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- [00:02]
Grainger Representative
If you're alignment in charge of keeping the lights on. Grainger understands that you go to great lengths and sometimes heights to ensure the power is always flowing. Which is why you can count on Grainger for professional grade products and next day delivery so you have everything you need to get the job done. Call 1-800-GRAINGER, click granger.com or just stop by Grainger for the ones who get it done.
- [00:30]
Instacart Advertiser
This summer Instacart is bringing back your favorites from 1999 with prices from 1999. That means 90s prices on juice pouches that ought to be respected, 90s prices on box Mac and cheese and 90s prices on ham, cheese and cracker lunches. Enjoy all those throwbacks and more at throwback prices only through Instacart. $4.72 maximum discount per $10 of eligible items. Limit one offer per order. Expires September 5th while supplies last. Discount based on CPI comparison.
- [01:04]
Kristen Bell
Hi, I'm Kristen Bell and if you know my husband Dax, then you also know he loves shopping for a car. Selling a car, not so much.
- [01:11]
Grainger Representative
We're really doing this, huh?
- [01:12]
Kristen Bell
Thankfully, Carvana makes it easy. Answer a few questions, put in your VIN or license and done. We sold ours in minutes this morning and they'll come pick it up and pay us this afternoon.
- [01:23]
Grainger Representative
Goodbye Truckee.
- [01:25]
Kristen Bell
Of course we KE the favorite.
- [01:28]
Grainger Representative
Hello other Truckee.
- [01:30]
Kristen Bell
Sell your car with Carvana today. Terms and conditions apply.
- [01:39]
Dr. Michelle Wong
It's July. That means three things. You just bought a brand new bottle of sunscreen and a distant relative probably just posted a meme claiming that UVA rays are the deep state. Don't even bother engaging with that. Just put that energy into leaving us a nice little comment on Apple podcasts. But back to the sunscreen. I'm sure it took a long time to find the right one. You probably went online and scrolled for an hour or stood in the drugstore like I do for way too long, staring at the shelves, reading the back of every bottle, wondering what any of the labels actually mean. SPF 30, SPF 50, mineral chemical, broad spectrum water and sweat resistant. Then you see a baby's butt on a bottle. So later in the show, I talk with Dr. Michelle Wong. She's admuffin beauty science on Instagram. She breaks down how sunscreen actually works, what those numbers mean for you, and how to tell the difference between science, slick marketing and pretty packaging. We also take a look at Vitamin D. You've heard the claims about sunlight and health and we've got a walkthrough of what your body actually absorbs from the sun and how much of it you really need. That's all on Curiosity Weekly. I'm Dr. Smith. You mean. But first, let me give you a reality check on something else that's in your skincare. There's a booming demand for it, but it's been shown to be one of the driving forces of deforestation in the Amazon. That means this really isn't just an environmental crisis. It means we've got a massive scientific one on our hands, too. One of the most frustrating things about living in our modern world is how easy it is to forget where our products actually come from. And that disconnect between the product and its origin carries real consequences, especially when it comes to the planet collagen. You've definitely heard about it. This miracle ingredient for younger skin, stronger nails, and healthier joints. But behind that promise is a very real environmental cost, particularly in the Amazon rainforest. As demand for collagen explodes, so does the pressure on Brazil's cattle industry, and with it, deforestation, not to mention displacement of indigenous communities and a supply chain that's anything but sustainable. Collagen is produced naturally in our bodies and makes up a lot of our skin, muscles, tendons, bones, and cartilage. It keeps those tissues strong and able to withstand repeated stress. Our bodies naturally produce less and less collagen as we age. So the idea came about that if we maintain a certain level of collagen internally, then we can look and feel younger. That's why collagen entered the supplement and skin care industry, and it's been booming. According to a study from SNS Insider, the global collagen market was valued at nearly $10 billion in 2023, and it's expected to be worth about $23 billion in about 10 years. And that increase in harvesting is hurting the Amazon. First thing you need to know is that unlike milk or wool that can be collected without harming the animal, collagen can only be harvested by slaughtering the animal. Now, typically, the rest of the animal can also be used for other products. Sure, but the high demand for collagen is still a large part of the driving economics. It's driving the demand for more and more animal slaughters for collagen harvesting. So what's happening with the collagen industry is that farmers in Brazil, which is the world's largest beef exporter, suddenly have a much higher demand for this product, and they need to raise more livestock in order to meet it. And in order to raise more livestock, the farmers need more land. So they are clear cutting massive areas of the Amazon rainforest. Not only is the Amazon referred to as the lungs of the planet because of its role producing oxygen and absorbing carbon dioxide, but many of these areas are also indigenous territories. There was an independent investigation published by the Bureau of Investigative Journalism and also done in collaboration with other journalists and publications. They found that the cattle industry is responsible for 80% of tropical deforestation in Brazil. They also linked collagen production to violence against indigenous peoples in that region. And for what? Consider this Collagen supplements or creams are typically marketed as beneficial for skin, nail and hair quality, but the research is still very much out on a lot of those claims. As for the collagen you ingest, the science does not match the hype. Some early studies suggest modest effects on joint pain or skin elasticity, but many of those trials are privately funded and have small sample sizes. The data is far from conclusive and topical collagen performs even worse. The molecule is too large to penetrate the skin, and cosmetic scientists and dermatologists consistently point out that most creams just don't deliver collagen where the body actually uses it. Besides, if you really want to give your skin a collagen boost, decades of clinical trials support the use of retinoids. To get the job done, think over the counter retinol or prescription tretinoin. These vitamin A derivatives trigger your skin cells to make new collagen, modestly increase elasticity and visibly reduce wrinkles. And if you want to learn more, we have an incredible guest coming up who has a wealth of resources explaining the science behind skincare. Michelle Wong up next.
- [06:59]
Instacart Advertiser
This summer, Instacart is bringing back your favorites from 1999 with prices from 1999. That means 90s prices on juice pouches that ought to be respected, 90s prices on box Mac and cheese and 90s prices on ham, cheese and cracker lunches. Enjoy all those throwbacks and more at throwback prices only through Instacart. $4.72 maximum discount per $10 of eligible items. Limit one offer per order expires September 5 while supplies last discount based on CPI comparison.
- [07:34]
Grainger Representative
If you're alignment in charge of keeping the lights on, Grainger understands that you go to great lengths and sometimes heights to ensure the power is always flowing. Which is why you can count on Grainger for professional grade products and next day delivery so you have everything you need to get the job done. Call 1-800-GRAINGER click granger.com or just stop by Granger for the ones who get it done.
- [08:03]
Dr. Michelle Wong
Buying A car in Carvana was so easy I was able to finance it through them.
- [08:06]
Kristen Bell
I just.
- [08:07]
Dr. Michelle Wong
Whoa, wait. You mean finance? Yeah, finance. Got pre qualified for a Carvana auto loan, entered my terms and shot from thousands of great car options all within my budget.
- [08:15]
Kristen Bell
That's cool.
- [08:15]
Dr. Michelle Wong
But financing through Carvana was so easy. Financed, done. And I get to pick up my car from their Carvana vending machine tomorrow. Financed, right? That's what they said. You can spend time trying to pronounce.
- [08:25]
Kristen Bell
Financing or you can actually finance and.
- [08:27]
Dr. Michelle Wong
Buy your car today. On financing subject to credit approval, additional terms and conditions may apply. As a gal who spends, let's just say, a decent amount of time online and who also loves a good skincare routine, I'm always shocked by the latest fad in my newsfeed pretending to be backed by science. Once you get tapped into it, you start to see it everywhere. One area of online discourse that needs debunking time and time again is sunscreen. I reached out to Dr. Michelle Wong. You may know her as Lab Muffin Beauty Science Online, and she not only has excellent taste when it comes to skin care, but she has a PhD in chemistry. She's written two books and is a fierce advocate for evidence based knowledge and transparency in the world of beauty products. Welcome Michelle.
- [09:21]
Kristen Bell
Thanks so much for having me.
- [09:22]
Dr. Michelle Wong
I am so thrilled to chat with you. I gobble up your blog and always learn so so much from you. Let's talk about the basics of sunscreen. So first off, what is sunscreen protecting against and what do all the numbers on the bottle mean with respect to that?
- [09:39]
Kristen Bell
Everyone knows that it protects against the sun spread. Specifically, it protects against UV from the sun. So there's two major types of UV rays. There's uvb, which is shorter wavelength, uva, which is longer wavelength, and both of them contribute to skin cancer and skin aging. SPF tells you how much protection you get. So SPF 50, for example, will be approximately double SPF 25. If you're applying the same amount, bigger number is better. Generally aim for 30 or above. The flip side of that is that sometimes higher numbers might feel a bit heavier. These days they're really good. But if you have a choice between let's say an SPF 30 that you can apply a lot of versus an SPF 50 that you can only apply a tiny bit, then go for the one you can apply more of. Because you do need to apply the right amount to get the number on the bottle.
- [10:28]
Dr. Michelle Wong
When it comes to applying the right amount, you did this iconic video where you put pieces of tape on your face to try to measure the surface area of your face so that you could mathematically determine how much you actually needed to apply to get the SPF on the bottle.
- [10:45]
Kristen Bell
Yeah. So the bottle number is like, it's 2 milligrams per square centimeter. But obviously we all have different face sizes. So some people need to apply more, some people need to apply less. And there's always been, like debate about exactly how much you need to apply. And I was like, right, I'm going to work out how much I need to apply. I don't care about the rest of you. You guys can tape your face if you want. But, like, I'm going to know how much I need to apply. Yeah. So the general recommendation is a quarter teaspoon for your face alone for most people. And I think the easiest way is to get like a baking spoon, one of those baking measures and literally pour it out onto there. Yes. A quarter teaspoon for your face alone. In Australia, we also have this guideline which is really handy, which is about a teaspoon for your head, neck and ears, another teaspoon one for each of your limbs, 1 teaspoon for the front of your body, and 1 teaspoon for the back of your body. And that should add up to a shot glass for your entire body, which is.
- [11:39]
Dr. Michelle Wong
It doesn't seem like a lot if you just picture a shot glass, but if you actually pump out product. I did this experiment last year and I realized I wasn't using enough. And you really need to put more than you think.
- [11:49]
Kristen Bell
Yeah, I think going over is usually a good bet. There's some studies that show that people generally apply half or less, which means you get half or less of the protection. It's not too bad if you're going for a really high SPF, which is why people generally recommend a high SPF, because if you apply, half of 50, 25 is still pretty respectable. But then if you're going down to SPF 15 or if you've got something like foundation where you can only apply a tiny bit, then you're getting into like the single digit territory, which is not so good.
- [12:17]
Dr. Michelle Wong
There's also sometimes those pa. Can you talk about that and what that means on the bottle?
- [12:23]
Kristen Bell
Yeah. So SPF is mostly about uvb, a little bit of UVA as well. But SPF is basically about your skin turning red. That does correlate to both skin cancer and skin aging. But UVA also contributes to that as well. So UVA protection ratings, it's a bit annoying because there's different standards in different countries, which makes them more complicated. SPF is just the one standard. So for uva, there's broad spectrum. Just like the words broad spectrum. That means that the UVA is going to be proportional to the SPF rating. Generally, if you see broad spectrum in a place like Australia or the eu, that's going to give you very good projection. In the us, it's a bit lower, like it's a weaker sort of standard. But generally same broad spectrum is a good sign. The other standard that's used a lot in Asia is the PA rating. And with pa, it goes from one plus to four pluses. More pluses is better. There's also a few other ones, like there's ppd and then there's. Sometimes they just say uvapf, but basically, bigger number is better.
- [13:28]
Dr. Michelle Wong
A big thing people talk about online is the differences between mineral and chemical sunscreens.
- [13:34]
Kristen Bell
Yeah. Been this very persistent myth online, which is that mineral sunscreens reflect uv. Chemical sunscreens absorb UV and turn it into heat. So by chemical, like, everything is a chemical, of course. But by chemical sunscreen, people usually mean organic filters. These are based on carbon and they have the long, scary name. So there's just a lot of. A lot of bad vibes around them. But they're actually really good. Most people prefer chemical filters, and there's all this stuff about how they're unsafe and how they're not as effective as mineral sunscreens. And none of that is true. The only real exception is if you have sensitive skin and you're allergic to a particular chemical sunscreen, you should avoid it. But then, apart from that, they're really awesome. They work really well. I guess it's really just the limitations of what we're given from nature, Right? Like, nature gives us stuff and we can improve on it. And usually those improvements are chemical sunscreens, mineral sunscreens. There's so many limits with them. So with this reflecting versus absorbing thing, there's a sort of idea that reflecting the UV away is better somehow than turning into heat. And part of this is just because kind of sounds better when it just like goes away completely out of your body. But in reality, what happens is not all of that gets reflected away. Some of it actually gets reflected deeper into your skin, so it's still uv. But if you have a chemical sunscreen, it absorbs and converts it to heat, which is a tiny, tiny amount of heat. But also, more importantly, mineral sunscreens don't actually Reflect that much. They only reflect about 5 to 10% of the UV that comes in. The rest of it, the 90 to 95%, also gets absorbed and turned into heat. So the difference between chemical and mineral is really tiny, just that 5%. And the amount of heat is so low anyway, it doesn't make a difference. So either way, absorption is actually better than reflection.
- [15:28]
Dr. Michelle Wong
And that's. And that's all just some chemistry happening on the surface of your skin. And it's. It's not harmful in any way for that conversion to be happening.
- [15:36]
Kristen Bell
Exactly, yeah. So that conversion, there's all this stuff about how, like, when it does the conversion, the sunscreen breaks down and it stops working. That isn't true at all. Most chemical filters these days, they last for ages. They keep on doing the conversion for ages before they break down, longer than you would need to reapply it.
- [15:53]
Dr. Michelle Wong
Oh, that's interesting. From my understanding, a lot of mineral sunscreen, what makes them reflective, also tends to give them white cast. And so no one wants that thick of a material on their skin. So they end up being a combination anyway.
- [16:06]
Kristen Bell
Yeah.
- [16:07]
Dr. Michelle Wong
Is that right?
- [16:07]
Kristen Bell
Yeah, that's exactly true. Yeah. So mineral sunscreens, because they reflect a bit, they actually reflect more at longer wavelengths, which is where we go from UV to visible light, and that's what you start seeing. Some sunscreen experts believe that mineral sunscreens on their own, or zinc oxide, actually on its own, cannot give a high spf, like, the maximum you get. I can't remember if it was like 15 or 30. It's pretty controversial whether or not they give that high protection, whether it's just like flukes and testing. But either way, you do need a very high amount of zinc oxide to get any sort of decent protection. And because it gives white cast, it also feels really dry. Because zinc oxide, it's a mineral, it kind of operates a bit like clay. So if you have something that is like 20% zinc, which is pretty standard, that's 1/5 of your sunscreen that is like clay particles. It generally tends to feel dry. It goes white. It's just not very comfortable, which is why so many people prefer chemical sunscreens. So to try to reduce that from happening, some sunscreens will reduce the amount of mineral filters, and then they add in what are called SPF boosters. And these are basically chemical sunscreens, except they have a few extra atoms, sometimes very slight modifications to their structure. And technically, they don't count as sunscreens. So they don't have to be listed in that separate part on a drug facts panel, for example. So they kind of go under the radar, and they're in lots of mineral sunscreens that have less white cast, and they tend to be the ones that people like. But the problem is, because they're not technically regulated as sunscreens, they're less strictly regulated, which means we have a lot less data about them. In theory, they should be pretty similar to chemical sunscreens in terms of risk and stuff like that, but it's just less regulated and we don't know. And it is, to me, it's pretty unethical to be marketing them as 100% mineral sunscreens because perpetuating this idea that chemicals are terrible things with long names are scary. I guess they're trying to have their cake and eat it, too.
- [18:15]
Dr. Michelle Wong
Interesting. And I feel like part of the mineral sunscreen conversation ends up being this claim about whether or not certain types of sunscreens are reef safe or better for the environment. Are there elements to this that are true? What should we think about in choosing a sunscreen? When it comes to sustainability for the.
- [18:34]
Kristen Bell
Planet in general, sunscreens have very little impact on the environment compared to what we think. In 2022, the National Academies got together a whole bunch of eminent scientists in environmental toxicology and environmental impact, and they looked at all of the data on sunscreen and environmental impact, and it looks like the amount of contributions sunscreens are making to coral bleaching is very minimal. And also, it turns out mineral sunscreens have a larger impact than a lot of chemical sunscreens. All of them are quite low. But zinc oxide itself is an ecotoxin. We think of it as natural, but in reality, there's not that much zinc near the reefs. So if you are adding zinc to a reef, even if it's natural, it's in the wrong place. So overall, it doesn't look like there's that much of an impact by far. The big impact is probably you flying on holidays.
- [19:31]
Dr. Michelle Wong
Yeah, that's definitely a big one. There was one thing you mentioned earlier about some sunscreens, especially the mineral sunscreens with those adapted chemical filters put in them with the extra atoms that they're not regulated as sunscreen, but they can sometimes be marketed as such. But is there something consumers should be looking out for on a bottle to see if it's an approved sunscreen, especially when you're shopping online?
- [19:57]
Kristen Bell
Oh, yeah. Online shopping, depending on which country you're in, is such a minefield. So sunscreens are regulated Pretty much everywhere around the world as either a drug or. Or a special use cosmetic. And that means there's a whole bunch of things in place that regulate how they're made, what's in them, that kind of thing. So sunscreen, active ingredients, a lot of people think chemical is less safe, but all of the chemical sunscreens go through lots and lots of safety testing, and they get reassessed all the time. So the eu, in the last few years, they've reassessed a whole bunch of chemical sunscreens, including all the ones commonly used in the US Again, big trope online that the EU is much safer and the US has like all these toxic ingredients in their products. There are no ingredients used commonly in US cosmetic products that are banned in the eu. This includes parabens, phthalates, chemical sunscreens, all the ones that everyone freaks out about, not banned in the eu. The other big thing that gets regulated is the SPF testing. It needs to be tested. This is changing, which is really cool. It used to have to be tested on 10 people in a special lab.
- [21:06]
Dr. Michelle Wong
And these really funny experiments. Yeah. Where they have this little strip Right. Where they test it under.
- [21:11]
Kristen Bell
Yeah, they're all lying on their front and it's like a little strip on their back and there's like these little circles. It's pretty funny. Yeah. So that used to have to happen. Now they can do it on slides, which is cool, but that's still rolling out. But it's very technical. It's regulated, it's expensive, which is why it's really hard to launch a sunscreen. But the other important thing is that it needs to be manufactured in a way that's consistent. SPF is really finicky. You can't just add 20% zinc oxide to a product and expect it to give SPF 30. It depends on how that ingredient is spread out, how it interacts with everything else inside the product, and also how it interacts with your skin when you apply it. So if you change something in the manufacturing, which has happened, there's been a few mini scandals where there's been a change in manufacturing. It's changed the spf, and there's products going out with the wrong spf. If people are diying this, there's no way they can get that consistent.
- [22:08]
Dr. Michelle Wong
Yeah, definitely not recommending the DIY sunscreen, just to be clear.
- [22:12]
Kristen Bell
Right, Definitely. And also, yeah, be really careful because people are selling their DIY sunscreens that they've made in their kitchen online. I see a lot of DIY Sunscreens being sold on places like Etsy, where it won't have the drug facts label, it'll say water resistant, but it won't say like 80 minutes. There's lots of little things like this which is regulated. And yeah, there's a lot of DIY sunscreens online. Usually they have zinc oxide. Usually they say non nano zinc oxide. Usually it will just be in an oil base a lot of the time. Now it's tallow as the base. It'll say organic all over it. Organic should not be in the ingredient names. Like they'll have organic all over their ingredients.
- [22:53]
Dr. Michelle Wong
Not recommending the DIY sunscreen. One thing I did check, in Canada, sunscreens are regulated under our Food and Drugs Act. So I think they're regulated similarly to how they are in the us. But one thing I hear about between the different countries and how they're regulated is that it can mean that it takes longer for newer filters and newer innovations in sunscreen technology to make it through into consumer markets. Assuming that's true, I wanted to ask how often are these technologies for sunscreen changing and evolving? And is there anything on the horizon right now that you're super excited about?
- [23:29]
Kristen Bell
This is. It's fascinating. So the US only has a limited set of sunscreen filters, but everywhere else, pretty much everywhere else has a much larger set. This includes Canada. There are these newer sunscreen filters that were launched, I think early 2000s in the EU. Australia, they're pretty much everywhere around the world. And that's why the rest of the world has better sunscreens than the us. Like, they're lighter, they work better under makeup, they have less sensitivity, they have higher spf. It's to do with regulations. Like in the eu, sunscreens are regulated as a cosmetic. In the US they're regulated as a drug. So the approval processes are different. And in the US the approval process is much stricter because it's regulated as a drug. Very similar. It's using the same sorts of guidelines as, like oral medications. But in the eu, there's been an animal testing ban that was rolled out in the early 2000s, and I think it was pretty complete by 2013. So because sunscreens are cosmetics, they cannot test their sunscreen ingredients on animals. In the us, their drug regulation requires testing on animals. And so the safety data that the US wants cannot be collected anymore under EU regulations. The EU regulations are quite strict. If it's been tested on animals anywhere in the world, it cannot be used in cosmetics. And so most of the Sunscreen manufacturers, the ones who are making these new sunscreen ingredients, they are based in the eu, so they kind of have a choice. They either test on animals and get it approved in the US or they don't test and keep it approved in the rest of the world. And this also means that the sunscreen ingredients we have, that's probably the end of all the sunscreen ingredients because they can't do the safety testing until new safety tests are developed, which could be a while.
- [25:16]
Dr. Michelle Wong
Oh, that's so interesting. It's interesting that it's a regulation and the policy thing that's impacting the science innovation. And it's just to say that those two things always go hand in hand. You started lab muffin in 2011, and obviously since then, even in the last five years or so, beauty and skincare sales and interest have gone up exponentially. So I'm curious how it's felt from your point of view, seeing so many more people engaged with skincare, with beauty, and maybe trying to understand some of the science. Have you seen a change?
- [25:49]
Kristen Bell
Yeah, I've seen a massive uptick. I think it was mostly during lockdown when everyone was like, I'm gonna go into lockdown and then I'm gonna come out like I'm a brand new butterfly. And also with the rise of TikTok, I think there's just been so much more information out there. Everyone has access to more, but then it's so much harder to tell what's real and not. There's just been so much more misinformation as well, and it's getting kind of stuck smarter. Like back in the day, a lot of it was pretty obviously bs. I think a lot of people who think of themselves as critical would have easily seen through it. And now a lot of it is harder to see through. Like, we see lots of people who seem to be experts making very weird claims, and I think part of it is also algorithmic. So, for example, I do debunk a lot of medical doctors and dermatologists, but I think most of the time it's not like the majority of medical doctors think these things or dermatologists. It's just the people who say the weirdest outrageous stuff that gets boosted by the algorithm and it just ends up much more visible.
- [26:50]
Dr. Michelle Wong
Very much that. Thank you so much, Michelle. It was such a thrill to have you on the show again. I'm such a fan. I think I've read, like, every blog post that you've written, or at least most of them. So what a treat. To have you. Thank you for being on the show.
- [27:04]
Kristen Bell
Thank you so much for having me. This was a pleasure.
- [27:13]
Grainger Representative
If you're alignment in charge of keeping the lights on, Grainger understands that you go to great lengths and sometimes heights to ensure the power is always flowing. Which is why you can count on Grainger for professional grade products and next day delivery. So you have everything you need to get the job done. Call 1-800-GRAINGER click granger.com or just stop by Granger for the ones who get it done.
- [27:45]
Dr. Michelle Wong
Vitamin D. There are seemingly never ending headlines about it being the answer to everything from cancer to Covid. Well, spoiler. There's a lot of misinformation about what vitamin D can and can't do. So let's dive into the controversies and the actual science. Let's start with the science. Look, I get why vitamin D is so hyped. It's an essential nutrient. Without it, you can get rickets, a softening or weakening of the bones with prolonged vitamin D or calcium deficiency. See, vitamin D helps our intestines absorb calcium and it keeps enough calcium and phosphate circulating for the healthy maintenance and growth of our bones. Our bones are constantly being remodeled. Bone growth slows down as we age and especially for those undergoing menopause, meaning vitamin D is very necessary to keep calcium levels up to prevent osteoporosis. But it does more beyond the skeleton too. Vitamin D plays a role in immunity, including your body's defense against infections, and it can even reduce inflammation. Vitamin D is even involved with cell growth and metabolism. Okay, so hype warranted. The tricky part is it's only naturally found in a few fatty fish like trout or salmon fish, liver oil and egg yolks, for example. Now, luckily in Canada and the U.S. a lot of dairy products have been fortified with vitamin D for decades. But what makes it really unique is in its nickname, the Sunshine Vitamin. It's the only nutrient your body can actually make on its own from sunlight. When you go outside and sunlight hits your skin, something pretty cool happens. The sun's UVB rays kick off a chemical reaction in your skin. Basically, there's a special type of cholesterol in your skin cells that sunlight changes into a new form. You can think of it as pre vitamin D, but it's not quite ready yet. Your body uses a bit of heat to finish the job, turning that pre vitamin D into actual vitamin D. Once it's made, your body sends the vitamin D into your bloodstream. Then your liver and kidneys do a little extra work to turn it into the final form your body can actually use, especially to keep your bones strong and healthy. So in short, sunlight plus your skin, that starts the whole process. Your body finishes the job and makes the vitamin D your organs get it ready for your bones to actually use. And that's how your body turns sunshine into vitamin D and healthy bones. It can take as little as 10 minutes in the sun to produce your daily intake of vitamin D. But it all depends on where you live, the season, your age and even your skin tone. For example, in Canada, we don't tend to get enough sunshine in the winter months to get our vitamin D only from sun exposure. And melanin in skin absorbs UVB rays, slowing down vitamin D production. So people with darker skin actually tend to need more sun exposure to produce vitamin D than those with lighter skin. But this doesn't mean you should be sitting out bare in the sun for the sake of vitamin D. You don't want to be exposing your skin to the sun unprotected because that comes with risks of skin cancer, food, and if your doctor suggests it, vitamin D supplements are safe ways to get your daily intake. You got the lowdown on your skin, the sun and what's good on land. So now over the next step two episodes, we're going underwater and it's all about sharks. How they hear, how they react to climate change and even what they do on staycation. Summer 2025 is kind of shark centric for everyone. Not Only is it Jaw's 50th anniversary, there's a new and improved Shark Week on Discovery. And like subscribe and leave a comment. Have you done it yet? Because if not, you better get on it. We're interested in hearing what you're curious about, but it also really helps bump us up in the charts too. Thanks for listening for Warner Bros. Discovery Curiosity Weekly is produced by the team at Wheelhouse DNA. The senior producer and editorial correspondent is Teresa Carey. Our producer is Chiara Noni, our audio engineer is Nick Karisimi. And head of Production for Wheelhouse DNA is Cassie Berman. And I'm Dr. Samantha Yamin. Thanks for listening.
- [32:11]
Grainger Representative
If you're alignment in charge of keeping the lights on, Grainger understands that you go to great lengths and sometimes heights to ensure the power is always flowing. Which is why you can count on Grainger for professional grade products and next day delivery. So you have everything you need to get the job done. Call 1-800-GRAINGER click granger.com or just stop by Granger for the ones who get it done.
- [32:41]
Dr. Michelle Wong
50 years after Jaws scared an entire.
- [32:43]
Kristen Bell
Generation out of the water, I looked down. There was this great big head, these big white teeth. Radiolab is pulling you back in.
- [32:53]
Dr. Michelle Wong
There was just like so much fear.
- [32:55]
Kristen Bell
Building of what's going to come out of that blue. Listen to Swimming With Shadows, a Radiolab week of sharks.
- [33:02]
Dr. Michelle Wong
Anything you dig down on is fascinating.
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Kristen Bell
These creatures wherever you get Podcasts.
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Grainger Representative
Acast.
- [33:13]
Dr. Michelle Wong
Powers the world's best podcasts. Here's a show that we recommend. Love music.
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Kristen Bell
We do too. Well, if you ever feel like it's.
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Dr. Michelle Wong
Hard to keep up though, don't worry, we're here to help. Monday through Friday, Daily Music Headlines gets you the top happenings in music from.
- [33:31]
Kristen Bell
Chart toppers, news releases, concert announcements and.
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Dr. Michelle Wong
More, all in less than five minutes.
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Kristen Bell
Don't miss out.
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Dr. Michelle Wong
Get the show at dailymusicheadlines.com Acast helps creators launch, grow and monetize their podcasts everywhere.
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Kristen Bell
Acast.com.