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RHR: What Your Skin Is Trying to Tell You, with Dr. Trevor Cates


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The skin is the largest organ system in the body. And because of that, it becomes a great outer reflection of our overall health. But when people struggle with various skin conditions, it’s more common for them to turn to skincare items, beauty products, and topical or oral medications, instead of addressing the root cause. In this episode of Revolution Health Radio, I talk with naturopathic doctor and skincare expert Dr. Trevor Cates about using food as medicine, reducing our exposure to toxins and endocrine disruptors, and building up the skin’s microbiome for better health inside and out.

Revolution Health Radio podcast, Chris Kresser

In this episode, we discuss:

  • The skin as our “magic mirror”
  • Redefining traditional skin types
  • Cates’ Two-Week Program
  • Reducing sugar in your diet for more healthy and young skin
  • Reducing exposure to endocrine disruptors in personal care products
  • Why the skin hasn’t developed a strong barrier system
  • Building up the skin’s microbiome, and our awareness
  • Marketing claims in the skincare field and beyond

Show notes:

Hey, everybody. Chris Kresser here. Welcome to another episode of Revolution Health Radio. This week, I’m excited to welcome Dr. Trevor Cates as my guest. Dr. Cates is the author of the USA Today and Amazon best-selling book Clean Skin from Within and founder of The Spa Dr. natural skincare line. She received her medical degree from the National University of Natural Medicine and was the first woman licensed as a naturopathic doctor in California.

She currently lives in Park City, Utah, where she helps patients from around the world achieve naturally growing skin. She’s been featured on various TV shows, including The Doctors and Extra TV. Dr. Cates has interviewed over 250 experts on The Spa Dr. podcast and hosted her own PBS special, Younger Skin from Within. She believes the key to healthy skin is inner and outer nourishment with natural nontoxic ingredients.

So I’ve always been fascinated by the skin. It’s the largest organ system in the body. And because of that, it’s a pretty good reflection of what’s going on inside of the body. That’s something I am often discussing with my patients who have skin issues. So I’m looking forward to talking with Dr. Cates about her approach. And I hope you enjoy the episode. Let’s dive in.

Chris Kresser:  Trevor, it’s such a pleasure to have you on the show. I’ve been looking forward to this.

Trevor Cates:  Yes, it’s so great to be here with you.

Chris Kresser:  So I’m excited to talk about skin. It’s always been a fascinating topic to me because the skin, as we know, is the largest organ in the body. And because of that, it tends to really reflect what’s going on inside of the body, which I know [is] something you’ve spoken a lot about in your work. So why don’t we start there and just go into a little bit more detail about that. You’ve referred to the skin as our “magic mirror.” What do you mean by that?

The Skin as our “Magic Mirror”

Trevor Cates:  Yeah. Well, pretty much you said some of what that means, which is our skin is our largest organ. And because it’s right on the surface of our bodies, it is this outer reflection of overall health, and it can give us great clues about what’s happening with our health overall and also if we’re on track with our lifestyle choices. And I know that people are often quick to grab a cream or topical steroids just to suppress a skin symptom or, for women, to just use more makeup to cover up blemishes. But I want to really encourage people to look at your skin as something that’s giving you messages, important messages. And you don’t need special imaging equipment and X-rays or [computed tomography] (CT) scans or anything like that to see it. All you need to do is just look in the mirror, and it can give you great clues. Often, our skin gives us the early warning signs that something is out of balance. And so when we can catch things early, it’s certainly a lot easier, of course, not just to help the skin but to help our overall health.

Chris Kresser:  So when, let’s say, a patient comes into the clinic and they have acne or eczema or psoriasis or some other skin condition, what’s going through your head from a differential diagnosis perspective? Obviously, you’re going to look at it differently than a dermatologist might. They’re thinking about what steroid or cream or topical thing they might prescribe based on the name of the condition. But you’re thinking about it a little bit differently. So what are some of the main kinds of internal imbalances that you might suspect when somebody has a skin issue?

Trevor Cates:  Yeah, absolutely. When I’m looking at skin problems, especially chronic skin issues, I want to help try and figure out what we can do, both from an internal perspective but also what we can do on the outside. So it’s really both. And I think a lot of times, doctors either just use topicals, or they’ll just —also sometimes even as a naturopathic doctor, for many years, I was just [focusing] only on the inside. But what we put on the skin is also important. So what I found is that the combination approach is what’s really key to help with skin problems. And so when we’re looking at, especially from an inside-out perspective, I found that there are six root causes behind skin issues. And when we can find out which of these are, it really does help with addressing whichever skin problem we’re dealing with. So there are things like inflammation, microbiome imbalances, blood sugar dysregulation, oxidative damage, and hormonal imbalances. So obviously, as I’m saying these things, they’re not just a skin problem, but they’re definitely connected to [the] skin. And when we can figure out what’s going on with these root causes and our skin starts to improve as we’re addressing these, we also know that we’re helping prevent and possibly even address other health issues with similar root causes.

And I think what’s really interesting is, so when I was a kid, I had a lot of health struggles. I had a lot of allergies that showed up on my skin as eczema, hives, mysterious bumps, and itchy rashes that would appear. And I’m so grateful, even though it took a little while for us to find a holistic approach to help with my skin and my allergies, because as a naturopathic physician, I’ve seen in my practice where people will have something like eczema as a child, and they’re given topical steroids without really addressing that internal inflammation and some of the other root causes going on. But later on in life, then they’ll start to develop asthma because, again, the immune system [irregularities] haven’t been addressed, and then they’re given an inhaler. And then they go a little bit further down their life. And maybe at that point, they come [to] see me, and they have an autoimmune disease because these underlying causes are just going to keep coming up until we address them. And we can hide them for a little while with a topical cream. But until we truly address them, they’re just going to show up in our health in some other way.

Chris Kresser:  Absolutely. And I think we both agree that’s not only the case with skin issues but so many of the symptoms that conventional medicine has designed with medications that suppress or often missing opportunities to address deeper issues that if they’re not addressed, as you said, can turn into bigger problems down the line. So in your book, Clean Skin from Within, you talk about different skin types. So tell us a little bit about what you mean by that and what those types are.

The skin is the largest organ system in the body. And because of that, it becomes a great outer reflection of our overall health. In this episode of RHR, I talk with Dr. Trevor Cates about digging into the root causes of skin imbalances. #chriskresser #foodismedicine

Redefining Traditional Skin Types

Trevor Cates:  When people think of skin types, they usually think of dry, oily, mature, or sensitive, those types of skin types. But those are really more descriptive. It doesn’t really give us information about what’s going on behind the skin problem. So what I decided to do is to redefine skin types. And I came up with some skin personality types, and I gave them all human names because we like to see our patients as people, not just a skin issue or a health issue. Right? So they’re Amber, Olivia, Sage, Emmett, and Heath. And these are the skin types. But the reason why I categorize is I was seeing certain patterns in my patients. And while I found there are six root causes behind skin issues, not everybody has all six. So I started to see these patterns. And that’s why I gave each one of these skin types a few of the root causes. So that way, when people identify their skin personality type, it helps them hone in on the root causes behind their skin problems. So I created an online skin quiz. People can take it at theskinquiz.com. And they can find out which of these skin personality types they are.

Chris Kresser:  And then how do you use those types? I assume it’s a different approach for different types. Or are there similar approaches with just some differences based on the types?

Trevor Cates:  So definitely, with my book, Clean Skin from Within, I have a two-week program I lead people through. And within that two-week program, they can customize their approach depending on their skin type. So I recommend specific supplements for various skin types, food recipes, as well as DIY skincare recipes based upon various skin types.

Chris Kresser:  And what are those? For someone who’s pretty keen to make a big difference or make a change with their skin in a short period of time, two weeks is not that long. What are those four points that underlie that plan?

Dr. Cates’ Two-Week Program

Trevor Cates:  Yeah. When I first started—I’ve been a naturopathic doctor for 20 years. When I first started, I started doing six-week programs for my patients, and I realized six weeks is a long time for people to commit to things. So then I shortened it to four weeks, and then I realized that even with just two weeks, it’s enough time for people to see an improvement in their skin that gives them hope. And so we don’t necessarily expect, in two weeks, a complete cure, especially for a long-term, lifelong skin issue. But I have seen people completely clear up skin issues in two weeks. But for the most part, at least they want to see an improvement. They know they’re going in the right direction, so they’ll continue the program. So with the two-week program, there are four different aspects. There’s clean plate, clean slate, clean body, and clean mind. So the “clean plate” are the foods to eat and the foods to avoid. So when we look at these root causes, we want to use food as medicine. We want to eat more anti-inflammatory foods or foods rich in antioxidants, those kinds of things, and then avoid the ones that tend to trigger the root causes.

And then the “clean slate” section has more to do with what we’re putting on our bodies, on our skin, and ingredients to avoid as well as healthier alternatives. And when it comes to skincare products, we want to reduce toxins in skincare products because that is one of the big sources that we’re exposed to endocrine disruptors and toxic ingredients in our day-to-day lives. But we also want to use products that help support the skin microbiome. So that’s also a key, important part of this program. And then there’s “clean body,” which is about reducing toxins in our environment in other ways as well as improving the body’s detoxification pathways. And as you know, our bodies are so wisely designed with these incredible detoxification pathways, and they just need extra support to make sure that they’re working optimally. This two-week program is a great time to give it a little boost. And the “clean mind” is the last section. And that’s about stress management and mindfulness practices because we know that skin issues are triggered by stress. They also do stress us out. So then we get caught in this vicious cycle. So, of course, this stress management and mindfulness piece is also a really important part.

Chris Kresser:  So what do you think are maybe two or three of the biggest offenders from a dietary perspective and then also from a personal care products perspective? If somebody is wondering, “Where can I get the biggest return on investment if I had to make just a couple of changes in both of those areas?” what would they be, in your experience?

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Reducing Sugar In Your Diet for More Healthy and Young Skin

Trevor Cates:  Yeah, absolutely. So when it comes to food, the biggest one is sugar, which I’m sure that doesn’t surprise you. It’s a problem food for a lot of different reasons. And, of course, the skin is one of those reasons. And I think, for the most part, your audience is not part of that misunderstanding that the only reason why you would need to give up sugar is if you want to lose weight. Right? There are way more reasons to watch your sugar intake beyond just trying to maintain a healthy weight. So when it comes to skin, a couple of things to think about with sugar is that, first of all, sugar tends to be a more pro-inflammatory food. So any kind of inflammatory skin issues, which they generally are, [will] be worsened by sugar.

And then the other thing is, of course, acne being the most common skin condition, [a] chronic skin issue that people struggle with. Well, when people eat sugar, it increases their blood sugar, increases insulin. And an increase in insulin will trigger excess sebum production, oils in the skin, as well as excess androgen activity. So then that activity will trigger acne breakouts, especially [for] people that are susceptible to acne. And then when it comes to the aging process, we know that sugar, because of glycation problems, can actually speed up the aging process. So with glycation, glucose binds to proteins in the body. In the case of skin, we’re talking about collagen. Collagen, of course, gives our skin that nice texture and firmness. So when glucose binds to it, though, it will make it more rigid and less elastic. So that leads to more wrinkles and sagging skin, which, of course, none of us want to look older than we are. And actually, when you look at someone and they look physically older on the outside, they look physically older than their actual age, there’s a good chance internally, like, their joints and even on a cellular level, that they’re just not aging as well as would be expected for a healthy person their age.

Chris Kresser:  And then what about things we might put on our skin, soap, shampoo, other kinds of chemicals? What do you think are the biggest or the most problematic things in the industrialized world, let’s say?

Reducing Exposure to Endocrine Disruptors in Personal Care Products

Trevor Cates:  Well, on average, we use nine personal care products a day, which exposes us to about 126 unique ingredients. That was from a study done by the Environmental Working Group. And 126 unique ingredients [is] a lot of ingredients, especially when you realize that the United States [Food and Drug Administration] (FDA) has banned only 11 ingredients in personal care products, whereas in Europe, they’ve banned over 1,000 ingredients in personal care products. So– [a lot] is left unrated by the FDA within the skincare industry. So it really is up to the consumer to be careful about what we put on our skin because what we put on our skin doesn’t just sit on the outside. We use topical medications as a route of administration—

Chris Kresser:  Drug delivery, yeah.

Trevor Cates:  -—of medication. Yeah. And so we know that we get things absorbed into circulation that we put on our skin. But yet, so often, we mindlessly put products on our skin, the sunscreens, lotions, deodorants, even shampoo, conditioner for women, makeup galore. All of these things that we put on our bodies, we are absorbing a lot of these. One of the biggest concerns with these is a group of chemicals called endocrine-disrupting chemicals. And I’m sure you’ve talked about this on your podcast. This group of chemicals [is] known to be hormone-disrupting chemicals. Basically, they’ll bind the hormone receptors and mimic hormones or just alter the function of the receptors so that our hormones can’t function in the way that they’re designed to. And endocrine-disrupting chemicals have been linked to a number of different health concerns, from infertility to weight gain, weight problems, to certain types of cancers, breast cancer, prostate cancer. When you think of hormones, anything can go, there are so many things that can go wrong with hormones. And these endocrine-disrupting chemicals can really wreak havoc on our endocrine system. So we are exposed to these chemicals in our air, our water, our food, [and] our personal care products. So we don’t have control over all the different ways we’re exposed to it just because of living in today’s world. But there are certain places where we can reduce our exposure. And personal care products are one of those easy places to reduce exposure.

So when we look at personal care products, it’s often really confusing, though, to look at a label and know what’s what. When you look at a label and you see vitamin E or argan oil, you’re like, “Okay. That’s great. I know what this is.” But when you get down the list and there are all kinds of things—even in so-called natural products, there can be a lot of other ingredients that we just don’t know. And it’s really unfortunate because, for example, there’s a group of chemicals used in personal care products, especially a lot of lotions, called formaldehyde releasers. And it doesn’t actually say formaldehyde on the label. It’ll say something like DMDM hydantoin, which nobody really knows what that is unless they’re doing a little bit of research into this. And so with these different chemicals, what happens is when you apply them to the skin, they release formaldehyde into the air around you. And we know that formaldehyde is a carcinogen. We know that it’s really toxic when it’s inhaled. And the last thing I want to do is be surrounded in a bubble as we’re putting different lotions and things on our skin.

So that’s one example. And then we also have things like parabens, which probably people have heard about. The nice thing with that one is you can see “paraben” at the end of the words, so you know to avoid those. And a lot of skincare companies have taken those out. But one ingredient that is in so many personal care products, and not just personal care products but also cleaning products and many other things, is fragrance. And fragrance is listed as a single ingredient, but yet, it’s a huge, whole list of other ingredients that contain endocrine-disrupting chemicals. So, for example, diethyl phthalate is used in fragrance to help the scent last longer, but it is a known endocrine-disrupting chemical, and it has shown up in human samples. So we really want to be careful with ingredients like this.

Why the Skin Hasn’t Developed a Strong Barrier System

Chris Kresser:  Yeah, it’s a long list. And I think it’s really interesting to consider the skin as a barrier system, which it is, and then the gut. With the gut, we evolved a pretty complex ability to keep things out that we didn’t want to get into our bodies because our ancestors were exposed to toxins through things that they might eat a lot more than they were exposed to any toxins that might get onto their skin. Living in a pretty pristine environment and in that kind of Paleolithic Era, for example, they didn’t have sunscreen. They didn’t have all these chemicals that they were putting on their skin. So the skin never evolved that selective barrier kind of quality that the gut did. So that’s often how I explain it to my patients. The skin is just a kind of very open, permeable membrane. And pretty much [as] you said, anything you put on your skin is going to get in your body. Whereas we have some ability, when we eat something that’s not great, to at least keep that out to some extent.

Trevor Cates:  Right. It’s so true. And we have done so much damage to our skin in modern-day living, too, with overzealous hygiene practices, and not just even our own personal care but also how we clean our homes and all of the different detergents, the antimicrobials that we’re using in and around our homes and our bodies. We’ve completely disrupted our own microbiome of the skin. And it already really varies from one person to the next. When you look at the skin microbiome, it is impacted by people that live in the home with you. So if you live alone versus you live with other people, their hygiene practices impact you, the health of their skin microbiome impacts you. If you have animals in the home, that impacts your skin microbiome. So like you’re saying, it’s this open system to the outside world, and it’s impacted by all of these different factors around us. So our skin is constantly trying to rebalance itself. And part of that comes from the gut-skin connection and the gut microbiome. So when we do things to help support the gut microbiome, we can definitely help the skin microbiome heal itself. But what we’re putting on our skin on the outside and what’s around us also definitely impacts the skin microbiome.

Chris Kresser:  Yeah, that’s really fascinating. And it’s kind of like, with the gut, of course, we have antibiotics and nonsteroidal anti-inflammatory drugs (NSAIDs) and all of the other medications that have become ubiquitous, that people take internally, that really [have] a negative impact on the gut microbiome. And you’re saying the chemicals that we use and even that people around us are using are having a similar effect on the skin microbiome.

Building up the Skin’s Microbiome, and Our Awareness

Trevor Cates:  Yeah, absolutely. So when you think about all the different antimicrobial agents, one that’s obvious is hand sanitizers. Right? So people are using hand sanitizers like crazy, especially right now, to kill off viruses and the various things they’re exposed to. But they’re also killing off some of the beneficial bacteria [that are] living on their skin [that are] there to help protect their skin. And yeah, our skin has this amazing function and ability to act as a barrier to the outside world. But yet we’re constantly doing things to break it down. And so instead, we want to think about ways that we can build up the skin microbiome. So, first of all, people are a little too quick with hand sanitizers. Now, hand sanitizers can be very convenient if you don’t have a place where you can go wash your hands. So yes, I get that. And using more of a natural one with some essential oils and aloe is a nice alternative. But people forget that washing your hands just with regular soap is actually better than using hand sanitizer. So just simple things like that, not overdoing it with our hygiene practices, is such an important thing.

And then when it comes to the skin, a lot of times, we’re using ingredients and skincare products that have this sort of occlusive effect. So, for example, there’s an ingredient called dimethicone. And it’s used in a lot of lotions and makeups to give that kind of dewy, glowy hydrated look. But the problem with that kind of occlusive effect that dimethicone has is it’s not allowing the skin to breathe. And microorganisms can get trapped under that layer. And it’s particularly concerning if you go outside and you get hot or you’re exercising and there’s this layer of heat under there, and it can actually start to alter the skin microbiome. So even things like you would just think of something so simple as that can actually start doing some damage, as well. So it’s not just the antimicrobial agents but also these occlusive agents.

Chris Kresser:  That’s fascinating, and it’s a good reminder. One way to think about it is the modern world, it’s not—we’re kind of swimming upstream. Right? There are a lot of things that we need to be aware of. And I know that can be stressful for people. And sometimes, it’s just like, “Throw up your hands in the air.” It’s just one more thing to worry about. But we’re so far now from what our natural habitat is for human beings. And a lot of this stuff has consequences that we’re only now just beginning to understand. A lot of the effects of the chemicals that you mentioned have been studied, but that hasn’t necessarily trickled down into the mainstream. And as you pointed out earlier, the regulation of chemicals in the [United States] is just ridiculous.

It’s basically innocent until proven guilty. Any company can introduce any chemical into the space without really proving that it’s safe. It’s essentially, “Nothing will happen until it’s proven that it’s not safe,” which is just an insane way of going about it, I think, especially when you’re talking about chemicals that have been shown, not only to—a lot of these chemicals we’ve been talking about don’t just mess with your skin. They also mess with reproductive health and cause birth defects, in some cases, and, arguably, much more serious issues. So there is a certain level of vigilance that, [as] you said before, we have to be our own advocates because the companies that are manufacturing these things and selling products that contain them certainly are not going to advocate for us in that regard.

Trevor Cates:  Yeah. And that’s actually why I started this product or skincare line is because my patients just kept asking me for natural products and solutions because they knew I would educate them on the endocrine-disrupting chemicals, all these different things. I wanted them to avoid these ingredients. But yet they were finding that they weren’t liking the results they were getting from the natural skincare products out there. Plus they were concerned. They didn’t know who to trust. And so I started digging into the research and looking at, “What are truly natural ingredients that do help support the skin microbiome? What else helps support the skin microbiome?” I also started to learn about the pH of the skin and how crucial that is in helping support a healthy skin microbiome. And with that barrier function, that natural barrier function the skin has, part of that is with mild acidity, which allows it to do that. So a lot of skincare products actually have a high pH in the products, and that will disrupt that natural mild acidity that helps support the skin microbiome.

So when I was starting to look at these different factors—and I was actually able to find a formulator to help me—I started off making my products in Europe because their standards are so much higher. And I knew that the ingredients that I was going to be getting over there and the people that I was working with were going to be at a much higher caliber as far as clean skincare, truly natural skincare. So I started to make my products over there, made sure that all of the formulations were in that mild acidity range, the 4.6 to 5 pH range, to help support the skin microbiome. And it really has been rewarding to know that not only can I provide truly natural and clean products for my patients, my customers, myself, my family, and my friends but also products that create a difference in the skin. So I started off just really wanting something clean for my patients. And then I realized what was possible when you give your skin the right nutrients because so many ingredients out there, even if they say they’re natural, they’re not truly active. And the purity of the ingredients, the quality [of the] ingredients goes a long way, along with the formulations to actually see visible results on the skin.

Marketing Claims in the Skincare Field and Beyond

Chris Kresser:  Yeah, that’s so helpful because, over time, I think the words natural and organic have become—I wouldn’t say meaningless, but approaching that. Right? And that’s not just with skincare. It’s with foods and as bigger corporations have seen that there’s money to be made there. Okay. I’m a little bit of a cynic there. I admit. But you can’t see a label that says natural and organic and just trust that what you see is what you get. Right? With skincare, I think that’s true as it is with food.

Trevor Cates:  Yeah, absolutely. And a lot of times, people don’t realize that there’s a lack of regulation around terms like “natural” and even the word “hypoallergenic.” You would think that sounds medical. It sounds like something that would be regulated. Actually, it has no regulation around it. It’s just a marketing claim, which is so unfortunate and misleading. So it’s now a matter of finding companies that you can trust, that you really believe that they are doing the work. No. I’m always amazed when we make a new batch of skincare products and we go through the quality control and do all the testing before we get the products out to the public at how many times, I mean, the people involved in the process, in the lab will say, “Do you realize how few manufacturers actually do all the steps that you do?” And I say, “Well, it doesn’t really matter. I’m creating my own standards because I want what’s best for my customers.” But I know that most companies, especially the big companies out there, [are] really just concerned about making money. And it’s unfortunate, but we know it’s true.

Chris Kresser:  Yeah, that’s the reality of the situation. And like I said, earlier on, when organic food was just more coming onto the scene, I think it was more trustworthy as a standard. And over time, as bigger companies have entered the space, that’s gotten inevitably diluted. And I think that’s also happened with skincare. So, Trevor, if people want to learn a little bit more about your work and about your skincare product line, how can they do that?

Trevor Cates:  Well, my website is thespadr.com. And as I mentioned before, I have the skin quiz. So people can go to theskinquiz.com, [and] find out their skin personality type. And if people want to get a copy of my book, there’s a place where they can go and just pay the shipping fee to get it. The book’s free. Just pay the shipping and handling fee, and that website is book.thespadr.com.

Chris Kresser:  Great. Well, thanks so much for coming on the show. It’s been really fascinating. I’m sure the listeners got a lot out of it. And yeah, I just appreciate you taking the time to do it.

Trevor Cates:  Thank you, Chris. Thanks for having me on. Now we just need to get out there and go ski.

Chris Kresser:  [laughter] Just need some more snow. That’s right. That’s the champagne problem. Right? But it’s one of the ways that I know we both love to get out and enjoy nature and be active in a safe way during COVID-19 time. So I’m grateful to have that opportunity.

Trevor Cates:  Yeah, absolutely. All right. Thank you, Chris.

Chris Kresser:  Okay. Thanks, everyone, for listening. Keep sending your questions in at chriskresser.com/podcastquestion. And we’ll talk to you next time.