Sunscreen: Could It Be Toxic??

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Wait, so the melanocytes, the cells that make the melanin,
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then the melanin is like sunscreen for your DNA, like
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natural sunscreen for your DNA?
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Yeah.
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So like this melanin, it's directly responding to the sun.
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It's moving up there and it's wanting to protect you
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from those UV rays. And in essence, protects you from
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the DNA damage that could cause skin cancer.
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Wow, that's so cool.
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Hi, I'm Wendy Zuckerman, and this is Science Versus. Today
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on the show, we're pitting facts against frying.
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In the sun.
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We're talking about sunscreen. All over social media, people are
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telling you to ditch your sunscreen. They say that it's
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doing us more harm than good. Like, some say that
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if you really want to be healthy, you shouldn't be
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blocking out the sun's gorgeous rays at all.
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You should be going outside.
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And letting the sun help us make that sweet, sweet
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vitamin D.
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No sunscreen, no fear.
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Just me and the light my body was begging for.
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Vitamin D is free, it's powerful, and it's meant for us.
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Others claim that sunscreen itself is straight-up toxic, that it
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seeps dangerous chemicals into our blood and might even be
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messing up our hormones. I'm going to show you what
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they're putting in our sunscreen, and it's going to make
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you just as mad as it's made me. Most people
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don't realize how toxic our sunscreens are.
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Two hours after applying it to the skin... These toxic
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environmental estrogens can actually be detected in the blood. And
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this is exactly why I stopped using toxic sunscreens from
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the grocery store.
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But of course, a lot of us wear sunscreen to
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protect our skin from skin cancer. The problem is that
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now I'm hearing of scientific studies that apparently show sunscreen
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could be causing cancer.
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What is going on here?
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When they compare sunscreen users to non-sunscreen users, the sunscreen
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users faced increased risks of all the major skin cancers.
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We use more of this chemical sunscreen than we ever
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have before.
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Skin cancer rates increasing. You've got to just use your head.
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For a minute.
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All of this has led people to say, stop buying sunscreen.
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Or online, you can even find people giving recipes on
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how to make your own sunscreen at home.
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This is your answer.
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Get that bullshit out of your life and start using
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a really good quality sunscreen.
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So what is going on with sunscreen?
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Should we use it or not?
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Is it making us vitamin D deficient and leaching toxins
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in our blood? And if we still want to use it,
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are some sunscreens safer than others?
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When it comes to sunscreen, there's a lot of.
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Most people don't realise how toxic our sunscreens are.
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But then there's science. Science vs.
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Sunscreen is coming up just after the break. If you
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have a friend who's worried about sunscreen, maybe share them
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this episode.
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Welcome back.
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Today on the show, we are looking into whether sunscreens
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are dangerous.
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Should we be slapping them on our bodies?
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To tell us all about it is producer at Science Versus,
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Michelle Dang.
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Hey, Wendy.
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Michelle, this question of whether sunscreen is safe has been
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in the zeitgeist for so long.
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I feel like you've wanted to do this episode for ages.
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Yeah, I think I pitched it like seven years ago
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when I was an intern.
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Wow, no, did you really?
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So it's taken us a while, but we're coming back
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to it.
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I know, and you know, as you've been sort of
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getting whispers of the science that you've been finding, and
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it's making me wonder, you know, have I just been...
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swallowed by big sunscreen, by the sunscreen propaganda machine. It's
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making me question everything I think I know about sunscreen.
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I do always hear online Australians talking about Sid the Seagull?
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The Seagull?
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What, you got a problem with Sid now? The Seagull?
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No, tell me more. But the uninitiated Sid the Seagull
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was this seagull that for decades has taught Australians how
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you got to put sunscreen on and more broadly protect
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yourself from the sun. And Sid would tell us, and
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he says, you got to slip, slop, slap. So you
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slip on a t-shirt, you slap on a hat and
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you slop on some sunscreen.
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I thought it was all like slip, slop, slop, sunscreen.
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Yeah, it's a whole array of things you've got to do.
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Have I been lied to all my life?
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I mean, presumably sunscreen is protecting my.
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Skin, but now we're sort of hearing that it's also
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getting into my body, these chemicals from the sunscreen getting
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into my body, causing damage.
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So what's going on? Where do we begin?
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Yeah, let's start there about all these claims about sunscreen
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being toxic for us. And so people will often point
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to all these active ingredients that we find in sunscreens.
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And there is this one ingredient in particular that I
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want to focus on called oxybenzone. This one people are
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particularly worked up about.
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Oxybenzone.
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Okay.
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What is it actually doing in the sunscreen? Why is
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it there to begin with?
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So it's one of the ingredients that's there to literally
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help filter out the sun.
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Right.
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The UV rays.
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Right.
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And why are people worried about it?
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Yeah, so some of these worries about oxybenzone go back years,
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even decades. So for example, I want to tell you
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about this one study that came out in 2001 that
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looked at rats and oxybenzone.
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Okay.
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So in this study, scientists took a bunch of young
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female rats and exposed them to the chemical. And what
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they found was that it made their uteruses grow bigger
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and not in a good way.
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Okay. So this suggested.
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That chemicals like oxybenzone were acting like estrogen or essentially
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hormone disruptors.
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Oh.
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This really freaked people out. It's been a very widely
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cited study.
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Yeah. Yeah, I'll bet. But of course, it's just, you know, rat.
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I mean.
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Yeah, it's.
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Not just that it's just in a rat.
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There's a couple other things that were going on that
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don't mimic how we as humans use sunscreen, for example.
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Oh.
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They made the rats eat the sunscreen chemicals. They basically
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spiked their rat chow with it.
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Uh-huh. I was going to ask, did they put it
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on their fur? But so they were eating the chemicals.
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That's not how we do it. And then how much
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of the stuff were they getting in their bodies? Is
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it at all related to what I might get if
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I absorb it through my skin?
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That's the next point. They gave them a lot of it.
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So I talked about this with Dr.
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Brandon Adler from Keck Medicine of the University of Southern California.
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And he told me that it would take a long
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time to get this level.
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Of exposure that the rats did.
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Looking at humans, it was estimated that it would take
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anywhere between about 35 and 277 years of use. of
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oxybenzone-containing sunscreen.
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Oh my gosh.
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Anywhere between 35 and 277 years. And the shortest scenario
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would require applying sunscreen to absolutely every part of our bodies.
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Right.
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So this is a classic case of the dose makes
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the poison. And Brandon's basically saying these were unrealistic levels
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of these chemicals. Even for me, avid sunscreen user, I
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wouldn't be getting this much. sunscreen into my system in
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such a short space of time.
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Right exactly yeah yeah okay and it's a study in
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rats so do we have anything in people that's more
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realistic that can help us understand if these chemicals are dangerous.
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Right yeah so to get to the bottom of this
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i want to tell you about these couple of fda
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studies that came out right before the pandemic and they
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did what are called maximum usage trials where they bring
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people into the lab And over multiple days, they slather
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sunscreen like.
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All over their bodies.
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Sounds fun. It's like my dream.
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Here's Brandon.
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So sunscreen was applied to 75% of the body surface area.
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If you look at a chart of what that means,
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that is a lot of your body. That's essentially everywhere
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besides maybe your bikini zone.
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How many weeks were they getting that sunscreen on for?
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Four or five days total in the lab.
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And then what did the researchers do next?
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So then they measured their blood throughout that study, but
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also 21 days afterward. And they looked to see how
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much of this chemical was showing up in the blood.
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And we did see oxybenzone there. And it was in
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a high enough level that it passed this FDA threshold.
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And this is something that people online really love to
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point out.
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Now, it's very easy for this to lead to headlines, right?
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Sunscreens are absorbed into the body and then you very,
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very quickly get words like toxic and dangerous to get
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thrown out.
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I mean, yeah, it doesn't sound great.
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Yeah, that our body is absorbing these and 21 days
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later they're found in our blood at all.
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I don't love. I know, it's kind of icky. And
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then at some.
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Increased threshold level, obviously our scientist friend doesn't sound concerned.
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Oh, so like those FDA studies, that threshold was very misleading.
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People kind of took that and ran with it and
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said like, hey, look, sunscreen is toxic.
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Yeah, yeah.
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But the threshold in those studies didn't actually suggest danger
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at all.
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In fact, the FDA concluded that study, quote, these findings
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do not indicate that individuals should refrain from the use
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of sunscreen, end quote.
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So if they were at very high levels, toxic, dangerous levels.
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what would you start to see?
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Yeah, so I found this systematic review of around 30 studies.
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And they looked at, like, studies are kind of trying
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to find out, like, does oxybenzone actually affect our hormone levels?
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Okay.
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And what they concluded was that there's no clear evidence
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in the literature that oxybenzone actually harms us.
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Uh-huh. So it looks like at the doses that most
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people are getting their sunscreen at, We don't need to
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worry here.
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Exactly.
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Yeah.
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And what about the coral reef? People are very worried
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about the coral reef.
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Your sunscreen is killing the coral reefs.
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Oxymenzone, which has been known to bleach our coral reefs.
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It can damage coral reefs and wildlife, so you don't
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want to do that.
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So do I need to worry about that?
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Yeah.
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So oxybenzone is one of those chemicals that has been
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banned in places like Hawaii. Because they're worried about their
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coral reefs? Yeah, they're worried about their coral and the bleaching.
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When you take a closer look at these studies, the
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science is also a bit more nuanced. Scientists would bring
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young coral into the lab and then expose them to
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these sunscreen chemicals and find that it was toxic to
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their DNA.
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It caused coral bleaching.
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But when you look in a real-world setting and actually
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measure the amount of this stuff that's floating around in
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the ocean, we don't see it in nearly as high
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scary levels.
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Mm-hmm. It's all about the dose.
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Yes. It's all about the dose, whether you're talking about
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the coral, whether you're talking about the people. Mm-hmm.
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We know beyond a shadow of a doubt that the
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primary cause of coral bleaching is climate change, right? That's
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been shown now. It has been suggested by more realistic
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and moderate studies that sunscreen exposure, especially oxybenzone, may add
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what they call insult to injury. But it's certainly not
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the primary cause of the decimation of coral reefs.
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That we've been seeing.
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Guys, it's climate change.
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But despite that, all of these studies did lead to
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some changes. A bunch of manufacturers have taken out this
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chemical oxybenzone from their sunscreens anyway. because people just weren't
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buying them from the shelf anymore.
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Oh, okay. Because consumers didn't want it. And so what
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are they putting in the sunscreen these days? Should we
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be worried about that?
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Well, here's the thing.
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People are worried about all the other ingredients that come
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in sunscreens. There's a bunch of other chemicals that also
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showed up in these same studies. But the story is
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pretty much the same. They do get into our blood,
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but we have no evidence that they hurt us. And
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as someone who has dug into the research, Brandon isn't
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worried about them.
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I have chemical sunscreens on my face right now. I
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was outside this morning in the early morning sun, and
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I applied chemical sunscreens. So I personally do not believe
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that there is a significant risk with routine use of
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these ingredients.
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And he said chemical sunscreen. Aren't all sunscreens chemical sunscreens?
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So they can break down into like two major pools.
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There's chemical sunscreens and then there's mineral sunscreens.
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Oh, yes.
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I have heard this. Sounds like marketing fluff.
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No, mineral sunscreens are legit.
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Are they really? What is the difference?
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It's like it's all a chemical. But mineral sounds, you know,
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like a nicer chemical you'd get at a spa.
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Yeah, I mean, it's a little, to get a bit nerdier,
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the chemical sunscreens have organic molecules in them and the
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mineral sunscreens have inorganic ones.
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These are things like zinc oxide.
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So by organic chemical, just because I don't want the
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audience thinking that means it doesn't have pesticides in it,
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you mean it's carbon-based?
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Yeah.
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Okay, and then inorganic, like zinc oxide, no carbon in there.
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And are they better?
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So the people who.
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or maybe still freaked out about the fact that chemical
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sunscreens get into your blood at all. Mineral sunscreens are
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the other option because they more so like sit on
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the surface of your skin and they don't go down
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into your blood in the same way as those chemical
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sunscreen ingredients. However, they are more likely to give you
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a white cast.
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They leave a white cast on your skin.
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And then these DIY sunscreens that people are making.
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I mean, do they work?
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Yeah, I was curious about that too. So I asked Brandon.
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00:15:33.960 --> 00:15:37.039
And what I'm seeing more and more is that whenever
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an ingredient or a product gets called toxic, the next
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sentence is, let me sell you a non-toxic alternative. And
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00:15:46.370 --> 00:15:50.830
this is when we get into homemade recipes for sunscreens
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that we're finding on the internet and People are turning
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00:15:54.330 --> 00:15:58.539
to making their own sunscreens with zinc oxide and beef tallow.
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00:15:59.080 --> 00:16:02.289
How are they getting their zinc oxide from sunscreen? Is
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00:16:02.389 --> 00:16:04.169
this like the Simpsons? You made a spoon out of
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a bigger spoon?
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00:16:05.230 --> 00:16:07.070
I got to process that for a second. You made
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a spoon out of a bigger spoon. I guess they're
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00:16:11.460 --> 00:16:13.899
buying the mineral.
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You took sunscreen and then made a different sunscreen out
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00:16:17.019 --> 00:16:17.279
of it?
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You just added beef tallow to the sunscreen you bought
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at the store?
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00:16:20.460 --> 00:16:22.919
I actually found one study that looked into these kind
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00:16:22.940 --> 00:16:26.830
of online recipes. What they did was find 15 recipes
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00:16:26.889 --> 00:16:30.870
from online recipes And they whipped them up in the
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00:16:30.909 --> 00:16:32.450
lab and then tested them out.
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00:16:33.090 --> 00:16:34.500
Ooh, and what did they find?
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00:16:34.649 --> 00:16:36.360
It turns out a few of them didn't even have
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anything in them that could act as a sunscreen. And
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00:16:41.059 --> 00:16:43.720
then the rest were less than an SPF of 6.
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00:16:43.720 --> 00:16:47.500
Uh-huh, which is unlikely to help you.
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00:16:47.519 --> 00:16:48.860
It's not going to help you, yeah.
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00:16:49.600 --> 00:16:53.840
When people have looked at how effective these homemade sunscreens are,
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00:16:53.899 --> 00:16:55.620
they really aren't at all.
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00:16:56.580 --> 00:16:59.929
So don't DIY your sunscreen. No shockers there.
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00:17:00.149 --> 00:17:02.580
For those of us in the US, there is some
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00:17:02.679 --> 00:17:07.380
sunscreen news. There was this chemical sunscreen ingredient that was
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00:17:07.440 --> 00:17:11.990
recently approved. It's called Bemotrizinol, and it's the first sunscreen
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00:17:12.009 --> 00:17:14.349
ingredient that we've gotten approved in like 20 years.
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00:17:14.880 --> 00:17:15.819
Wow.
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00:17:16.130 --> 00:17:19.359
Good job. Good work, guys. It's been in Australia for
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a while, this ingredient, and Europe.
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00:17:21.420 --> 00:17:24.960
But why are people getting excited about it?
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00:17:25.220 --> 00:17:27.319
Yeah, so I talked to Brandon about it, and he
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says it has a lot going for it.
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00:17:29.630 --> 00:17:32.269
I would say the U.S. is just barely catching up.
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00:17:32.769 --> 00:17:36.789
So Bemotrizinol does a great job being a true broad-spectrum
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00:17:36.809 --> 00:17:42.470
sunscreen ingredient. it is very stable and mixable with other
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00:17:42.509 --> 00:17:47.420
sunscreen ingredients, which is a real plus here. And in addition,
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00:17:47.500 --> 00:17:52.240
bematrizinol is a large molecule that is not easily absorbed
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00:17:52.599 --> 00:17:54.019
into the skin or into the body.
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00:17:55.000 --> 00:17:58.579
So, okay, so it doesn't get absorbed too much. So
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00:17:58.640 --> 00:18:00.740
it's kind of like the mineral sunscreens. What are some
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00:18:00.779 --> 00:18:01.359
other benefits?
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00:18:02.000 --> 00:18:04.440
So it's very stable.
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00:18:04.519 --> 00:18:06.730
So the sun, like, You know how you have to
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00:18:06.769 --> 00:18:10.240
reapply sunscreen every couple of hours. But this means that
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00:18:10.259 --> 00:18:12.000
it's a little bit more stable. It's probably going to
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00:18:12.039 --> 00:18:14.720
protect you for a little longer. So kind of guarantee
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00:18:14.759 --> 00:18:18.519
your safety a bit more. And then it also, if
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00:18:19.599 --> 00:18:22.960
you've heard about like European and Asian sunscreens being like
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00:18:23.079 --> 00:18:27.089
really nice and easy to sort of like rub into
361
00:18:27.130 --> 00:18:30.190
your skin, just like applies really nicely and finely.
362
00:18:30.849 --> 00:18:32.269
Why are you laughing?
363
00:18:32.369 --> 00:18:36.670
It just feels like this classic, like the grass is greener.
364
00:18:37.250 --> 00:18:39.730
Over there, they have the best sunscreens in the world.
365
00:18:39.829 --> 00:18:42.170
It's true, though. Have you tried Korean sunscreen?
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00:18:44.150 --> 00:18:46.490
I guess I've traveled. I just shove it on my face.
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00:18:46.589 --> 00:18:47.710
I don't think too deeply.
368
00:18:47.730 --> 00:18:47.809
Yeah.
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00:18:48.789 --> 00:18:50.829
I mean, maybe you've had the good one all along, though.
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00:18:51.089 --> 00:18:52.390
It's true. It's true.
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00:18:52.410 --> 00:18:54.450
It's been 20 years and we've been without it.
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00:18:55.190 --> 00:18:58.259
Okay. It's true. So it rubs it nicer.
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00:18:58.720 --> 00:18:58.960
Yeah.
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00:18:59.259 --> 00:19:02.680
And... Then when you have studies look to see if
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00:19:02.740 --> 00:19:03.799
it gets into your blood?
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00:19:04.220 --> 00:19:07.079
Yeah, there's been studies and it does not get into
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00:19:07.140 --> 00:19:09.960
the blood in the same way. It sits on top
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00:19:10.099 --> 00:19:11.579
more like the mineral sunscreens.
379
00:19:11.900 --> 00:19:14.380
Oh, awesome. So will you be buying that one now?
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00:19:14.640 --> 00:19:16.450
Yeah, for sure. I'm going to keep an eye out
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00:19:16.490 --> 00:19:16.750
for it.
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00:19:18.109 --> 00:19:22.250
Okay, so here's where we're at so far. Your sunscreen
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00:19:22.410 --> 00:19:25.690
is not toxic, although... It.
384
00:19:25.700 --> 00:19:29.210
Does have chemicals in it that, depending on the kind
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00:19:29.250 --> 00:19:32.029
of sunscreen you get, may turn up in your blood.
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00:19:33.150 --> 00:19:39.329
And in super high doses, that can cause trouble, particularly
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00:19:39.369 --> 00:19:41.789
in rats or in rat studies.
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00:19:42.630 --> 00:19:45.230
But most of us, all of us, are probably not
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00:19:45.250 --> 00:19:47.490
getting those high scary doses.
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00:19:49.109 --> 00:19:49.980
So, so far.
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00:19:50.589 --> 00:19:53.960
I'm sticking with my sunscreen.
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00:19:53.240 --> 00:19:54.799
Regime, Michelle.
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00:19:54.819 --> 00:19:55.880
Okay, sounds good.
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00:19:55.980 --> 00:19:57.880
But what's coming up after the break?
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00:19:58.299 --> 00:20:01.240
After the break, we're going to be looking at vitamin D.
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00:20:01.259 --> 00:20:02.009
Ooh.
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00:20:02.309 --> 00:20:02.549
Ooh.
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00:20:04.019 --> 00:20:09.170
Yes, because that could change things for me. I have
399
00:20:09.369 --> 00:20:13.710
always wondered, am I blocking out too much of the
400
00:20:13.769 --> 00:20:16.750
sun's rays? Am I lowering my vitamin D.
401
00:20:16.589 --> 00:20:17.359
Levels too much?
402
00:20:17.380 --> 00:20:18.680
Yeah, with your sunscreen, right?
403
00:20:18.720 --> 00:20:18.940
Yeah.
404
00:20:19.200 --> 00:20:19.500
Yeah.
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00:20:20.180 --> 00:20:22.099
And while we're heading into the break, if you have
406
00:20:22.140 --> 00:20:33.259
a friend who's afraid of sunscreen, maybe send them this episode. Hey,
407
00:20:33.599 --> 00:20:35.759
it's Wendy from Science Versus, and I want to tell
408
00:20:35.799 --> 00:20:39.240
you about a podcast that I love, Science Friday. They
409
00:20:39.259 --> 00:20:41.809
cover all sorts of amazing things in the weird and
410
00:20:41.970 --> 00:20:46.150
wonderful world of science, from how concussions affect our brain
411
00:20:46.289 --> 00:20:49.430
to the inner secrets of a snake with a spider
412
00:20:49.569 --> 00:20:50.369
on its tail.
413
00:20:50.470 --> 00:20:52.759
It's a lot of news that you can use and
414
00:20:52.799 --> 00:20:54.859
some that you can't, but you're going to love anyway.
415
00:20:55.079 --> 00:20:58.759
It's hosted by Ira Flato and Phyllis. Flora Lichtman, who.
416
00:20:58.680 --> 00:21:01.220
Is an old friend of the show and loves a
417
00:21:01.240 --> 00:21:03.940
pun as much as we do. Science Friday is on
418
00:21:04.140 --> 00:21:06.440
every day wherever you get your podcasts.
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00:21:15.160 --> 00:21:15.660
Welcome back.
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00:21:15.700 --> 00:21:19.039
Today on the show, we're talking all about sunscreen. Should
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00:21:19.059 --> 00:21:23.589
you stop wearing it? Next up, vitamin D. We know
422
00:21:23.619 --> 00:21:27.359
it's important. Is sunscreen the reason? that your vitamin D
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00:21:27.380 --> 00:21:31.319
levels are too low. Michelle Dang, producer at Science Versus,
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00:21:32.180 --> 00:21:32.980
tell us the science.
425
00:21:33.569 --> 00:21:36.769
Yeah, so let's start with why vitamin D is so important.
426
00:21:37.630 --> 00:21:41.470
It's like this middle manager that helps calcium get absorbed
427
00:21:41.490 --> 00:21:42.089
into our gut.
428
00:21:42.630 --> 00:21:45.309
And we need calcium to keep our bones strong, right?
429
00:21:46.170 --> 00:21:49.920
So a really bad vitamin D deficiency actually can make
430
00:21:49.960 --> 00:21:54.019
your bones start to become soft and even break more often.
431
00:21:54.039 --> 00:21:54.109
Ooh.
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00:21:55.160 --> 00:21:58.319
And this can manifest as a disease called rickets in
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00:21:58.400 --> 00:22:02.619
kids or osteomalacia in adults. So I talked about this
434
00:22:02.640 --> 00:22:07.180
with Professor Rachel Neal from QIMR Berghofer Medical Research Institute
435
00:22:07.329 --> 00:22:10.720
in Australia. And she was like, yeah, you really don't
436
00:22:10.769 --> 00:22:11.809
want to go through this.
437
00:22:12.509 --> 00:22:17.369
So certainly being really badly vitamin D deficient, that's worrying
438
00:22:17.430 --> 00:22:19.049
and that needs to be corrected rapidly.
439
00:22:20.210 --> 00:22:22.529
Yeah. I mean, vitamin D deficiency has also been linked
440
00:22:22.549 --> 00:22:25.000
to a bunch of chronic diseases, right?
441
00:22:25.259 --> 00:22:27.039
Yeah, we think it might play a role in the
442
00:22:27.059 --> 00:22:29.559
immune system. And there's a bunch of studies linking it
443
00:22:29.599 --> 00:22:35.779
with things like having worse COVID, worse cancer outcomes, multiple sclerosis.
444
00:22:36.119 --> 00:22:39.440
Yeah, so super important. So is wearing sunscreen a risk
445
00:22:39.500 --> 00:22:40.039
factor here?
446
00:22:40.559 --> 00:22:40.920
Yeah.
447
00:22:40.960 --> 00:22:44.559
So, you know, we get some vitamin D from our food,
448
00:22:44.880 --> 00:22:46.799
but most of it we get from the sun.
449
00:22:46.819 --> 00:22:50.079
And so how exactly does that happen? Does the sun...
450
00:22:51.119 --> 00:22:53.309
Stimulate vitamin D in us.
451
00:22:53.789 --> 00:22:57.130
Yeah, so it's super cool. And it's one of the
452
00:22:57.190 --> 00:22:59.089
only vitamins that our body can actually make.
453
00:23:00.170 --> 00:23:02.569
And it happens from the sun, which is just crazy.
454
00:23:03.670 --> 00:23:06.539
So what happens is that the rays from the sun
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00:23:06.559 --> 00:23:11.440
hit our skin cells. And inside our skin cells, there's
456
00:23:11.799 --> 00:23:16.200
this chemical that's a cholesterol. And when the UV rays
457
00:23:16.390 --> 00:23:20.289
hit that chemical... it changes shape a couple of times
458
00:23:20.380 --> 00:23:24.769
from the energy. And then that molecule goes on to
459
00:23:24.809 --> 00:23:29.250
become vitamin D. It leaves the skin, goes into our blood,
460
00:23:29.930 --> 00:23:32.069
and then here's Rachel to tell you about the rest.
461
00:23:32.539 --> 00:23:35.319
It gets carried in our bloodstream to the liver, and
462
00:23:35.339 --> 00:23:37.940
then that molecule gets carried to the kidneys and to
463
00:23:38.039 --> 00:23:40.339
other cells to become the active form of vitamin D
464
00:23:40.359 --> 00:23:41.640
so it can do what it needs to do.
465
00:23:43.180 --> 00:23:44.380
Okay, so how much.
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00:23:45.700 --> 00:23:49.930
sunlight do we need to get enough vitamin D in
467
00:23:50.009 --> 00:23:50.509
our lives?
468
00:23:50.990 --> 00:23:54.470
Yeah, so it can depend on several different things, like
469
00:23:54.970 --> 00:23:57.130
where you live, the time of the day, the time
470
00:23:57.150 --> 00:24:01.089
of the season. But just for example, it can be
471
00:24:01.230 --> 00:24:04.670
really fast. Rachel told me if you went out in
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00:24:05.069 --> 00:24:07.529
the middle of a summer day in Brisbane on the
473
00:24:07.589 --> 00:24:10.019
east coast of Australia, it takes.
474
00:24:09.859 --> 00:24:13.220
About Five minutes wearing shorts and a t-shirt. Wow, that's
475
00:24:13.259 --> 00:24:13.759
really quick.
476
00:24:14.259 --> 00:24:15.359
It's not long, yeah.
477
00:24:16.180 --> 00:24:19.740
Now that's if you have pale skin like Rachel. And
478
00:24:20.099 --> 00:24:22.039
another important part here is if you have darker skin,
479
00:24:22.180 --> 00:24:25.519
it's going to take longer, about 20 minutes under the
480
00:24:25.539 --> 00:24:26.339
same conditions.
481
00:24:27.259 --> 00:24:29.960
To get enough vitamin D for your daily needs.
482
00:24:30.940 --> 00:24:32.059
And that's in Australia.
483
00:24:32.079 --> 00:24:35.180
There are probably across different places in the world. If
484
00:24:35.200 --> 00:24:38.009
you're looking at summer and you're looking at midday, you
485
00:24:38.029 --> 00:24:38.869
see a similar thing.
486
00:24:39.660 --> 00:24:40.079
Okay.
487
00:24:40.140 --> 00:24:42.960
Winter, it's going to take longer. 6 a.m., it's going
488
00:24:42.980 --> 00:24:43.539
to take longer.
489
00:24:43.819 --> 00:24:47.980
But it's not huge amounts of time. So does.
490
00:24:49.160 --> 00:24:54.430
Sunscreen affect this or do you kind of just get
491
00:24:54.509 --> 00:24:57.329
enough sun even if you put sunscreen on to get
492
00:24:57.609 --> 00:24:58.630
your vitamin D needs?
493
00:24:59.650 --> 00:25:03.710
It's a valid question because The same exact UV ray
494
00:25:03.869 --> 00:25:07.250
that we need to create vitamin D, it's called UVB rays,
495
00:25:08.250 --> 00:25:11.819
is the same exact one that sunscreen is designed to block.
496
00:25:13.519 --> 00:25:16.440
So let me tell you about a study that we have,
497
00:25:16.539 --> 00:25:20.119
which was done by Rachel and her team, where they
498
00:25:20.140 --> 00:25:23.319
wanted to test this all out. Does sunscreen affect your
499
00:25:23.359 --> 00:25:26.400
vitamin D levels? And so they did this study in Australia.
500
00:25:27.200 --> 00:25:30.039
And they gathered 600 people for it who said that
501
00:25:30.059 --> 00:25:33.950
they don't wear sunscreen that often, about two or less
502
00:25:33.990 --> 00:25:37.910
times a week. And then they split them into two
503
00:25:38.049 --> 00:25:41.750
different groups. One of them, they told, like, just carry
504
00:25:41.809 --> 00:25:42.430
on as usual.
505
00:25:42.450 --> 00:25:43.829
Do what you're doing.
506
00:25:44.930 --> 00:25:48.259
The other group was told to put on sunscreen in
507
00:25:48.279 --> 00:25:52.140
the morning every time it was forecasted that the sun
508
00:25:52.180 --> 00:25:54.160
was going to be strong enough to.
509
00:25:54.180 --> 00:25:55.000
Harm their skin.
510
00:25:55.019 --> 00:25:55.740
Okay.
511
00:25:55.759 --> 00:25:56.059
Okay.
512
00:25:56.490 --> 00:25:59.009
And for the sunscreen nerds out there, that's when the
513
00:25:59.130 --> 00:26:01.309
UV index is at.
514
00:26:01.329 --> 00:26:04.509
UV3. Or higher. Yes, you got it. Okay.
515
00:26:04.730 --> 00:26:07.339
And that's pretty much every day in Australia except for
516
00:26:07.359 --> 00:26:07.740
the winter.
517
00:26:07.759 --> 00:26:09.279
Uh-huh.
518
00:26:09.559 --> 00:26:12.740
So on these days, the sunscreen group were told to
519
00:26:12.779 --> 00:26:16.680
wear SPF 50 sunscreen. And they had to wear it
520
00:26:16.839 --> 00:26:20.970
everywhere that they had skin exposed to. And to make
521
00:26:21.039 --> 00:26:23.339
sure that they actually used it when they were supposed to,
522
00:26:23.559 --> 00:26:24.140
Rachel and her.
523
00:26:24.099 --> 00:26:25.910
Team bugged them a lot about it.
524
00:26:26.140 --> 00:26:29.000
We sent them text message reminders every week saying the
525
00:26:29.059 --> 00:26:30.759
UV index is going to get to three this week.
526
00:26:30.799 --> 00:26:33.099
Make sure you use your sunscreen. And we phoned them
527
00:26:33.160 --> 00:26:35.660
and we made sure that they were doing it as
528
00:26:35.720 --> 00:26:36.940
much as they possibly could.
529
00:26:38.519 --> 00:26:40.809
And how long did this go on for? A whole year.
530
00:26:40.829 --> 00:26:42.250
A year?
531
00:26:42.450 --> 00:26:45.950
Wow, what an amazing study. Okay, so what did they find?
532
00:26:46.710 --> 00:26:50.509
So they measured the vitamin D levels at the beginning
533
00:26:50.529 --> 00:26:53.710
of the study, after the summer, and after the winter.
534
00:26:53.730 --> 00:26:57.180
And what they found was that throughout the summer, it
535
00:26:57.220 --> 00:27:00.460
looked like on average, vitamin D levels were fine.
536
00:27:01.039 --> 00:27:03.339
Levels were going up in both groups.
537
00:27:05.259 --> 00:27:08.740
And they didn't see vitamin D deficiencies across the board
538
00:27:08.880 --> 00:27:09.740
in the sunscreen group.
539
00:27:10.099 --> 00:27:11.900
Oh, so in summer.
540
00:27:13.029 --> 00:27:16.250
the groups had the same amount of vitamin D. It
541
00:27:16.289 --> 00:27:20.750
wasn't just that the sunscreen group wasn't deficient. They actually
542
00:27:20.789 --> 00:27:25.049
were all making an equal number on average of vitamin D.
543
00:27:25.069 --> 00:27:29.609
Well, actually, to clarify, the people wearing sunscreen nearly every
544
00:27:29.630 --> 00:27:33.950
day actually made a little bit less vitamin D than.
545
00:27:33.789 --> 00:27:34.450
The control group.
546
00:27:34.859 --> 00:27:35.410
Got it.
547
00:27:35.950 --> 00:27:38.650
And so, you know, people wearing sunscreen were still making,
548
00:27:38.670 --> 00:27:41.930
they were still making vitamin D because... We know that
549
00:27:41.970 --> 00:27:45.269
sunscreen is not like a perfect blocker. It still lets
550
00:27:45.369 --> 00:27:46.230
in some of.
551
00:27:46.210 --> 00:27:49.230
Those UV rays. What happened in winter?
552
00:27:49.250 --> 00:27:52.839
Yeah, so they kept following these people. And by the
553
00:27:52.990 --> 00:27:56.539
end of winter, they did notice something very interesting.
554
00:27:56.980 --> 00:28:01.180
And there was about a 35% increased risk of being
555
00:28:01.220 --> 00:28:04.119
vitamin D deficient at the end of winter in the
556
00:28:04.160 --> 00:28:05.799
sunscreen group than in the control group.
557
00:28:06.529 --> 00:28:09.970
Ooh, I mean, they were really wearing a lot of
558
00:28:10.009 --> 00:28:11.009
sunscreen there.
559
00:28:11.269 --> 00:28:16.359
But what does Rachel make of this? I was really
560
00:28:16.400 --> 00:28:22.619
surprised by the results. Mmm.
561
00:28:22.640 --> 00:28:26.279
Okay. Now, everyone in the study made less vitamin D
562
00:28:26.319 --> 00:28:28.509
in the winter, which is what you'd expect.
563
00:28:28.589 --> 00:28:28.950
Yeah.
564
00:28:29.750 --> 00:28:32.950
But the fact that the sunscreen group made less vitamin
565
00:28:32.970 --> 00:28:35.930
D throughout the summer is what made the difference here.
566
00:28:36.839 --> 00:28:40.049
Because another interesting thing is that our bodies can actually
567
00:28:40.069 --> 00:28:44.210
hold on to vitamin D in our fat tissues and
568
00:28:44.289 --> 00:28:49.670
release it slowly over several months. I asked Rachel, was
569
00:28:49.730 --> 00:28:52.890
it that the daily sunscreen wearers built up less of
570
00:28:52.990 --> 00:28:56.000
a storage, like a store of vitamin D that would
571
00:28:56.059 --> 00:28:57.200
last them through the winter?
572
00:28:57.819 --> 00:28:58.799
Through the winter, correct.
573
00:28:58.859 --> 00:28:59.220
Yeah.
574
00:28:59.240 --> 00:29:02.359
So the store ended up lower at the end of summer,
575
00:29:02.759 --> 00:29:05.390
which meant that as they went down in winter... they
576
00:29:05.470 --> 00:29:07.369
ended up lower at the end of winter. And if
577
00:29:07.390 --> 00:29:10.329
you imagine that that happened year after year after year,
578
00:29:10.890 --> 00:29:14.069
so you've used sunscreen for a year, you're lower in winter,
579
00:29:14.289 --> 00:29:17.339
you go up less in summer because you're using sunscreen
580
00:29:17.359 --> 00:29:19.559
every day. So now your store's even lower than it was.
581
00:29:19.960 --> 00:29:21.420
You end up even lower at the end of the
582
00:29:21.460 --> 00:29:25.400
following winter. So with these repeated yearly cycles, you can
583
00:29:25.460 --> 00:29:27.720
imagine that if you did this all the time, you
584
00:29:27.740 --> 00:29:29.359
could end up quite deficient.
585
00:29:30.059 --> 00:29:34.410
So I guess now we play the game of.
586
00:29:35.549 --> 00:29:38.549
Risks and benefits, Michelle. Do, do, do, do, do, do.
587
00:29:40.059 --> 00:29:43.299
Okay, wearing a lot of sunscreen does put you at
588
00:29:43.319 --> 00:29:48.599
a risk of vitamin D deficiency. But we're not doing
589
00:29:48.640 --> 00:29:51.349
this for fun. We're doing this to protect our skin
590
00:29:51.809 --> 00:29:56.569
from cancer, effects of aging.
591
00:29:56.589 --> 00:29:56.650
So.
592
00:29:59.490 --> 00:30:02.490
Is that still real? Because some people online say even
593
00:30:02.529 --> 00:30:03.170
that's a lie.
594
00:30:03.549 --> 00:30:05.690
So yeah, here's the concern with skin cancer.
595
00:30:05.930 --> 00:30:08.579
Those UV rays from the sun are coming down, hitting
596
00:30:08.630 --> 00:30:11.700
our skin, getting through those cells to the DNA and
597
00:30:12.759 --> 00:30:16.700
causing a mutation in that DNA. And then again, we're
598
00:30:16.720 --> 00:30:17.920
talking about doses.
599
00:30:18.900 --> 00:30:20.019
Repeated exposure to.
600
00:30:19.980 --> 00:30:23.759
The sun can help those mutations accumulate over time.
601
00:30:24.380 --> 00:30:27.319
Yes, yes. This is what we've known for a long time.
602
00:30:27.420 --> 00:30:28.099
So why is.
603
00:30:29.259 --> 00:30:31.380
And then the obvious next step would be if you
604
00:30:31.420 --> 00:30:35.519
can wear sunscreen, block those UV rays, reduce the chance
605
00:30:35.559 --> 00:30:39.430
of DNA damage, you can protect your skin. That's the
606
00:30:39.509 --> 00:30:42.890
line from the health authorities, Michelle.
607
00:30:42.970 --> 00:30:47.309
But what is... Is it true when we look at
608
00:30:47.349 --> 00:30:48.829
the new science?
609
00:30:49.289 --> 00:30:51.609
So when we get into the real world studies, it
610
00:30:51.650 --> 00:30:52.829
gets a little bit messy.
611
00:30:52.849 --> 00:30:53.690
Uh-huh.
612
00:30:54.069 --> 00:30:56.549
The kind where they gather a bunch of people, ask
613
00:30:56.589 --> 00:31:00.509
them about their lifestyle and what they do, whether they
614
00:31:00.529 --> 00:31:03.690
wear sunscreen, and then later look to see, you know,
615
00:31:03.990 --> 00:31:05.279
do they have skin cancer?
616
00:31:05.519 --> 00:31:05.779
Yeah.
617
00:31:06.259 --> 00:31:08.680
And some of these studies find that some people who
618
00:31:08.720 --> 00:31:11.779
wear more sunscreen get less skin cancer.
619
00:31:12.160 --> 00:31:13.480
Yeah, what you'd expect.
620
00:31:13.789 --> 00:31:17.650
But, you know, not every study finds that. People really
621
00:31:17.710 --> 00:31:20.869
like to point to this one study that was done
622
00:31:20.910 --> 00:31:22.410
in 2023 out of the UK.
623
00:31:22.430 --> 00:31:23.269
Okay.
624
00:31:23.650 --> 00:31:27.009
Where it looked at the health data of over 400,000 people.
625
00:31:27.029 --> 00:31:31.250
And it found that people who wear more sunscreen more
626
00:31:31.329 --> 00:31:34.309
often are more likely to get skin cancer.
627
00:31:34.750 --> 00:31:39.630
Wait, so that people who wore more sunscreen were more
628
00:31:39.710 --> 00:31:40.349
likely to get skin cancer?
629
00:31:41.190 --> 00:31:42.549
To get skin cancer.
630
00:31:43.190 --> 00:31:43.450
Mm-hmm.
631
00:31:43.769 --> 00:31:44.009
Yes.
632
00:31:44.670 --> 00:31:50.819
That sounds, big study, 400,000 people. It sounds damning for
633
00:31:51.299 --> 00:31:56.799
the sunscreen propagandists out there like me. But it is
634
00:31:56.839 --> 00:32:00.680
making me wonder, could it be that the people who
635
00:32:00.720 --> 00:32:04.819
were wearing more sunscreen were actually out in the sun
636
00:32:04.880 --> 00:32:09.869
more often and they were badly applying sunscreen and that's why.
637
00:32:11.119 --> 00:32:13.309
they had more skin cancer.
638
00:32:13.339 --> 00:32:15.859
Yeah you are right on track the authors of this
639
00:32:15.900 --> 00:32:18.599
study like came out to say that people online are
640
00:32:18.640 --> 00:32:22.660
misinterpreting this study and even though they found a link
641
00:32:23.079 --> 00:32:26.500
what's likely really happening here is that people who wear
642
00:32:26.539 --> 00:32:28.839
more sunscreen are more likely to go outside and be
643
00:32:28.900 --> 00:32:32.880
outside in the sun but maybe under this like false
644
00:32:32.920 --> 00:32:36.200
security because maybe they're not wearing it enough they're not
645
00:32:36.259 --> 00:32:39.769
wearing enough of it or you know not reapplying and
646
00:32:39.789 --> 00:32:41.470
that kind of thing So do.
647
00:32:41.390 --> 00:32:43.289
We have any better studies here that can help us?
648
00:32:43.970 --> 00:32:44.089
Yeah.
649
00:32:44.109 --> 00:32:47.589
So, Wendy, we actually have one RCT, randomized controlled trial.
650
00:32:47.609 --> 00:32:48.529
Uh-huh.
651
00:32:48.789 --> 00:32:52.549
And this one happened in Australia. It looked at 1,600 people.
652
00:32:53.490 --> 00:32:56.730
And similar to Rachel's study, it split these people into
653
00:32:56.819 --> 00:33:01.000
two different groups. One was given sunscreen and told to
654
00:33:01.059 --> 00:33:03.940
wear it every day. And the other was told to
655
00:33:04.000 --> 00:33:05.819
carry on as usual, do whatever they want.
656
00:33:05.839 --> 00:33:06.660
Okay.
657
00:33:07.119 --> 00:33:10.220
And, Wendy, they followed these people for over a decade.
658
00:33:10.240 --> 00:33:10.319
Okay.
659
00:33:10.779 --> 00:33:11.779
Wow.
660
00:33:12.559 --> 00:33:14.549
This is an amazing study.
661
00:33:14.569 --> 00:33:18.450
This is exactly what we need. 1,600 people followed for a.
662
00:33:18.609 --> 00:33:22.250
Decade because skin cancers can take a while to develop.
663
00:33:22.309 --> 00:33:25.589
So what did they find? Did the sunscreen group get
664
00:33:25.630 --> 00:33:26.299
less cancer?
665
00:33:26.650 --> 00:33:26.980
Yeah.
666
00:33:27.319 --> 00:33:29.359
So they looked to see who in the study got
667
00:33:29.420 --> 00:33:33.799
skin cancer. And there are three main types of skin cancer.
668
00:33:33.859 --> 00:33:39.390
There's squamous cell carcinoma, basal cell carcinoma, And then there's
669
00:33:39.450 --> 00:33:43.049
the scary one, melanoma, which is more likely to spread
670
00:33:43.269 --> 00:33:46.869
and kill you. And what the RCT found was that
671
00:33:46.930 --> 00:33:49.210
the sunscreen worked pretty well for that one type of
672
00:33:49.230 --> 00:33:55.230
skin cancer, squamous cell carcinoma. It basically dropped cases 40%
673
00:33:55.230 --> 00:33:56.279
between the two groups.
674
00:33:57.079 --> 00:33:59.740
Aha, aha, but what about melanoma?
675
00:34:00.000 --> 00:34:03.039
Yeah, so when it came to melanoma, the evidence was
676
00:34:03.180 --> 00:34:08.710
actually less clear. There was 11 people who got melanoma
677
00:34:08.829 --> 00:34:13.010
in the sunscreen group versus 22 in the control group.
678
00:34:13.190 --> 00:34:15.429
That's a 50% lower risk, Michelle.
679
00:34:16.210 --> 00:34:19.210
Yeah, but it actually didn't come out to statistically significant,
680
00:34:19.369 --> 00:34:21.690
probably because the cases were just too low.
681
00:34:23.590 --> 00:34:25.889
Okay. Interesting.
682
00:34:26.150 --> 00:34:29.010
It does seem like then sunscreen is still protecting you
683
00:34:29.070 --> 00:34:29.849
from skin cancer.
684
00:34:29.909 --> 00:34:32.590
That story is still true, even if it's not your
685
00:34:32.650 --> 00:34:33.989
silver bullet, right?
686
00:34:34.010 --> 00:34:36.119
Yeah. And yeah, like the dermatologist I spoke to, they
687
00:34:36.159 --> 00:34:39.340
were like, hey, if we were to redo this study
688
00:34:40.400 --> 00:34:44.090
looking at melanoma, which is the scarier one, maybe the
689
00:34:44.110 --> 00:34:46.750
data would be even stronger today because back then they
690
00:34:46.769 --> 00:34:50.809
were using SPF 16 and now we're using SPF 30,
691
00:34:50.809 --> 00:34:51.809
SPF 50.
692
00:34:51.809 --> 00:34:54.409
And in that study, did it matter about your skin tone?
693
00:34:54.949 --> 00:34:57.159
If you have darker skin or lighter skin, does that
694
00:34:57.199 --> 00:34:59.199
affect your risk here? Yeah.
695
00:34:59.239 --> 00:35:01.820
So here's the thing with that study. Most of the
696
00:35:01.860 --> 00:35:06.219
people in it were white. which brings us to this
697
00:35:06.380 --> 00:35:09.420
other idea where some people say that people with darker
698
00:35:09.460 --> 00:35:11.039
skin don't.
699
00:35:10.880 --> 00:35:12.659
Get the same benefits from sunscreen.
700
00:35:12.940 --> 00:35:13.340
Okay.
701
00:35:13.400 --> 00:35:15.340
Well, we already know if you've got darker skin, you're
702
00:35:15.360 --> 00:35:18.500
at an increased risk of vitamin D deficiency. So if
703
00:35:18.519 --> 00:35:21.769
we're playing this risk-benefit game, got to be some strong
704
00:35:21.809 --> 00:35:25.389
benefits here. Is it true that if you have darker skin,
705
00:35:25.429 --> 00:35:27.429
you're at a lower risk of skin cancer?
706
00:35:27.949 --> 00:35:29.449
So I talked about this with Dr.
707
00:35:29.530 --> 00:35:33.650
Adai Adamson, who's a dermatologist from Dell Medical School at
708
00:35:33.750 --> 00:35:38.170
University of Texas, Austin. And based on Adai's own experiences
709
00:35:38.309 --> 00:35:41.170
in the clinic, like with melanoma, he told me.
710
00:35:41.190 --> 00:35:44.050
Well, one, as a dermatologist, if I just think about
711
00:35:44.449 --> 00:35:50.619
the people that I see, right? And like, maybe I
712
00:35:50.659 --> 00:35:52.739
can only may think of one or two black people
713
00:35:52.820 --> 00:35:55.960
that in, you know, doing this for 15 years, having
714
00:35:56.039 --> 00:35:57.519
actually seen or diagnosed one.
715
00:35:58.179 --> 00:35:58.400
Right?
716
00:35:58.800 --> 00:35:59.440
You don't see it.
717
00:35:59.440 --> 00:36:03.429
A melanoma. He's talking about melanoma specifically?
718
00:36:03.639 --> 00:36:04.389
Yes, exactly.
719
00:36:04.699 --> 00:36:07.510
If you look at the data, people of color do
720
00:36:07.570 --> 00:36:11.530
get melanoma a lot less than white people. For example,
721
00:36:11.690 --> 00:36:15.949
a black person's risk of getting melanoma is 30 to
722
00:36:15.949 --> 00:36:19.690
40 times less than a white person. And that's specifically
723
00:36:19.730 --> 00:36:22.659
the kind that spreads. And not only that, when it
724
00:36:22.800 --> 00:36:26.510
does show up in people with darker skin, it's often
725
00:36:26.590 --> 00:36:28.329
showing up in a very particular way.
726
00:36:28.550 --> 00:36:32.949
You know, people that mostly get melanoma on the palms
727
00:36:32.989 --> 00:36:36.119
of their hands, soles of the feet, places that are
728
00:36:36.539 --> 00:36:37.900
not related to sun exposure.
729
00:36:38.699 --> 00:36:41.000
So all of this was very curious to Ade.
730
00:36:41.420 --> 00:36:43.980
And he wanted to take a step back and understand
731
00:36:44.039 --> 00:36:47.659
whether sun exposure is linked to melanoma and people of
732
00:36:47.719 --> 00:36:50.880
color in the first place. Like, is there a connection
733
00:36:51.000 --> 00:36:53.550
here at all? And so he said.
734
00:36:53.969 --> 00:36:54.369
You know what?
735
00:36:54.889 --> 00:36:57.050
Let me do a systematic review, which is the top
736
00:36:57.269 --> 00:37:01.110
of the evidence pyramid, right? You get all the studies
737
00:37:01.130 --> 00:37:04.469
looking at this and see what comes out of it.
738
00:37:04.769 --> 00:37:08.139
Is there actually data to support UV is an important
739
00:37:08.159 --> 00:37:10.139
risk factor for melanoma.
740
00:37:10.460 --> 00:37:12.699
So they got together this big review on it, and
741
00:37:12.929 --> 00:37:15.789
he and his team wrangled up the data, crunched the numbers,
742
00:37:16.530 --> 00:37:18.690
and the answer to whether or not sun exposure is
743
00:37:18.929 --> 00:37:22.050
linked to melanoma in people of color.
744
00:37:22.570 --> 00:37:26.260
And to sum it up, no, it is not. It
745
00:37:26.320 --> 00:37:31.039
is not in anyone that identifies as non-white. Not Asian,
746
00:37:31.519 --> 00:37:36.760
not Hispanic, not Black, right? There is, there is like,
747
00:37:37.570 --> 00:37:40.889
almost zero data to support that.
748
00:37:41.909 --> 00:37:43.650
Whoa.
749
00:37:44.550 --> 00:37:49.510
And why is that? Is melanin is super protective for melanoma?
750
00:37:49.590 --> 00:37:50.360
What's going on?
751
00:37:50.739 --> 00:37:56.000
Yeah, so that's also really cool what's happening there. No
752
00:37:56.039 --> 00:37:59.920
matter your skin color, we all have these cells in
753
00:37:59.980 --> 00:38:03.630
our skin called melanocytes that make the pigment melanin.
754
00:38:04.670 --> 00:38:06.340
And When we step.
755
00:38:06.179 --> 00:38:10.940
Outside, our melanocytes start pumping out melanin in response to
756
00:38:10.960 --> 00:38:11.300
the sun.
757
00:38:11.519 --> 00:38:12.800
And that's why you tan.
758
00:38:12.969 --> 00:38:15.369
Yeah, over time, you would eventually tan.
759
00:38:15.949 --> 00:38:18.769
But before that, Ade told me that melanin actually gets
760
00:38:18.869 --> 00:38:23.610
packaged up and it makes its way toward the surface
761
00:38:23.829 --> 00:38:24.409
of your skin.
762
00:38:24.429 --> 00:38:28.260
I don't know if you've ever noticed a phenomenon in
763
00:38:28.280 --> 00:38:30.690
the first, you know, 10, 15 minutes of some people
764
00:38:30.730 --> 00:38:34.309
getting some sun. They make it slightly darker. That's your melanin.
765
00:38:34.389 --> 00:38:36.730
If you have enough, at least, that's it moving up
766
00:38:36.909 --> 00:38:40.389
around the cell in order to protect the DNA from
767
00:38:40.949 --> 00:38:44.960
the incoming UV exposure. That's like one immediate response.
768
00:38:46.079 --> 00:38:52.159
Wait, so the melanocytes, the cells that make the melanin,
769
00:38:53.039 --> 00:38:58.510
then the melanin is like sunscreen for your DNA, like
770
00:38:58.650 --> 00:39:00.650
natural sunscreen for your DNA?
771
00:39:00.909 --> 00:39:04.429
Yeah, so like this melanin, it's directly responding to the sun.
772
00:39:04.519 --> 00:39:09.159
It's moving up there, and it's wanting to protect you
773
00:39:09.719 --> 00:39:13.909
from those UV rays and, in essence, protects you from
774
00:39:13.929 --> 00:39:16.550
the DNA damage that could cause skin cancer.
775
00:39:16.570 --> 00:39:19.869
Wow, that's so cool.
776
00:39:19.889 --> 00:39:20.070
Mm-hmm.
777
00:39:20.659 --> 00:39:22.900
And the more the more melanin that you have in
778
00:39:22.940 --> 00:39:26.710
your skin, the more likely it's doing a similar job
779
00:39:26.909 --> 00:39:27.750
to sunscreen.
780
00:39:28.630 --> 00:39:29.250
Here's a day again.
781
00:39:29.860 --> 00:39:35.000
So it is helping absorb some of the harmful effects
782
00:39:35.500 --> 00:39:39.840
that the UV will have on the DNA. And depending
783
00:39:39.920 --> 00:39:43.800
on how dark you are, you can have an SPF
784
00:39:43.820 --> 00:39:48.739
of 15 plus, equivalent at least, if you're of a
785
00:39:48.909 --> 00:39:49.679
darker skin tone.
786
00:39:50.889 --> 00:39:53.030
That's so cool. It is, right?
787
00:39:53.369 --> 00:39:57.309
Yeah. So does this mean if you have a darker
788
00:39:57.329 --> 00:40:00.130
skin tone, then wearing sunscreen is not a good idea
789
00:40:00.170 --> 00:40:03.380
because then you're at an increased risk of vitamin D
790
00:40:03.400 --> 00:40:06.780
deficiency and you don't get this skin cancer benefit? I
791
00:40:06.800 --> 00:40:11.079
guess specifically for melanoma, there are other skin cancers to
792
00:40:11.119 --> 00:40:11.840
worry about.
793
00:40:12.409 --> 00:40:13.590
Yeah, so you're right on track.
794
00:40:13.610 --> 00:40:17.289
Like after studies like A Days came out, Countries like
795
00:40:17.389 --> 00:40:23.449
Australia actually changed their guidance on sunscreen recommendation. So people
796
00:40:23.489 --> 00:40:27.039
that are of the darkest skin types don't routinely need
797
00:40:27.099 --> 00:40:30.800
to wear sunscreen to prevent skin cancer. They classify it
798
00:40:31.000 --> 00:40:35.579
by what's called the Fitzpatrick scale. So there's six different
799
00:40:35.820 --> 00:40:40.550
skin tone types. And the two darkest skin tones are
800
00:40:40.639 --> 00:40:43.929
not recommended to wear sunscreen for skin cancer in Australia.
801
00:40:44.250 --> 00:40:45.670
So we'll throw that up on screen.
802
00:40:46.070 --> 00:40:46.389
Uh-huh.
803
00:40:47.119 --> 00:40:49.179
On the flip side, though, places like the U.S., the
804
00:40:49.199 --> 00:40:53.539
American Academy of Dermatology, haven't changed their guidelines. And this
805
00:40:53.619 --> 00:40:55.780
is something that annoys a day a lot.
806
00:40:56.119 --> 00:40:59.739
We're not science-based. The recommendation is not. And it's also
807
00:40:59.840 --> 00:41:04.329
wild because we're in this era of personalized medicine, right?
808
00:41:05.630 --> 00:41:10.909
There should be personalized risk stratification related to the sun.
809
00:41:12.409 --> 00:41:17.880
Anyone saying sunscreen saves lives for personal color is lying
810
00:41:17.940 --> 00:41:20.769
there's a bald face bald.
811
00:41:20.469 --> 00:41:24.369
Face lie should people of color wear sunscreen then does
812
00:41:24.409 --> 00:41:25.869
this change the equation.
813
00:41:25.429 --> 00:41:28.849
Yeah so i asked today and he said that you
814
00:41:28.869 --> 00:41:33.579
know sunscreen isn't useless like it still prevents sunburn and
815
00:41:33.659 --> 00:41:38.699
could have cosmetic benefits Because we think that melanin better
816
00:41:38.739 --> 00:41:44.179
protects against UVB rays versus UVA. And UVA rays are
817
00:41:44.199 --> 00:41:46.619
the ones that penetrate a little bit deeper into our
818
00:41:46.699 --> 00:41:51.519
skin and messes with things like elastin and collagen and.
819
00:41:51.440 --> 00:41:54.059
Can contribute to an effect of aging.
820
00:41:54.079 --> 00:41:57.099
Okay, and wrinkles and things like that.
821
00:41:57.960 --> 00:42:02.460
I asked Ade, does he still recommend his patients who
822
00:42:02.500 --> 00:42:04.119
are people of color to wear sunscreen?
823
00:42:04.389 --> 00:42:08.309
Sure, I do. Sunscreen has a lot of important uses.
824
00:42:09.070 --> 00:42:12.889
No matter your skin type, you can sunburn, right? That
825
00:42:12.949 --> 00:42:16.550
is possible. People like to use it for anti-aging. But
826
00:42:17.030 --> 00:42:20.130
for listeners that might not see my image, I'm a
827
00:42:20.329 --> 00:42:24.610
black male dermatologist. And so, yeah, I wear sunscreen. I
828
00:42:24.630 --> 00:42:27.650
went to the beach a few weeks ago. I had
829
00:42:27.670 --> 00:42:31.429
sunscreen on. I didn't want to get burned. But do
830
00:42:31.650 --> 00:42:32.269
I wear it daily?
831
00:42:33.070 --> 00:42:34.590
No, I don't.
832
00:42:35.519 --> 00:42:39.929
But that's me. I'm a different risk, say, than somebody
833
00:42:40.369 --> 00:42:42.630
that looks like Pippi Longstocking.
834
00:42:46.670 --> 00:42:52.659
And I guess for anyone worried about a vitamin D deficiency,
835
00:42:53.159 --> 00:42:56.539
no matter your skin tone, can you just take a
836
00:42:56.579 --> 00:42:59.760
supplement if you still want to wear sunscreen?
837
00:43:01.050 --> 00:43:02.889
Is vitamin D supplementation okay?
838
00:43:03.710 --> 00:43:06.070
Yeah, going back to Rachel Neal, who we heard about
839
00:43:06.130 --> 00:43:09.860
with the vitamin D study, I asked her, like, can
840
00:43:09.880 --> 00:43:13.059
you just take a supplement? And she's like, yes, that's
841
00:43:13.219 --> 00:43:15.969
the easy fix to this if you're worried about it.
842
00:43:16.179 --> 00:43:16.460
Great.
843
00:43:16.679 --> 00:43:16.920
Okay.
844
00:43:17.199 --> 00:43:20.230
Now, Rachel herself, she doesn't look like Pippi Longstocking, but
845
00:43:20.269 --> 00:43:23.829
she does have pretty pale skin. And skin cancer is
846
00:43:23.869 --> 00:43:27.329
something she's very concerned about. She's also had it before.
847
00:43:27.710 --> 00:43:29.369
When I brush my teeth, I put my sunscreen on
848
00:43:29.409 --> 00:43:29.909
every day.
849
00:43:29.929 --> 00:43:29.989
So.
850
00:43:32.219 --> 00:43:34.039
For me, I think that's really important.
851
00:43:34.119 --> 00:43:35.880
We know that that reduces risk of skin cancer, and
852
00:43:35.900 --> 00:43:39.110
I've had three. So I had my first skin cancer
853
00:43:39.139 --> 00:43:42.849
when I was 29, which shows how problematic the Australian
854
00:43:42.869 --> 00:43:45.889
sun can be. And it's the same in other parts
855
00:43:45.909 --> 00:43:49.090
of the world as well, where there's a really high UV,
856
00:43:49.150 --> 00:43:52.280
which means that just popping outdoors is enough to cause damage.
857
00:43:53.400 --> 00:43:56.480
All right, is it time for our sunscreen summary?
858
00:43:56.900 --> 00:43:57.340
Sounds good.
859
00:43:57.840 --> 00:44:03.880
Okay, so sunscreen summary. does have chemicals in it, obviously.
860
00:44:04.719 --> 00:44:06.780
Some of them can get into our blood, but as
861
00:44:06.820 --> 00:44:07.119
far as.
862
00:44:07.099 --> 00:44:10.739
We can tell, they're not causing harm while they're there,
863
00:44:10.760 --> 00:44:15.039
at the doses that they're there. If you are worried
864
00:44:15.079 --> 00:44:18.559
about it, though, you can try mineral sunscreen, which is
865
00:44:18.679 --> 00:44:20.840
more likely to stay on the top of your skin
866
00:44:20.909 --> 00:44:22.130
and not go into your blood.
867
00:44:22.849 --> 00:44:25.849
Sunscreen does increase your risk.
868
00:44:25.789 --> 00:44:31.599
Of having vitamin D deficiency, which is particularly concerning if
869
00:44:31.619 --> 00:44:34.320
you have darker skin, you're at a high risk of that.
870
00:44:35.099 --> 00:44:36.960
On the other hand, if you have darker skin, you
871
00:44:37.179 --> 00:44:40.679
also don't need to worry so much about melanoma and
872
00:44:41.110 --> 00:44:43.710
not great evidence that sunscreen can protect you from that.
873
00:44:43.869 --> 00:44:46.650
But if you have lighter skin, then sunscreen is going
874
00:44:46.670 --> 00:44:47.789
to protect you from skin cancer.
875
00:44:48.269 --> 00:44:49.130
Yeah, you got it.
876
00:44:49.570 --> 00:44:53.389
I think based on all of this, I'm going to
877
00:44:53.489 --> 00:44:57.519
keep wearing my sunscreen. But I am going to start
878
00:44:57.559 --> 00:44:59.159
taking a vitamin D supplement.
879
00:44:59.179 --> 00:44:59.260
Okay.
880
00:44:59.719 --> 00:45:00.820
Yeah, that's good.
881
00:45:01.199 --> 00:45:01.579
All right.
882
00:45:01.780 --> 00:45:03.820
We got a lightning round ready to go?
883
00:45:04.119 --> 00:45:04.360
Yes.
884
00:45:05.050 --> 00:45:08.289
Lightning round, lightning round. It's where we say some quick
885
00:45:08.389 --> 00:45:10.550
facts that can help you in your day.
886
00:45:12.250 --> 00:45:14.630
We've had a lot of questions about this, just the
887
00:45:15.230 --> 00:45:18.650
practicalities of sunscreen. If you're still on Team Sunscreen after
888
00:45:18.690 --> 00:45:23.130
listening to this episode, here's some tips and tricks about
889
00:45:23.469 --> 00:45:25.230
putting it on properly. Okay.
890
00:45:25.250 --> 00:45:27.610
Okay. When should you wear it?
891
00:45:28.110 --> 00:45:31.329
Okay, so if you open up your weather app, you
892
00:45:31.369 --> 00:45:34.849
will see a section that says UV index, basically telling
893
00:45:34.869 --> 00:45:37.730
you how strong the UV rays are that are coming
894
00:45:38.090 --> 00:45:39.309
through the atmosphere.
895
00:45:39.710 --> 00:45:41.969
Okay, weather app. Here we go.
896
00:45:42.250 --> 00:45:42.530
Yeah.
897
00:45:43.010 --> 00:45:47.139
All right, so here's what I got. Melbourne, middle of winter,
898
00:45:47.159 --> 00:45:50.349
low all day. It's going to be one.
899
00:45:50.719 --> 00:45:54.219
So you need to wear sunscreen if the UV hits
900
00:45:54.320 --> 00:45:57.719
three or above. So today, you actually don't need to
901
00:45:57.739 --> 00:45:58.340
wear sunscreen.
902
00:45:59.679 --> 00:46:02.199
Next question, which SPF should you wear?
903
00:46:02.440 --> 00:46:09.159
So in Australia, they recommend SPF 50+. Other places recommend 30+. However,
904
00:46:09.199 --> 00:46:10.940
the dermatologist I spoke to said you might as well
905
00:46:11.000 --> 00:46:14.099
wear 50% because we know from studies that most of
906
00:46:14.159 --> 00:46:16.880
us are bad at putting on sunscreen. and that we
907
00:46:16.920 --> 00:46:18.440
don't put enough of it on.
908
00:46:18.460 --> 00:46:22.780
Okay, speaking of badly putting on sunscreen, even though I'm
909
00:46:22.860 --> 00:46:26.409
mad for it, I shove it on as soon as
910
00:46:26.469 --> 00:46:27.199
I leave the house.
911
00:46:28.219 --> 00:46:30.329
But I hear you need to put it on 20
912
00:46:30.329 --> 00:46:32.409
minutes before. Is that real?
913
00:46:33.130 --> 00:46:33.730
You do.
914
00:46:34.429 --> 00:46:37.309
Yeah, it's fascinating because, like, you actually need time for
915
00:46:37.349 --> 00:46:41.110
it to dry and set on your skin. It will
916
00:46:41.190 --> 00:46:42.909
adhere a little bit better, and then you're kind of, like,
917
00:46:43.010 --> 00:46:44.409
guaranteeing protection.
918
00:46:44.429 --> 00:46:44.489
Oh.
919
00:46:47.409 --> 00:46:50.800
All right. Do I need to wear it if I'm
920
00:46:50.840 --> 00:46:51.719
behind a window?
921
00:46:51.739 --> 00:46:53.320
It's surprising.
922
00:46:53.340 --> 00:46:57.800
The windows block some of the rays, but let's do
923
00:46:57.820 --> 00:46:59.820
a bit of UVA rays.
924
00:47:01.010 --> 00:47:04.110
Do you know there's a fascinating case report of a
925
00:47:04.170 --> 00:47:10.199
guy who was a truck driver and for decades would drive...
926
00:47:10.719 --> 00:47:13.300
half of his face would be exposed to sun and
927
00:47:13.320 --> 00:47:15.920
the other half would be in the shade. And you can,
928
00:47:16.000 --> 00:47:21.280
it was published in a scientific journal because you could actually.
929
00:47:21.039 --> 00:47:23.280
See more wrinkles on the side of his face.
930
00:47:23.619 --> 00:47:25.530
Yeah, exactly. Yeah, yeah.
931
00:47:25.860 --> 00:47:27.730
So those UVA rays are getting through and we know
932
00:47:27.750 --> 00:47:31.329
that they're connected with signs of aging and also play
933
00:47:31.349 --> 00:47:32.989
like a little bit of role in skin cancer.
934
00:47:33.309 --> 00:47:34.130
Okay, last question.
935
00:47:34.329 --> 00:47:36.269
How much do you actually need to put on?
936
00:47:36.670 --> 00:47:39.570
So for the whole body, an easy guideline is one
937
00:47:39.849 --> 00:47:41.659
full shot glass of sunscreen.
938
00:47:41.780 --> 00:47:42.739
What about just the face?
939
00:47:43.110 --> 00:47:46.280
Yeah, so let me get out my measuring tool. I'm
940
00:47:46.320 --> 00:47:49.900
showing you a teaspoon, a 5-milliliter teaspoon, which is the
941
00:47:49.920 --> 00:47:50.760
same in U.S.
942
00:47:50.780 --> 00:47:51.280
And Australia.
943
00:47:52.400 --> 00:47:57.480
And the recommendation is one whole teaspoon for your face, ears,
944
00:47:57.519 --> 00:47:57.880
and neck.
945
00:47:59.119 --> 00:48:01.780
But for your whole body, you actually want seven of these.
946
00:48:03.079 --> 00:48:03.659
Thanks, Michelle.
947
00:48:04.099 --> 00:48:04.539
Thanks, Wendy.
948
00:48:04.960 --> 00:48:08.400
That's Science Versus. How many citations are in this week's episode?
949
00:48:08.679 --> 00:48:10.269
There are 92 citations.
950
00:48:10.750 --> 00:48:12.710
And if people want to see them in all their glory,
951
00:48:12.730 --> 00:48:14.769
learn more about the science of sunscreen, where should they go?
952
00:48:15.050 --> 00:48:17.349
Head over to our transcript that you can find in
953
00:48:17.369 --> 00:48:17.780
the show notes.
954
00:48:18.719 --> 00:48:21.039
This episode was produced by Michelle Dang with help from
955
00:48:21.079 --> 00:48:24.420
Meryl Horne, Rose Rimler and Aketi Foster-Keys. We're edited by
956
00:48:24.480 --> 00:48:28.460
Blythe Terrell, Wendy Zuckerman, that's me. I'm the executive producer.
957
00:48:28.840 --> 00:48:32.090
Fact-checking by Erica Akiko Howard. Mix and sound design by
958
00:48:32.150 --> 00:48:35.929
Bobby Lord. Music written by Bobby Lord, Bumi Hidaka, So Wiley,
959
00:48:36.050 --> 00:48:39.329
Emma Munger and Peter Leonard. Science Versus is a Spotify
960
00:48:39.369 --> 00:48:41.989
Studios original. You can find us on Spotify. We are
961
00:48:42.050 --> 00:48:45.110
also on YouTube. You can like and subscribe. If you
962
00:48:45.159 --> 00:48:48.139
liked this episode, please share it with your friends. Helps
963
00:48:48.199 --> 00:48:51.469
other people know about the science in the world. I'm
964
00:48:51.489 --> 00:48:53.159
Wendy Zuckerman and I'll back to you next time.