70. Debunking Incorrect Claims About Sunlight, Tanning & Health

In this episode I provide a comprehensive analysis of claims made in an internet blog post titled 'Ask the Expert: What Is a Solar Callus? By Skin Cancer Foundation, which advocates for total sun and UV light avoidance. This episode comes with slides and images, so is best watched on YouTube.

Learn more about the cardiovascular benefits of sunlight my talk, ' What Your Cardiologist Doesn't Know About Sunlight & Heart Health':  https://youtu.be/NaeqPHEM-d0?si=dmYJrmsQB6oYdhAS

This presentation is also the final lesson of SOLAR CALLUS, my course on how to safely get deliberate sun exposure for health & longevity optimisation. Purchase SOLAR CALLUS here - https://www.drmaxgulhane.com/offers/MbTx2Siw

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DISCLAIMER: The content in this podcast is purely for informational purposes and is not a substitute for professional medical advice, diagnosis, or treatment. Never disregard professional medical advice or delay in seeking it because of something you have heard on this podcast or YouTube channel. Do not make medication changes without first consulting your treating clinician.

#sun #solarcallus #tan

Transcript

Speaker 1: 0:06

Okay, hello everyone. The title of this presentation is what is a Solar Callus? Debunking Incorrect Claims About Sunlight, tanning and Health. This is a presentation. It is also a special episode of the Regenerative Health Podcast and it is also the final lesson in my Solar Callus course. So the purposes of this presentation is really to address some claims being made online specifically about sunlight and health.

Speaker 1: 0:40

And really this presentation is in response to this Google search, and if you type into Google what is a solar callus, then you get a hit. The first hit it's a blog post titled ask the expert what is a solar callus? By the Skin Cancer Foundation, and what comes up is you don't even have to actually click on the hit. Google will provide it for you and it says that Ramzi Saad MD. And I'm quoting first, there is no such thing as a solar callus or sun callus. These are made up terms not recognized in the medical field, and that's highlighted. You cannot build up a tolerance for sun exposure. Further, there is no such thing as a safe or healthy tan. So if we click the link, then we're brought to this website.

Speaker 1: 1:33

It's a blog post. It's a lady blocking the sun with her hand, and the blog starts off with a question which is by a hypothetical person, or maybe this was someone. Anonymous person submits a question. I've heard online health coaches talk about building up a solar callus to help your body produce vitamin D. Is it ever okay to expose your skin to the sun without sun protection? So interesting framing of that second question.

Speaker 1: 2:03

But look, let's have a look at this blog post, and there's a lot of claims being made in this blog post and I'm not actually going to read it all out, but I'm really going to identify five claims that we're going to address in this video. So the first one is by Dr Ramzi Saad is that there is no such thing as a solar callus. The second claim we're going to address is that you cannot build up a tolerance for sun exposure. The third claim is that there's no such thing as a safe or healthy tan. The fourth claim is that more research is needed on how much vitamin D the body can produce, the level of vitamin D necessary, and vitamin D is important in overall health. And finally, the fifth claim is that the risks of unprotected sun exposure far outweigh any benefits. And potentially in another video then we can go through some of these other claims, because they also will need addressing.

Speaker 1: 3:00

But before we dive in, let's have a look at who wrote this and what are their professional affiliations. So Ramzi W Saad MD is a board-certified dermatologist practicing in Plymouth, massachusetts. He is a fellow of the American Academy of Dermatology, a member of the Massachusetts Academy of Dermatology, a member of the Massachusetts Medical Society and a member of the Skin Cancer Foundation's Amonet Circle. So what I'm going to do in this presentation is address these claims with specific references to historical clinical evidence of the practice of heliotherapy and the therapeutic use of sunlight, mechanistic physiology of UV light effects on skin and systemic health, mainstream dermatological perspectives on deliberate sun exposure, evolutionary biology of humans and the melanocortin system, epidemiological studies on the role of sunlight, uv light, vitamin D deficiency in all-cause mortality and expert perspectives on the role of sunlight in systemic health. So let's get started.

Speaker 1: 4:02

Started claim one there is no such thing as a solar callus. So let's address this claim in through the lens of medical history. And this gentleman, auguste rollier md, is basically the person that we really need to know about. He was a swiss physician. He lived in from 1874 to 1954. He was a pioneer of heliotherapy. So if you break that down into its component part. Helio, meaning sun therapy, is treatment. So he cured and treated a lot larger but actually cured more than 1,200 patients of extra pulmonary tuberculosis using sunlight and it was called back then surgical tuberculosis because it implied and often the standard of care before heliotherapy was used widely was surgery and that had significant detrimental effects and side effects and adverse effects compared to what Dr Roliere would later do.

Speaker 1: 5:03

So here's a picture and for those who are listening on the podcast feed, I really encourage you to watch the YouTube video so you can see these amazing pictures. But it's a before and after and it's a child with multiple tuberculous lesions. He looks like he's got some cutaneous tuberculous lesions on his lower legs and upper arm and lower arms and that's a before and then. After a year of heliotherapy he is looking, his lesions have healed, he's gone from emaciated and cachectic to bright and looks very well and obviously he's been turned around from a health point of view. So here's another image and this is five children and they're on skis, they're in the Swiss Alps, they're wearing simply white underwear and white hats and having their full skin exposed, obviously soaking in a massive amount of ultraviolet light, not only because of the full spectrum of sunlight, but also this is going to be increased by the altitude and the fact that the snow is reflecting that light. So this is just one of just to give you an idea about the degree of ultraviolet light that was being used therapeutically in this heliotherapeutical protocols for the treatment of, in this case, predominantly extrapulmonary tuberculosis.

Speaker 1: 6:35

So I want to make reference to this Nature paper in 1922. So Nature remains today the preeminent medical and scientific journal, and the title of the paper was the Advance of Heliotherapy, by Dr CW Salabry, and I'll quote the treatment of disease by sunlight is the newest of old things. It was systematically practiced by Hippocrates, the father of medicine, and perhaps we need not trouble ourselves with questions of priority in our own times. At any rate, the first clinic for the heliotherapy of surgical tuberculosis was opened by Dr A Rollier at Leysen in 1903, and at last it would appear that his methods are to be followed throughout the world. Already in France and Italy the sun cure is practiced, and I recorded lately in Nature, march 2, the finding of many heliotherapeutic institutions on the Riviera from Cannes to San Remo. The city of Lyon wisely sends its sick children to the Villa Santa Maria at Cannes, and the Italians have recently established the Istituto Heliotherapeutico, which I found outside San Remo a few weeks ago. So this is 1922.

Speaker 1: 7:54

Let's take another look at some of these images and how Dr Roullier implemented heliotherapy, and you can see that children have their desks set up outside in the snow. They're all again wearing only white underwear and they are doing their lessons outside in full spectrum sunlight. This image shows more people and there's just beds laid out in the sun and people are sunbathing. They've got their heads covered, they're wearing hats, but they are soaking in a massive amount of light and they're almost doing yoga, it seems like in that second image. So it looks very happy and content.

Speaker 1: 8:38

So why am I raising this point? Because the claim made in this paper is that there's no such thing as a solar callus. But what we can really understand is that heliotherapy is a therapeutic implementation of the solar callus. That much is abundantly clear. So when we make a claim like there is no such thing, really, it is from a position of ignorance of the historical use of sun as a medical tool. So what does modern dermatology have to say about heliotherapy? And I'm referencing dermnet, and this is a free and open source repository of diagnostic images and dermatological clinical and treatment guidelines are written by dermatologists, and they have a section on heliotherapy and they describe it as the use of natural sunlight for the treatment of certain skin conditions.

Speaker 1: 9:34

It is a form of phototherapy, also called climate therapy. So how does it work? Well, the ultraviolet part of the spectrum has beneficial effects in and, they've said, in small doses. I would argue that also in large doses. Short wavelength UVB and longer wavelength UVA induce vitamin D production and other chemicals that protect skin cells. The UV radiation is anti-inflammatory, immune suppressing and anti-proliferative.

Speaker 1: 10:01

They've mentioned here that heliotherapy can be used in psoriasis, that it has a potential to reduce the extent and severity of psoriasis, improve quality of life and they've mentioned a really clear psoriasis and in 10, sun exposure can aggravate it. It also is indicated in eczema and atopic dermatitis and vitiligo. What what? Well, this paper suggests that the current indications for judicious use of heliotherapy include severe cases of acne vulgaris, psoriasis, eczema, seasonal affective disorder with depressed mood, jet lag, vitamin D deficiency. The mechanism of sunlight therapy's beneficial effects have been studied and discussed extensively in the medical literature. So the claim that there's no such thing as solar callus is false, and it is false because it is ignoring what has been historically used and is recognized in dermatology as a therapeutic approach using the sun, called heliotherapy.

Speaker 1: 11:01

So second claim you cannot build up a tolerance for sun exposure. Let's see what auguste rollier had to say about that, and this is a excerpt from his paper heliotherapy in the high alps exposure always begins with the feet, the legs, the thighs, the abdomen and thorax, following in this order with an interval of a varying number of days between each. Only a few minutes of exposure is allowed to each part, each part on first day. In insulation, this amount is gradually increased until at the end of a period of time which varies with each subject, degree of pigmentation and absence of excessive reactions being the criterion, the patient is able to expose the whole body in the sun for several hours daily without any inconvenience, either in summer or winter. So that goes again quite in opposition to the claim that you cannot build up a tolerance to sun exposure.

Speaker 1: 11:55

Let's look at some more recent physiological and scientific evidence. So this is a review article titled the Intrinsic and Extrinsic Regulation of Human Skin Melanogenesis and Pigmentation, published in 2018. And the authors write UV-induced human skin pigmentation suntanning requires the induction of several pathways leading to increased melanin production by melanocytes, which occurs to protect the neighboring keratinocytes. So if we look at what is occurring in the epidermis in response to ultraviolet light, and particularly ultraviolet B light exposure, is that we have these melanocytes which have these dendritic protrusions in and amongst the keratinocytes, close in the basal layer and they produce melanin. And they do so and then essentially pass the melanin in these melanos nucleus of the keratinocyte, specifically to absorb and protect and defend the DNA and the nuclear material from the ionizing radiation of ultraviolet light. And to think about the difference between those with the lightest to the darkest skin is simply the amount of melanin that exists in the epidermis and the amount of melanin and the prototype, the genetic endowment of melanin, is a physiological response or reaction to the evolutionary ultraviolet light conditions. So what more you cannot?

Speaker 1: 13:42

In terms of addressing the claim that you cannot build up tolerance to sun exposure, this review paper by Anthony Young, titled Acute Effects of Ultraviolet Radiation on Human Eyes and Skin, writes that melanogenesis is evident three to four days post-irradiation and can increase over eight weeks depending on complexion and ultraviolet radiation dose protocol. It may take several weeks for the skin to return to its base colour. So the claim that you cannot build up a tolerance for sun exposure is false. What's the third claim? There is no such thing as a healthy tan. Once more, I'm going to reference and this is the last time that I'll reference Auguste Rollier, but I think his perspective is so important because this is a man who again treated well over 2,000 patients and managed to cure 1,200 of extra pulmonary tuberculosis and set up massive amounts of therapeutic centers. So this is someone with an immense amount of clinical experience and that shouldn't be minimized. So what did he write? He wrote that I frequently have noticed that the resistance of a patient against disease is closely proportional to his degree of pigmentation, and pigmentation does not take place under clothes.

Speaker 1: 15:10

What else can we look for from history? Well, this is a flyer from the US Department of Labor Children's Bureau in 1931. And it is titled Sunlight for Babies and it's got a picture of a happy-looking baby sitting in a chair outside. And what did they have to say? What was the purpose of this? And it was really distributed to families, to housewives, to advise them on sun exposure for the prevention of rickets, which is severe bone skeletal manifestation of vitamin d deficiency. So I'm quoting this entry is called Sunlight, health and Growth.

Speaker 1: 15:58

The sun that tans the child's skin helps him to grow normally. It gives his body the power to use food so as to help build straight bones, strong muscles and well-formed teeth. A child needs the sun most when he's growing fast in babyhood and early childhood. This next section is titled Give the Baby a Coat of Tan. The baby should get tanned all over, but the tanning should take place gradually. Care should be taken not to burn him. Some babies tan more quickly than others. Some burn more easily tan more quickly than others. Some burn more easily. Dark-skinned babies need more sun to tan them and to protect them from rickets than fair-skinned babies. And it's got a drawing of a happy-looking baby lying down without clothes on a picnic blanket outside. Give the baby a coat of summer tan. So that's very interesting.

Speaker 1: 16:52

That was publicly disseminated from the us government in 1931. What else? Every mother who wishes her baby to have a robust health should give him regular sun baths from early infancy until he is old enough to play in the sun himself. Sun baths may begin when the baby is three or four weeks old, in warm weather outdoors, in cold weather, indoors, at an open window. So essentially advocating for sun exposure for neonates and today we supplement babies with oral vitamin D. But in 1931, they were advising for sun exposure and advising families and women to begin sun baths early. Sunshine for older children. Now that so many children wear sun suits when the weather is warm, it is easy for them to get tanned. Older children, as well as babies, need plenty of sunlight and they ask the parents to get your children used to sunlight. So very interesting historical perspective and illustrating that the narratives, these claims that we're addressing in this blog post, that there's no such thing as a safe or healthy tan that has not been the argument or the narrative forever. That has not been the argument or the narrative forever. It is only a more recent advice. I would say, given historically what was advised and practiced.

Speaker 1: 18:31

Let's look at some more detailed physiology and let's look at some evolutionary biology. What I want to explore here is a gene product. It's a master pro-hormone. It's a peptide pro-hormone that gets cleaved into a whole bunch of other peptide hormones that is highly conserved, even very much older than mammals, for addiction to sunlight and addiction to ultraviolet light. So this gene or this product is called Pro-OPO, melanocortin or POMC, and the name really gives you an indication or an idea about its function. So Pro, obviously, is the precursor opio, referring to opioid or opiate, and melanocortin. So melan is a Greek word for dark or black.

Speaker 1: 19:34

So if we see here that this compound essentially gets cut up, it gets cleaved into a range of separate peptide hormones. One of them is ACTH adrenocorticotrophin hormone, gamma lipoprotein, beta endorphin and other fragments. And ACTH further gets cleaved into alpha MSH. That has roles in melanin synthesis, immune response and food intake. The reason why this is relevant is because UVB light stimulates the release of pro-opioid melanocortin and encourages the production of these gene products, these peptide hormone products. So what is the role? Well, if you cleave alpha-MSH from ACTH and POMC, then that is the signal for the skin darkening and melanin synthesis in melanocytes the skin darkening and melanin synthesis in melanocytes. What happens to alpha-MSH in the brain? It feeds back onto total body metabolism and actually reduces food intake and therefore induces weight loss. And finally, beta-endorphin is this opioid-like chemical and it has a profound role in rewarding ourselves, rewarding our bodies, for getting in ultraviolet light. This is a very, very important point that you are being rewarded. You're being rewarded by a feel-good hormone when you get in ultraviolet light.

Speaker 1: 21:17

So this claim that there's no such thing as a healthy tan is in odds or opposition to what we know biochemically of the role of POMC and beta-endorphin. So this paper, mitf and UV responses in skin from pigmentation to addiction, and I'll quote there are proposed mechanisms underlying physiological reinforcing properties of UV to drive tanning addiction from both preclinical and clinical studies. In 2014, a group demonstrated in mice that beta-endorphin produced upon ultraviolet exposure from cleavage of the POMC propeptide induced an opioid receptor-mediated addiction-like response to ultraviolet light. These responses were reversed by an opioid antagonist, naloxone, and absent in beta-endorphin knockout mice. So what else?

Speaker 1: 22:10

And this is a paper that they were referring to, which is titled Skin Beta-Endorphin Mediates Addiction to Ultraviolet Light, published in 2014. And I quote here that. And they've written although and I think that is not indicated, but I'll read the quote for you Primordial UV addiction mediated by the hedonic action of beta-endorphin and anhedonic effects of withdrawal may theoretically have enhanced evolutionary vitamin D biosynthesis. And they've added that it may now contribute to the relentless rise in skin cancer incidence in humans. That's something I disagree with, but the essence of the quote is, I think, accurate, and not only vitamin D biosynthesis, but also the benefits of synthesizing POMC and the role that POMC has in regulating so many diverse body functions from we didn't even mention, but their roles in immunity, in roles in sex development and a whole bunch of other very important roles. So what does this circuit look like?

Speaker 1: 23:18

Well, when UV light hits the epidermis, you get cleavage or you get synthesis and increased synthesis of POMC and then therefore beta-endorphin and that signals to the opioid receptor, and this is in the mouse brain, in the ventral tegmental area, which then synapses to receptors and areas, including the prefrontal cortex. So that is a conserved pathway, and a conserved pathway, how can we think about again this idea that there's no such thing as a healthy tan? How can we think about that? And this is a way of understanding the role of UV light and melanin synthesis. And you can see that it does take cellular damage to activate P53, which activates Pp C transcription. So the production of alpha MSH from pomp C does require cellular damage from ultraviolet B light, and this is a key point that we're going to talk about soon, which is this is a hormetic stressor and an ultraviolet light.

Speaker 1: 24:32

Ultraviolet B light is a hormetic stressor, but the response of that alpha msh cleavage and then signaling to these melanocortin receptors is that you get the upregulation of eumelanin in melanocytes which then get transferred, as I mentioned, in these melanosomes to therefore protect the underlying keratinocytes, the overlying keratinocytes. And we're not going to go into the mechanisms of skin physiology and the nuances, but suffice to say the purpose of the continual shedding of keratinocytes up and from each layer of the epidermis is one of those evolutionary roles of clearing out those keratinocytes which have accumulated excessive mutations. So the body is incredibly wise, it's incredibly intelligent and it's evolved over billions of years, with the sun as an ever-present input, to both harness its benefits and also compensate with evolutionary, evolved mechanisms, the other side of ultraviolet light which can cause this DNA and cellular damage. So really, the claim that there is no such thing as a healthy tan really needs to be addressed under the with the perspective of evolutionary biology.

Speaker 1: 26:01

And if there were no such thing as a healthy tan, why did mother nature build ultraviolet light addiction deep into our genomes with this 500 million year old peptide brohormone POMC? And to give you an idea of how ancient this is, it appears to have arisen in these ancestral nathostomes more than around 500 million years ago. And that is a proposed or speculated arrival or development of POMC and the various melanocortin receptors, because there isn't just one, there's multiple, there's at least five, and the point is that this is a pathway that has been conserved in cartilaginous fishes, which branched off maybe 450 million years ago, and then in the telosts and then also in tetrapods. So what we have to really think about is how critical, how important is this compound, is this pathway of UV light addiction, if it has been so ubiquitous and so conserved over selection pressures of more than 500 million years? That is a very, very important question that we all need to ask ourselves, especially the people that are claiming that there's no such thing as a healthy tan and that we need to avoid ultraviolet light. And here are some photos of some nathostomes for you. So I'm going to pronounce these Dunkleosteus, the spotted wobbegong, the silver arowana and a Nile crocodile. So these are all various nathostomes who have also these UV light addiction pathways because of their presence of POMC. And anyone who's seen a crocodile in a zoo lying in the sun, you bet that he is getting a massive hit of beta-endorphin and being rewarded for his ultraviolet light sunbathing. So does Mother Nature make mistakes? No, mother Nature fundamentally doesn't make mistakes, and if we don't understand a system or we don't understand why it exists, then we have to look at ourselves and try and answer the question, not presume that Mother Nature has made a mistake mistake. So really we have to hold these two simultaneous truths that UV light can cause DNA mutations in keratinocytes and other skin cells, but that it is also critically important for health and human health. So the claim that there is no such thing as a safe or healthy tan is false.

Speaker 1: 28:54

Claim four it's true that you can obtain a limited amount of vitamin D from the sun's rays. Still more research is needed on how much vitamin D the body can produce, the levels of vitamin D necessary and vitamin D's importance in overall health. So let's take the first claim and address that first, about more research that is supposedly needed on how much vitamin D the body can produce. So this is a graph, and on the x-axis is time in hours and on the y-axis is serum vitamin D in nanograms per mil. And this is a comparison of the serum vitamin D3 levels after total body exposure to one minimal erythemal dose of simulated sunlight. So ultraviolet-rich light in a tanning bed compared with a single oral dose of either 10,000 or 25,000 international units of vitamin D2. And this is a study done by Professor Michael Hollick, who discovered the active form of vitamin D many decades ago. What you can see is that the oral vitamin D dosing gives quite a large peak of your serum vitamin D, but that comes down much quicker, whereas the skin the skin irradiation from the simulated sunlight gives a much more prolonged vitamin D raise. Ultraviolet light is equivalent to, but gives a more prolonged release of vitamin D equivalent to 25,000 units of vitamin D2. The reason for this and we're not going to go into the physiology, but essentially the conversion of the precursor 7-dehydrocholesterol into vitamin D. It essentially gets absorbed or it transfers into the dermal capillary bed and gets uptaken by vitamin D binding protein predominantly, whereas orally ingested vitamin D has a split between that and serum lipoproteins Again, not the focus of this talk.

Speaker 1: 31:33

But my point is that we do have research on how much vitamin D the body can produce, and this was done in the early 2000s. So it's a false claim that we need more research, so much so that Professor Michael Holick's team made an app called D-Minder and it advises on how long to expose yourself to UVB light based on height, weight, gender, fitzpatrick, skin type, any current vitamin D level and supplementation. Current vitamin D level and supplementation, your location and skin exposure. So this is not an unknown quantity. It is so known that there's actually an app, again made by Professor Holick's team, that is advising you on these realities. So, yeah, it's a completely false claim to say that we need more research about how much vitamin D the body can produce. So what about its importance in overall health, the early 2000s and the mid-2010s, that there's a massive amount of health benefits by raising the public's vitamin D levels to a level of 125 nanomoles per liter?

Speaker 1: 32:56

I'm not going to read them all out, but rickets osteomalacia reduced by 100%. They are the most severe. Skeletal, as I mentioned, impacts of vitamin D deficiency Cancers all combined, reduced by 75%. Breast cancer reduced by 50%. Ovarian cancer reduced by 25%. Colon cancer reduced by 67%. Non-hodgkin's lymphoma reduced by 30%. Kidney cancer reduced by 67%. Endometrial cancer reduced by 35%. Type 1 diabetes reduced by 80%. Type 2 diabetes reduced by 50%. Fractures all combined, reduced by 50%. Falls women reduced by 72%. Not sure how they calculated that one. Multiple sclerosis reduced by 50%. Heart attack in men reduced by 50%. Peripheral vascular disease reduced by 80%. Preeclampsia reduced by 50%, peripheral vascular disease reduced by 80%, preeclampsia reduced by 50%, cesarean section reduced by 75%. So that is the work of Michael Hollick, phd, md, from the Boston University School of Medicine. I told you that I wouldn't read them out, but I did, so there you go.

Speaker 1: 34:00

But the point being is that we don't need any more research on vitamin D's importance in overall health. If we type vitamin D health into PubMed, the search engine for clinical and scientific evidence and I did this recently, in June of 2024, then we have 29,856 results, the first hit being calcium and vitamin D. Skeletal and extra-skeletal health. The beginning of that abstract of that paper is that vitamin D is known for its role in calcium homeostasis for optimal skeletal health, and they review that with regard to skeletal health and extra-skeletal diseases. This is another paper paper and this is a review article of vitamin d is a protector of arterial health, its potential role in peripheral arterial disease formation and it's extremely well elucidated the sources of vitamin d dietary and sunlight derived and its role in these various diseases. So much so that this elegant diagram explains that 25-hydroxyvitamin D sufficiency is linked to improvements in the neuromuscular system.

Speaker 1: 35:18

Reduced osteomalacia and osteoporosis is optimal calcium and phosphate metabolism, increased balance in skeletal systems, increased respiratory function, optimal parathyroid control and then deficiency, increased cardiovascular diseases, reduced immunity and increased infectious disease susceptibility, reduced reproductive outcomes, increased insulin resistance, obesity and autism, increased diabetes, metabolic syndrome and autoimmunity, reduced memory and cognitive functions, increased tumorigenesis and increased cell proliferation and cancer, all leading to increased morbidity and increased all-cause mortality as a result of 25-hydroxyvitamin D deficiency. So I'm going to really hammer this point home, because I think it's one of the most damaging claims in this blog post, which is this idea that we need more research on vitamin D's importance in overall health. This is a meta-analysis of all-cause mortality according to serum 25-hydroxyvitamin D. This was published in the American Journal of Public Health in 2014, so that's 10 years ago. Garland et al reported that people with serum 25-hydroxyvitxy vitamin d less than 22 nanomoles per liter had nearly twice the age-adjusted death rate compared to those with greater than 125 nanomoles per liter. What about this paper?

Speaker 1: 36:39

Vitamin d and the risk of all cause of cause specific death systematic review and meta-analysis of observational cohort and randomized intervention studies published in the British Medical Journal in 2014. Chowdhury and Al studied serum 25-hydroxy D data from 849,000 participants and concluded that 12.8% of all US deaths 340,000 per year and 9.4% of all deaths in Europe 48,000 per year could be attributed to serum 25-hydroxyvitamin D less than 75 nanomoles per liter. What else? Vitamin D status and risk of all-cause and cause-specific mortality in a large cohort results from the UK Biobank and this was published in 2020. Compared to participants with 25 hydroxyvitamin D concentrations below the cutoffs, those with higher concentrations had a 17% lower risk for all-cause mortality. That hazard ratio was 0.83 and the confidence interval 0.79 to 0.86. A 23% lower risk of cardiovascular mortality. That was even more significant, with a hazard ratio of 0.77 and a confidence interval of 0.68 to 0.86. And 11% lower risk for cancer mortality, and that hazard ratio was 0.89 and a confidence interval of 8.84 to 0.95.

Speaker 1: 38:00

So what else do we know? We know that vitamin D supplementation can't get us the same results, and the reason I say this is from this randomized control trial titled Vitamin D Supplements and Prevention of Cancer and Cardiovascular Disease, and it randomized 25,871 participants to either vitamin D or placebo, followed them up for five years and found that supplementation with vitamin D did not result in a lower incidence of invasive cancer or cardiovascular events than placebo. So I think this is where the vitamin D advice has really become derailed because a lot of clinicians and guidelines have seen these findings and advised that we don't need to check or optimize vitamin D. We should only avoid frank deficiency for the skeletal complications. But what they don't realize and this is a critical point is that oral vitamin D supplementation does not produce long-term beneficial outcomes equal to the observational literature, because serum 25-hydroxy-D is merely a proxy for full spectrum sunlight exposure and that necessarily includes ultraviolet, obviously, because that's what is producing the 25 hydroxy B via UVB radiation, but also infrared light and full spectrum visible. So that is the key point that not many people are talking about.

Speaker 1: 39:31

What did Professor Michael Hollick, endocrinologist, professor of medicine and vitamin D research scientist, say? What's his take on this whole topic? He said that there is no downside to obtaining sensible sun exposure. You do not need to be a genius to know this. We need sensible sun and vitamin D supplementation recommendations. This is not a hypothesis. We don't need more research. So the claim for that we need more research that the level of vitamin D necessary and vitamin D's importance in overall health is somehow unknown it's false and really it's quite egregiously false and I think it either demonstrates complete ignorance of published research, going back at least a decade, or deliberate obfuscation, I'm not sure which, but it's clear, if we do a cursory look through the literature, that these claims are completely wrong. So the final claim that we're going to discuss is that the risks of unprotected sun exposure far outweigh any benefits.

Speaker 1: 40:43

The paper that I really want to draw your attention to is titled Avoidance of Sun Exposure as a Risk Factor for Major Causes of Death a Competing Risk Analysis in the Melanoma in Southern Sweden Cohort, and this was authored by Peli, lindqvist and Al. What they did is they got a cohort of Swedish women, native Swedish women and they really ascertained their sun exposure habits by asking them do they sunbathe during winter, do they sunbathe during summer, do they ever go to tanning beds and do they ever travel overseas for tanning holidays? They controlled for confounding variables like socioeconomic status and a range of other relevant as much as possible in this observational cohort design that could potentially confound these results. The premise of the study was to basically see they expected to see the women who got more sun got more melanoma died more often, and they were surprised by their findings. What they found was that the survival of those women who avoided sun was significantly increased over this study period and it was at least it's up to 20 years of follow-up now, but in this diagram is showing up to 15 years of follow-up. They concluded that women who avoid sun exposure are at an increased risk of all-cause death, with a twofold increased mortality rate as compared to those with the highest sun exposures. And what I want you to really take away from these graphs is that this is a dose-dependent response, meaning the more sun you got that they reported, the better the outcome was.

Speaker 1: 42:42

What else did they find? They found that avoidance of sun exposure was actually the magnitude of the effect was equivalent to that of smoking. What that meant is that the women who smoked but sought the most sun out had the same mortality as those who avoided the sun but smoked, and Lindquist makes the point that this is novel but in agreement with systematic reviews of vitamin D and the risk of cardiovascular disease. What else did they find? And they noticed that there was obviously development of melanoma within the cohort, but they found that those who contracted malignant melanoma in the melanoma in Southern Sweden cohort 35% of women with low sun exposure and 10% of those with the greatest sun exposure habits died during the follow-up period. What that showed is that the sun exposure was protective of mortality, of skin cancer mortality in the women who developed malignant melanoma.

Speaker 1: 43:54

So, even developing malignant melanoma, the more sun you got, the more protected you were from death, and that is a repeated finding. That was initially found in 1937 by Pelder and Stevenson in their study of US Navy personnel and it has since been repeatedly observed. That is a really important point. The findings that there was a dose dependency in sun exposure to inverse risk of all-cause mortality and the magnitude of the differences indicate a causal relationship and not only an association. We conclude that the increased mortality rate among those who avoid sun exposure is mainly due to an increased risk of death from cardiovascular disease and diseases not related to cancer or cardiovascular disease. We hope that our findings add to a more balanced and adequate view regarding the effects of sun exposure on our health. So that is not the only finding and this paper that is currently a preprint but will be published soon it was submitted in 2023.

Speaker 1: 45:03

It's titled Higher Ultraviolet Light Exposure is Associated with Lower Mortality mortality analysis of the data from the uk biobank cohort study, and this team included professor richard weller, who is a dermatologist, an expert on the systemic effects of of sunlight on health. It. It used a massive cohort of 376 000 people and they determined uv light exposures by both the latitude that they lived at and determining sun-seeking behavior, and they followed them up for a median of 12.7 years. What they found was similar to Lindquist and Al the more UV light you got, the lower your risk of death. There was lower all-cause mortality, lower cancer mortality, lower cardiovascular mortality and even lower skin cancer mortality with the more UV light that one got. And this translated on absolute terms into approximately 50 days of extra life for those with the greatest sun-sinking behavior and those living further south of an extra 16 days of life. So is this a causal relationship? I think Peli Lindquist made it pretty clear that he believes it is and I want to raise the fact that these are repeated findings and this is not the first time that we're encountering. These findings showed that although Navy personnel were getting more skin cancer, they had less risk of other cancers and lived longer. Frank Apley, 1940, showed that the more UV light exposure, the more solar radiation lower the cancer mortality in US and Canadian states and Garland, and Garland in 1980 1980 noticed a strong inverse association between vitamin D status and between sunlight and colon cancer.

Speaker 1: 46:59

So what does Professor Richard Willer say about this? Well, he said that public health advice on sunlight exposure is at the crossroads. Almost a century of data has confirmed the carcinogenic effects of UV radiation on the skin and delineated the mechanisms by which this occurs. And the point to say about that is a lot of that data is actually in mouse models using isolated ultraviolet narrow bands and not balanced UV light with red and infrared. But that's a side point, another whole topic in and of itself. But what Weller says is that there is a remarkable absence of any evidence that ultraviolet light reduces lifespan, in sharp contrast to other heart disease risk factors. The UV-induced reduction of cutaneous nitrate and its export to the systemic vasculature, which he has helped delineate, is an additional mechanism by which sunlight may exert beneficial effects on health. But other mechanisms surely exist.

Speaker 1: 48:05

All-cause mortality and its reduction should be the primary aim of physicians, not the narrow avoidance of skin cancer. I'm going to repeat that. So it all sinks in All cause mortality and its reduction should be the primary aim of physicians, not the narrow avoidance of skin cancer, of skin cancer. So food for thought, especially for any doctors listening. So what does Dr Jack Krew say?

Speaker 1: 48:37

He's a neurosurgeon, theoretical, quantum biologist, longevity and health optimization expert. He said that longevity in humans is linked to optimal solar exposure. The reason is simple. This protects the seven layers of energy generation inside a cell. The more sun human gets, the more diseases they can avoid, and the number one risk of most diseases is age. Solar exposure effectively makes you younger because it lengthens the TET mechanism inside of cells to improve the Hayflick limit in all cell lines. So everything in medicine is a risk versus benefit equation. That is something that we get taught basically at the beginning of medical school. And if we think about sunlight as one of these interventions and really form a population level formulation, then we can see that the benefits of deliberate sun exposure include reductions of all cause death, reductions in cardiovascular death, reductions in cancer death and reductions in skin cancer death. And what are we trading up? We're potentially trading up photo aging and an increased number, potentially, of skin cancer diagnoses in fair skin phototypes.

Speaker 1: 49:56

So the claim that the risks of unprotected sun exposure far outweigh any benefits again, this is very, very misleading and it's simply wrong. So this blog post titled Ask the Expert a solar callus by the skin cancer foundation in november 8th 2023. This is incorrect, it's misleading and it's uh, it's biased. So, to wrap up, let's examine what a bunch of experts, including professor rich Richard Weller, including Professor Peli Lindquist, have said about sun exposure. They've titled their review article Insufficient Sun Exposure has Become a Real Public Health Problem, and what the purpose of the article was to alert the medical community and public health authorities to the accumulating evidence of the health benefits of sun exposure, suggesting that insufficient sun exposure is a significant public health problem.

Speaker 1: 50:55

Studies in the past decade indicate that insufficient sun exposure may be responsible for 34,000 deaths a year in the United States and 480 deaths a year in Europe, and an increased incidence of breast cancer, colorectal cancer, hypertension, cardiovascular disease, metabolic syndrome, multiple sclerosis, alzheimer's disease, autism, type 1 diabetes, asthma and myopia. And what they've also mentioned, which is the point that I made earlier, was that oral vitamin D supplements have not been convincingly shown to prevent the above conditions. Thus, serum vitamin 25, hydroxy vitamin D, as an indicator of vitamin D status, may be a proxy and not a mediator of beneficial effects of sun exposure. So that is another whole topic, but my point is that sunlight avoidance is a massive global. Their point, and my point is that it's a massive global public health problem.

Speaker 1: 51:52

Sunlight avoidance narratives such as the one in this blog post are incorrect, they're lacking nuance, they are incomplete and they're narrowly focused, and they're misinforming and damaging to public health by scaring people off sensible sun exposure. So let's take this all the way back to the beginning. What is a solar callus? And although the author stated there's no such thing, I'm going to give you a definition, and this is the lay definition A solar callus is a tan developed by gradual, progressive exposure to full spectrum natural sunlight that allows one to harness the health benefits of the sun and tolerate increasing doses of sunlight without burning. And I've also written a definition for my medical colleagues, and that is solar callus is heliophototherapy involving full body exposure to increasing doses of full spectrum UV-containing sunlight titrated to Fitzpatrick, skin type and ambient ultraviolet light conditions aimed at stimulating melanin, vitamin D synthesis and other non-vitamin d related biochemical and biophysical pathways for the purposes of longevity optimization, prevention and adjunctive treatment of a wide range of chronic and infectious diseases.

Speaker 1: 53:04

So my claim is that we need more sun, not less, and it's time to change the paradigm regarding sun exposure. It's time to give and offer people a more balanced and clearer communication about the systemic health benefits of sun exposure. And it's time for common sense sun exposure advice and, again, titrated to skin type and ambient ultraviolet light conditions. And these are the happy kids at one of Dr Auguste Rollier's heliotherapeutic clinics in Leysen, switzerland. So if you want to learn more, and particularly hearing from Professor Richard Weller, from Dr Jack Cruz, from other experts on sunlight and health, then listen to the Regenerative Health Podcast, because there is a growing list of excellent interviews and discussions on this specific topic.

Speaker 1: 54:02

If you want to explore more about the exact mechanism by which sunlight and ultraviolet light full-spectrum sunlight is having such a profound benefit on cardiovascular disease prevention, then check out my recent talk at Regenerate Melbourne 2024. It's on YouTube, titled Sunlight what your Cardiologist Doesn't Know About Sunlight and Heart Health. And finally, if you want to learn how to develop your solar catalyst, if you want to learn how to extend longevity and harness the sun for that goal and to build your vitamin D safely, then I prepared a course that is the most comprehensive guide to deliberate sun exposure that's been put together and it has over eight hours of lessons specifically describing in depth the topics that we've talked about in this presentation specifically what the solar callus is. What are the benefits of sunlight on a physiological point of view? What are the benefits of sunlight from a clinical evidence point of view? How can we understand sunlight and its systemic effects?

Speaker 1: 55:15

How does your skin and what are these homeostatic, hormetic responses to skin exposure? And what are the preparations you need to make in order to get sun exposure healthily? What are the nuances you need to make based on your ancestry, skin type and what I'm calling a skin type latitude, mismatch, um, how do you execute this? How do you build your solar callus and you do it and monitor it, and how do you, um, make sure that you remain healthy from a skin point of view as well? So, and it contains another a bunch of bonus lessons too and, like I said, it's the most comprehensive guide.

Speaker 1: 55:56

So if you want to also meet and learn more in person, then we have a, a health summit in aubrey, new south wales, the third or fourth of august, and Day two is all about light and health with a bunch of very experienced and knowledgeable guests. Tickets to that you can follow the links in the bio. Thank you for listening. If you've got this far, like I said, you can find out more on my YouTube channel, on my podcast, on my social media, instagram and Twitter. So thank you very much.