Sun Exposure Reduces Cancer Risk and Thoughts on Tanning Beds with Researcher Dr. Marianne Berwick

We have recently discussed the array of benefits provided by sun exposure.  Today, we speak with researcher Dr. Marianne Berwick who authored one of my favorite papers detailing the health benefits of sun exposure.  She also provides some simple guidelines for how much sun exposure you should obtain. We will also broach some of the contentious issues regarding tanning beds.

Dr. R’s Fast Facts

How much sun exposure do humans need?

If you have lighter skin, spend about 15 minutes in the sun with face, arms and legs exposed (half that time if in a bathing suit) 2 to 3 times per week between 11:00 AM and 3:00 PM during the warmer months.

If you have darker skin, longer sun exposure 20-30 min, would be safe and appropriate. Use common sense, if you seem to feel like you burn at 30 minutes, do not stay out that long without sunscreen.

Insufficient sun exposure has become a major public health problem, demanding an immediate change in the current sun-avoidance public health advice. The degree of change needed is small but critically important. The public must be advised to obtain enough sun exposure and vitamin D supplementation to maintain a serum 25(OH)D level of at least 30 ng/mL.

Melanoma (the most dangerous form of skin cancer)

  • Non-burning sun exposure reduces risk of Melanoma while burning increases risk.
    • Some studies show that sunburns double the risk of melanoma.
  • The STRONGEST RISK for Melanoma is intermittent sun exposure.

Does Sunscreen Reduce the Risk of Melanoma?

  • Most studies show that sunscreen does NOT prevent Melanoma
    • Some say sunscreen actually increases the risk for Melanoma because people take for granted they have applied a “shield” of protection and fail to use it appropriately.
      • Note: there is some evidence showing sunscreen reduces risk, but it is not high-quality dat.

Photoadaptation

  • Increased darkening of the skin
  • Small increments of UV will increase your DNA repair capacity

Proper Use of Sunscreen

  • Apply sunscreen half an hour before you go outside and reapply every two hours
  • In addition, use shade or clothing to protect yourself if you feel like you may be getting a sunburn

Non-Melanoma Skin Cancer

  • While non-burning sun exposure is associated with decreased melanoma risk, it appears that it does increase the risk of SCC and BCC (squamous and basal cell carcinomas).
    • Not all the data here agree (some studies show no association) and the relationship between chronic sun exposure and non-melanoma cancer is not entirely clear.

All-Cause Mortality (death from any cause)

Sun exposure can be beneficial.

  • Association data shows higher vitamin D levels equate to better health. (But, the association does not mean cause).
    • More endorphins
    • Lowered blood pressure
  • A 20-year follow-up study found avoiding the sun increases all-cause mortality.
  • Another study found that sun avoidance also increases all-cause mortality to a degree similar to smoking.

Sun Exposure, but NOT vitamin D levels or supplementation, reduces risk in:

  • Obesity & Type II Diabetes
  • Type I Diabetes
  • Multiple Sclerosis (MS)
  • Cardiovascular Disease
  • Non-Hodgkin’s Lymphoma, Colorectal, Prostate and Breast Cancer

**All the of the links to these studies are located below in the links section

Tanning Beds

  • One big issue is that they are not regulated
  • Much more research is needed
  • In a critical appraisal of recent research Holick  states that “is crucial to distinguish cause from association, and that this is especially important because some evidence suggests tanning bed use is associated with an unhealthy lifestyle (smoking, drinking and over-exposing to sun during summer months)  So, it might be the unhealthy lifestyle that is responsible for increase skin cancer risk.”

Clinical Takeaways

  • Vitamin D supplementation may not be an acceptable substitute for sun exposure
  • Obtaining chronic, non-burning sun exposure is a key practice for optimum health
  • Obtain at least 15 minutes (or more for darker skin types) of direct, unprotected sun exposure 2-3 days a week, midday, during the sunny months
Sun Exposure Reduces Cancer Risk, And Thoughts On Tanning Beds with Researcher Dr. Marianne Berwick
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Episode Intro … 00:00:39
Vitamin D Supplements are Not a Substitute for Sun Exposure … 00:03:06
Standard Sun Exposure Recommendation … 00:06:02
Melanoma … 00:09:40
Photo Adaptation … 00:11:05
Sunscreen … 00:14:00
Non-Melanoma Skin Cancer … 00:17:30
Melanoma in People with Darker Skin … 00:22:20
All Cause Mortality … 00:25:14
(click gray Topics bar above to expand and see full outline/time stamp)
Tanning Beds … 00:29:00
Episode Wrap-up … 41:24

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Episode Intro

Dr. Michael Ruscio: Hi, everyone. Before we jump into today’s show with Marianne Berwick, I wanted to apologize for the fact that our recording was abruptly cut off at the end. But thankfully, it was cut off so distal in the conversation that all the important messaging was still there and essentially our just saying goodbye to one another and signing off was cut off.

This was a great conversation. We get into some of the details regarding the health benefits of sun exposure but also being careful to look at both sides of the evidence. I thought Dr. Berwick did an excellent job of helping to distill the topic down to some very simple guidelines for sun exposure that are very practical, very common sense, and will help keep you at the beneficial end of the sun exposure curve and prevent you from experiencing any detriment and doing so with some very salient, practical recommendations.

We also touched on the topic of tanning beds which is, of course, a contentious issue, but we discuss some of the data there. And there were some interesting points, points that we did not necessarily—I don’t want to say that we disagreed on, but there’s contradicting evidence. So we grappled with some of those contrarian claims to one another and came away with what I think is a very reasonable conclusion there also. So with no further ado, we will now jump into today’s podcast with sun and vitamin D researcher, Dr. Marianne Berwick.

Hey, everyone. Welcome to Dr. Ruscio Radio. This is Dr. Ruscio. And today, I’m here with Dr. Marianne Berwick who is going to help us dive deeper into our previous conversation with Dr. Michael Holick on sun exposure’s impact on your health. So Marianne, thanks so much for being here today.

Dr. Marianne Berwick: Well, I’m delighted to be here.

DrMR: You wrote one of my favorite papers on this topic, entitled “The Risks and Benefits of Sun Exposure,” 2016. I thought it was an exceptional paper, and I am, in a nerdy way, very excited to dig into some of the details that are rolling around in your brain after writing this paper.

DrMB: Good. What would you like to know?

Vitamin D Supplements are Not a Substitute for Sun Exposure

DrMR: I thought what we could do is I could give you kind of a series of lay-ups here with quotes from your paper and you could expound upon those a bit.

DrMB: Sure.

DrMR: Ok. So one of the first quotes that I think is important for everyone to be aware of: “It is apparent that vitamin D supplements are not an effective substitute for adequate sun exposure.” And we’ll get into some of the details supporting that statement. But from a broad stroke perspective, is there anything there that you’d like to elaborate on?

DrMB: That’s sort of my favorite statement in the whole paper, actually. I think that there’s a lot of data, and I’ve published other papers that show that sun exposure is actually highly beneficial for melanoma and for other illnesses, other diseases, other pre-diseases such as high blood pressure. So it’s sort of foolish to think that a pill is going to solve these problems.

Sun Exposure and Vitamin D LevelsFurthermore, most of the data that we cite in this paper shows really that sun exposure is driving the health benefits rather than the vitamin D pill itself.

DrMR: Absolutely. And I think that’s a very key point, and this is something that we’ve touched on briefly in the podcast in the past which is we can’t just claim from the association that healthier people have higher vitamin D levels. And then, therefore, if we supplement those people with vitamin D, they are going to experience the same health benefit as people with higher vitamin D levels. We need to have more proximal data, looking between the outcome and the issue being measured.

So of course, the best thing we could do was look at what happens to people’s health when they supplement with vitamin D and compare that to what happens when people obtain time in the sun. In your paper, just like you said, you said a number of trials showing that there are specifically some conditions that don’t seem to improve from vitamin D supplementation but do improve from exposure to sun.

DrMB: Right. A lot of this is epidemiologic data which has many, many caveats because we’re relying on people’s memories, recent memories as well as past memories. So we do have to be a little bit careful about broad statements we make.

DrMR: Do you think it’s fair to say if we’re looking at epidemiological data for benefits and risks, we’re at least looking at it in as balanced of a fashion as possible, meaning we’re not cherry-picking.

DrMB: Yes.

Standard Sun Exposure Recommendation

DrMR: That’s important because there are some areas where there’s a little bit of contention, and I want to get into that. But before, let me ask you one more kind of high-level question here. And I’ll quote. “White people with type 2 skin”—this means skin that’s fairly prone to burn—“at 40 degrees latitude”—which that puts you I guess in the mid to North US or US at large. Would you say that’s correct?

DrMB: Pretty much the mid US. Not the North. The North is sort of above 42.

DrMR: And “40 degrees latitude”—mid US—“can obtain their annual requirements of vitamin D by spending about 15 minutes in the sun with face, arms, and legs exposed two to three times per week between 11 a.m. And 3 p.m. During the months of May through October.”

And I think that’s a pretty good recommendation for people to start with because people may get confused. You’re recommending more sun exposure. Does this mean I need to spend an hour every day and become a pagan sun worshipper? Where do I draw the line here?

Is there anything there that you’d like to add to help people know what to do? I’ve been avoiding the sun previously. Ok, I’m getting on board with the concept of obtaining more time in the sun. Here’s an easy benchmark for me to shoot for. And I should just briefly mention that Dr. Holick mentioned the dminder app, which I think is great. But I’ve found it almost takes the enjoyment out of going into the sun for me personally, because every time I go outside now, I’m trying to start that app. And then if I forget, I go, “Oh, I forgot.”

Some people who love data, that’ll work for them. But for me, I try to be on my phone and plugged in minimally. So it’s helped for me—and I’m assuming people like me—to have a kind of standard recommendation to get them in the ballpark.

dreamstimem47378420DrMB: Right. And the question you asked raises many other questions. So we’re talking about 15 minutes. That’s not very long. Face, arms, and legs, that’s sort of normal, and those are places—arms and legs—where you don’t get melanoma or basal cell or squamous cell carcinoma. The face, of course, you can. And many women, of course, don’t want to put their face in the sun because of the wrinkling aspect of it. But we’re talking about sun exposure that won’t give you a sunburn.

So erythema is another name for sunburn and sub erythema sun exposure is really, we think, fairly valuable for people. We did evolve in the sun throughout our life. There are lots of other facts that are important. So there’s a big increase in melanoma incidence over the last, gosh, 50 years at least. What mirrors that incidence is a decline in outdoor work.

As we all know, people are now working indoors, watching TV, playing with their apps. Kids are playing their games. So they haven’t had a chance to adapt to sun exposure. And we can talk about that more too: photoadaptation. But 15 minutes is pretty easy. Most people get a 15-minute break or a 10-minute break at least in their workday.

I go sit on the steps outside my building. Of course, I am in New Mexico. But it’s really a pleasant break from staring at the screen all day. I don’t know if that answers what you want.

Melanoma

DrMR: Yes, it does. And you touched on something that I’m very happy that you did—or a number of things. One is that melanoma seems to be increasing. And one may say to themselves after hearing that, “Well, shouldn’t I avoid the sun then because this is a skin cancer? And doesn’t sun exposure cause skin cancer?”

However, you cite a few papers that show that non-burning—and I’ll read another quote here. “Non-burning sun exposure is associated with a reduced risk of melanoma, while sunburns are associated with a doubling of the risk of melanoma.” And you make such a fantastic point. When I read it for the first time, it was a huge epiphany for me which is this photoadaptation or this skin conditioning.

DrMB: Yes.

DrMR: Instead of getting small doses on a regular basis of sun, thus conditioning our skin and knowing our skin’s limits, so to speak, we work indoors and we get these episodic bursts of sun exposure with a much higher chance of burning. And it’s the burning that increases the risk. But it’s the regular, small doses of sun that decreases the risk.

And I thought what a wonderful concept that is and very important thing for people to understand. And just as you put it, this could be a pleasurable break, three or so times per week outside in the sun for about 15 minutes. It’s hard to argue with that.

Photo Adaptation

DrMB: Right. And I think if people were to think about it very much, they’d realize that they really do understand what photoadaptation is. As you know, it’s increased melanization, that is increased darkening of the skin very slightly. But we all know what a farmer tan looks like. And a little bit of thickening of the skin.

There’s a number of papers showing that small increments of UV will increase your DNA repair capacity. And I think that more and more people are understanding that mutations causatively have unrepaired DNA. Then of course it does help with vitamin D production which is a good thing as well. So I think photoadaptation is a really important concept that many people really don’t want to recognize. And I’m sorry that they don’t.

So I’m talking about some controversy that I stimulated many years ago, more than 20 years ago, when at that time there was no evidence that sunscreen prevented melanoma. There’s a little bit of evidence now, but there were physicians who got very angry with me by saying that. They said, “You have to give a simple message that is ‘stay out of the sun.’”

But the problem is people are smarter than that. People can think with nuance. People can think that it’s not so simple. And in fact, I don’t think people like being treated as if they’re idiots.

DrMR: I agree. I absolutely agree with you. One of the things that I’ve noticed is the concept can be somewhat advanced. There can be some nuance. But as long as the language is simple and you’re not using a 10-syllable word when a two-syllable word would do, most people will be able to hang with you regarding the concepts.

Sponsored Resources

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So Biocidin definitely has some helpful products for improving your gut health. And I would definitely recommend checking out Biocidin for more information on a few of these tools that can help you in optimizing your gut health.

Sunscreen

And that brings me to another quote, and I’d love for you to elaborate on this a bit also. “We can find no consistent”—and I think that’s a key word—“consistent evidence that use of chemical sunscreens reduce the risk of melanoma.”

And I would just underscore that by saying there is some evidence, as you alluded to. But from my purview of the evidence, it does not seem to be high-quality data which may be counter to what some people think. They may have the feeling that by putting on sunscreen, they’re putting on this pseudo-armor, if you will. Please elaborate on that a little bit.

DrMB: Sure. Well, there is one piece of evidence that has been brought out quite a bit. A few years ago, an Australian researcher found in a randomized clinical trial that people who used the sunscreen she gave them were less likely to develop melanoma than people who did their usual precautions.

The trouble is that study was done in Queensland, Australia, which is similar to being in Hawaii actually. So the usual care would mean using sunscreen. So it’s not clear that that study is the be-all and end-all of studies. But at the same time, another colleague of mine and I were studying sunbeds and the development of melanoma. Tanning beds.

We found that people, yes, if they said that they used sunscreen they were less likely to develop melanoma than people who said they never use sunscreen. However, what was even more important was people who used shade or long-sleeves. People who use clothing to protect themselves. That was a much stronger effect, but we weren’t looking at it as closely. So it didn’t get quite the publicity that the other one did.

But most studies will show that sunscreens do not prevent melanoma. And in fact, in some cases, they tend to increase risk for melanoma because people think they’ve got this suit of armor on. And people don’t use them appropriately, the sunscreens appropriately. You’re supposed to reapply two hours after being in the sun, put it on half an hour before going out.

And so, the best thing is to, as we’re talking, use common sense. Use shade, use a hat if you need to, but also, get a little bit of the sun so your skin is adapted because the strongest risk for melanoma is that intermittent sun exposure that you alluded to rather than the chronic or the little bit of sun exposure each day.

So if you have sun exposure that you just get on the weekend when you go out boating after working inside all week or fishing without any protection, then you’re getting intermittent sun exposure and you’re very likely to be getting a sunburn too. And that seems to be a much higher risk for melanoma in the data that’s available than the chronic.

Non-Melanoma Skin Cancer

And let me just say one more thing. Outdoor workers are not at higher risk for melanoma. People who are outdoors all the time do not have an increased risk for melanoma. So that would go along with the idea of photoadaptation, that they adapt to being in the sun in a very positive way.

Walking, Running, Sun Exposure

DrMR: Precisely. The person who I visualize at the highest risk is the—I’ll paint a bit of a stereotype here, and I apologize for doing so. But the person who is going to go for a walk from point A to point B which would involve them being in the direct sunlight for about 10 minutes. And they wear a hat and they have an umbrella. And I’m assuming they probably put sunscreen on also.

It’s that person who goes so far in the direction of sun avoidance. And there’s some data showing that all-cause mortality increases in some populations who practice the most religious sun avoidance. It’s really that person who seems to be putting themselves at the greatest disservice.

DrMB: I actually published a paper where we showed that sun exposure was protective for overall mortality. We put it in the supplement because we were actually more interested in melanoma-specific mortality. But in our data, which is population-based, so population-based data is different from hospital-based data in that we try to get a representative group from the entire population at risk.

So those are the people we used, and we found that those people who had more sun exposure, particularly out at holiday sun exposure, water-related activities, especially UVB dose recently, they were at reduced risk for dying from melanoma. And I’m so glad that we’re doing this—and we published that about four years ago. And it didn’t create very much of a stir, but I would like to go back to that and really understand better that phenomenon.

DrMR: Well, hopefully anyway, the tide is starting to shift a little bit where people are starting to realize that this very ardent avoidance of the sun is maybe not the most well-advised piece of information. There is one other area here that I think is perhaps the most contentious and the area that a critic of sun exposure would reach to which is the data regarding non-melanoma skin cancer, so your squamous cell carcinoma, your basal cell carcinoma.

And the data here seem to be a little bit more mixed. And you even cite some data that suggests that even non-burning sun exposure may be associated with a small increased risk of non-melanoma skin cancer. But again, the data there appear to be mixed and in keeping with our theme of nuance, what would you offer someone who has heard this criticism and gets a little bit apprehensive in light of that?

DrMB: Gosh. I would suggest if you’re very worried about basal cell carcinoma or squamous cell carcinoma, which are concerns. There’s a little bit of surgery involved if you have one of these, and you do have to take care of them. You can’t let them grow. I would offer just normal sun protection. And certainly, what we suggested with the 15 minutes, three times a week, you’re not going to get basal cell or squamous cell carcinoma.

So a fellow named Bruce Armstrong in Australia many years ago published a set of curves of how much sun exposure you need to get squamous cell carcinoma. And it’s much, much, much higher than in basal cell or melanoma. Once you get past that though, then it starts to go up sort of on a quid pro quo basis.

So I think if you’re very light-skinned and tend to be kind of reddish in your coloring and don’t tan easily, then certainly you should use some sun protection. But a little bit of sun that we’re advocating is absolutely not likely from everything I know to lead you to develop either squamous cell or basal cell carcinoma.

DrMR: And then if you’re darker skinned, you’ll likely need more. We should probably clarify that. If you have a darker skin type that’s more prone to tanning, then more than that 15 minutes a few times per week is likely advisable, correct?

Melanoma in People with Darker Skin

Sun Exposure and Vitamin D LevelsDrMB: Yes. And one thing that a lot of people are concerned about these days is melanoma in particular among people of color. It’s such a rare occurrence in every place that has looked at it, with two exceptions. One is California and one is Florida where they have published papers showing with people of Hispanic ethnicity that melanoma rates are increasing.

Again, they’re not increasing a lot, but they did not do any skin color typing or any way of measuring the type of skin that the person had. So it’s my belief, based on our New Mexico data, that those are people who are mixed, that is they’re Hispanic or Latino and Northern European, because California has a history of large Spanish population, Hispanic population, as do we here in New Mexico. But there’s somewhat less mixing here.

Anyway, I do think it has an awful lot to do with skin color as opposed to ethnicity. I don’t know if that’s confusing.

DrMR: No, that makes a lot of sense. Again, back to the nuance and also some common sense, we could say this in a very simple way which would be the lighter your skin, the more on the side of safety you will err and make that only perhaps a 15-minute exposure to the sun. And if you’re darker skinned, that could creep up to 20, maybe 30 minutes.

DrMB: Sure. Absolutely.

DrMR: And with this chronic exposure to sun and the adaptation that you obtain from that, you will get a sense for if I get any more sun than this, I tend to get a little bit of irritation in my skin. And then, I know how much I can do. I think that’s just such a simple concept. It also keeps us in the lines of where the data shows the most benefit and minimal risk.

DrMB: Right. I agree with you. Most people still have common sense.

DrMR: Thank God.

DrMB: We hope. So therefore, as you say, use common sense. If it feels good, do it. If it doesn’t, don’t.

DrMR: Gosh, there’s a lot of sub-topics I want to get into here in terms of all-cause mortality and cardiovascular disease. But I want to make sure we have some time to touch on the tanning bed stuff. So let me sneak in one or two more of these before I move us to what is almost unquestionably the most contentious aspect in this conversation which is tanning beds.

But before we go there, one or two quick stops. First, all-cause mortality—for the audience, that just means death from any cause—decreases when people obtain time in the sun, at least according to some fairly compelling data.

All Cause Mortality

You cite one 20-year follow up study, and I’ll quote again. “The mortality rate amongst avoiders of sun exposure was approximately two-fold higher compared with the group with the highest sun exposure.”

That’s fairly compelling data. Regarding all-cause mortality, we’ve kind of touched on that briefly. But what would you expound upon there for the audience?

DrMB: I think you notice in our paper there are all sorts of reasons that sun exposure is beneficial. So other cancers aren’t as strong in their relationship or inverse relationship with sun exposure, but colorectal cancer, breast cancer, non-Hodgkin’s lymphoma, prostate, pancreatic. But I think hypertension is one of the most important things that is enhanced by sun exposure.

Sun Exposure and Vitamin D LevelsSo the more sun exposure you have—not the more sun exposure, the more common-sense sun exposure you have—then you have more endorphins. You have lower—it’s shown to lower your blood pressure. And then there are other things such as—you can read the paper as well as I can—type 2 diabetes. Just many, many things that lead to all-cause mortality and some that are just plain uncomfortable to have such as myopia, macular degeneration. So it’s really, really nice to get a little bit of sun.

DrMR: And to clarify, with these different subsets, let’s say, breast cancer incidence and mortality or colorectal cancer, I made sure to carefully read your paper to make sure that you—because I’m a skeptic at heart here, in part—were not citing vitamin D supplementation data or high levels of blood vitamin D correlating with these health benefits.

There is some data, but you were able to cite for the majority of your references papers that correlated time in the sun to reduced risk of whatever the outcome was being measured. That’s a very important thing for the audience to be aware of. We’re not cherry-picking or spinning the data here. The data does seem to be, while not perfect—they’re not necessarily randomized control trials, but we do show an association between those obtaining more time in the sun and reduced incidence in mortality from a variety of parameters measured.

DrMB: Right. For some reason, these haven’t been followed up as carefully as they need to be. And after talking with you, I’m hoping to do more of that because it’s very important for our public health for people to realize they do need a little bit of sun. Not tons, but a little bit.

DrMR: That’s a great segue to your conclusion. Let me read the conclusion, and then we can go into tanning beds because that’s where I think we might get a little bit off the rails because it’s such a contentious issue. But your conclusion, “Insufficient sun exposure has become a major public health problem, demanding an immediate change in the current sun avoidance public health advice.”

And this is what I think is key. “The degree of change needed is small but critically important. The public must be advised to obtain enough sun exposure and vitamin D supplementation to maintain a serum level of vitamin D of at least 30 nanograms per mL.” That degree of change is small, and I think that’s key. We’re not necessarily asking for a lot. It’s a small shift. But would you add anything to that?

DrMB: I don’t think so. Not at this point.

Tanning Beds

DrMR: Well, you wrote it. Fair enough. So let’s talk about tanning beds now. This is something that I have also been digging more deeply into some of the details. And it seems that there are some data—and I’m not as familiar with these data as I am the sun exposure data. It seems there are some data showing an association between sun exposure and increased melanoma or other forms of mortality, but there’s also some data showing no association.

Let’s start there because there are some things that may confound or account for that discrepancy in data. But wade us into this issue. What do we need to know here?

DrMB: Well, first of all, you said some data showing sun exposure and mortality. That’s old, old, old data from the 50s, I believe.

DrMR: I’m sorry, sun exposure or tanning bed use?

DrMB: Well, I thought you said sun exposure. But tanning bed use is associated—I don’t think there’s any contention that it’s not associated with the development of melanoma.

DrMR: There’s one metanalysis that Holick cites that showed no association of sunbed use with an increased risk of melanoma in a European population. Have you come across that metanalysis?

DrMB: No, I should look at that. I’m very surprised. It might’ve been Sara Gandini. She does a lot of metanalyses in Europe. I’d be very surprised… I wish I could look it up right now. But go on.

DrMR: I’ll send you this paper afterward. Let me find the topic of the paper. And I should now mention the topic, since the audience is probably wondering. The name of the paper—and I’ll give the PubMed ID because I’m sure you probably have PubMed at the ready. The PubMed ID is 29374748.

DrMB: Ok.

tanning bed

DrMR: The title of the paper is “A Critical Appraisal of the Recent Reports on Sunbeds from the European Commission Scientific Committee on Health, Environmental, and Emerging Risks and from the World Health Organization.”

This paper was a bear. There was a lot in here. It was just published.

DrMB: Oh.

DrMR: A couple of months ago.

DrMB: I think I know what you’re talking about.

DrMR: It may have slipped your gaze. There was a lot in this paper to dig into, and essentially Michael Holick, amongst a few others, were challenging some of the recent criticisms. And they were trying to, not necessarily advocate for tanning beds, but make a criticism that the European Commission’s appraisal was biased in only citing one side of the data.

And essentially, the European Commission was condemning tanning bed use. And Holick’s group did not feel that that’s what the data showed. The data at least showed that there may be a—I believe they used—mild-to-moderate increased risk of different health measures from using tanning beds. But there was also some data that was refuting that and may be confounded by…

And this is what I thought was very insightful—Holick cited that there was an association to unhealthy lifestyle behaviors, like smoking, drinking alcohol, and eating unhealthy foods, and that may be a major confounder. Essentially, people who tan tend to smoke, drink, and eat unhealthy foods. And that hasn’t been accounted for in some of the data.

There was one other piece that they also brought up which was there may be a threshold where if you use tanning beds more than 12 times per year, that presented a risk. But those using tanning beds less than 12 times per year actually were associated with a reduced all-cause mortality.

So there’s some nuance here. It’s contentious. But what are your thoughts on tanning beds? You may be anti-tanning bed. And that’s totally fine. I think there’s a lot here that we don’t know yet. So I think we’re all going to be updating our opinion as the data evolves. But any additional thoughts on tanning beds?

Dr. Ruscio Resources

Hey, everyone. This is Dr. Ruscio. I quickly wanted to fill you in on the three main resources that are available to you in case you need help or would like to learn more. Of course, I see patients both via telemedicine, via Skype, and also at my physical practice in Walnut Creek, CA.

There is, of course, my book Healthy Gut, Healthy You, which gives you what I think is one of the best self-help protocols for optimizing your gut health and, of course, understanding why your gut is so important and so massively impactful on your overall health.

And then, finally, if you’re a clinician trying to learn more about my functional medicine approach, there is the Future of Functional Medicine Review which is a monthly newsletter which is a training tool to help sharpen clinical skills.

All of the information for all three of these is available at the url, DrRuscio.com/resources. That’s D-r-R-u-s-c-i-o. And in case you’re on the go, that link is available in the description on all of your podcast players. Ok. Back to the show.

DrMB: Well, I’m a little bit confused about what you were actually saying. While you were talking, I was looking at the metanalysis. And there’s one by Boniol, Botteri, Boyle, and Gandini. And then there’s another one that’s a critique of the international. Is that the one you were talking about?

DrMR: Yes, I’m sorry it’s a critical appraisal of the report. Yes. Holick, Grant, Kimball, Hills.

DrMB: Ok. All I have is Grant, which is 2009. For some reason, I’m not calling it up. In any case, it’s very hard to answer that because the data up until now has been rather weak and yet the International Agency for Research on Cancer found that as they put it together, that it seemed to get stronger each year. And then, I did a paper with DeAnn Lazovich at the University of Minnesota. She was the lead author on that and the lead investigator.

Skin cancer, melanomaAnd we found a very strong association between any tanning bed use and the development of melanoma and the more tanning bed use, the more melanoma. There are a whole lot of issues with tanning beds. And certainly, they’re not all bad. You’re not going to have one tanning bed session or even five tanning bed sessions and get melanoma. That’s unlikely.

But one of the big issues is they’re not regulated. I know I’ve been approached by the tanning bed industry to be an advocate for them because they know I like sun exposure. And they told me, “Oh, yes. It’s regulated here in the United States.” But the fact is, it’s not. Nobody’s measuring the output.

In Norway or Sweden, somebody had measured the output at different tanning beds. And even though they’re supposed to be certain UVA and UVB outputs, none of them were exactly what they were supposed to be.

It’s very hard to say. You’re right that there is more work that needs to be done in the area. There was even a paper, maybe it was this one, maybe it was that you’re talking about, that showed that there was some survival benefit for people who use tanning beds. So we need to do more careful work. That’s all I feel like saying at this point.

DrMR: I think that’s fair.

DrMB: Ok.

Episode Wrap Up

DrMR: I think that’s absolutely fair. One of the things I’ve remarked in the past is with things that are natural, like exposure to the sun—and this is a broad statement but it helps guide you from a big-picture perspective—things that are naturally occurring, I would comment that those are usually innocent until proven guilty. Things that are not natural—so a tanning bed would be an unnatural application, trying to replicate the sun—I would say are guilty until proven innocent.

Until we have the data to semi-conclusively prove these to be safe, I would caution people to be very cautious and advise against tanning bed use. But I was just curious to see what your take on the data was. And again, even in this critical appraisal, they’re not endorsing tanning beds, but they’re just trying to call attention to the fact that we want to be objective in our analysis. And it seemed that the European Commission’s analysis was a bit biased, and it just seemed like they weren’t trying to present all of the data.

But I think we’re in agreement that get time in the sun. That’s a great practice. Tanning beds, probably better to avoid at least until there’s some sort of data to prove otherwise.

DrMB: Yeah. I think so. I used to go and talk to my daughter’s class when she was 12 or 13, just before spring break. And I used to say, “Now, you want to be really careful in the sun.” They’d come back to me afterwards, and they’d say, “Oh, guess what. We used baby oil and iodine,” which is what we did back in the day. “But we won’t do it again.”

DrMR: Yes. We’ll recommend to avoid that also. Ok. I think we’ve given people a good narrative on this issue which perhaps some of the data and the details may sound a little bit complex, but when we summarize it, we’re just trying to recommend some common-sense exposure to the sun, routinely and in conservative doses.

What do you think? I would like to hear your thoughts or experience with this.

Dr. Ruscio is your leading functional and integrative doctor specializing in gut related disorders such as SIBO, leaky gut, Celiac, IBS and in thyroid disorders such as hypothyroid and hyperthyroid. For more information on how to become a patient, please contact our office. Serving the San Francisco bay area and distance patients via phone and Skype.

Discussion

I care about answering your questions and sharing my knowledge with you. Leave a comment or connect with me on social media asking any health question you may have and I just might incorporate it into our next listener questions podcast episode just for you!

20 thoughts on “Sun Exposure Reduces Cancer Risk and Thoughts on Tanning Beds with Researcher Dr. Marianne Berwick

  1. I would love an answer to the Vitamin D injections. Do they increase your Vitamin D over taking supplements or using the sun as mentioned above. My Dr. is suggesting it for me .

  2. Thanks for this interesting interview. Does Dr. Berwick have a table or algorithm or other resources to help clinicians make appropriate sun exposure recommendations to patients of various skin types in various latitudes?

    thanks,
    LT

  3. I lived in the south of France for several years and was surprised in the first winter when I looked for a vitaminD supplement in both the pharmacy and health food store that there was none to be found. I wa told that a person could only get it with a prescription from a doctor. I asked my doctor for a prescription and she said it was good for two months. It came in liquid form that I had to drink. She was reluctant to give it to me because we were in the sunny south but because I can only take very small amounts of sun she caved and gave me the script. Is there such a thing as having too much vitamin D?

  4. Regarding how there may be multiple mechanisms, not just Vit-D synthesis, for the positive effects of sun bathing..

    Richard Weller has a good Ted Talk about how the skin releases Nitric Oxide into the blood when exposed to sunlight, causing better circulation and lower blood pressure, and according to Dr. Daniel Shapiro, increasing nitrates in the blood may be beneficial for brain health..

    There was also a recent study suggesting that UV + urocanic acid may increase glutamate in the brain!
    https://www.cell.com/cell/fulltext/S0092-8674(18)30507-5

  5. Curious if you’ve come across any research on whether it’s still beneficial if it’s only seasonal regular exposure. Us Canadians realistically only get about a 4-6 month window to have regular sun exposure, then it’s indoors for 6-8 months again. Is regular exposure during the spring/summer still beneficial or would that be considered a bad thing?

    1. Hi Kristy,

      Thanks for your question – I’m adding it to the list for Dr R to hopefully answer in an upcoming listener Q+A episode of the podcast. Stay tuned!

  6. Thanks for this interesting interview. Does Dr. Berwick have a table or algorithm or other resources to help clinicians make appropriate sun exposure recommendations to patients of various skin types in various latitudes?

    thanks,
    LT

  7. Curious if you’ve come across any research on whether it’s still beneficial if it’s only seasonal regular exposure. Us Canadians realistically only get about a 4-6 month window to have regular sun exposure, then it’s indoors for 6-8 months again. Is regular exposure during the spring/summer still beneficial or would that be considered a bad thing?

    1. Hi Kristy,

      Thanks for your question – I’m adding it to the list for Dr R to hopefully answer in an upcoming listener Q+A episode of the podcast. Stay tuned!

  8. Regarding how there may be multiple mechanisms, not just Vit-D synthesis, for the positive effects of sun bathing..

    Richard Weller has a good Ted Talk about how the skin releases Nitric Oxide into the blood when exposed to sunlight, causing better circulation and lower blood pressure, and according to Dr. Daniel Shapiro, increasing nitrates in the blood may be beneficial for brain health..

    There was also a recent study suggesting that UV + urocanic acid may increase glutamate in the brain!
    https://www.cell.com/cell/fulltext/S0092-8674(18)30507-5

  9. I lived in the south of France for several years and was surprised in the first winter when I looked for a vitaminD supplement in both the pharmacy and health food store that there was none to be found. I wa told that a person could only get it with a prescription from a doctor. I asked my doctor for a prescription and she said it was good for two months. It came in liquid form that I had to drink. She was reluctant to give it to me because we were in the sunny south but because I can only take very small amounts of sun she caved and gave me the script. Is there such a thing as having too much vitamin D?

  10. I would love an answer to the Vitamin D injections. Do they increase your Vitamin D over taking supplements or using the sun as mentioned above. My Dr. is suggesting it for me .

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