Regenerative Health with Max Gulhane, MD
I speak with world leaders on circadian & quantum biology, metabolic medicine & regenerative farming in search of the most effective ways of optimising health and reversing chronic disease.
Regenerative Health with Max Gulhane, MD
Sunlight & Cancer: Beyond Skin Deep | Dr Max Gulhane at Regenerate 2025
In this presentation, I disucss the evidence for sunlight, Vitamin D system and circadian rhythms in regulating cancer defense and immune function in the body. I also discusses nuances surrounding skin cancer and how to safely obtain sunlight in a skin-type appropriate manner.
Watch this talk on Youtube for slides and video.
Filmed live at 75 Reid St, Fitzroy for the fourth REGENERATE summit on March 23rd, 2025.
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The topic of today's talk. I've intentionally titled it Sunlight and Cancer Beyond Skin Deep, and the purpose of that is because I believe that there is sufficient evidence to support a profound role of natural sunlight in supporting health and in supporting cancer and, given Australia, particularly our narrative and our discussions and experiences with skin cancer and attitudes to sun, that I think this is going to be an important exploration of the whole story, or part of the whole story. So cancer is a growing problem and sometimes I like to look at economic data because it can tell a very, very interesting story in and of itself. But these companies these are the most profitable pharmaceutical companies in the world, and this business website made the comment that the global oncology drugs market was valued at $201 billion in 2023, and this is forecast to grow to $518 billion by 2030. What did they attribute this market growth down? To Well, factors such as the rising prevalence of different types of cancers, increasing new drug launches and product approvals, and growing research activities by pharma. Well, factors such as the rising prevalence of different types of cancers, increasing new drug launches and product approvals, and growing research activities by pharma companies in the field. So what is cancer? I mean a definition of cancer, any various malignant neoplasms characterized by the proliferation of anaplastic or de-differentiated cells that tend to invade surrounding tissues and metastasize to new body sites. That's interesting. But what causes cancer? That's not going to be the topic of today's talk.
Speaker 2:But I'll give you a couple of insights into perhaps the latest of what we think about could be causing cancer. These are perspectives from some of the top researchers in the world. Professor Thomas Seagree talks about a metabolic disorder, mitochondrial metabolic disorder. Professor Michael Levin is talking about the loss of cellular coherence from a bioelectric point of view and potential regression of that cell into a more embryonic state. And also Dr Jack Cruz has talked about the altering of Warburg metabolism, but really one being reliant on a change in light signals. But, as I mentioned, that's not going to be the topic of today's talk. What I want to talk about is sunlight and cancer particularly, and the link between sunlight and cancer. How can we frame that with respect to what we've been told about skin cancer and how can we add nuance to this topic? And finally, I'll be touching on how we can use the sun to help reduce death from cancer.
Speaker 2:So this story it starts it's actually quite an old story and this is an ecological paper by a US MD back in 1940. His name was Frank Appley, and what he noticed, and he drew a conclusion, was that when he observed the mortality rates from cancer in the United States and Canada, that there was essentially an inverse relationship or an association, and he made the comment that the total cancer mortalities of the various American states and Canadian provinces are shown to fall with increasing solar radiation and the number of people exposed. So this generated an interesting hypothesis that basically wasn't touched for a whole about 40 years until two brothers, cedric and Frank Garland, who are epidemiologists in California, san Diego, and they in 1980, posited or asked the question does sunlight and vitamin D reduce the likelihood of colon cancer? So they're interested in colorectal cancer and they proposed that vitamin D was a protective factor against colon cancer. What they did is they did and I guess drawing on the work of people like Frank Appley, because they noted that if they were looking at the geographical distribution of cancer and cancer deaths, that the mortality and colon cancer prognosis, which is another key aspect of this was that it was lowest in places with higher solar exposure and it was highest in places where the populations were exposed to the least amounts of natural light, namely major cities and rural areas at high latitudes. So what they did is a study, and this was eight years later. They did an eight-year prospective cohort study and what they found? And they essentially compared the risks of developing colon cancer and they were stratified that by the level of vitamin D, and we're going to talk about vitamin D and its role in this story. But essentially what they noticed was the lower that your vitamin D level was, the more likely you were to develop colorectal cancer. And what they said in this paper back in the 1980s was that the results are consistent with a protective effect of serum 25, hydroxyvitamin D on colon cancer.
Speaker 2:So to frame this talk, we need to understand a little bit about physiology and about how the sun affects our skin and affects our biological system. So what we have is sunlight and uniquely UVB sunlight, and that's a narrow range of light that actually hits planet Earth and it's only present for the majority of time when a sufficient solar angle allows for these high energy photons to penetrate the atmosphere. What it does is it hits the skin and it converts cholesterol 7D hydrocholesterol into vitamin D-like structure. So that process is reliant on a whole bunch of different things, but the key things that will affect that is the presence and absence of enough UVB-containing sunlight, as well as how much melanin exists in the skin, and we're going to talk about melanin and skin pigmentation and how relevant that is, particularly with regard to skin cancer. So what happens and this is a schematic of the physiology of vitamin D is that vitamin D is formed and then it binds in circulation to a binding protein before being taken to the liver and then the kidney and undergoes a range of hydroxylation and, essentially, activation steps before it is able to be used. As you can see here, you can also obtain vitamin D from the diet and it's essentially preformed because you've consumed animals that themselves have made this fat-soluble hormone. But really, the vitamin D level is primarily going to be determined by solar exposure, because the sun is the main way that we, as humans, generate and maintain our vitamin D level.
Speaker 2:So what's the role of vitamin D? Well, most of you would know about the bone effects and the research or the benefits of sunlight and UV-containing light predated the actual discovery of this compound, and in the late 1800s, in the ghettos of Europe during the Industrial Revolution, there was smog that was preventing ultraviolet light from penetrating into these areas and kids were getting severe vitamin D deficiency, and that was manifesting as rickets and the bow leg look of young children is the unfortunate consequence of inadequate bone development and ossification as a result of vitamin D deficiency. But what we've learned, and particularly over the last 15, 20 years, is that vitamin D and the vitamin D system is not only important for bone health, and it's actually far from it. It's a critical part of immune system function and, by extension, the cancer story, because it turns out that cancer in and of itself is extremely reliant on or dependent on the state of your immune system function. So things like the proliferation or growth of cells, inflammation and new blood vessel growth, which is all again a key part of the cancer story this is regulated by vitamin D. So where else does this vitamin D sunshine hormone, how, what else does it touch? Well, I'm not going to speak about it in this lecture, but it it is, covering a such a wide range of of really critical aspects of optimal health and metabolic health, particularly insulin resistance, obesity, diabetes, metabolic syndrome, as well as I mentioned tumor formation, cancer formation and immunity, and I'm going to explain now, but I'll explain later is that vitamin D is actually also and one way of thinking about this is this is a proxy for your total sunlight exposure. So that's going to be something I'll emphasize more.
Speaker 2:What else does the data suggest about cancer and vitamin D? Well, this study essentially is plotting breast cancer risk and it plotted it against the serum vitamin D level. So what you can see is a pretty profound relationship where, as the vitamin D concentration increases and we've got both nanograms per mil, which is the US metric, and nanomoles per liter, which is us in Australia so, of the women who had in this whole cohort of 5,000, those who had a vitamin D level in the upper ranges, their risk of developing breast cancer was significantly lower. What about for those who've already developed cancer? And that's another part of this story? Well, it turns out that not only incidence but also prognosis of cancer is profoundly related to associated with serum vitamin D concentration, and this study suggested that the higher your vitamin D level, the lower your fatality rate in people who've already developed breast cancer. And again, patients with the highest concentration of 25-hydroxy-D had approximately half the fatality rate compared to those with the lowest.
Speaker 2:This systematic review covered, and it summarized, the state of the research and it basically it says that the evidence that chronic, non-intermittent sun exposure decreases the risk of colorectal breast prostate cancer, non-hodgkin's lymphoma is accumulating and gradually getting stronger. This is nothing that we get taught in medical school and this is not something that you, as members of the public, get communicated, especially with public health messaging around sun exposure in Australia. But this isn't locked in a musty case next to the JFK files. This is not private information. You can go into PubMed and you can search this evidence and it exists. So what this is pointing to is that we've got a strong evidence that the higher someone's sunlight exposure, as we measured via the vitamin D system, the lower the risk of the cancers that really kill people, and that's a key point. And I'll contrast that with skin cancers because, as a cause of death in society, these are the cancers that are killing the most number of people.
Speaker 2:This is one of my favorite studies it was actually published last year, finally by Professor Richard Weller. Now, richard Weller is the rarest of dermatologists who's actually looked into the data and found that sunlight exposure has a holistic benefit on health, and in this study he essentially examined a database of over 400,000 people in the UK called the UK Biobank over about 12 years. And what he did is he stratified these people. He classified them based on their ultraviolet light exposure. So he used UV sorry, he used their latitude, which was a proxy for their UV exposure, as well as their sunbed tanning habits, and he correlated that to vitamin D levels. So what did he find? He found that participants with more active sun-seeking behavior and those living at lower latitudes had lower crude mortality of cancers of the digestive system. So I already told you that we already had strong evidence that it was linked to lower rates of colorectal cancer, but also breast cancer. Participants with active sun-seeking behavior had lower crude mortality from skin cancer Big pause there.
Speaker 2:Cancers of respiratory and intrathoracic organs, cancers of lymphoid, hemopoietic and related tissues, which are the leukemias, and cancers of the male genital organs. And they also summarize what I've just told you, which is an inverse relationship between solar exposure and cancer mortality in multiple sites organs. And they also summarize what I've just told you, which is an inverse relationship between solar exposure and cancer mortality in multiple sites, including the bladder, the colon, hodgkin, lymphoma, prostate, stomach and breast. So this is really elegant because we've got multiple lines of epidemiological data, one using vitamin D, serum vitamin D, which is an indirect marker of sunlight exposure, and one more direct, looking at all-cause mortality and basically finding the same thing. So if sunlight lowers the cancer mortality, what are the mechanisms?
Speaker 2:So we have to talk a little bit about the solar spectrum. We have to talk a little bit about light and how that affects the body. So what you have here is you have the spectral irradiance, so this is the solar energy that we get hit with on planet earth just standing outside, and we have the wavelength of light here On this tiny corner here. This is the ultraviolet light that is a UVA, and the UVB light UVB is only 5% of this is that is a uva and the uvb light uvb is only five percent of of this. The rest is uva. So you're only making vitamin d out of a small amount of of uv light, and that is also going to change depending on your latitude, it's going to depend on your season and it's also going to depend on time of day. What you can see with your eyes is the visible spectrum, and the largest area here by photon count is in the infrared and that's non-visible. So ultraviolet is essentially below the visible spectrum we can't see in ultraviolet and infrared is beyond visible.
Speaker 2:The key point that I'd like you to understand about this diagram is that each one of these wavelengths of natural sunlight have a profoundly important effect on human physiology and human biology. The reason for that is because these are the conditions of evolution for three billion years, and we evolved under this light, not under this light. As I said, vitamin d is only able to be made with with uvb light. So so what are the effects of uvb? And and I'll be really specific because it's not only a vitamin d story it stimulates this incredibly ancient and incredibly uh unique, uh poly uh peptide pro-hormone called POMC or pro-opio-melanocortin.
Speaker 2:Pro-opio-melanocortin, as I mentioned, is incredibly evolutionarily conserved. It's found in ancestral nathosomes, which were relics from prehistoric time. It regulates things like immune function, appetite and metabolism centrally in the hypothalamus, as well as blood pressure and, obviously, skin pigmentation. What it also regulates, and the downstream product of POMC, is the skin tanning system. I think the most interesting part of one of the most interesting parts of POMC and its effect is that it contains an endorphin-like chemical. So when you get in the sun, the same peptide hormone that is assisting in tanning your skin is releasing a beta-endorphin, an opioid-like chemical, to reward you for that tan. So again, think about this idea of tanning your skin cells in trauma, which is a half-truth. But if the sunlight is inducing tanning, but it's also rewarding you from being in there, and that's a 600-million-year-old program built into your biology. Who's in the wrong here? What else does it do? As I mentioned, it can cause DNA damage and particularly creates these photo products and sunburn. What I'll explain about as we go through is that Mother Nature built in an extremely elegant program to help you repair those DNA damage caused by ultraviolet B light. So UVB is a double-edged sword, but it's absolutely essential for optimal human health.
Speaker 2:So what did Garland and Michael Holick, who is the world leader on vitamin D, what did they say about the effects of vitamin D in cancer prevention? Because they were trying to explain this finding that there was lower colorectal, breast prostate and lower lymphoma findings with vitamin D exposure and sunlight. What they found is that the vitamin D compounds reduce the formation of new blood vessels in tumors. It reduces the malignant and excessive proliferation of cells. It increases or upregulates controlled cell death of cells. It increases or upregulates controlled cell death, or known as apoptosis, and it increases cell-to-cell adherence. And I mentioned briefly about this bioelectric model or theory of explaining cancer and this idea that the cell potentially loses its understanding that it's part of a structure in a whole and therefore induces these anaplastic type phenomena in the cells. But luckily vitamin D is helping those cells adhere to each other. Now this is a complicated slide, but the purpose is really simple, and that is to explain to you that when you get in natural sunlight, it's not only the chemical that you take in a pill from the chemist, because it turns out that the body makes a whole enormous pharmacy of related compounds that were initially thought to be biologically inert but have since been discovered to have profoundly beneficial effects, and again, anti-cancer effects, effects of promoting DNA repair in the skin cell scales and really systemically. So what else? How else can we account for this? Lower rates of cancer in people with greater sun and vitamin D exposure?
Speaker 2:Well, it turns out that your circadian rhythm is critical in regulating the essentially oncogenic process. And what is a circadian rhythm? Many of you might already know, but it's an endogenous 24-hour, almost 24-hour cycle that runs in the brain. The master clock exists in the hypothalamus, behind the eye, and it sets a rhythm that needs to be synchronized across all tissues and that rhythm programs the most critical functions of the body, from hormonal secretion, sleep-wake cycles, activity, metabolism, immune function, stem cells you name. It is regulated on a 24-hour cycle. What you can do is that you can program your circadian rhythm by the behaviors and the lifestyle that you lead. So if you get bright light during the day, if you sleep at nighttime and you consume your food during the day in a circadian appropriate manner, then you're going to get perfect synchrony between the clock in your eye and the peripheral clocks in your body, and that's going to lead to optimal health and optimal function of the body.
Speaker 2:If you do the opposite, then you are going to disrupt your circadian rhythm and that's a problem. And that's a problem because your immune system, which is supposed to be killing these precancerous cells that were spontaneously being generated, they're not going to be able to do that effectively. So circadian rhythm and cancer. Like I mentioned, not only do you have clocks in all these different bodies that regulate these critical bodily processes, but the cancer killing mechanisms, so key cancer genes they're all under circadian control. So cell cycle regulation, dna repair, cell proliferation and controlled cell death If you are up all night till 2am looking at, looking at a blue lit screen. If you're giving your body those profoundly uh disrupting circadian signals, it will derail your endogenous cancer fighting and cancer killing mechanisms. So I think that is a big part of of of potentially these findings is is that those who had a higher vitamin D were more likely to have a more regulated circadian rhythm and therefore this circadian system was likely working more effectively.
Speaker 2:What's another way to account for these findings? Well, this is extremely new research, and Scott Zimmerman and Russell Ryder are experts in mitochondrial medicine and physiology. What they discovered is that the melatonin, which is the body's most potent antioxidant system, was not only being produced sorry, not only antioxidant but it's also a signal for darkness and it induces sleep. It's not only being produced in the pineal gland in the circulatory system on the absence of blue light, but it was actually being produced on site in your cells, in the mitochondria, during the day with exposure to near infrared light. So so why is that important? Because it turns out that when the body is making this melatonin extremely important antioxidant, this free radical scavenger and antioxidant is, it is protecting the mitochondrial DNA and the mitochondrial DNA. Mutations in mitochondrial DNA underlie all this march towards chronic disease, including underlying the physiology of cancer and cancerous transformation. So, simply being outside and being in greenery, next to the green areas, you are absorbing massive amounts of near infrared light that are penetrating through your clothing and through your body up to at least 8 to 10 centimeters and helping your body to synthesize melatonin, which it's using to essentially protect the cellular and subcellular machinery that is allowing your cells to work properly.
Speaker 2:How else is this working? Well, if we drill down into the mitochondria, we can see that this is the process by which energy is actually generated, and it's a passage of electrons. It's taking food electrons, it's taking light information and it's allowing this electrochemical gradient to make energy in the form of ATP and also in the form of metabolic water, and metabolic water is this deuterium, depleted water that gets produced at the fourth complex cytochrome C oxidase. That process is optimized by natural sunlight in the form of all types of red light. These are chromophores, meaning they absorb light wavelengths and they're modulated by light wavelengths. So when the body is humming along and when this mitochondrial engine is humming along and you put the appropriate fuel in in the form of a low-carb seasonal diet that's rich in animal foods and deuterium-de depleted animal fats, then this process is aided. But it's never going to be optimally aided unless you're in natural sunlight which, as I told you, is extremely rich in red light, because the red light is helping your mitochondria produce this metabolic water that is essentially hydrating all the proteins and enabling them to work properly, as well as spinning this fifth complex, which is producing ATP.
Speaker 2:So mitochondrial dysfunction is a prerequisite for cancerous transformation. It is one of the key problems that goes wrong when a cell becomes cancerous, and natural sunlight not uv but essentially red and infrared is helping smooth this process. So the question I think is interesting is do we have a marker? Do we have a marker of how much sunlight we have of have had? Do we have a fuel gauge? Because that would be really helpful in seeing where people are at with respect to the sunlight exposure. And we do, and that's essentially what the 25-hydroxyvitamin D test that you can get from your doctor will tell you. It's a storage form, but it is a rough proxy and a good indicator of your total sunlight exposure. And that's not only the UVB and vitamin D system, and that is why I believe it's one of the most important tests to get and we can explain about what we want, and from an optimal level. So it can give us an indirect idea, because if someone's got a robust vitamin D level, then it will imply that they've had full spectrum sunlight exposure, including ample, near infrared, which was the ancestral norm for our species. But if they've got a low, insufficient or deficient level, then you can imply it implies that not only have they got the daytime sunlight exposure wrong, but they're probably exposed to some artificial light at night and they're therefore having some degree of circadian rhythm disruption.
Speaker 2:Okay, so what about skin cancer? And now? This is the critical point. That, as I mentioned, is the nuance we need to give to understand this system and this process. So melanoma Melanoma is the most concerning and dangerous of skin cancers and the reason for that is because it has relatively, compared to the non-melanoma skin cancers, a much higher proportion for metastasis, spread and therefore mortality. This is compared to the non-melanoma or keratinocyte cancers known as squamous cell and basal cell carcinoma. These non-melanoma skin cancers are not the cause of death in people. They're easily identified and they're easily treated. So the critical and most important issue here is the identification and prevention of melanoma, and no one's in argument or disagreement about that as a strategy.
Speaker 2:So how does skin cancer fit into this model about vitamin D? Because I just told you that all these really important cancers are associated with low vitamin D and therefore can be thought of as a product of sunlight deficiency. I don't know if anyone likes Star Wars, but this is one of my favorite memes and Padme is asking skin cancer patients should have a high vitamin D level from excess sunlight, and that again is the corollary of the advice to avoid the sun above a UV index of three because of the development of skin cancer. So if you extend that train of thought, those people who are developing skin cancer should have a pretty robust vitamin D level, because I told you that the only way you're generating meaningful amount of vitamin D is through UVB exposure. So that stands to reason if we're following this logical train of thought.
Speaker 2:So this is a study from South Africa. It was a bunch of dermatologists did this research, so they looked at the vitamin D status of patients in Cape Town so a very high UV index environment with non-melanoma skin cancer. So what did they find? They found that 49% of those with non-melanoma skin cancers were vitamin D deficient and 31 were insufficient, and they used a cutoff of 15 nanomoles per liter. So, interesting, even in the tumors and the cancers that are canonically said to be related to cumulative UV exposure, we're still seeing a significant association with vitamin D deficiency.
Speaker 2:What about this one Malignant melanoma vitamin D status as a risk and prognostic factor? Now, this is a meta-analysis that was published in January of 2025. So this one is hot off the press and it is a synthesis of the research for the past, well up to date with respect to the relationship of melanoma and vitamin D. So what did these researchers find? This is the conclusion. We observed significantly increased risks for thicker tumors, mitotic tumors, so those with higher cell replication, higher tumor stages, so cancers that are more down the track of spread in vitamin D deficient patients. The conclusion was this study demonstrates an association between low vitamin D status and both increased melanoma risk and worsened prognosis, and that's further contributing to the growing body of evidence supporting the tumor-effective role of vitamin D. So Vince thinks that's pretty astounding. That's pretty against what we're being told.
Speaker 2:We've been told to avoid the sun to prevent melanoma and prevent UVB exposure above a UV index of three with broad-spectrum sunscreens, but that's flying in the face. So what else? What about in patients that already have malignant melanoma? And this is a British study, and it looked at 123 patients and they had malignant melanoma, and it obviously excluded patients taking supplemental vitamin D. What did it find? It found that 84% of these patients were vitamin D deficient and of these, 31 were severely deficient. How did that break down? So, as you can see, the more mild your malignant melanoma, the less likely you were to have vitamin D deficiency. And all the way at the bottom, the stage four, distant metastasis, very poor prognosis. It's improved since the invention of immunotherapies, which has been a great invention, but it stands to reason that this is a massive finding. 89% were vitamin D deficient. Again, these are in patients with metastatic melanoma.
Speaker 2:So the question then and I think I've already answered it, but I'm going to continue to prompt you to think about is how do you become vitamin D deficient? The reason you become vitamin D deficient is because you're avoiding UV light and you're using UV blocking broad-spectrum sunscreens, which necessitate or necessarily block the block UV light. The dermatologists know this and they are trying to understand this to the effect of supplementation unsuccessfully, but they haven't understood that the critical reason why this is happening is or association is because the patients are lacking in key anti-cancer compounds made by full-spectrum UV-containing sunlight. So this is just a pause and a digestion of what I've just said. So how, again, can UV light be so intimately associated with both optimal health but also the severe cancer outcomes?
Speaker 2:This is a really interesting study and again it was done to investigate health outcomes in women and they took 20,000, 25,000 Swedish women and they followed them for 20 years, inquiring at baseline about sun exposure habits. Do they tan in winter, do you tan in summer, do you use tanning beds and do you travel overseas to tan? And the hypothesis of these researchers was that those who tanned the most, who had the most sun-seeking behavior, would get the most melanoma and then would die more frequently. And really that was their hypothesis and that's why they called it the melanoma in southern Sweden study. So they were right about the first thing the women with the most sun exposure did get the most melanoma. But they were completely wrong about the second part, because it turned out that the women with the most active sun-seeking behavior had the lowest mortality, and that was a dose-dependent effect, with the ones who avoided the sun having the greatest mortality. The conclusions of the paper was that sun avoidance was a risk factor on par with smoking for all-cause mortality. And the way they worked that out is that they found that the women who smoked but got sunlight and sought the sun and went tanning they had the same mortality as the women who avoided the sun and didn't smoke. So that's a magnitude equivalence of risk factor for all-cause death. What they put it down to was the women who were tanning were dying less of cardiovascular disease, stroke, but it turns out that they were also dying less of skin cancer. So this graph was a plot of those without skin cancer, those with non-melanoma skin cancer and those with malignant melanoma, and it was the odds of death, odds of all-cause mortality, and, as you can see in the groups, the women who avoided the sun in each situation they diligently wore their sunscreen they had the highest odds of all-cause mortality. And the tanning the ones getting up there in their bikinis from the morning to the evening in Sweden had the lowest mortality. And that was consistent finding.
Speaker 2:What did Peli Linkwes say? He's the chief investigator and he's one of the world leaders in investigating the systemic effect and benefit of sunlight on health. He said there is a relationship between high sun exposure and malignant melanoma incidence, but an inverse relationship to prognosis. But an inverse relationship to prognosis. Thus, high UV exposure increases the incidence as in more people are going to be diagnosed with melanoma, while low sun exposure habits on vitamin D levels have been linked to thicker, more aggressive melanoma with shorter survival times. So a very, very profound study which is explaining that there's this trade-off, a very important trade-off.
Speaker 2:I'll quickly revisit this data from Professor Weller, because what did they find? They replicated the findings of the melanoma in Southern Sweden study. They showed that those with greater sun exposure had lower mortality. Those with greater sun exposure had lower mortality. So what's the mechanism here? How can we explain this? Well, I told you about these chemical cousins of vitamin D. Well, it turns out that they have an immense and very fascinating and profound anti-cancer benefit. So this vitamin D here pre-vitamin D3, becomes vitamin D. If you stay in the sun and you continue to irradiate your skin with ultraviolet B, this becomes lamisterol, tachysterol and a whole bunch of other compounds. What do these do, these upregulate DNA repair enzymes in the skin. The UVB is damaging it and the basic cision repair and all kinds of other DNA repair mechanisms are promoted by these vitamin D metabolites. So I think that is going to be one of the profound reasons why we're seeing lower mortality in people with greater sun exposure.
Speaker 2:Now, what are the causes of skin cancer? And look, I'm going to explain my current thinking about this and this isn't by any means complete, but it's how I'm thinking about it at the moment. And there's always going to be an interaction of genetic predisposition with environmental factors. So I always tell my patients that genetics loads the gun and your environment, your choices, your lifestyle it pulls the trigger. Okay, what are the genetic predispositions? Those with pale skin types, those with less melanin in their skin, and it's very rare very certain genetic syndromes and there's one there called xeroderma pigmentosum. It's characterized by mutations that prevent those basic excision repair enzymes, those DNA repair enzymes, from working. So how do you marry this with lifestyle? Well, it turns out, if you have a disrupted circadian rhythm by looking at blue light all night and not enough full spectrum sunlight during the day, you're going to impair DNA repair and the cancer defense mechanisms. If you have a low vitamin D level and you're near infrared light deficient, you're not going to be making that antioxidant melatonin hormone If you're immunosuppressed. People on transplant recipients have extreme high risk of developing non-melanoma skin cancer. And that explains because they're hamstringing their body's natural repair and immune surveillance mechanisms.
Speaker 2:What else? And I haven't talked a lot about food, but it's an extremely common and recurrent anecdote that once people go carnivore, well, they cut out polyunsaturated vegetable oils, seed oils, refined oils that they find that they're prevented from burning. They're essentially resistant to the effects of UVB light. They're less photosensitive. We know and it's not a talk for today, but we know that omega-3 and the DHA, the EPA fatty acids they confer photoprotective benefits in the skin. And as a society we've collectively deviated from an ancestrally normal and appropriate omega-3 to 6 ratio because everyone is under-eating marine seafoods and everyone's over-eating refined seed oils. So I think that that is a key effect modifier for the development of skin cancer.
Speaker 2:What else? Melanoma is unique and we do see melanoma commonly in more younger people. Again, they're typically an indoor worker, they have low vitamin D, but it turns out that there's a photoreceptor system, the melanopsin non-visual photoreceptor system. This regulates melanocyte function. So if we're sitting in front of a blue-lit screen all day and we're sitting under blue light, then this light is highly stimulatory to melanocytes. So I believe that the indoor environment is a key part of particularly melanoma diagnosis in younger people.
Speaker 2:So how can we think about deliberate sun exposure really on a broad level? Because we have to be weighing up the benefits and the risks of sunlight exposure and sunlight avoidance. Well, I think that data and evidence suggests that we're trading up a reduced all-cause death, reduced cancer death, reduced skin cancer death and a lower cardiovascular death up against potentially a greater number of skin cancers, both melanoma and non-melanoma skin cancers, and they're particularly going to be in those fair-skinned prototypes. Reduction in cardiovascular death is a massive part of the benefit of natural sunlight, and that was a talk I did last year, which is a critical part of this story. So quickly, let me discuss how we're going to use the sun to help reduce our mortality from cancer.
Speaker 2:So there's a couple of really general steps here, but what we want to do is we want to understand our ancestry. We want to understand our ancestry, we want to understand our risk factors, we need to understand our ambient UV conditions and we're going to titrate our sun exposure based on those things. We want to target a vitamin D level. Again, this is going to be a marker of our sun exposure to a certain amount in approximately around 125. And obviously we're going to check for any suspicious lesions that might be forming as a result of an increased sun exposure habits.
Speaker 2:For a quick explanation, this is the Fitzpatrick photo scale, and from one to five and on one you have the most pale northern European, the Ranga, and at six you've got the darkest Sudanese, west African, somalian, perhaps Australian Aboriginal phototype and what you have here is a gradient of melanin in the skin and that's a gradient of pigment in the epidermis. The number of melanocytes aren't changed, but the amount of melanin that they've secreted into the skin has. And the question is what accounts for this difference? The answer is the ambient UV light. In Scandinavia the UV index doesn't climb above six most of the year and for one week it hits about six In the places where people have the highest pigmentation. They're being bombarded year round at the equator with massive amounts of UV light. So it's a response to the ambient UV conditions.
Speaker 2:The other key point and I put it in small letters, but it's important to note is that the less melanin you have, the easier it is to make vitamin D. That means because the melanin is itself is absorbing and dissipating this UV light as heat. So if you amongst a range of other effects, but the benefit of being pale in a high UV area is that you need a very little amount. And really, when we're thinking about light, we're thinking about essentially a drug-like replacement. So we need to consider that this is a dosing that we're giving ourselves and we can dose ourselves, but we have to be smart about the dose.
Speaker 2:Another way of thinking about this is what I'm calling a skin type latitude mismatch. So you have to ask yourself do you live in a similar solar environment to your ancestors? If yes, then you're matched and your skin type's appropriate for the conditions that you live in. Sun exposure habits are much easier then because you don't have to mitigate as much, because you're in the environment that your ancestors were evolved and you've had the appropriate amount of melanin in your skin. But us in Australia, most people are mismatched and you can actually be mismatched in two directions. You can be a fairer skinned person in a higher UV index area, which is most of Australia's Northern European migrants historically or you can be a darker person in a lower UV environment.
Speaker 2:As you can imagine, it's much more difficult to be dark in an area with low UV light than it is to be a light skin pigment in a high UV area. The reason is because if you're shame-worn, you can go in the shade. That a key point. You can titrate your solar exposure by using shade. Unfortunately, uh for stormzy here there is not enough uv light in the uk year round to give him his sunlight needs and that and that that actually is associated with a whole bunch of of uh you know interesting phenomenon, um related, related to sunlight deficiency and how that's affecting health disparities and this disparity in health outcomes, particularly in the US but also in the UK, between African-American, african-british and the native population greater rates of obesity, diabetes, cancer, stroke and heart attack. I believe it's related to the solar exposure and the inadequate amount of solar exposure that you're going to get as a dark person in a low UV environment.
Speaker 2:What are some key risk factors? So, if you've got a personal history of melanoma, if you've got a family history of melanoma again, if you're taking medications that are going to suppress the body's response or repair mechanisms to UV light, and if you've got many atypical nevi or funny moles, none of these are necessarily absolute contraindications to UV exposure, but it has to be taken on a case-to-case basis. You have to understand the solar conditions. The UV index is a measure of UVB intensity and if you go into any weather website you'll be able to see what that UV light is doing during the day. So, again, as I mentioned, seasonally this will change. But here in Australia we typically we can get in summer many days, you know, 11 and above, and that's a very high UV dose. Compared to Tassie, brisbane, townsville, everyone is extremely different.
Speaker 2:So it pays to understand how much UV light you're dealing with. It also is relevant to know that you can't make vitamin D and you therefore can't get burnt at all parts of the solar day. Again, the sun angle is primarily determinant of how much UV light comes in and when that is reaching above 45 degrees you're going to be getting UVB light. So the morning and the evening you can safely get your full body out and it's encouraged to do so prior to UV light exposure. But just be aware that you're not going to be making vitamin D in that time but you're getting other benefits for circadian rhythms and other physiological functions. So regulating your circadian rhythm it's easier said than done Bright light during the day and darkness or moonlight at night, and we can disrupt the circadian rhythm either by getting insufficient natural sunlight during the day or excess light at night.
Speaker 2:So, minimizing light at night, mitigating with things like blue light, blocking glasses with red and light, or candle light close to the ground these are all relatively straightforward but give you very high value ways of helping preserve your circadian rhythm and therefore preserve your immune cell function, preserve the cancer machinery's ability to kill cancer cells at the right time. And what do you do then? You can titrate your sun dose, and this is an app that was developed by Professor Michael Holick, his team, to help dose sunlight, based on your phototype, based on the ambient UV conditions. It makes it really easy. Circadian is another app to help you understand what time of day is sunlight present in my environment. Finally, you want to build your solar callus, and really you want to expose your solar calyx, and really you want to expose your whole body.
Speaker 2:What was the norm before clothes were invented? Well, from sunset to sunrise, sunrise to sunset full body irradiation on our skin. That is what our biology needs, and a lot of people haven't had sunlight on private parts in decades, and that is a problem if we're trying to prevent cancer, when we understand the potential and powerful role of these vitamin D and these other secosteroids, as well as near-infrared light. So what's an appropriate vitamin D level? Well, this work by Hollick et al. They looked at where does the vitaminD level land in free-ranging humans, in non-human primates, it gets to anywhere between 125 to 200. In the Maasai and Hadzabe in Tanzania it sits at about 115. These guys look like a prototype, five or six. They have a massive amount of melanin, but they're still maintaining a serum vitamin D level that is double the average Canadian and I would say double the average Australian, because they're simply outside all day. I mean, how else can we look at this? Outdoor workers they'll naturally have levels of 163. Puerto Rican farmers 135, 122. So the average Canadian is 68.
Speaker 2:I would tell you from anecdotal clinical experience measuring my patient's vitamin D, it's probably a little bit higher than that, maybe 78 or 80, but it's nowhere near. Most people are not getting close to those levels, and Australian dermatologists this is an interesting one because it's proof that they're eating their own cooking. But 35 nanomoles is deficient, and it's deficient no matter what metric you use, and this is a graph that explains the different units for both UK and US. But under 50 is classified as mild deficiency in Australia. Above 75 is where we stop seeing bone complications like subtle subclinical osteomalacia. If you can get your vitamin D above 75, and that's a good threshold for supplementation to get above. But really the sweet spot for cancer prevention long-term is going to be above 100. And that is putting yourself into the lowest risk groups of those epidemiological studies that I presented to you earlier on.
Speaker 2:Obviously, if you have suspicious lesions, they need to be identified and we're really particularly worried about pigmented lesions. So identify concerning factors that include asymmetry in any lesions, multiple different pigments, rapid change anything's concerning. Luckily we have some of the best skin doctors in Australia. These can be readily identified and excised, which is great. The slide I didn't include is a story about melanoma over diagnosis and it's a little bit of an interesting and controversial topic. But the data is clear that there's some degree of that happening, not only in the US but here in Australia too, and it's driven by diagnostic creep in terms of what previously would have been known as called a pre-malignant lesion or is now being called a melanoma in situ, and that's been driven by a whole range of factors, particularly in the US. It's related to profit and the structure of their system that rewards melanoma diagnosis, but that's not really relevant to you as individuals, because if you have anything that's concerning, it needs to be looked at.
Speaker 2:So let's end on a meme, because I love memes, I love the matrix, and what Neo is saying here is you're saying that those people with cancer cancer patients should, including with melanoma should sunbathe to reduce the risk of dying.
Speaker 2:Keyword being dying and Morpheus says yes, that is exactly what I'm saying. So if you're interested in any more of this, then join my private community group. I've actually put together a much, very detailed course about safe and appropriate, sensible sunlight exposure that includes the nuances I've touched on, called solar callus, with a whole bunch of lessons, and include on things like photosensitizing medications, the role of circadian rhythms and how to optimize everything. So check that out if you want to dive into a bit more depth, and I've got a whole bunch of free podcasts on my channel that go into this in further depth, including with Professor Richard Weller and Dr Jack Cruz, who have done a lot on this topic. My talk last year is aimed at the cardiovascular benefit and if you want to learn from me and you want to experience how I do the solar exposure and how I recommend you do it, then join me on a couple of retreats in July. That's always a fun time. So thank you very much for listening.
Speaker 3:Max Goldhain, everybody Give it up, applause.
Speaker 2:A beacon of wisdom and knowledge. We've got a couple questions. Yeah, okay, we've got Cindy over here. Look at those hands. Shoot up, gary.
Speaker 3:Everybody goes out into the sunshine and they put their sunglasses on. Will you address that please?
Speaker 2:Yes, so photoreception is not only a cutaneous process and that basically means that your eyes are detecting light wavelengths and there's a feedback loop that exists between the eye, the brain and the skin that regulates pigmentation. That means, for that process to occur properly, you need a coherence between the signal that the eye is receiving with regard to its ultraviolet environment and the skin. If you wear sunglasses that block ultraviolet A and B they broke up to 400 nanometer light you are going to deactivate or create a discrepancy in those signals. That is going to impair the tanning process and and that evidence is very old and it's been done in fish and lower, lower order animals that, like frogs, that um show the pigmentation is is occurring because of what is the light information that's being received through the eye.
Speaker 2:Does that include seeing glasses? So, to a lesser degree, depending on the lens. It's a different thing type, but if they're UV blocking, then to some degree they're going to impair that process. Yeah, so any car windscreens? Yes, absolutely, because they again are just changing the proportion of light that you're receiving, because they preferentially block UVB, they permit a little bit of UVA and they permit more blue than infrared, so they're changing the proportion or the form by which the light is being delivered to the eyes and skin, and that's different to the three billion years that your body's evolved with.
Speaker 1:Max, thank you for continuing my confusion with vitamin D and UVB light, because I think there's a double paradox there which keeps articulating it very well. I'd like to come to the defence of UVA and ask you a couple of questions about that. Uva light, which we've got a lot more here the further south you go stimulates nitric oxide production. Nitric oxide is the critical chemical which actually is involved in our t killer cell response to cancer. So uva light is very beneficial for cancer mop-up rather than cancer prevention.
Speaker 1:Uric acid, byproduct of fructose, inhibits nitric oxide production. That's in some of my talks. But I want to defend UVA because not everyone can get out just for the right number of minutes in the middle of the day. The other one is linoleic acid, which you alluded to. There is well associated now with 10 years of literature that there are. People with melanoma have much lower, higher levels in the fat cells of that, because melanoma is increasing and predominantly found now in the non-sun exposed areas. So how can we worry about UVB that? The worrying thing about linoleic acid is it just comes from the seed oils as a half-lifer it's probably about four years. So if you want to get rid of it out of your diet, you can improve your metabolic health straight away, but it's going to probably take a few years. So can you defend UVA?
Speaker 2:Yeah, so UVA is a critical part of this whole sunlight story and I didn't particularly include its mechanisms as it relates to cancer. But with respect to optimal health, uva is key and for the reasons that you mentioned, not only, as you've said, it liberates nitric oxide from the vessels, the blood vessels, and it helps to dilate it. So you know if we're thinking about a patient with essential hypertension, with metabolic syndrome, who's got hypertension yes, it is an insulin resistant component to that and the effect of insulin on you know, renal sodium absorption. But I think that patient is sunlight deficient and they're UVA deficient, amongst a bunch of other things. The other point about UVA is that Weller's group noted that UVB actually can lower blood pressure too. So it's not only an isolated UVA effect but it's essentially a lot of the short wavelength, including blue, can cause photorelaxation and dilation of blood vessels. So I'm a massive fan of uva. As I mentioned, the vitamin d here is the biomarker of total sunlight exposure. So I think the benefit for cancer too, absolutely could be uva related, but um and near infrared related, so it's the whole package. It it's difficult no, exactly, we don't have a biomarker as like we do, that I'm aware of to measure someone's UVA exposure in isolation.
Speaker 2:On the point of linoleic acid and melanoma, yeah, I definitely agree. I think to be really nuanced. It seems like you know the cancer in non-sun exposed areas. That seems to be super because there's multiple types of melanoma which we didn't go into. Superficial spreading melanoma in younger patients on non-exposed areas, like on the finger, typically in a very pale, you know, 25-year-old office worker, absolutely. And that's why I alluded to the artificial light, alluded to the fatty acid components In older patients who have lentigo maligna, some of these more chronic sun-exposed areas do get melanoma but they're nowhere near the metastatic risk of those other melanoma types.
Speaker 2:So, yeah, I guess I agree with you, Gary. I think this story is so much more nuanced than what we're being presented with. And the strategy of slathering everyone in sunscreen and sunlight avoidance is essentially preventing anyone from building any resistance or building the natural physiological response to sunlight. So they're even more weakened when they do go into sunlight, which might be a couple of times a year, get fried to a crisp and you know the epidemiology suggests that's the predominant risk factor for developing melanoma. From an epidemiological point of view.
Speaker 3:Great talk, max. Thanks so much. My understanding of melanomas is that it's skin sun damage in children, infants, children rather than adults, and I just wonder how that would affect some of the figures you found, because you're looking at adults who may have then stopped their sun exposure and so they may have been burned as a child and say I'm going to protect myself. So I'm worried also that people may be watching this and then go away and say, oh, I'm going to protect myself, so I'm worried also that people may be watching this and then go away and say, oh, I'm going to get my kids out there, but are they still at risk?
Speaker 2:Yeah, so the emphasis needs to be made that there's no evidence that low-level amount of non-burning sun exposure is linked to any adverse health effect. The issue, as you've identified, is signal for intermittent severe sunburn sun exposure is linked to any adverse health effect. The issue, as you've identified, is signal for intermittent severe sunburn in childhood. I, I think, and and maybe I'll explain it a little bit more the average age, the median age of melanoma diagnosis, is 68. It's in the late, late 60s. So so what I believe is actually happening here is people with a pale phototype.
Speaker 2:One or two Australians most Australians are getting potentially had a number of severe burn episodes early in life. They then ate their high CEDOL diet the whole time. They went inside and worked in a bank or office for 50 years and then, age 60, because they're so vitamin D deficient and their sunlight sunlight avoided and they're circadian rhythm disruption, they develop a malignant melanoma that metastasizes and kills them. So potentially that early in life sunburn was impactful for them. But is that a reason to dissuade people from appropriately getting gradual, safer amount of UVB containing light? I don't think that's the case. But, as I said, I'm not advocating for burning by any means. And the paler you are, the earlier in the day you can safely get UV light before going in, because the UV index is lower and that's probably the most conservative way to advise UV exposure.
Speaker 2:If your ancestry is from Sweden, where it doesn't get above a UV index of six, then know the UV conditions of your environment. And the moment the UV index climbs to 10, because you've got your Swedish ancestry go inside, you've still generated sufficient more than enough vitamin D and beneficial sunlight in that time. But it's culture in Australia for us to go out in the big day but we've got our sunscreen on, you know, and really spend a lot of time in an area that would require us to be as dark as those Sudanese people. But not many people are really getting that. Sorry, guys, that's all we've got time for. If you've got any more questions, ask Max in the break. Dr Max Gahlhain. Thank you.
