Best of: The future of skin longevity
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Hey everyone, this is your host Russ Altman from the Future of Everything. Happy Holidays! However you're celebrating, I hope you'll be able to connect with friends, family, and loved ones. To accompany you through the season, we're rerunning one of our most popular episodes from 2024, The Future of Skin Longevity, with Professor Zakiya Rahman. As an expert in dermatology, Professor Rahman explains that our skin is our most photographed organ,

And taking care of it is not about vanity, it's about vitality. Tune in to hear our conversation about everything from laser therapy to sun protection. Before we get started, please remember to follow The Future of Everything on whatever app you're listening to to make sure that you get access to all of our episodes and never miss the future of anything.

Whether we like it or not, we are continually seeing images of ourselves and others in social media and in mirrors. Now, we've had mirrors for hundreds of years, but social media is relatively new, and many of us are exposed to images of ourselves

much more frequently than we were even 10, 20, 30 years ago. That means that we're looking at ourselves and we're evaluating. Do I like how I look? Am I too tan? Am I too pale? All of these things have deep cultural relevance because there are these icons of what you're supposed to look like. Some of us may be more susceptible to those than others. In addition, if we see things we don't like, the toolbox for dermatologists to change how we look

with skin protection, laser therapies is growing. What do we do in the midst of all of these opportunities and all of these concerns about our skin, our skin health, and our skin cosmetics? Well, Zakia Rahman is a professor of dermatology at Stanford University. She's an expert on dermatology, ethnic differences of dermatology, laser therapy for dermatologic issues, and general skin protection and sun exposure.

Zakiya, you're an expert dermatologist. And one of the things you've talked about a lot is the emergence of digital technologies. And so I think it means that we're all looking at our faces and other people's faces and bodies all the time. And that has implications for you as a dermatologist. I found that fascinating. Could you expand on how this gets on your radar and why digital technologies and cell phones are actually impacting the practice of dermatology?

I love that question. And I think that certainly as a dermatologist, I see this in my everyday practice. So being at Stanford, I can't tell you how many requests I get from people who are in medical school who are interested in dermatology, but now the requests are getting younger and younger. I remember last year I got a request from somebody whose granddaughter in middle school wanted to be a dermatologist when they grow up.

And I thought at that time, how do you even know what you want to be when you grow up? But I think that certainly this expansion of digital technologies has really affected how we view each other and ourselves. It's postulated that people put about 3.2 billion still images online every single day. So that's about 1.1 trillion in a year. And it's going to go up to 2 trillion by the end of 2030. Okay, so...

So what I'm hearing is that people are aware of this and they might see things in the pictures of themselves in particular, let's say that they either don't like, or they're worried that their skin won't always be perfect. You know, the way a nine year old has perfect skin typically. So are you finding yourself treating and making prescriptions for people? Like, is this a healthy set of requests? Like how can I protect my skin so that I, so that I age in a healthy way? Or are you detecting that there's some problems there?

Yeah, I think both. I think one is certainly what I do as a laser dermatologist is that I help people look their best. And I think so often and for so long, we kind of looked down on people who wanted to look their best. But I think with these digital trends and longevity trends, I think there's nothing wrong with people wanting to look their best.

And I think what my tagline is, it's not about vanity, it's about vitality. And when I talk to patients about that, they definitely feel more comfortable because sometimes they feel a little ashamed coming in asking for procedures or something to look their best. But I think our skin is the most imaged organ and it's the one that conveys vitality to others and to ourselves. But of course, there are some negative consequences, particularly in young people.

particularly young girls. So that's really significant. And we see these effects on them for their self-esteem, depression, eating disorders. - And you mentioned your expertise and I wanted to get to that. And since you mentioned it, in using lasers for therapeutics. And I think we'll go back to these big issues about skin health and sun exposure.

But let's talk a little bit about the role of lasers in dermatology because I learned a lot just in preparing for our conversation in the variety of ways that laser technology can address kind of skin issues. Can you give us kind of a, and I think a lot of people who haven't had this kind of treatment might be very surprised because, you know, we think of lasers as they're hot things, they burn. Like, why would you be putting that on your skin? So can you just take us through how lasers are kind of revolutionizing certain parts of dermatology?

Absolutely. So let's take a little step back and look at the electromagnetic spectrum. So we look at short wavelengths of light like X-rays and gamma rays and ultraviolet. Those have really negative health consequences, but most of them are filtered from our ozone and our environment.

And then you look at far infrared light. But in the middle is kind of where we use lasers and light-based technology for positive effects. So you have visible and then you have the far infrared or near infrared range. And there's this great concept called the Arndt-Schultz law. And this is often used in homeopathy, but it applies to lasers. And it says at really high levels, you kill.

And at moderate levels, you damage. And at low levels, you actually stimulate biological functions. So often when we use laser and light-based technologies in our office, we're kind of in that moderate. We use lasers for very precise, controlled tissue damage to exactly the target we want, say a blood vessel or some pigment. And then the wound healing process causes new skin to be formed.

But we also use light-based technologies at really low levels, like with red light, which I think is really popular now. And that's in that stimulation of biological function. Okay. So this is really exciting. So is it the case... So you mentioned a couple of things. I think you mentioned pigment and blood vessels. So I'm assuming that perhaps somebody has something on their skin that they don't like. It's a blood vessel that's very obvious or a mole or some kind of pigmentation. Is it that you pick...

Do you have special wavelengths of the laser that are good for these different things? Or is it generally the same kind of treatment, but just where you point it is different? Yeah, it's usually the wavelength of light. So there's this concept when we're talking about a blood vessel or pigment, there are these things called chromophores. So a wavelength of laser light will target certain chromophores. So we know certain wavelengths target pigment or melanin.

Others target hemoglobin. And actually, oxyhemoglobin and hemoglobin have different wavelengths that they attract. And that's kind of how our smartphone or smartwatches detect our oxygen. The difference of the absorption spectrum between oxyhemoglobin and hemoglobin. And that's just for people who don't follow, if I'm getting it, that's the difference between the blood that's in the arteries and the blood that's in the veins. And so you can distinguish them.

Exactly. Yeah. How much oxygen we have, which is like really critical. If it goes down, then we can't supply oxygen to our brain and other vital organs. And then water is also a chromophore. So what we can do is very, very precisely target one thing and spare the surrounding tissue. When we go back and talk about skin cancer, it turns out the chromophore for DNA is ultraviolet light. So ultraviolet light targets our DNA.

So we know specifically how ultraviolet light damages our DNA and causes cancer and premature aging as well. Are lasers used at all in the treatment of skin cancer or not? Absolutely they are. Yeah. So a lot of lasers have FDA clearance, which is the pathway that the FDA goes through with devices. So, you know, there's the FDA looks at drugs and devices. And so lasers are devices.

And so the pathway is usually a clearance pathway. And so there are a lot of them that are actually FDA cleared for precancers or actinic keratoses. So we use them routinely in our practice for precancers and even certain types of skin cancer. So this is great. So nobody should really be surprised if their dermatologist recommends that a laser might be useful because it sounds like it's an incredibly powerful tool that you can use across the spectrum of kind of skin issues. Right.

And then this is your expertise. And do all dermatologists do this or has this become a specialty within dermatology?

It's definitely a specialty within dermatology, but in order to become a board-certified dermatologist, also to become a board-certified plastic surgeon and an oculoplastic surgeon, you have to have this training. So we have 25 residents at the Stanford Dermatology Department, and so we specifically train them on this because it's required for board certification.

So these group of people are really the experts in this. And then there are people like myself who love lasers and it becomes my area of passion. The laser professor of dermatology. Yes. Okay. So that was great. And thank you for that background because now it really is quite an exciting kind of technology. You did mention skin cancer. We talked a little bit about laser treatments. Let's go right to the issue. How are we doing? We being, I guess, like America, United States, maybe the world.

And by the way, I know that you study the effects of skin and sun exposure in multiple different ethnic groups and there's differences. So I'd like to get there. So how are we doing on skin cancer? You know, many of us grew up at a time where we just went out in the summer and we didn't apply anything. And I can remember peeling, blistering burns as a kid. And then I read about as I went to medical school, I read, oh, this wasn't good. Yeah.

Have we made progress? And what are the current issues in prevention of skin cancer? Yeah, we've made some progress, but we haven't in other areas. So we know skin cancer is actually the most common type of cancer. And about two people die every hour from skin cancer. So it's, you know, we're not doing that great. We can definitely do better. And there are some environmental effects. So we know skin cancer rates are really high in Australia.

And one of the reasons is that their ozone layer thinned. And so actually the Nobel Prize in 1995 were two chemists who looked at the ozone and the ozone layer. And so when we don't have those protections, then shorter wavelengths of light like ultraviolet light see penetrate and actually can cause a lot of damage.

So we're not doing great, but I think we have the technology and we have the wherewithal to really get ahead of the game if we make a few changes. And I think some of those are regulatory changes, too, that need to be made. Now, is it really with respect to prevention of skin cancer? And those statistics that you just cited are quite, I think you're right, that is not very reassuring. I don't think we're doing that great.

Is it all about sun protection or is it mostly about sun protection and how are we doing there? Is our understanding of how to protect, who should protect like the most aggressively, is that all very clear or are we still learning?

I think we're still learning, and certainly in the dermatology community, there's a lot of debate about this. But I think questioning our assumptions is really what – you know when you're questioning your assumptions that you're getting someplace where you're going to find new things and discover. So I think it's fine to do that. Yes. So, yeah, I think that we're questioning a lot of assumptions.

And I think preventive care and prevention is kind of like the best way to really treat anything, and it's actually the least costly. So by the time someone gets a skin cancer and gets it treated, we know the cost and the morbidity associated with it is really high. So if you can prevent it, that's great. Now, I hear from a lot of people like you,

We didn't know about sunscreen when I was growing up, but it turns out that even now, even though as much as we know, there's still a lot of social media trends and a lot of young people who still are going out and getting sun exposure. Now, I'm not anti-sun exposure.

I love the sun. I love being in California and I definitely love being outdoors and there'd be no life on earth without the sun. So I'm not saying that's bad, but it's just doing it in a way that is safe. Yeah. So I think people would be interested in some of these guidelines. So for example, like if I'm wearing a hat or if I'm wearing a shirt, am I fine or do I need to do a little bit more work to make sure that that hat or that shirt is protecting me if I care about protection?

I think that's a great question. So like I go to the demographics, like what is the data showing us about skin cancer that's different between men and women and what side of the face? And actually in the 80s, it was shown that people are more likely to get skin cancer on the left side of their face.

And particularly for men, including melanoma. And so it turns out that windshields in the U.S. are required to have UVA protection. And the way they have it is there's not like a UVA film. But Ford, I think in the early 1900s, adopted this.

So when you get into an accident, you don't want all of that glass to shatter into pieces. And so what they do is they have two pieces of glass and a lamination in the middle. And so that lamination from the index of refraction, the UVA light gets blocked. So it's kind of a bonus. They kind of didn't do it on purpose, but we all benefited.

Exactly. And we see that effect where on the side mirrors, we don't have that. So ultraviolet light A goes in through windows. So people who are working at home or an office, there's this beautiful image in one of our dermatology texts of a woman who worked next to a window for 40 years. And she looks like different people on one side of her face as opposed to the other side of the face. Wow. So this is the, like you're driving down the road and the sun is coming in from the side. Yeah.

That matters and we should pay attention to that. Absolutely. And so I often will give like tint letters to my patients who have not only a history of skin cancer, but they have pigmented disorders. So a lot of people, as we were seeing the demographics in the U.S. change, is that certainly that can cause skin cancer, but also increase pigmentation. And so what's a skin letter? I'm sorry. I just want to make sure I understand. Okay.

It's a letter that basically they can present if they have tint in their windshield saying, okay, this is the reason why. Because there are specific laws in each state about how much tinting they can have because certainly you don't want to look like a criminal trying to hide. Right, right. I gotcha. I gotcha. So this is when you're stopped by the police. Dr. Rahman can give you a letter that says, no, I'm not a – well, if I am a criminal, I also have skin problems. Right.

Okay. And what about... Are clothes protective in general, or do I have to check? So I have, I must admit, I have purchased shirts that are advertised for SPF 50, like for going to the beach. And then my family members who are a little bit more skeptical say, Dad, do you know...

They happen to be my children. Dad, do you know if that actually is any more SPF than you would get from a normal shirt? And I actually don't. So should we be paying attention to the SPF ratings of our clothes?

Yeah, absolutely. So for when it comes to clothing and physical protection, there's something called UPF, which is ultraviolet protective factor. So it's kind of like the clothing version of it. Now, everything doesn't have to be labeled as that. If you're wearing a denim shirt or a wool shirt, like that's going to block out the light. So that's fine. But there are other ones that are specifically tested with UPF.

Okay.

And, you know, obviously it's not only for vanity, but it's also for vitality. Yeah, and grip. I'm sure it helps with the grip on the, okay, that's kind of fun. Okay, so now I'm imagining I'm going to get some Italian gloves. I'm going to get a little hat. It's going to really, I'll get a scarf. Okay, so we do have to. A wide brim hat though. You got to get, yes. So baseball hats don't do it.

No. And it's interesting. So men are more likely to get skin cancer on their lips and their ears than women are because we tend to have hairstyles that cover exactly. And then we tend to wear products on our lips that actually can protect if they have some pigment in them. So baseball caps look great, but they're just not going to protect you. So there's a couple of options. You could grow your hair longer. That would cover that might look cool or a wide brim hat.

This is The Future of Everything with Russ Altman. We'll have more with Zach Rahman next. Welcome back to The Future of Everything. I'm Russ Altman. I'm speaking with Professor Zach Rahman from Stanford University. In the last segment, we had a great discussion about how lasers can be therapeutically useful, some of the issues of protecting yourself from sun damage, and also the issues of increased exposure to your own face through social media and selfies and what that's doing to people.

In this next segment, we want to talk about ethnic differences and demographic differences in skin health, even in cultural expectations of what the ideal skin should look like. We'll also talk about red light, red light masks, and whether they're based on good science or not. It turns out that there are, and you might want to take a run in the sunset.

In this section, Zach, I wanted to ask you about, because I know this is an area of specific interest, ethnic differences in the importance of skin and how the skin deals with sun and aging. So where are we? I know this is an area of expertise for you. What is our understanding of the differences across different demographies?

So in the 1970s, these two scientists actually partnered at NASA, and they looked at indigenous skin color. And what they found is this link to ultraviolet light and vitamin D.

But of course, with mass migration, like everything has changed. And I think the U.S. is one of those countries that, again, it's like the melting pot. So we see the diversity in our population is really increasing. We see Asian-Americans and Hispanic-Americans really going up. And then whites will become a minority of the population. So it's really important, particularly as dermatologists, to understand how skin varies. And I think a lot of that variance is melanin.

And one of the great things is that people who have more pigment and melanin in their skin actually get that protection from sun-related skin cancer, but also from premature aging. But that patient population also gets a lot more pigment-related skin concerns. And so they will often come and see me for that. So it's a double-edged sword. They get protection from sun damage, but they may be at increased risk for other pigmentation issues. Right.

Yes. And I don't want to miss out on the fact that, um, even Hispanics and African Americans, they certainly can get skin cancer Asians. And it turns out that, um, melanoma of the palms and souls is actually the same incidents, no matter what race someone is. And that's more related to trauma. Um,

And so a lot of our skin cancer prevention and screening really incorporates a lot of people. So just because you have pigment in your skin doesn't mean you can't get skin cancer. You do have protection against certain types of skin cancer, but not those on the palms and soles. On this issue, I wanted to ask, this is...

I've always wondered about this. So obviously, as a white person, I have an ability to tan. I tan when I'm out in the sun. And that seems to be a natural reaction to the sun exposure. Is that providing me protection in the summer? And like a base tan is kind of okay and I shouldn't worry about it? Or is that to you as a dermatologist just a sign that I'm not using enough sun protection?

So that's kind of a hotly debated topic. It's true that ultraviolet light causes the melanin that we already have to oxidize. So ultraviolet light A does that. And so we get that immediate darkening. And then ultraviolet light B causes those melanocytes that make pigment to make connections with keratinocytes and they produce more melanin.

And we know that melanin is like an umbrella on a rainy day. It does protect you. But there's sort of other ways that you could protect your skin. Now, people love the sun. And one of the reasons is it's actually our skin is an endocrine organ. So it doesn't just make vitamin D. It also makes endorphins. Oh. So that's why it feels so good to be outside.

Right. We co-evolved like we wouldn't evolve. Oh, I didn't know that. That's problematic. Knowing that I was addicting. Yeah, of course. It feels great.

And there's a reason it does. Like that's, you know, it's necessary for our survival. So again, you don't have to live in a cave, but probably there's other ways to get that protection. If you like to look tan, which a lot of people do, you can actually do fake tanning. So there's spray tans and topical dihydroxyacetone, which is a chemical that cross-links proteins.

And that actually gives you a little bit of ultraviolet light protection and makes you look tanned. So in a summertime, if I'm doing a good job protecting myself, thank you for doing this. I'm really interested. And this is a little bit off of our topic. But if I do a good job with my skin protection with sunscreen and whatnot, will I not tan at all? Will there be baseline tan even?

even with appropriate protection. I'm trying to figure out if I should use tanning as a indicator that I'm not doing a good enough job, or if that will happen even with a good job of sun protection. - You may still, particularly because of the sunscreens that are approved now in the US,

Our regulations actually have slowed down the progress of sunscreens that are available in the European Union and Japan and South Korea. So we don't have sunscreens here that are really good with UVA protection. So even with that, you might get a little bit of a tan.

But certainly a burn or a blistering sunburn is bad, but you may still get a slight tan. Okay, so back to what we wanted to talk about. As part of your interest in ethnicity, ethnic differences, and demographics, I know that you've been looking at aesthetics and cultural implications. And it sounds fascinating. So can you tell me about that?

Yeah. So Stanford has a center on longevity that's headed up by Laura Karstensen, who's a psychologist. And she and I met like a lot of us do at Stanford. And I started chatting about what I do, which is I remove skin cancer in my veteran population, centenarians and near centenarians. And then I also help people look their best with lasers and other energy-based devices to

And really, we understood kind of a – we had a meeting of the minds because we realized all of this goes to longevity, which is we're living the longest we have since our Homo sapien ancestors walked the earth 300,000 years ago. And we want people to really be vital and –

We want them to contribute to society and we want them to be healthy as long as possible. And so we're looking at how we do that, how it is that people are motivated to look their best. Are they willing to do things for their health because of how they look? And so if we can promote healthy behaviors,

and that allow people to look their best and are motivated by how they look, then I think it's a win-win. Yes. Have you seen any cultural practices either in the West or in any culture where they actually, the things that they value in terms of their looks are actually not the most healthy? Or do the healthy habits tend to correlate with the aesthetics?

Yeah, certainly we do. But I like to focus kind of on the positive. So my colleague Ann Chang and I have a Stanford Skin Longevity Program. And so we looked at the psychology data. And there's a really elegant study in 2014 that was published in Social Psychology. And it took images and it made them more melanized or more pigmented or tan. And then it made them more carotenoid.

So, you know, beta carotene makes us really healthy. And it's actually a retinoid, which, you know, we love putting retinoids on our surface of our skin. And so they had people just look at the pictures and rate their attractiveness. And they found the carotenoid faces looked more attractive. So it turns out all of these signals that we're sending subconsciously, the healthy signals are really correlated with attractive signals. So that's good news. That's good news that we can be pleased with.

Well, the final thing I want to ask you about is red light. You talk in your work, you've looked at red light masks. I'm sure you see it clinically. What is the point of red light masks? Because they were really not on my radar. And what's the science underlying their potential benefit? It's so funny to see things that we've researched and worked on for many years become popular because of social media trends.

And I think red light masks have. And we talked a little bit about this idea of selective photothermalysis or what are the chromophores, right? DNA or melanin or pigment. And it turns out in our mitochondria, which are like the powerhouse of our cells to give all of our cells energy, cytochrome C oxidase, which is the enzyme that makes ATP, the energy. That chromophore for that is red and near infrared light.

And if you use it at very low levels, you actually stimulate that function and you cause increased energy production.

And I'm going to share with you an article from 2015 that's an alternate theory of evolution that said that as our ancestors became less hairy in sub-Saharan Africa, the red and near-infrared light actually gave them more energy and allowed their brains to grow. So there was a selective advantage to losing the hair because of the ability to absorb good wavelengths of light.

Yeah, we're like plants. Light gives us more energy. And so when you're seeing these red light masks and people doing, is it generally safe in your opinion and we're doing this in a responsible way? Or is this going to turn out to be the new tanning, you know, they have these tanning salons in the 60s and 70s, which were probably not the best for people's health. Yeah. Well, there's certainly tanning salons now. So that wavelength is not an ultraviolet light. It's at the other end. So it's at the far visible and near infrared light. Right.

And then so I think like looking at ones that are FDA cleared because a lot of that clearance is on safety and then certainly not overdoing it. But they there's a lot of really great data on them, certainly for hair growth, but also for stimulating biological functions in the skin. And these are these wavelengths of red light that we can perceive like this is red. This looks red to a human. Is that is that right?

Yes, there are some wavelengths that are outside of the visible spectrum, which is about 4 to 800. So there are some that we don't see, but often when you use those masks, it is red because it is that wavelength. And do we get these benefits from things like a beautiful sunrise or sunset? We do, and especially sunset. I think one of my favorite things to do is to do a little sunset run.

And one is obviously exercise is great for you. And I'm getting a little bit of that red light. And so I feel like, okay, well, I'm getting a little bit of benefit too. Thanks to Zakir Rahman. That was the future of skincare. Thanks for tuning into this episode. You know, we have more than 250 episodes in our archives. And so you can listen to a wide variety of conversations about the future of anything.

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