended up thinking that they know better than the body and kind of are interfering. And actually, the more we learn about that the more we realize that that's probably not a good idea. And vitamin D is one of those things. And there were kind of two parts to that. One is that we know that low vitamin D is associated with all those things I talked about before.
But once you start supplementing with vitamin D, you don't completely reverse the problems. So there is some benefit for in terms of osteoporosis or elderly ladies with, or men, with osteoporosis. If they take vitamin D, they usually see an increase in bone health. And there's a lot of other stuff that's important like vitamin K2 and activity and stress and all that stuff, which people don't really talk about, then they say it's calcium which is not. Osteoporosis isn't really that much of a disease of calcium in itself.
But if you're taking -- People with autoimmune disease, I mean, know that low vitamin D is associated with flares of autoimmune disease and increased risk of autoimmune disease. If we just give those people vitamin D tablets, they don't just heal their autoimmune disease. And part of the reason that is, is because when vitamin D is synthesized in the skin, other stuff happens at the same time. So you get some small amounts of damage from UV rays and there are other things happening all around that vitamin D synthesis.
And there's this really fascinating paper. It was a study. I mean, it was done in mice so you always have to take these things with a pinch of salt. But what they found was that supplementing vitamin D, this is in a model of multiple sclerosis, supplementing with vitamin D doesn't really help the symptoms that much. It does a little bit. But if you get that vitamin D from exposure to light then what happens is the combination of producing vitamin D in the skin plus small amounts of inflammation from the sunlight together they regulate the immune system in a way that taking vitamin D from a pill doesn't.
So then it looks like actually making vitamin D in the skin even though it's chemically the same, it doesn't have the same effect as just popping a pill. And then when you're talking about something like melanoma this becomes very interesting because in melanoma people who work outdoors and have a chronic low level of sun exposure they have a lower risk of melanoma compared to somebody who works inside and then just goes out into the sun occasionally, say, recreationally to go and sunbathe.
So when I was starting to see that when you're exposed to sun on the skin, you get things like vitamin D production.
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There are certain molecules of something called RNA which is like a messenger made from your DNA to make proteins. And they kind of have an anti-cancer effect and they're made when you're exposed to sunlight. So it looks like actually in order to sort of minimize your risk of something like melanoma, it might involve chronic very low levels of sunlight because actually when you're making vitamin D in the skin there are lots of other things that are going on and then they can overall reduce your risk as well. So it's definitely not as simple as just popping a pill.
Christopher: Okay. So far I'm pretty sold on sun tan cream then. So say I'm an office worker and I'm working in London and I spend eight hours a day in the office and maybe certain time of the year there's not much sun anyway. It's dark quite a lot of the time. What should I do then in terms of the sun tan cream? Because it seems like the numbering system, that the SPF factor is it's kind of confusing. I'm not sure that more is more with that scale, right?
Tommy: No, it's not. I've read something recently where the FDA in the States was planning on banning anything that was listed above SPF50. So basically, the SPF is supposed to be the amount, the number of times that you're reducing the amount of UV that's going to the skin. So if your SPF20, then you're reducing that to a 20, so 5% of the amount of UV that's getting to the skin. But it also really depends on how much you're using.
People have tested these and it never really seems to be what it says on the bottle. It could be a lot more. It could be a lot less. And there's really sort of diminishing returns once you get above sort of 30, 40, 50. It's not a linear scale. So you definitely get to a point where unless you're kind of putting on layer that's super, super thick and you can actually visibly see it, you can't completely block it.
Christopher: Right. I think that's the problem. Non linear is the other magic word for understanding SPF. You just can't keep increasing that number and get more and more benefit. I think that's what the FDA. I don't see it so much in the UK actually. Do you get like anything greater than about factor 25 in the UK?
Tommy: 30 is very common. But I do know some people, they get 50. I've heard that you can get stuff greater than 50 in the States but I haven't seen that in the UK. I don't know. Maybe that's coming, I don't know.
Christopher: Yeah, for sure. I've seen people -- I've definitely seen factor 60. I've heard people talking about factor 80. And, of course, if you were a businessman producing suntan cream, then if factor 60 is good, then factor 80 has got to be better. I mean, that's just -- That makes intuitive sense to people. But that's not actually the case. I guess that's what the FDA have a problem with. I think the answer then, to get more protection is not to get a higher SPF but to reapply the sun tan cream more often.
Tommy: Yeah, I think that's probably the best way to do it. 20 to 30 is something that we're very happy with. We know that it works the way it says it does. And so I'd rather people rely on that and frequently reapply and just be mindful of what's happening to their skin. Do they think that it's starting to feel hot or painful? Or are they starting to burn or whatever? You obviously get to know yourself. And the longer you spend in the sun, so say you're in a long holiday or whatever, then obviously you need a bit less because your body will produce melanin to darken the skin and you're tanned and then you'll get less of a problem. I think, again, it's just being mindful of yourself and don't just slap on a factor 50 and expect it to do the job all day and then find out if it's too late.
Christopher: Right. Yeah, it's really hard. I think it's one of the hardest things actually because you get -- You can get burned so quickly. And you really don't get that much feedback until it's way too late. I get this problem a lot. I wear these cycling jerseys and they deliberately by design have quite high necks and quite long arms even though it's a short sleeve jersey. And it creates this ludicrous tan lines on me. But when I wear a normal shirt, it leaves a bit of white exposed which will get burned in six minutes if I'm not careful. I think it's really, really tricky.
Okay. So we're all in for sun tan cream so far. So what about all these chemicals? So recently, for no particularly good scientific reason, I've tended towards the more, the mechanical sun tan creams, so the ones that have things like zinc oxide in.
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And the reason I like those is I kind of -- I read the list of ingredients and I get a warm fuzzy feeling because I sort of know what they are, which doesn't really mean anything at all. Is it possible to say which is best like chemical or mechanical or should we be concerned with any of the ingredients that are in these sun tan creams?
Tommy: I mean, that's a really good question. I don't think that we have -- There is no firm evidence that any of the chemicals used in sun tan screen, sun tan lotion or sunscreen, in the doses that we use them are like detrimental to health. But that's the case for a lot of things that may be suspect and floating around in our environment. And so for people who aren't really sure, you get two broad types of sunscreen.
So you either get a minimal based type, which has something like titanium dioxide or zinc oxide, and they're kind of what you use to reflect the sunlight or they absorb the sunlight. Or you can have organic chemicals as UV filters and they could be things like para-aminobenzoic acid derivatives or things called cinnamates or benzophenones or octocrylenes and your list--
Christopher: That's exactly what I'm talking about. I can't even pronounce them when I read the list of ingredients. Whereas, the zinc oxide stuff -- So when I think of that, I think of cricketers with a ludicrous stuff on their nose. That's the mechanical sun tan cream.
Tommy: Yeah, absolutely. So there's been a lot of worry about the organic chemicals and that's because a lot of them -- We talk a lot about endocrine disruptors at the moment and all these chemicals are sort of getting into the body and they can kind of interfere particularly with our sex hormones, testosterone and estrogen and progesterone, all that stuff. And a lot of the chemicals that are in the sunscreen, say something like the cinnamates, methyl cinnamate, they do have the potential to cause endocrine disruption.
And we know that from rat studies. And I say that because as soon as you talk about rat studies, you have to be kind of wary. And that's because -- So if you're looking at something like a cinnamate, the study which shows that it affects fertility, so it interferes with hormones is when you're putting huge doses into the rat's water over a long period of time. And all this stuff, all these endocrine receptors, the dose definitely makes the poison. And I think the best studies and the best reviews of all the studies that I've just sort of talked about, you need to minimize your total exposure.
So something like sunscreen may not be a huge amount of exposure but if you're also microwaving meals in plastic and drinking lots of bottled water and you use a lot of products on your skin anyway that might contain some of these things then the dose is kind of, they all add up. So sunscreen by itself is maybe not an issue but I personally, if I had to pick one, I'd probably go something like zinc oxide or titanium dioxide.
And there's been some scares about those that we can kind of talk about as well but I would definitely, I would tend towards those because I know that they're very minimally absorbed from the skin compared to some of those other chemicals which are fat soluble and they can kind of end up in the body.
Christopher: Okay. So I'm right in thinking then that lovely smell of sun tan cream that reminds of you being on holiday in Spain as a child is, in fact, the smell of your testosterone going down.
Tommy: Yes, something like that, maybe if you're using huge, huge doses, then there's absolutely -- There is potential for that. We're seeing more and more of these chemicals in the environment can have these effects. And they all add up. So individually, maybe not an issue but if you're exposing yourself to a lot then potentially you can have those problems.
Christopher: Okay. Yeah, I've definitely noticed like over the last year especially I've become a little bit of a soap dodger because of all the stuff that I've been finding out about these things. You look at your list of ingredients and things and you think, "Do I really need that?" And I've noticed that Julie, my wife, has been doing the same. And so we're just using less and less of these products. And we use washing powder that's like some natural whatever organic thing. And it's true that it doesn't actually do a very good job of cleaning the clothes.
I think it has fewer of these offensive chemicals in which could potentially be endocrine disruptors or something else bad. So maybe we are reducing our overall burden. But then the weirdest thing is you come to the UK, everybody stinks. Like it is unbelievable like the amount of stuff that people use when you kind of not had it for a while. I walked through Heathrow Airport and just the smell of all these different perfumes and aftershaves, Julie and I are just gagging because it's so strong. It's really weird, kind of how culturally we become sort of used to the stinking of flowers and essential oils and other weird things.
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It just becomes the new norm. I think that's a bad thing. people just have natural smells and we should just get on with it.
Tommy: Yeah. I'm tempted to agree with you. Obviously, if you're not very good at your general cleanliness the rest of the time then that can dramatically reduce the number of people that want to be friends with you.
Christopher: I've never had any friends to begin with, so I'm not really worried about that.
Tommy: Yeah, that's fine. If you have sort of your happy smelly family then no one would really mind.
Christopher: Yeah, I know. It's fine. Yeah, it's weird. It's kind of like -- I feel like I stink less as well now that I don't eat so much food that doesn't agree with me. It's like the easiest way to summarize it. Before, if I was to forget to put on deodorant, I would get to 3 o'clock in the afternoon and I would know. It would be horrendous. I have to go home and have a shower and put some on. Whereas now, I can go a whole week just having cold showers once a day. And that's a good thing, I think, for another reason.
In California, there's a bit of a drought and whatever. I don't know whether that makes a meaningful contribution. But it makes a contribution in my head that I'm not using, taking 20-minute hot showers. So I'm in and out of the cold water in probably two minutes. I don't really feel like I stink that much. My wife doesn't tell me that I stink. I don't know whether that's because she can't smell because of her own stink but I'm pretty sure she would tell me if I did.
Tommy: But that could -- I mean, there's a lot of people talking about the skin microbiome now as well. And if you actually culture sort of a healthy skin microbiome and then they kind of eat up a lot of the stuff that can accumulate under your -- So some of the smells you get, say on the armpits and stuff are due to certain bacteria and if you cultivate other, end up having another bacteria then they can sort of neutralize them. So that could potentially be possible as well.
Christopher: Yeah, yeah. So using some of these products then might be a bit like using antibiotics in that they kill some bacteria and leave others alone. And then you might end up with the kind of an overgrowth of one thing and not so much the other and that might be what leads to weird smells and all the other weirdness.
Tommy: Yeah, and then it kind of -- Then it's free forward effect because you end up having to use more to cover the smell and that's definitely possible. I think this is just something that people are really just beginning to look into now. But there are definitely some products now where you can, other than soap, you can get like a probiotic for the skin and subjectively at least, maybe we don't have any sort of real trial dates or anything, people are saying that it sort of helped making them smell less throughout the day.
Christopher: That's definitely another ancestral health thing though. I'm saying it's like kind of -- You can see how this is like, well, it kind of I did well by paying attention to what people didn't have before. Should I think the same way with sun tan cream? But I think the answer is no, that sun tan cream is good. But what about the mechanical, the zinc oxide and the titanium oxide? So is there a chance that those could get into our blood supply or blood stream, sorry, and cause any harm?
Tommy: So this has been looked at a fair amount. So one study, you look at -- So, they looked at -- So, zinc is interesting to want to look at because we have a lot of zinc naturally in the blood. It's a mineral that we need for various things. And so they put basically like a label zinc into a sunscreen and put it on the skin. I think it was twice a day for six days or something. And the amount of zinc that, tagged zinc that ended up in the blood was like less than 1/1000th of the zinc that they were measuring. So it's tiny, tiny amounts. And it's probably not really causing much issue.
The other one that we talked about is titanium dioxide. Titanium dioxide is interesting because it's actually not an inert substance. So you can use it for stuff like -- They use it as a catalyst to break stuff down, so it can break down certain proteins. It's been used to kind of clean sewage water and clean waste water because they can sort of like actively break down things. And there was this -- I think I sent it to you. We were talking about this, Chris. There was this piece on the French news from before where they basically were talking about titanium dioxide and how eight million tons of titanium dioxide ends up in the food and cosmetics industry every year.
And then this stuff gets into the body and accumulates in the brain and all that stuff. And actually, I had a look at this. So they said eight million tons a year. And we only make 293,000 tons of titanium a year, which would be if we turned all into titanium oxide, it will be 471,000 tons of titanium dioxide. So the eight million tons is like way off. There's no way that that much is entering the food and cosmetics supply.
[0:40:03]
And because 80% of our titanium dioxide is used as like a whitener in things like paints and plastics and things like that. So then a much smaller proportion of the total titanium dioxide we use ends up in the food supply. And it is used in some foods because it looks very white. And it's also used in things like washing powders because it makes your clothes look whiter. So I think Krispy Kreme or Dunkin' Donuts used to put titanium dioxide in the outside of their donuts to make them look whiter.
And then so, so then people are worried because it's not like a completely inert substance and then it might end up and sort of cause problems. But when they've looked at whether titanium dioxide gets across the skin, it sort of gets like a little bit into the skin but it doesn't penetrate all the way through and it isn't absorbed. And then if you actually, through the gut is also very, very small amount to absorb and probably to a point where we don't even need to worry about it.
And so but what people are -- The data that people are talking about is where you're basically -- Take a mouse and you make them inhale a huge amount of titanium dioxide -- And I sent one of these studies to my girlfriend who's basically like a world expert on how very, very small things get into the brain. So these are considered nanoparticles. She's an expert in nanoparticles and getting them into the brain.
And when she read this paper, she was like basically you're suffocating them with liquid nanoparticles so it's no wonder that some of them end up in the brain. So these poor mice are just basically being made to inhale these huge amounts of nanoparticles. And then some does end up in the brain but if you put it on the skin and maybe you inhale a little bit of vapor from your sunscreen, most of that is going to settle out before it gets into the lungs. It's not going to get absorbed. It's certainly not going to get into the brain.
So there's really -- I think particularly with titanium dioxide, I don't think we have any evidence that it ends up, if you're putting it on the skin, that it ends up anywhere you don't want it to.
Christopher: So do you think it's a good idea to avoid the sun tan cream sprays rather than the -- So use cream rather than aerosol for whatever the type of sunscreen there is.
Tommy: I think because of the -- Yeah, obviously if you're spraying it then there's an increased chance that you'll breathe it in. But compared to, say, like the mouse lung which is very, very small, the human lung is very, very good at settling stuff out and then coughing it back up. You cough up mucus or whatever. You have a continuous movement of stuff out of the lung the whole time. Your body kind of has these cilia, these little basically like wavy tales on the top of its cells throughout the lungs which kind of like sweeps stuff out of the lung.
So, I mean, I would go for just like a zinc or titanium dioxide based sunscreen that you can just, probably from a lotion that you put on the skin. But even if you were using a spray, the likelihood that you're going to get a big enough dose to get into the lungs that then gets absorbed is very unlikely.
Christopher: Okay. Excellent. I think the point -- That's kind of a lot of information. So we should, I think, provide like a sort of summary wrap up. Back at the beginning, vitamin D really, really important. So what do we think there? There's at least 40, maybe 80 nanograma per milliliter is sufficiency and you can get that checked in the blood test. It's 25-hydroxy vitamin D. It's better to get that from the sun rather than taking supplements. And so that's definitely -- I think that's probably a lifestyle thing in general, isn't it?
If you can get some bright light or sun exposure first thing in the morning and then obviously maximum vitamin D exposure is probably going to happen around noon, then avoid bright light late at night is probably going to help with you sleep anyway so that's kind of a double edged, like a double advantage there by doing that. And then, so the skin cancer part, the main thing we need to worry about is burning, right?
Tommy: Yeah.
Christopher: Whatever you do, don't get burned. And unlike a lot of things, you really are going to have to think ahead. So people worry about dehydration but you probably don't have to worry about dehydration because you're going to get thirsty before you really get dehydrated. Whereas I'm not sure that is true of sunburn, like you could easily get sunburned before you feel anything. So you are going to have to plan ahead. And then the sun tan cream, it sounds like we're in favor of -- This is what I was using already, is the zinc dioxide. The brand I like is made by Badger I believe. You can get it on amazon.com and have to have a look to see what's available in the UK.
[0:45:00]
Yeah, it doesn't work as nicely as the chemical sun tan cream. I'd have to say it kind of goes on thick and it doesn't really rub in and it's definitely visible compared to the chemical screens. But it sounds like it might be better just to reduce our overall burden of like toxic stuff that we're exposed to every day.
Tommy: Yeah.
Christopher: Okay. That's it. We've done it. Wrapped it up.
Tommy: Yeah. I think that's a good point to finish. That was a good point to finish on. If people have any questions about any of this, they can obviously contact us. Chris, you're at nourishbalancethrive.com.
Christopher: Yes, that's correct.
Tommy: And @nourishbalancethrive on Twitter.
Christopher: Yeah, that's right. I think it's actually -- Just email me, chris@nourishbalancethrive.com. That's the easiest. And then if you got any questions, you like us to cover different topic in the future episode, then yeah, please do get in touch.
Tommy: Yeah, absolutely. People can also tweet @primaleyemag or me at Dr. Ragnar. And hopefully, Chris and I will be doing more of this. So any random questions about any of this, diet, lifestyle, Paleo, anything like that, let us know and we'll cover them in the future.
Christopher: Excellent.
Tommy: Thanks, Chris.
Christopher: Cheers then.
Tommy: Bye.
[0:46:19] End of Audio
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