Regenerative Health with Max Gulhane, MD

Sunlight as Medicine - Key Mechanisms

β€’ Dr Max Gulhane

I explain the biological effects of key light wavelengths on human health, the role of Vitamin D, and the concept of 'skin type:latitude mismatch' to guide safe UV exposure based on ancestral origin.

Watch this presentation on YouTube to see slide presentation with diagrams. This presentation was delivered for Genbiome Clinic, Sydney, Patient Salon.

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Speaker 1:

And so this talk is titled Sunlight as Medicine, and it is going to be an overview of not only the different types of light but also how these light wavelengths interact with our body and have a health-modulating or health-promoting effect for our body. And so the first part is going to be, as I mentioned, talking about that particularly, and then some main concepts that come up with regard to this concept of light as medicine, particularly around vitamin D, and some thoughts at the end about how we can safely get sunlight. So to start off the talk, we have to zoom all the way out. We have to zoom beyond planet Earth into our solar system and to understand the effect of me, because we have to really appreciate that all life on Earth essentially relies on this external energy input orbits the sun and the Earth spins on its axis. There's a changing amount of light wavelengths and light information throughout the day atmosphere to filter the full brunt of all the electromagnetic energy that's being radiated from the sun through space to our planet. This is really critically important because if you try to, I guess, serve yourself the full ladder of electromagnetic radiation without the protection of the Earth's atmosphere, magnetosphere as well, then you will get sick very, very quickly, and that's part of the reason why the astronauts on the space station are getting sick is because they are getting an exposure to the amount of type of light in the proportions that is very unusual and not expected by the human body.

Speaker 1:

And the human body has evolved over 3.4 billion years, or created, depending on your school of thought, to have this very, very specific tranche or combination of light wavelengths that we're going to talk about. So what is getting through onto us on planet Earth is predominantly by photonic energy is actually visible light, but by number of photons is actually infrared light there's. By number of photons is actually infrared light, and how you can think about this graph is the total amount of light energy and we've got it by wavelength, and I won't go into the nuances of this, it's a very physics-based topic, but essentially the properties of light are a function of their wavelength. So what we have here is the shortest wavelength light which is actually non-visible. Is this ultraviolet light, but it is very, very important for our health. The next lot is this visible light, which our eyes have essentially evolved to be able to recognize, and then, as I mentioned, the largest area is this infrared light, which again, is non-visible. But just because this light is not visible doesn't mean it's not having a very important biological effect, and that's what we're going to talk about.

Speaker 1:

The other point that I alluded to earlier was that the properties of the light that we get throughout the day are varying, they're not constant, and what I mean by that is at the morning, at the sunrise, because of the angle of the sun in the sky, we're getting visible and mostly a whole lot of infrared light, a lot of longer wavelength light, and that is because the light essentially has to travel through a thicker layer of atmosphere when it's really low in the horizon to reach us, and that atmospheric predominantly ozone filters out ultraviolet and all the shorter wavelength light. So as the sun rises as an angle in the sky, then you get a UVA and this longer wavelength UV light, and then when the sun is above an angle in the sky, then you also get UVB, which is the highest energy light and the most potentially damaging in terms of sunburn, but also is critical for vitamin D and these other functions. The key, I guess, point about this slide is as it relates to a topic that we're not going to talk about tonight, but particularly this idea of indoor lighting and the indoor light environment, which is completely unchanging. But what your body needs and wants is this really nice, gradual exposure to changing wavelengths and intensities throughout the day, and that is what your body is adapted to receive. So let's start with UV, and UV light comes in a couple of different flavors. The shortest wavelength UV is actually filtered, as I mentioned, by the ozone, so that most of the UV light that's hitting Earth is actually UVA and a small amount of UVB. Now, uvc is an interesting topic, especially when it comes to the actual endogenous production of light in our bodies, but that's not also a topic we're going to talk about today.

Speaker 1:

As I mentioned, what you're getting on planet Earth is going to be a function of the angle of the sun in the sky as well as, if you think about where we live, the latitude. The latitude on planet Earth, the further away from the equator you are, and this depends again on the season, which is the next point is going to dictate how high or low the sun is in the sky. Obviously, the time of day is also because the sun is traversing through the sky as the Earth rotates. What this essentially means is that, as the solar angle, the zenith angle, increases, the amount of UVB radiation is reduced. So at higher latitudes and this applies to anyone who's living in Europe or the USA, or even down south in Melbourne and Tasmania is that at high latitudes and the greater distance from the equator, the more UVB radiation is absorbed by the ozone layer, thereby reducing or eliminating the production of vitamin D in the skin. And if you think about the skin characteristics of people who have been adapted to these colder northern climates, is that they have actually lost the melanin pigment in their skin. And that is precisely an adaptation to a low UV environment, particularly to preserve their ability to make vitamin D and make the most of the scarce amount of vitamin D that is simply not present for large amounts of time in the year. And that's what I mean. There's some latitudes that seasonally you can't make any vitamin D if you stood naked in the middle of the day, and again, that day is going to be very dark because it's very north.

Speaker 1:

But the point to understand is that the light and the light that is reaching earth is really dependent on these latitude and other factors. The other points that I again didn't elaborate, but things like altitude, things like pollution. These are all environmental factors that will also influence the availability of UV light. Why is this important? Because UV light, this really high-energy light, was likely instrumental in the actual evolution of life and there's the suggestions that it was the Cambrian explosion. So one of the key time points in essentially paleontological history, the evolution of life on Earth, that massive proliferation of these different organisms really coincided with this huge increase in terrestrial UV yield, the light that was hitting earth.

Speaker 1:

So what are the properties? Again, I don't want to belabor this, but UV light, as I mentioned, it's most of the UV light that's hitting in the earth. It can penetrate deeper in the skin, it can photo age you and pass through glass, but it also has a range of other beneficial properties. These include stimulating nitric oxide and the release of nitric oxide in the blood vessels and that, as I mentioned, relaxes the blood vessels. It has a very powerful immunosuppressing effect and the effect on the immune system is to dampen down the immune system. So anyone who suffers from autoimmune disease and this in many ways is a UV light deficiency Autoimmune disease is, I'll say it again is in many ways simply a UV light deficiency, and there's lots of data if we plot the incidence of autoimmune diseases like rheumatoid arthritis or multiple sclerosis or type 1 diabetes against latitude. It's like a U-shaped curve based on latitude, meaning that these diseases are practically unheard of at the equator under large amounts of UV light and they become a problem for people in Tasmania or in New York, whatever. So UV light is also having a profound effect on activating neurotransmitters and stimulating their function and, as I mentioned, can cause indirect DNA damage.

Speaker 1:

And that's important to realize because the crux of the effect of UV light for our health is it's always double-sided and my message is that we have to understand that UV light can be both harmful to the skin but profoundly beneficial for our overall health, can be both harmful to the skin but profoundly beneficial for our overall health, and we have to basically understand that if we are to make a decision for ourselves about how much we want to expose ourselves to. So, as I mentioned, if you are under UVA light, you will relax your blood vessels and therefore your blood pressure. So it's actually not only UVA, it's actually UVB and even blue, which is next to UV on the spectrum. So, again, if you have high blood pressure, if you have someone that you know someone has high blood pressure. Ask that person or ask yourself when was the last time that I had this short wavelength natural sunlight actually on my skin, that I had this short wavelength natural sunlight actually on my skin? When was the last time I had my torso exposed to this light and really hypertension? Yes, there's a strong relation to insulin resistance, but I again think that primary or central hypertension is very much a function of people simply not meeting their fundamental light needs and their sunlight needs, and UV light specifically.

Speaker 1:

So UVB, it's again only 1% to 10% of UV light. It's very highly filtered by the ozone layer and it has this, more significantly, effect on sunburn and causing sunburn. And, as they've said here, this is a dermatology review article. They said it's carcinogenic, a thousand times more effective in causing sunburns. And I've added down the bottom vitamin D synthesis and pro-opioid monocortin, which are, these again, vital, absolutely indispensable functions. So UVB light will make you synthesize this pigment called melanin, and melanin is one of the most interesting chemicals in the whole animal kingdom and the reason is because it has so many amazing different functions that absorbing the UV light and dissipating it as heat to protect the skin is simply only one of them. It also has these antioxidant abilities. It has ability to chelate and bind heavy metals. It's's incredible.

Speaker 1:

The other point and I'm going to mention it again later is that there's a pathway that essentially mediates addiction to light by releasing a compound called beta-endorphin. So the same pathway that helps your body to produce melanin in response to this uv a damage essentially and uv light exposure in the skin is also rewarding you for uh, for actually being in the light, by giving you an endorphin, in the same way that you get endorphins for doing other types of behaviors that is beneficial for your health, like exercising or reproducing. And some points down here is that this UVB light is causing direct DNA damage. But it turns out that there are a whole host of mechanisms that the body has evolved to repair that DNA damage and we can optimize them if we are getting the sunlight in a really ancestrally consistent way. So UVB is making vitamin D in the skin and this is actually the main pathway by which we make vitamin D.

Speaker 1:

So what that means is that if we are covering up from the sun, if we are constantly wearing sunscreen, then we are preventing our body from deriving or generating not only vitamin D but a range of other products that are essentially related to vitamin D that have a profoundly beneficial effect on health. And the point here again, we don't need to belabor this, but essentially you get vitamin D from UVB light. It essentially goes into the bloodstream and then gets transformed at two steps one in the liver and one in the kidney and then has these amazing effects. You can also get preformed vitamin D through foods, particularly cod liver oil is traditionally the most rich source of that, as well as eggs, dairy and milk, and that was one of the reasons why the really pale-skinned in Scotland, in Iceland, in these northern, really high-latitude countries, were able to survive and thrive was because they were also having a source of vitamin D in the diet. But the overwhelming, the large majority of people, and historically we generated our vitamin D through sunlight and UVB exposure.

Speaker 1:

So vitamin D and this is another really key point point it's not just about bone health and although, yes, it does absorb calcium, help us absorb calcium from the gut it is a critical function of our immune system and that is both in terms of autoimmunity, a defense against viruses and bacteria, but also a defense against cancerous cells which your body is constantly forming, and you need a functioning immune system to kill those emerging cancer cells before they essentially become a tumor. So what are all the benefits of having a high or a robust vitamin D level? And these are things like reduced bone disease, reduced osteoporosis and osteomalacia, improved balanced skeletal system and reduced incidence of cancer and tumor formation and all these other situations and medical conditions that are associated with low vitamin D. And a key point that and I haven't written it, but I'll say it is that the serum vitamin D level is essentially a proxy of how much sunlight you've got. If you are vitamin D deficient, then you simply have a sunlight deficiency. You've lived an indoor lifestyle and those who have a robust vitamin D level, it just tells me that that person has been exposed to full spectrum sunlight, and we'll make some nuances about this in the next slides.

Speaker 1:

But what we know and this is from long-term studies of people followed over long periods of time is that those with the highest vitamin D levels, the association is that they have less death by all causes, and this paper reported that those with a 25-hydroxyvitamin D level less than 22 nanomoles had nearly twice the age-adjusted death rate compared to those with greater than 125 nanomoles. Similar paper was that they studied vitamin D data and they concluded that 12.8% of all US deaths and 9.4% of all deaths in Europe could be attributed to a serum vitamin D level less than 75. So the title of systemic review and meta-analysis vitamin D and risk of cause-specific death vitamin D and risk of cause-specific death. So what that essentially tells us is that having low vitamin D but simply being a sun avoider is a risk factor for death. And we know that because when we have tried to replicate these findings by giving people a tablet of vitamin D, then we don't get the same effect. And look, that should make sense to everyone.

Speaker 1:

I mean, you don't need a PhD or a professorship to realize that taking a couple of pills from chemist's warehouse is not going to replicate the effect of being in full spectrum sunlight. It's not equivalent in any way, shape or form. It's effective in preventing the most gross consequences of vitamin D deficiency, particularly for bone health, but it's not going to make you live longer in the way that getting out in the sunlight does. And again, that's because the vitamin D level and this discrepancy between the observational studies and the interventional studies is because the vitamin D level is simply just a marker of how much that person gets into full spectrum sunlight. So the difference between supplements and why they're not equivalent is because the sunlight-derived vitamin D is primarily transported in the body by a protein called vitamin D, binding protein. Dietary vitamin D is mostly carried in a lipoprotein fraction, such as your LDL fraction. So analogy to this is registered male versus unaddressed male, and when you generate your vitamin D from the sun, it's in this registered male and it's going to where it needs to go. And I won't go into the data, but there keeps being these randomized trials that fail to show as significant a benefit of supplementing people as the data that shows of those who have had naturally high vitamin D and look not to say that there isn't some benefit. And if there is a complete inability of someone to get outside into natural sunlight, then I still think there's enough evidence to support that person supplementing. So that's just an important point. But we're not replacing sunlight-derived vitamin D with a pill.

Speaker 1:

So let's talk about the biological effects. We've talked about UV. Let's quickly talk about blue. The main function that blue light is having on the body is through the circadian system, and what that is is that it's the recognition of blue light predominantly through the eyes and the skin, and that message being essentially sent along an information super highway connecting the retina of the eye to the brain, and that information telling the body and the master clock in the body what time of day it is. So it's specifically the recognition of blue light through these special cells that don't form images, they actually just sense the presence and absence of the presence of blue light and that tells your body what time of day it is. And this isn't a talk about circadian rhythms, but circadian. This clock timing mechanism in your brain is essentially how your body knows what to do at all times of day and night, and every single function of the body is timed. It's timed and optimized, and the reason it is is because it's the most efficient way for the body to operate is to have a certain time of day to do different things, and that is why you sleep, why you have a rest period and why you have an awake period, why most often you open your bowels in the morning, why you feel tired when the sun goes down. Everything from blood pressure, heart rate to feeding behavior, just name a function. It's regulated on this circadian clock and it is optimized to a specific time of day based on light information.

Speaker 1:

What about red light? So red light is having a pretty amazing effect on health, and predominantly through its effect on these mitochondria. And the mitochondria are essentially these energy. You can think of them as tiny batteries. You can think of them as tiny power plants. You can think of them as simply sites of energy transformation. So they're taking in energy in the form of food, in the form of light, and they are transforming it into cellular energy so that your body and your cells can get things done. So red light is actually activating multiple complexes on the electron transport chain of your mitochondria to help improve the efficiency of these little engines. And the relevance for this is because chronic disease so everything that I'm sure that everyone is interested in preventing, whether that's dementia, whether that's heart failure, whether that's aging in and of itself, diabetes is related to failure of your mitochondria in one particular organ. So it's our interest to optimize mitochondrial function as much as possible, and that is what red and infrared light is doing. So the image, just to show you the same thing.

Speaker 1:

And this complex process is essentially how life was able to really iterate, because we got these mitochondria to do this very important job of making energy for us and the cells were able to. After you know, what actually happened was one cell ate another cell and they decided instead of to, they decided to be roommates and what became? The mitochondria, which was a certain form of bacterium, started to again make energy and then the other cell was able to specialize to get other things done, and that's how complex or multicellular life evolved. But this process of electron transport is key and light is essentially optimizing the process and it's been described as essentially like lubrication. Imagine if you were running an engine, like a car engine, and you didn't ever lubricate the pistons, so it would take a while, but eventually the engine would seize up and die. That is how you can think about chronic disease and sunlight deficiency. If you don't lubricate the electron transport chain of your mitochondria with sunlight, with natural sunlight, then you will eventually on some times get mitochondrial inefficiency and, depending on your other lifestyle habits and perhaps your genetic predisposition, then that will manifest as a chronic disease of choose your flavor, depending on what else is going on.

Speaker 1:

There's actually overlapping effects of both red and near-infrared light and this is really something that the photobiomodulation field is exploring. But the other key point that I really want to emphasize is that it's not a clear-cut delineation between visible light. It's an arbitrary distinction, but somewhere along this line, around 780 nanometers, is the point at which your eye will perceive red and then won't be able to see anything else. And near-infrared is, by definition, beyond visible. That's why it's called infrared, but they're having overlapping but similar effects. So what else can red light do? Well, red light can lower your blood glucose level, and it actually does that by revving up your mitochondrial engines.

Speaker 1:

This was a study that was done at the beginning of the year by a researcher out of London called Glenn Jeffrey, and they essentially shone red light on the back of people for 15 minutes and then gave them a blood glucose test that some of you might have done previously, involving drinking 75 grams of glucose. Essentially, they measured their blood glucose over time and then they measured the amount of carbon dioxide that people were blowing off. What they found was that the group that were treated with the red light and they were able to control this with a placebo, because they could simply shine it on the back and no one knew if they were getting red light or the placebo and what they found was that those who had the red light shone on their back had lower blood glucose and more carbon dioxide excreted. So essentially showing you that the red light was having this pretty profound effect on lowering of blood glucose. And if this were a drug, then the pharmaceutical industry would be tripping over themselves to patent this. It's a significant and 27% is quite on average was a significant finding in lowering blood glucose.

Speaker 1:

So if you reverse this and you think about the opposite, then what is the implication of everyone's daily life now where no one is getting very few people are getting the amount of red light that we would have historically got, and maybe it's a good time to emphasize the point. It was that. Think about 25,000 years ago before, when we were in our ancestral niche, we were awake from sunrise to sunset. We would sleep throughout the night, but when we were awake we were essentially being irradiated. For let's presume we're standing on the equator, so there's equal day length of 12 hours. We were being irradiated 12 hours a day with full spectrum sunlight and that was the norm. And if you have darker skin types and you're from the equator, that is what your body wants. So think about what's happening now when people are indoors, day after day after day, without any red, without any infrared light, and then you can see why people are becoming diabetic and you can extrapolate how being deprived of sunlight could therefore lead to diabetes.

Speaker 1:

This is a paper that basically shows that the exposure of the cells in the skin to red light was mediating or generating a protective effect, and that was to do with upregulating DNA repair after being exposed to UV light. I'm going to emphasize this in another way for you guys to think about, but the translation of this complex paper is that red light is the antidote to UV light in terms of skin protection, and that makes sense when we consider that after UV light disappears from the environment, based on the sun angle, we're getting massive amounts of red light, and that is help promoting or help solving the problem or repairing the temporary damage that UV light was causing. And here's another paper that showed that they simply pre-treated the skin with red light and then exposed it to UV light and found that there was essentially a skin protective effect that was equivalent to SPF 15. What does that mean in practical sense is that you want to be getting red light before you get UV light, and that is a part of the process of safely building a solar callus and minimizing the damage of UV light is getting your red light beforehand. The whole field of photobiomodulation is based on these incredible effects of red and infrared light. So that's another way of thinking about how important it is.

Speaker 1:

Some quick points about infrared light. And again, this is around beyond 800 nanometers 780. So this is beyond what we can see. So what is it doing? So it is stimulating this substance called melatonin inside our mitochondria. And melatonin, which some of you might know of, you take it as a supplement to help you sleep. It is not only a signal to induce sleep into the body, but it actually is a very, very potent antioxidant. It's actually the king of antioxidants in the body and it does that and it speeds up. And if the red light is the lubrication of the mitochondria, then the melatonin is the coolant of the mitochondria. So what this neoremphrodite is doing is essentially it's getting into the skin and it's essentially being ping-ponged around and not being absorbed by anything for a while and then being absorbed by the mitochondria where it's having its effect and it's providing this antioxidant effect and it's also building exclusions of water, which I'll talk about soon.

Speaker 1:

But interestingly, look at this picture. So this is I'm not sure if they've edited it as well, but if you use a camera that is sensitive to near infrared light, you get these brilliant photos and essentially what these leaves are doing and this is another one what the leaves are doing is that they are actually reflecting near infrared light away. So the leaves use that you actually use a lot of red and blue light in photosynthesis and they reflect green and they reflect near infrared and that's why the leaves appear green and they reflect near infrared and that's why the leaves appear green. But that's important because our bodies actually need this near infrared light. So what's it doing? It's penetrating down and then it's helping us make this coolant for our engine, our engine coolant called melatonin. Why is this important?

Speaker 1:

Well, it turns out and this is actually very new science, no-transcript most sensitive organs. So it is concentrating it into the brain and it's concentrating it around the fetus in the pregnant woman, and this is both an anatomical function, via the curves in the brain and the actual structure of the skin, but it is also via the properties of the fluid that the brain is bathed in and the fetus is swimming in, actually optically optimized to transfer near-infrared light and bathe these structures in this light and, as I mentioned, it's because it's generating this antioxidant effect. His analysis of of the skin he basically made the comment that, uh, if you were, if you were optimizing a solar panel, then you, you would have designed that. The epidermis, the epidermal junction, yeah, in that way it's essentially concentrating light. That is, that is the anatomical, um kind of an analysis, but with it from an optics point of view, of the skin. So, um, what did he say in this paper?

Speaker 1:

He said the cerebrospinal fluid surrounding the brain optically acts as a light guide, distributing near-infrared photons, scattering off the surface of the brain, even into the deep folds of the brain. This is profound stuff that not a lot of people are talking about or understanding. The fetus is surrounded by the amniotic fluid, which has a peak transmission in the near-infrared, forming a dielectrically filled integrating sphere surrounding the fetus, ensuring uniform exposure to near-infrared photons impinging on the mother's belly. And it speaks to the fundamental need to have mom get full spectrum sunlight on her developing uterus and throughout the pregnancy, from before conception to the point of delivery, because that the body is obviously doing its utmost and it has adapted over millions of years to make use of this light. I'll really emphasize the point that more than 50% of bifoton count of light energy hitting the earth is in this infrared zone.

Speaker 1:

To think that humans or biology hasn't adapted or made adaptations to make use of this light, that's not how Mother Nature works. Mother Nature is ruthlessly Darwinian in the fact that only these most adapted, efficient designs essentially survive and anything that isn't dies off and doesn't get to reproduce. So the other point that I haven't included, but in discussions with Professor Robert Fosbury, who's an astrophysicist and amateur spectrometer, is that it appears that mushrooms are basically doing the same thing. They are concentrating this near-infrared light to the areas where their spores are, and same, I believe, with some seeds, that plants are making use of this light and just like we are, just like the human body is concentrating near-infrared around our babies, so are these plants and fungi doing the same thing? This is another whole topic in and of itself, and I actually did a whole talk on this.

Speaker 1:

But infrared light is also having an effect on changing the biophysical properties of water inside our blood vessels to aid in blood flow. So that's another kind of essential role of full-spectrum sunlight. So how can we think about this. Each wavelength of natural sunlight is a light nutrient and the UV is generating vitamin D, is generating pro-opium lanocortin, is generating nitric oxide. The UVA and visible is having a role in circadian signaling, amongst a whole bunch of other things like skin protection and lowering blood glucose, optimizing mitochondrial function and particularly the near-infrared is structuring the water in the body and is also helping in mitochondrial stimulation. So this is a light nutrient story and each one of these are important story and each one of these are important.

Speaker 1:

The point again, we've talked a lot about red and near-infrared is how do we maximize our near-infrared and red? Well, it's simply, it's at sunrise and sunset and it's because of that angle in the sky where, yes, we do get blue at sunrise and that's part of the circadian wake up, but there is a profoundly larger amount of red and infrared at sunrise and sunset because of the sun angle. So what about skin cancer? So I've just told you that UV light is critical for health. Uv light has these very important functions, but how do we think about skin cancer and this double-edged sword, this biological double-edged sword that I've been discussing?

Speaker 1:

So any sun recommendation, advice, it must take into account two things and that is the ambient ultraviolet light conditions wherever you're living, and two is your ancestral origin or the amount of melanin that you have in your skin. So what I mean by that and this is a concept that I've called the skin type latitude mismatch or the skin type UV light mismatch. So what does this mean? So the question you have to ask yourself is do you live in a similar solar environment to your ancestors and arbitrarily, I just said more than 20 generations ago? So the answer is if it's yes, then you are matched. Your skin type and your latitude is matched. If the answer is no, then you're mismatched.

Speaker 1:

So what does this mean? So if you are unmatched, then the skin type is appropriate for the UV conditions that you live in. That means that God or evolution gave you the right amount of melanin for the amount of UV light in your environment. That means that if you as much as possible, reflect the ancestral conditions of how your humans would have been exposed to light, then you have the toolkit to both harness and benefit from sunlight and repair its damage appropriately. So what about if you're mismatched? Well, then your skin type is inappropriate for the UV conditions in which you live, and I'll quickly talk about that. So if you are unmatched, then you are an Indigenous Australian living in Australia, you're an Indigenous African in Africa, norwegian living in Norway, peruvian living in Peru, but maybe you might also be South Indian with a lot of melanin living in Queensland, australia.

Speaker 1:

The point is that the amount of melanin in the skin is commensurate with the UV light environment. So what if you're mismatched? Well then your skin type is inappropriate for these UV conditions, and this can either be. You can either have more melanin in a lower UV environment, so that you're, say, you're Nigerian living in the United Kingdom or you're South Indian living in Tasmania, and what this issue is that there is not enough UV light in the environment for you to essentially thrive, and that is a bigger problem than the one that I'm about to talk about, because, again, you can be, no matter what you do, during winter there is zero UV light, and that's a massive problem, because that melanin is absorbing will absorb a whole bunch of UV light to prevent you from even being able to make vitamin D. So that's why they need so much more.

Speaker 1:

The other problem that is actually relevant to us living in Australia is if you have a low melanin level, ie you have pale skin but you're living in a really high UV environment, and that is any someone say, south African, dutch or English origin in South Africa, or Irish, english, scottish living in Queensland, australia. So to really understand this and this is again we're speaking to most of us who live in Australia is that we really need to adapt to this reality or accept this reality that we simply don't have the same amount of skin protection naturally that the Indigenous people of this area did, and what we need to do, therefore, is to use shade and to avoid the peak UV times. It's honestly that simple and it doesn't mean to cover up all the time. It doesn't mean to do white face with zinc every time we go out. It means to make use of clothing, make use of shade and simply avoid the most peak UV times, but use the time on either side of those to fulfill our light needs and get all these health benefits that we need.

Speaker 1:

A quick comment on the evidence behind sun exposure and essentially all-cause mortality, and this was a Swedish study that really looked at the sunbathing habits of women and they followed them over 25 years after ascertaining their sunbathing behaviors, and they essentially classified the women into three different groups those who sought the sun out by sunbathing in summer or winter, going overseas to sunbathe, using tanning salons, and those who had intermediate sun exposure habits and those with the lowest sun exposure habits or those who avoided sun exposure. And what they found was that those who avoided sun exposure, they died. They died at twice the rate as those who had the most active sun exposure, and that was a profoundly surprising result for the investigators. But it was a dose effect, meaning that it's very unlikely to this isn't a random chance event. That it's very unlikely to this isn't a random chance event. This is simply an epidemiological reflection of what I've just talked about on a mechanistic point of view, which is sun exposure extends life and sun avoidance is a risk factor for death. And that was the conclusion of the authors, which was that the women who avoid sun exposure are at an increased risk of all-cause death, with a twofold increased mortality rate compared to those with the highest sun exposure. So everything in medicine is a risk-versus-benefit equation. Every medicine that a doctor prescribes is going to be weighing up benefits versus potential downsides, and sunlight needs to be added to that equation. And although I didn't go through all the literature on sunlight and its effect on mortality.

Speaker 1:

That melanoma in southern Sweden cohort study is not the first one. It's subsequently been repeated with a recent biobank analysis by Richard Weller and his colleagues. But that have again showed that those who with the highest sun exposure habits have reduced all-cause death, reduced cardiovascular death, reduced cancer death and actually reduced skin cancer death, meaning even those having been diagnosed with skin cancer, those who have had more sun exposure, have a better prognosis. And that is actually also reflected in the vitamin D studies which show vitamin D deficiency is a risk factor for developing melanoma, a risk factor for severity, depth of basal cell carcinoma. It's actually also a risk factor for prognosis in melanoma, meaning that those patients with metastatic melanoma, the ones that are more vitamin D deficient, have the worst prognosis and live the least.

Speaker 1:

So what are we balancing this up again and apologies for the typo here Is photoaging, quite possibly, and we can mitigate that, I believe, at least on a mechanistic point of view. And the mechanistic data shows that you can minimize that with things like red light and getting red light, particularly in the morning and at the afternoon after UV. And it's also traded up against this likelihood or this increase in skin cancer diagnoses in fair-skinned prototypes like the Northern Europeans living in Australia, and that needs to be balanced and that needs to be something that everyone thinks about, which is there's a trade-off. There's always going to be a trade-off, but whether that trade-off is worth it for you, you need to think about that yourself. And I'll leave you with this thought, which is again that skin in beta-endorphin. It mediates addiction to ultraviolet light, and the same pathway that helps make you, provides your skin with melanin, is also providing you with an opioid chemical to reward you for being in ultraviolet light. So that's a 500-million-year-old gene called pro-opioid monocortin.

Speaker 1:

So if you want to learn more about light and health, then my podcast, the Regenerative Health Podcast, has all these interviews with world experts on this topic and I try and synthesize their different perspectives, because I think everyone has got a unique perspective. A lot of these are hyper-focused in different ways, but I'm trying to synthesize things together and present that for people to understand. Light has this profound effect. The evidence is just growing and growing and growing from a scientific and medical point of view. I think it's time. It's time for us both as doctors, but it's also time for patients to understand, for you all to understand that this is a critical part of health and it's foundational to optimal health.

Speaker 1:

If you want to learn more, then I have a private community where I do a weekly Q&A and answer all questions that you may have about lightness medicine. That's the link. It's on the school platform. I'm sure Christabel can provide it to you after this. And we've got a growing community. We're almost at 80 now and there's some great discussions, there's great support. So people of any level of understanding or readiness to implement all these light as medicine, behaviors and practices. We're here to help you. So if you're interested, then join up.

Speaker 1:

And if you want to go into depth then I've got two courses Circadian Res reset, which is about practical and applied circadian rhythms, and it's a short couple of hours around four, and solar callus. And solar callus goes into about nine hours of depth of the how and the why of deliberate sun exposure and why we actually want to be cultivating melanin and actually tanning, which is again the opposite of what the mainstream messages have been about sun exposure. But I go into depth about the research that really supports that position of tanning and optimizing the cutaneous generation of vitamin D and other compounds for optimal health. I've already talked about that. There's some more my links on my YouTube channel.

Speaker 1:

My podcast is on all the podcasting platforms. I have Instagram, I have Twitter or NowX and I have a website, although I haven't put a slide up here. I'm running a retreat at the end of November and we've got maybe a handful of spots left, but it's essentially four days. It's a luxury retreat, four days, and I'll be running you through the exact how and why of practically implementing Leiter's medicine, and we're doing this in the Byron Bay hinterland. We're going to have some expert chefs preparing some very, very delicious local produce, and there's a spa, there's a sauna and we've got a very special international yoga teacher to run us through some stuff. So that's all. So hope you enjoyed the talk and happy to answer some questions that you might have.

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