068: Vitamin A & Zinc Connections To Skin Rash Symptoms w/ Chris Masterjohn, PhD

Some vitamins and minerals have a key role to play in our skin health. Unfortunately, many of us are either slightly or very deficient in these nutrients, which can cause symptoms to manifest on our skin.

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My guest today is Chris Masterjohn, PhD. Chris earned his PhD in Nutritional Sciences from the University of Connecticut in the summer of 2012.

He served as a postdoctoral research associate in the Comparative Biosciences department of the College of Veterinary Medicine at the University of Illinois at Urbana-Champaign and as Assistant Professor of Health and Nutrition Sciences at Brooklyn College, part of the City University of New York.

Chris now works independently, producing educational content about nutrition.

Join us as we talk about the importance of different micronutrients for the skin, and how to address nutrient deficiencies.

Have you managed to improve your skin health with nutrition? Tell me about it in the comments!

In this episode:

  • Chris's eczema story
  • Why is vitamin A important for skin health?
  • Information on zinc and the skin
  • Chris's favorite food sources of vitamin A
  • Testing Nutritional Status: The Ultimate Cheat Sheet


“Probiotics are so individual that different probiotics are gonna work differently for different people.” [2:42]

“If you have active eczema, you really should try to only wash your hands when you absolutely need to for essential hygiene.” [4:58]

“Skin problems are not just about nutrition, but nutrition is a very important part of it.” [6:51]

“In addition to making the [skin] surfaces smooth and not over keratinized, vitamin A is also playing a critical role in the immune system. And so if your vitamin A is deficient, then you don't have the defense against the bacteria and fungi that shouldn't be there.” [11:11]


Find Chris online

FREE Course: Vitamins and Minerals 101

Testing Nutritional Status: The Ultimate Cheat Sheet Use code FUGO for 20% off!

Chris's articles on balancing fat-soluble nutrients

How to Cook Liver and Make it Taste Not-Bad by Chris Masterjohn

Follow Chris on Facebook | Instagram | Twitter | YouTube

068: Vitamin A & Zinc Connections To Skin Rash Symptoms w/ Chris Masterjohn, PhD FULL TRANSCRIPT

Jennifer: Hey everyone. Welcome back to the Healthy Skin Show. I have got a guest who I did admit before we started, I kind of stalked a little bit because I wanted to get him on the show to be able to talk to you about all of his expertise in micronutrients. He is very brilliant and I can say that because I have followed him for quite a while and on top of it I have this incredible resource that he created that blew my mind. We'll talk about it later, but first I want to introduce you to Chris Masterjohn. He earned his PhD in nutritional sciences from the University of Connecticut in the summer of 2012. He served as a post doctoral research associate in the comparative bio-sciences Department of the College of Veterinary Medicine at the University of Illinois at Urbana Champagne and as assistant professor of health and nutrition sciences at Brooklyn College, part of the City University of New York. He now works independently producing educational content about nutrition. Thank you so much for being here, Chris.

Chris: Thank you for having me, Jennifer. It's great to be here.

Jennifer: I know. So. Okay. The way I found you was through a bunch of friends, but then as I was doing a little bit of stalking, I discovered that you actually had eczema. Do you want to share just a little bit about your story? Just so that people can know that you have dealt with this before and you have a lot of empathy for what they're going through.

Chris: Yeah, I've been through a couple of episodes of really, really major skin problems. And then I didn't always have a clear diagnosis of what they were, but the first big one was where I developed what I called eczema. I never actually went to a dermatologist about it, but it was, it was a red and itchy skin that it would actually pus when I would go through extreme exertion, like lifting weights. But for the most part it was just really red and really itchy. It would go from my fingertips to my shoulders on both arms, all down the left side of my torso and all along the top of my left thigh. And, , I went through like a year of trying all kinds of different things for it and nothing worked until I tried a specific probiotic that had soil organisms and it had saccharomyces Boulardii in it and it was 80% gone within the first two or three weeks, and it was 100% gone within two to three months. I later have experimented with lots of probiotics and I find that saccharomyces Boulardii is really the key thing for me, although I think that probiotics are so individual that different probiotics are gonna work differently for different people. And so I'm not recommending that particular one for everyone. But later I went through a couple of other issues. So for the years after I cleared up my skin every once in a while, especially when I wasn't eating as well or was under a lot of stress or I wasn't sleeping as well, a little bit of Eczema would creep up. At first it was around my wrist. And then after a few years it changed to in between my fingers. And , at one point this got really bad to the point where not like it was the first time, but my gut was in pretty good condition at that time. I was doing all the gut-related things that I would expect to help and it wasn't healing. And so I did some research into Eczema and one of the things that I found was that in Eczema, the skin barrier that waterproofs the skin becomes defective and the skin dries out because all the water is evaporating. And although there are nutritional things and although there are a bacterial things that influence the skin barrier. How you wash your hands also in influences that as well. So every time you wash your hands with soap or you wash any part of your body with soap, you basically have a period of 90 minutes or so where if you have Eczema and you therefore have a defective skin barrier, the soap just pulls all of the lipids, which are fatty molecules that make up your skin barrier, that just pulls all the lipids right out of your skin. And so, you know, if you have very good skin or you don't have Eczema and you wash your hands with soap, you don't have that problem because the integrity of your skin barrier is so good. But if the integrity of your skin barrier is weak and you wash your hands with soap, then that weakness is a vulnerability that makes the soap just dissolve it. And it takes about 90 minutes to rebuild it. And during that period of time, bad things can happen. Things from your skin that aren't supposed to go inside, start creeping inside, including bacteria that aren't supposed to get in there. And the bacteria get in there, then they can create an inflammatory condition that makes that whole problem persist even longer. And so what I learned was if you have active Eczema, you really should try to only wash your hands when you absolutely need to for essential hygiene and every time that you do, you should follow up with application of some kind of, not a moisturizer, but a lipid based just like 100% fat. So I was using shea butter, but there are, you know, many other fats that you could apply to your skin that could work, but shea butter is a very good one. Cocoa butter would probably be good as well. And what that does is it, it just, it's like sort of putting a bandaid on a cut. It just patches up all those weaknesses in the skin barrier that you just wrecked with the soap and allows your body time to heal. But then I had another episode later than that when I was dealing with an indoor mold issue and I got a very bad, what a dermatologist ultimately told me was a fungal infection that was causing a very similar problem to that which I described the first time around. And actually there was another time in my life that the, these two stories end very similarly, there's another time in my life where I developed a problem in my scalp where I could scratch my scalp with my fingernails and I would just pull up fingernails' worth of crust from my scalp and it would eventually start coming at the border and like actually working its way down to my forehead. In both of those cases, I found that it was happening during a period or at a very low vitamin a intake and just getting my vitamin a levels up with food made those things disappear. I've learned number one that skin problems are not just about nutrition, but nutrition is a very important part of it. There's also a role for the microbiome for hygiene, etc. But also that there are many different nutritional issues that could be at play. And I have some particular vulnerabilities, like vitamin A is a very big one for me, but for other people at zinc or it's B vitamins or it's essential fatty acids.

Jennifer: And I want to also clarify too, we had spoke about this before we started…for anybody who's listening and going, oh this is just going to be about Eczema. No, it's not micronutrient issues. So where you have depletions of specific micronutrients like vitamins or minerals that there is some, you know, working with a lot of different skin conditions. What I found is that yes, there are some that might be a little bit more, might occur more often in certain conditions. But generally speaking, there's a lot of overlap. So for pretty much everybody listening who has chronic skin issues, no matter whether you have Eczema or psoriasis or Lichen sclerosus or Rosacea, we're Dandruff, or whatever: this may apply to you. So this is a really important conversation because the body, we don't just like make things, we don't make everything. We do need to take it in via food, and in some instances unfortunately we may need to supplement depending on how bad things get. But that's why I wanted to have Chris here. So Chris, you mentioned vitamin A and vitamin A, I feel like is a very overlooked vitamin. It's almost like we focus mostly on vitamin D, but for your skin vitamin A is really important. Can you talk a little bit about why vitamin a might be something everybody should pay attention to?

Chris: Yeah, well certainly if everyone's paying attention to vitamin D, then all the more they need to pay attention to vitamin a because vitamin A and D both work together through a lot of different functions. And if you supplement with vitamin D and you're not getting enough vitamin A, you're just going to aggravate the vitamin A deficiency. Vitamin A is just way more important to pay attention to when you are supplementing with D. Vitamin A plays a very important role in regulating all of the tissues that line the surfaces of your body. And when vitamin A is deficient, what happens is, in the very superficial layer of your skin, we have cells that are dominated by a protein called Keratin. And the Keratin basically stuffs the cells and makes them sturdier, but also kills them, basically. By the time they're keratinized, cells are just dead cells. So that top layer of your skin can flake off rather easily when it's time for those cells to go cause they're already dead. What happens in vitamin A deficiency is that much more than that top layer of skin becomes keratinized. Basically huge chunks of the upper surface become keratinized. And that can lead in some cases to little bumps of flaky tissue. But sometimes it's little bumps that look like goosebumps, but they never go away or they look like acne, but they're not really pimples. Or sometimes it's just your skin is crusty. Like the story I told before about my scalp, I could stick my fingers in my scalp and pullout like crusts underneath my fingernails. And that totally disappeared when I boosted the vitamin A in my diet. And part of the reason that it's so complicated is that nutrients are usually building part of the like essential parts of the infrastructure of your body. And then what happens to you when the infrastructure is wrong is gonna be filled in by, you know, what kind of bacteria and fungi are lying on the surface of your skin. For example, if you become more vulnerable to having an overgrowth of bacteria or fungi in general, or allowing them to get deeper into the skin than they should, then that might happen in the same nutrient deficiency for you and me. But I might have different bacteria and fungi in the surface of my skin than you do. And so what it looks like for us is gonna be different. But in addition to making the surfaces smooth and not over keratinized, vitamin A is also playing a critical role in the immune system. And so if your vitamin A is deficient, then you don't have the defense against the bacteria and fungi that shouldn't be there that you should. And so that also comes to play a major influence in what your skin might look like.

Jennifer: Interesting. And so could you just clarify, cause I'm listening in my mind to women's heads exploding right now because they're being told to take vitamin D, take vitamin D. Okay, I'm taking my vitamin D and then they hear, oh, I've gotta pair it with vitamin K. And that's all you hear is D and K and D and K. And now all of a sudden you're saying, wait, you've got to also pay attention to A. Is there something in particular that you could point people toward or just to help clarify that because I want to make sure that they understand that before we move away from this.

Chris: I have a bunch of articles on balancing the fat soluble nutrients that I could send you to put in the show notes.

Jennifer: That would be awesome. Cause I know people would love to take a look at that. That would be really, really great because, you know, it is so interesting in the nutrition world, we focus on one thing at a time. And I know that that's, we're kind of talking about today is like look at these individual components, but they all work together. And so if we go to the flip side of say like zinc for example, zinc is also really important for the skin. Could you talk a little bit about why that is?

Chris: Yeah. When you become zinc deficient on average, the first thing that happens is that you develop patches of dry skin. And as zinc deficiency gets worse and worse in some people that progresses into acne and other people at progressess into blisters or pustules. This is in the context of experiments where they took people who were otherwise in a healthy diet and they just gave them a zinc deficiency. They fed them a diet that was adequate and everything except zinc, zinc sort of zinc is also needed, for example, to make vitamin A and D do their job. And so like you can, you can have enough vitamin A, enough vitamin D and if you don't have enough zinc, vitamin A and vitamin D aren't doing their job. And so, you know, the most specific thing that you would expect from zinc deficiency is these patches of dry skin, that in most cases are probably going to progress into acne. But you know, there could, if you have an underlying zinc deficiency, there are a lot of other problems that might be a lot harder to fix as well.

Jennifer: And so with zinc, , I know for example, we studied a lot back in my Grad school program about zinc is involved in the zinc fingers that helps us replicate DNA. And so, you know, if you do have to produce healthy new cells, you need to make sure that they are being replicated appropriately instead of cells that are, maybe our DNA is a little funky. So as far as zinc is concerned, would you consider that, I mean obviously vitamin A is very important, it sounds like zinc as a mineral is also really critical. Is there a way that you could test at home like that you are familiar with for zinc? Have you ever heard of like the zinc challenge or something like that?

Chris: Yeah, there are, there are tests that exist like that, but none of them are validated against actual real measures. I don't think it's a very good idea to use a home test for zinc. I think that you should look at your diet and you should look at your signs and symptoms and you should measure your plasma zinc if you really need to know, but supplementing with small doses of zinc or increasing your intake of zinc rich-foods is relatively harmless. What you really don't want to do is supplement with high doses of zinc without adequate testing. But you know, if, if you're just talking about like adding a 15 milligrams zinc supplement or increasing the number of oysters, beef and cheese that you eat, all of which are the best sources of zinc, I think it's pretty harmless to do that just based on, oh my, I have those patches of dry skin. Maybe I'm a little zinc deficient. Let's see if improving my zinc status helps.

Jennifer: So hold on a second. For those people who are listening who are like, I'm following more plant based diet, what you kind of just mentioned are not really plant based.

Chris: Yeah, if you're following a plant based diet, you're more likely to be zinc deficient.

Jennifer: There we go.

Chris: To be clear, there's ways you can get zinc on a plant based diet. It's just that they're, you're way more likely to be zinc deficient. Part of the reason is that if you look at any zinc-rich plant food, that food is also rich in a chemical called phytate. And phytate is, some people call it an anti nutrient. Really it's a way of a seeds. When we talk about, when I talk about a seed, I'm talking about something that you can plant in the ground and it grows. So we think of seeds as seeds, but also beans are seeds. Nuts are seeds. In the broader sense of something that you can plant in the…grains are seeds, right? So whole grains, nuts, seeds and legumes are all rich in a chemical called phytate that the seed uses to bind up the minerals and prevent them from being released to fuel growth until the conditions are met for the plant to grow. Right? The seed doesn't want a sprout where there's no water around for example, cause it's just going to sprout and the plant is going to die. And so the plant has all these defenses to lock up the minerals and you can reduce the phytate content of whole grains, nuts, seeds and legumes by soaking them, by sprouting them, by fermenting them or by souring them. And you can't get rid of the phytate that way, but you can reduce it a lot. But this is really important because the overwhelming inhibitor of zinc absorption is phytate. And if you look at World Health Organization estimates, about 50% of the world's population is at risk of clinical zinc deficiency and the overwhelming risk factor is it diet, low animal foods and high-end plant foods. So I'm not saying you can't eat a plant based Diet and get enough zinc, but I am saying that if you eat a plant based diet, your options for zinc rich foods are limited. You need to pay more attention to soaking, sprouting, fermented or souring your whole grains, nuts, seeds and legumes. And you do need to be more conscious of the fact that you might be doing everything right. You might be looking at a nutritional database and it looks like your diet is good enough in zinc and you might still have a mild zinc deficiency because the zinc you're eating is less absorbable than the zinc from animal foods.

Jennifer: And actually if we circle back to vitamin A, I think you're probably the best person to ask this of you know, vitamin A, you have the more, I guess the active form that comes from typically more animal based sources. And then you've got Beta carotene. So do you find that they're equal from your research?

Chris: That depends on the person. So some people are very good converters of carotenes, which are found in plant foods to retinol, which is found in animal foods and it's retinol that we need in our bodies to prevent vitamin a deficiency. And some people make that conversion really good. Other people are very bad at that conversion. And part of that is genetics, but it's also part or mono status, a digestive health status of other nutrients. There are some factors that you can't control, like your genetics. There are other factors that you might not be aware of. For example, if you're anemic or you're hypothyroid or you have a parasite or deficient in another nutrient, that's something you can do something about. But you might not know you have that condition. And if you know it, you might not have fixed it yet. So you really have no idea if you're a good converter or a bad converter, until you kind of through trial and error, you discover if you're a bad converter that you developed vitamin a deficiency while you were eating a bunch of red, orange, yellow and green vegetables, which are rich in carotenoids.

Jennifer: Isn't that interesting? And I oftentimes see that I'll have clients that eat a very, very phyto rich nutrient diet. I'm eating lots of really good, healthy whole foods and they're like, how did this happen? How did I end up with low vitamin A? How did I end up with all these nutrient deficiencies? And I'm like, well, got a lot of challenges. You know, food does not necessarily fix everything. We've got a lot of other factors to consider. And I think that's a great point to make. Any favorite sources of yours of vitamin A cause it sounds like that's something you have a lot of experience with personally.

Chris: Well, I think that everyone should ever, you know, with the exception of people who don't tolerate these foods very well, everyone should eat red, orange, yellow and green vegetables. Those are providing a lot of carotenoids. They're providing a lot of other important nutrients. But the thing is, as we just discussed, you don't really know if you're getting enough vitamin A from them. As an insurance policy to make sure that you are getting enough retinol, the form that you need, liver and cod liver oil are really the best sources. Egg yolks and dairy provide small amounts, but if you want to hit the RDA for vitamin A as a retinol, you would not be able to do it with eggs and dairy and you would need to either eat liver once or twice a week or take cod liver oil every day.

Jennifer: Hm. Interesting. Oh, and for those of us like me that don't like either of those options, that would not probably be my choice. It's funny because those are like two things where people either you like them or you don't. And I know it's an acquired taste.

Chris: Oh, I hate liver. I hate liver. I hate liver and there is no changing of that.

Jennifer: Okay. Interesting. I like that. At least you're willing to admit that you are not a big fan of that. Some people are like, they try and sell it. Like they're like, no, no, no, it's really good for you. And I love it. I just have to do all this stuff to it. And I'm like, do you really like it? And they're like, meh.

Chris: I have an article called how to, how to cook liver and make it taste not bad. And there's a reason that I didn't call that, to make it taste amazing.

Jennifer: Maybe we can also share that in the show notes. And some people may be interested in venturing down that route. I will probably not be one of them, but if you're interested in doing it, I think it's worthwhile. And I love the fact that you've so many resources to share with everyone. And so I kind of want to circle back at this point, cause I know that you guys are listening to us talk about nutrients and nutrients status and just individual nutrients. But one of the reasons that I respect Chris so much is he just has so much knowledge and wisdom because of all the research that he has done over the years and continues to do. And he has this incredible guide. So for those of you like me, I'm kind of a little bit of a nerd and I like to read sciencey things. Not just because this is what I do, but I just also have an interest in it. He has this incredible guide called Testing Nutritional Status: The Ultimate Cheat Sheet. And when I got a copy of this, my mind exploded in so many ways. So I had to try to piece it back together and I'm not sure I got it quite right. So do you want to talk about this? Because it is an incredible resource, especially for practitioners who are listening or somebody who's really interested in all of these individual nutrients.

Chris: I would be happy to. So, you know, we talked a bit about vitamin A and zinc and my own eczema story. We didn't talk about some of the other nutrients that could be involved in skin conditions. So the essential fatty acids and most of the B vitamins have their all have their own particular way of manifesting in skin conditions and affecting things like Eczema and other forms of dermatitis. And so, whether you have a skin condition or whether you have a problem sleeping or whether you feel tired all the time or whether your hair is falling out or whether you're just too itchy or whether you don't tolerate certain foods…You want to understand, or even if you don't have a specific problem and you're just interested in investing in your long-term health, do you want to make sure that you're getting enough nutrients? And so what I have is called Testing Nutritional Status: The Ultimate Cheat Sheet. And it's called a cheat sheet because it's not really designed to be read from front to back as a book, although you could read it like that. And a lot of people who are healthcare practitioners who deal with a lot of clients might want to read it like that, but it's called a cheat sheet because it's meant to be a system that holds your hand and walks you through the process of, first of all, deciding, okay, I'm going to make some investment in optimizing my nutrition. What do I have available to me? Do I have the time to do it? Do I have the money to invest in comprehensive screening? Am I more limited in time or money or one or the other? And it helps you determine what resources you have and then what approach to take. And then it walks you through collecting the data that you would need for an initial screening. And you might focus more on laboratory data if you have the money or the insurance coverage, you might focus more on dietary data or indexing your signs and symptoms if you don't, or you might focus on all those things and then it walks you through. If this thing is off, read this section at this thing is offered free. This section guides you to an action plan and a way to monitor whether your action plan is working and it's called the ultimate cheat sheet because there's actually 78 pages of information that you may or may not need to read depending on where your data leads you in that story. And so yeah, I sell that for $30 and I'm offering a 20% discount to your audience and they can use the link in the show notes.

Jennifer: Yeah. So when I thought cheat sheet, I was like, oh, it's probably like three pages. When I opened it up and saw that it was like 82 pages, I was like, oh my gosh, and I started reading through and I was blown away and you know, a lot of this is, is information that we spent a lot of time covering in my master's program and even things, some things that I didn't even know. I even learned a ton from this and so I just thought, wow, you're a wealth of knowledge. I would love to have you here on the show and it's a great honor to have you, but also to be able to share this with people who are hungry for this and who recognize that there are other things just beyond what's happening at the skin level because right. It's more than just the skin. It's what's going on on the inside. It's also what's going on in the outside. It really is a two pronged approach here.There is no client that comes to me. I'm like, oh, we don't need to do labs. Like I want to see labs, I want to, there's probably some labs that we probably want to run that are conventional and some that we want to run that are functional. So this is a really great resource to have. And I'm so appreciative that you're willing to share a great discount with the community here at the Healthy Skin Show. And I hope that we can have you back sometime. It could be a lot of fun. Where can everybody find?

Chris: You can find me at chrismasterjohnphd.com and they can find me @chrismasterjohn on social media.

Jennifer: Awesome. And I highly recommend you guys follow him. He is brilliant. All right. Thank you so much Chris. Thank you for being here and I look forward to our next call.

Chris: Thanks Jennifer. Me too.

“Skin problems are not just about nutrition, but nutrition is a very important part of it.”