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Episode 8: Clean Skin From Within With The Spa Doctor

Episode 8: Clean Skin From Within With The Spa Doctor

Our skin is our largest organ, so it makes sense that its health would reflect the health of what’s going on internally, though not many people think about that connection. In fact, many of us try to fix problem skin by focusing first on the external with topical cleansers, creams, serums, and toners.

Dr. Trevor Cates (The Spa Doctor) was the first women licensed as a naturopathic doc in California and currently lives in Park City, Utah where she helps patients from around the world achieve graceful aging and glowing skin. She also hosts The Spa Dr. weekly podcast and has her own PBS special, Younger Skin From Within.

Her best-selling book, Clean Skin From Within, dives deep into why the health of our bodies is written all over our faces.

On this show, she talks about how the microbiome of our skin is disrupted when our gut microbiome is disrupted, how we can improve our skin by identifying the root cause of our skin woes, and gives she Andrea some tips on the best things we can do for our skin to maintain lifelong health.  

To take the skin quiz, go to Be sure to follow Dr. Cates on her website at and on social at the handles below:






On this show, you’ll learn:

  • How our skin is a reflection of what’s happening inside our body (3:32)
  • How our genetics and lifestyle choices play a role in skin health (5:44)
  • Are we getting too good at killing germs? (8:12)
  • Best food choices for the skin microbiome (10:12)
  • Find your skin type at (11:29)
  • The 6 root causes explained (12:34)
  • Skin care products for the skin microbiome (15:06)
  • Long-term effects of some skin care products (15:52)
  • How a skin care routine changes over our life (17:26)
  • The best things we can do for our skin (20:45)
  • What Dr. Cates is most excited about moving forward (24:37)

biohm gut quiz


Andrea Wien: Welcome to The Microbiome Report. I'm your host, Andrea Wien, and my guest today is Dr. Trevor Cates. Dr. Cates is the founder and owner of The Spa Doctor, an author of the best-selling book, Clean Skin From Within. She was the first woman licensed as a naturopathic doctor in California, and currently lives in Park City, Utah where she helps patients from around the world achieve graceful aging in blood and skin. She's also the host of her own weekly podcast, The Spa Doctor, and has her own PBS special, Younger Skin From Within.

On this episode, we talk about the microbiome that lives on our skin, and how it has a vital role in everything from acne and eczema to athletes foot. As someone who battled acne during my younger years, I wish that I had Dr. Cates' insight into how the microbes living in and on me could have helped my struggle. Let's get to the show. Dr. Cates, thank you so much for coming on the show.

Dr. Trevor Cates: It's great to be here with you.

Andrea Wien: I think most of our listeners are familiar with the gut microbiome, but they're less familiar with the mechanics of how the skin microbiome works. Can you educate us a little bit on the organisms that live on our skin?

Dr. Trevor Cates: Yeah, it's really interesting all of the microorganisms that live in and on our body that protect our health, and that there has been a lot of attention lately to the gut microbiome, and that's super exciting to see that. I think this is one of the reasons why other areas of the body, there's been some more research looking at other areas of the body, and what microbiome is going on with that area. Skin is one of those areas.

It's fascinating because there's so much, because our skin is on the outside of our body, there's so much that can impact it, but not only externally, but also internally, so there's also some great information coming out about the connection between the gut microbiome, and the skin microbiome. It's exciting to see all this coming to be.

Now, as a naturopathic physician, I know that naturopathic doctors have been talking about the connection between gut and skin health for a long time, and it's so great now to see the research lining up with that. Seeing that so much of what we're doing internally can impact the skin. The research is now unfolding about the skin microbiome, but basically it is similar to the gut microbiome. If you've spent a lot of time talking about that on your podcast, which I'm sure you have, it's a similar idea.

There are all these organisms living on the skin, and that they actually play a vital role in the health of the skin, and so we've got bacteria, good, bad, commensal, and we've got fungi. We've got these little mites that live on our skin. All kinds of things that actually live there, we can't see, but they're there, and they play an important role.

When we do certain things, like our hygiene practices, taking antibiotics, putting antibiotic types of treatments on the skin, it disrupts that, and there are things that we can do to help support the skin microbiome to keep our skin healthy, disease-free, and also aging gracefully because skin microbiome also plays a role in the way the skin ages.

Andrea Wien: I want to get into a little bit, in a few minutes, about the types of products that we're using, and the water even, for example, and how that can even affect our microbiome, but I want to take a quick step back, and just ask, is it a stretch to say that our skin is really a reflection of what's happening inside our body, and specifically inside our gut?

Dr. Trevor Cates: Yeah, absolutely. I often times, people often times hear me talking about how skin is our magic mirror, and it gives us great information about what's going on internally in the body, the health internally, and that if we can address the root causes behind skin issues, then that's really the best way, long-lasting, both acutely and long-term, in helping the skin. It's getting these external messages and signals of what's going on internally.

When there are imbalances, then it shows, often times, shows up on the skin, and sometimes it's the first thing that shows up in our health is a skin issue, like eczema, acne, rosacea, just mysterious little bumps, or itchiness, drying skin, all kinds of things that our skin can be showing us that something internally is out of balance. Now in my book, Clean Skin From Within, I talk about six root causes behind skin issues. Gut microbiome, gut is a huge part of that. It's one of the big root causes, and so absolutely it's important to look at what's going on internally, and it definitely plays a role in the health of our skin.

Andrea Wien: Yeah, I was diagnosed with celiac disease 20 years ago, and then all through my teens and early 20s, I had such bad acne, and now looking back, knowing what I know, it was obviously leaky gut at play, autoimmune disease, and really healing my gut cleared the acne, but unfortunately so much of what conventional doctors were telling me at the time was, "Take this Tetracycline for years, or take this cream that is antibiotic," and it was actually having a negative impact instead of the positive impact that they were hoping for.

Dr. Trevor Cates: As a naturopathic physician, I really like to use more of a natural approach. I can also prescribe medications. I see the role where all of this plays. For me, I struggle with eczema and hives as a kid, and so those are signs, and if we can find out what's behind it, and address that, it's such a better way to help support the body in the short-term and the long-term.

Andrea Wien: Now, is it very bio-individual, like for example, you said you had eczema, I had acne. Are those different issues that are happening internally, or could they potentially be the same issue, just expressing in different ways?

Dr. Trevor Cates: Well, part of it is our genetics. Our genetics are going to be different, so we just are born into this world with genetic predispositions, and certainly our lifestyle choices are part of what helps the genetic expression, the way that those genes that we come into this world with, how it shows up, and how it shows up in our health. Part of it is genetic, but part of it is our lifestyle, and what we're doing, and so it can manifest differently in different people.

Sometimes the root cause is similar. It can be gut related, it can be inflammation, but everybody is different to a certain extent, but at the same time, there are certain things that I notice in my practice, I've been practicing for almost 20 years, there are certain things I was noticing, which is what led me to write my book, and I was saying over and over again to people.

Those are the things that are the same. If we can figure that part out, it helps address a lot of the issues. I still think it's good for people to work directly with a healthcare provider who can individualize and customize a treatment plan.

Andrea Wien: Is it possible to have a skin issue, let's say, tinea versicolor or psoriasis, and not have something going on internally?

Dr. Trevor Cates: Oh, well certainly. There can be an acute infection, so if someone, like ringworm. You mentioned tinea, but I mean like athletes, but ringworm, it could just be that they picked up the infection from somebody. I do think that that's possible, but usually there's some other underlying cause because why don't we all have athlete's foot, because athlete's foot is very contagious. A lot of these skin conditions are very contagious, but not everybody picks it up all the time, so part of it is our immune system, our overall health, and other things, so I hope that answers the question.

Andrea Wien: Of course, yeah. I mean I think it goes back to the old debate that's been raging for millennia of is it the terrain or is it the bacteria or the germ, and so I think it's a combination of both. The terrain has to be weakened for that to take hold, so that makes sense. These days I think so many people too are terrified of bacteria and germs.

We have Purell. We have antibacterial soaps. We have all of these things that are really good at killing things around us, but it's really at the detriment of our overall health, as we're starting to learn. I think we've gotten too good at killing our germs, which is really impacting this whole symbiosis. Can you talk a little bit about that?

Dr. Trevor Cates: You know it's interesting, I just got back from a trip to Uganda, and it is, when you look at a country like that, where the sanitation is an issue, we want to be careful so that we don't get foodborne illnesses, and we want to make sure that we're drinking clean water, and so yes, there are very harmful microorganisms that can exist in our environment if we don't have good hygiene sanitation practices, but the thing is in our country, and many countries around the world, where we have great water, we have cleaner environments as far as not having these kinds of bacteria that are going to make us very sick.

There is this balance of it because we want to be smart about that. We want to have good practices, but yeah, I think we have gone overboard with it, and so it's about creating that balance. We want to make sure that while we're being mindful of washing our hands so we don't spread disease, and we want to make sure we have clean water, and those sorts of things, we also want to be careful that we're not overdoing with too many antibiotics, too many antimicrobial hand sanitizers, and soaps, and cleaning agents.

Just even using a bar of soap to wash your hands is effective enough to help protect us. We don't need all these hand sanitizers and things. We do overdo it, and we don't need to be taking so many courses of antibiotics. I think that we need to be selective of when we use these things, and be mindful of it, and remember that there's so many other things that we can do to support the body, and being healthy, and part of that is eating healthy foods, taking supplements if we need extra nutritional support, herbs, and natural substances, essential oils.

A lot of things that we can be doing in our home, and with our food, and our environments to support a healthy environment without going overboard with all these synthetic antimicrobial agents.

Andrea Wien: Are there certain foods that are best for the skin microbiomes specifically?

Dr. Trevor Cates: Well, when you look at foods, the way you're helping the skin is usually through the gut microbiome. Definitely you're seeing the research connecting when our gut microbiome is in a healthier state, our skin microbiome is in a healthier state, and when we have gut dysbiosis issues, that linked more to skin conditions, skin issues, and so what we eat, of course, can impact the gut microbiome, which then in turn could impact the skin microbiome.

As far as good things to eat, high fiber foods are going to help promote a healthy gut microbiome. Probiotic, prebiotic types of rich foods are also going to be beneficial, and then also avoiding things that are high in sugar, processed, highly refined foods, so it's really what are you eating, and what are you avoiding, and creating that optimal diet to help support the gut microbiome, which in turn helps the skin microbiome.

Andrea Wien: I would imagine just like the symptoms that can pop up would be very different. The foods that are best for each of us are very different too. The bio-individuality of everyone is so important, so really working with someone who knows about these things, and how to optimize them, like a naturopathic doctor, or functional nutritionist is probably the best way to find out what's best for your skin.

Dr. Trevor Cates: Right, absolutely. As I said, it's really, I think it's ideal to work one-on-one with practitioners. I think that there's a lot, like I said, I felt like in my practice there's a lot that I repeat, and that's what I put in my book, and so I think there's an underlying, there's certain foods, there's certain things to avoid, certain things to eat, certain things in our environment, and our water, and in our personal care products in our homes that we could all do that helps support a healthy body, but then there's a part where you get to where you need to individualize, and I do that to a certain extent in my book because what I did was I created skin types.

Each skin type is related to certain root causes with them, so if people can find out their skin type through taking my skin quiz, which they can go to Each of those skin types is related to a group of root causes. Not everybody had all six root causes, so then that is a way that people can customize to a certain extent.

Andrea Wien: Can you talk a little bit about what the root causes are, those six root causes?

Dr. Trevor Cates: Yeah absolutely. I mentioned, of course, microbiome is a big one I talk about in my book, one of the big six root causes, and that is the gut microbiome and the skin microbiome, and their connection between those. Also, hormonal imbalances can trigger skin issues. We see it with acne. When kids are going through puberty, a lot of times you'll see more of the acne breakouts.

Then also, women will notice acne breakouts. Sometimes at certain times of the month, or certain phases of their lives when their hormones are going through changes, and we see those that can indicate a connection between hormonal imbalances and a skin issue like acne. Other skin conditions can be related to that. Also, inflammation is a big root cause. I call it skinflammation when internal inflammation shows up on the sink.

Also, there's nutritional deficiencies. When we are deficient in certain nutrients like zinc, essential fatty acids, those can definitely trigger certain skin issues, and then there's also glycemic balance, so blood sugar issues can play a role in skin issues, and also oxidative damage. Oxidative damage is regularly occurring to us as we get older, but there are certain things that speed up that, the free radical damage that can occur that then shows up on the skin as things like premature aging.

Those are some of the big root causes, I think. When people take the skin quiz, it can help them figure out which of those are really playing a role in their particular skin issues and their health. Again, it all is connected, and as I go through these root causes, a lot of people are probably thinking, "Oh, well those root causes are connected to a lot of different diseases," and that's true, and that's part of my approach is when you address the root cause, you're going to help your skin, but you're also going to help your overall health.

Andrea Wien: Yeah, I think that makes a lot of sense, and as you were going through them, I was thinking even of the connections myself of okay, the microbiome maybe is not balanced, and so then you're not absorbing the right nutrients because you can't break down the foods that you're eating, and so it really does start to all just tie together.

Dr. Trevor Cates: Absolutely yeah, certainly when I talk to people about nutritional deficiencies, you want to know why did they have a nutritional deficiency in the first place? Is it because of they're not eating the right foods? They're not getting a healthy diet that's providing these nutrients, or are they eating a healthy diet, but their digestion is poor, so they're not absorbing, they're not breaking down the nutrients and absorbing them from their diet?

Andrea Wien: We talked a little bit about the internal, but what about the external? What do we really need to do skin care product wise, to be taking care of our skin microbiome?

Dr. Trevor Cates: Certainly what we put on the skin also impacts the skin microbiome. I think about 80% comes from the inside out, but also what we're putting on the skin plays a role too, and that is something that I learned later on. It's funny as a naturopathic physician I was so focused on what's going on internally, but then I started to look at what we're putting on our skin, and how it actually can disrupt our skin microbiome.

Andrea Wien: When we think about the types of products, obviously there's thousands of products out there, and I would say the majority of them probably are having a negative impact even if we might be seeing some more moisturizing or some benefits in the short-term. In the long-term, are most of the products that are out there pretty detrimental?

Dr. Trevor Cates: Well, I would say to a large extent, yes, and part of that depends on where in the world you live. In the United States, skin care, personal care products, are not a well-regulated industry, and there are a lot of toxic ingredients in skin care products that can disrupt the skin microbiome. Like we were talking about, there's been this trend towards being antimicrobial, antibacterial everything.

That, because we're seeing more of those in cleaning products, and personal care products, that is contributing to the problem, so certainly it's a combination of toxins in skin care, but also antibacterial ingredients that a lot of times people have been thinking, "These are good. These are going to help our skin," but we've created more imbalances in the skin microbiome as a result of that.

I was recently at an integrated dermatology conference, and there was a dermatologist there talking about this, talking about how we have actually been doing harm by with all the antibiotics that we've been prescribing and putting onto the skin, and the practices that we have been doing up until this time, and we've been creating some pretty significant chronic skin issues as a result of how we've been treating the skin.

Andrea Wien: When we think about our life cycle, so from childhood to teenage years, to adulthood, maybe even into pregnancy and then beyond into elderly years, how does this routine need to change? Does it need to update, or if we're using good quality products, are we able to use those for our entire life cycle?

Dr. Trevor Cates: I think we need to start with children, and certainly create this as a lifelong practice, and looking at what we're putting on our skin. One of the big things is getting back to nature, getting back to using natural substances, getting away from a lot of the synthetic ingredients that are creating more disruption, and looking at ways that we can support the skin.

A lot of times people put things on their skin to make their skin look better, to make it look shinier, happier, glowing, and healthier, but when you look carefully at the ingredients in some of these lotions and cosmetics, there actually can be harmful ingredients in there that may make the skin look good when you put it on, but as soon as you wash it off, you're actually realizing that you're not doing any good to your skin, and so there are lots of examples of this, or things like why are we using things like mineral oil and petroleum by-products that can potentially create harmful imbalances when we have plant-based oils that could actually nourish the skin, and provide a healthier environment for the skin to flourish?

Also, things like we commonly see in makeups and lotions, dimethicone, and dimethicone is an ingredient that's used to sort of trap in moisture, and make the skin look and feel moisturized, but it's actually not improving the quality of the skin, it's only just creating this temporary look and feel. What actually might be happening is if you think of it like you're…With dimethicone, it's almost like you're putting like a…

Think of it like a layer of plastic that you're putting on your face to keep the moisture trapped in, but if you go outside, and you're in the heat, or you go work out, and you're exercising, then your body's just trying to, your skin is trying to perspire, and so what happens is you've got all this trapped under this layer, and so that can actually create some disruptions in the skin microbiome.

Andrea Wien: If people are starting to look at their products, and saying, "Hm, I don't know if this is something that could be problematic," are there resources or places to go where they can check the products that they already have, and potentially find products that are safer?

Dr. Trevor Cates: Yeah, and there's a big section in my book, Clean Skin From Within, the section on clean slate. Clean slate and the section in my book on clean slate is about the products that we're putting on our skin, and which ingredients to avoid, and alternative healthier options to use that are going to both be less toxic for the body, and there are a lot of endocrine destructing chemicals that are in personal care products, so looking at ways we can reduce exposure to those, and using alternatives, as well as what are the ingredients that are going to help support the skin microbiome instead of damaging it.

Certainly my book is a resource, also Environmental Working Group, is an organization that has some information on toxic ingredients in skin care, how things are, skin care ingredients, are rated as far as harmful health effects.

Andrea Wien: Okay great. Thank you. When you think about the one or two best things that someone could do for their skin, say they're time-strapped, they're resource-strapped, they don't have the money to go out and redo all of their products, or suddenly start eating organic, what are the one or two things that will make the biggest difference?

Dr. Trevor Cates: In my book, I talk about there are four different aspects that really help with skin, and that is the clean plate, clean slate, clean body, and clean mind. Clean plate are the foods that we're eating, and the foods to avoid. Clean slate are the products that you are putting on the skin. Clean body is reducing toxins in your environment, and supporting the body's ability to detoxify, and then clean mind is the stress management and mindfulness practices, and so all of these things, it's really a well-rounded approach.

Whatever you can do in each of these categories, even if it's one small thing, then at least it's doing something to move in that direction, and to think of it holistically because I don't want people to just think about in one area, it's really essential to do it in all the different areas, and really the daily practices that we have. For example, when it comes to the clean plate section, there are three keys that I find are particularly important for the skin care products that we're using.

One is that they truly are clean and natural, that we're avoiding these toxic ingredients that I was talking about. Two, that those natural ingredients are in their active form because that's also important. You want to look for manufacturers that really are not just looking at removing toxins from skin care, but looking to source the best natural ingredients to get you the results you're looking for because yes, people want good results from their skin care products.

The third thing has to do with the pH of the skin care products. I think a lot of people aren't aware that the skin actually does best with a mild acidity with a mild acidic environment, and that is one of the ways it helps protect, and helps feed a healthy skin microbiome. It creates this really great environment for healthy skin microbiome to flourish when it has that mild acidity. A lot of the products that people use have too high of a pH.

What we want to do is have mildly acidic products, things that are in the 4.6 to 5.4 or 5 pH range. Those are the kind of products that are going to support our skin, and having a healthy skin microbiome. As you mentioned earlier on, even water has a higher pH. You mentioned water and how that actually isn't even particularly good for our skin because when we rinse our face with water, that pH of water is seven or eight, depending if you have more alkaline water, and that is too high for the skin, so then we need to follow that up with skin care products that have that mild acidity.

Now optimally we're in such a healthy state, our body is in such a healthy state, it's just going to bounce back to having that mild acidity, and naturally occurring. A lot of people already have these disruptions in the skin. It's good to support the skin, and so that it can be optimally healthy with the skin microbiome.

Andrea Wien: If people are curious how to find out the pH of their products, can they call the companies, or is the best way to just buy those inexpensive pH strips and test it yourself? What do you recommend?

Dr. Trevor Cates: Yeah, I mean people can certainly use pH strips if it's a liquid product, but it's not always easy to do that. For lotions, you can certainly do that. I've done that sometimes, and I'm surprised how many moisturizers have a pH over 5.5. It's actually not that easy to find in these products, but also you should be able to call the manufacturer and they can tell you that. We have that information at The Spa Doctor we have that information on the website so that people know the pH of all five of the skin care products that I make, and that they all fall within that mildly acidic range. We state the pH of every single product.

Andrea Wien: One last question. I know we're running out of time. When you think about the research that's coming out around the microbiome and the gut/skin microbiome connection, what are you most excited about?

Dr. Trevor Cates: Oh my gosh, there's so much great information coming out, and I think that we're seeing a lot, both from internally and externally, and I think that both are really exciting to see. I am excited. Because I make skin care products, what are the ingredients that we can be putting in our skin care products to help the skin microbiome? Are there certain probiotics that can be used in skin care products to actually help address skin care issues?

Some of that research is starting to unfold. It's still really early in that research, and I know that manufacturers are already starting to make skin probiotic formulas, but I think a lot of these companies are a little bit ahead of what the research is showing. I'm excited to see more of the research actually showing us the real science behind probiotics and skin care.

Andrea Wien: Dr. Cates, this has been so great. Thank you so much for coming on and sharing your knowledge. If people want to find your book, or your products, or learn more about you, where can they do that?

Dr. Trevor Cates: They can just go to, so, so Dr is abbreviated. They can find out about my skin care products, my book, my podcast, and lots more information, the skin quiz also. All of that information is on my website.

Andrea Wien: Great, and we will link to all of that in the show notes so people can go to to find that. Thank you so much. We'll talk to you soon.

Thanks so much for tuning in to this week's show. If you haven't already, please, please, please go leave us a review and rating on iTunes. It helps to keep us going, and it means the world to hear from you. We'll be back next week with an episode from two very special ladies from across the pond.


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