Episode 199 - Light, Sun and Vitamin D for Health
Mel:
[0:00] Welcome to the Great Birth Rebellion podcast. I'm your host Dr Melanie Jackson. I'm a clinical and research midwife with my PhD and each episode I cast a critical eye over current maternity care practice by grappling with research and historical knowledge to help you get the best out of your pregnancy, birth and postpartum journey.
Mel:
[0:24] Welcome to today's episode of the Great Birth Rebellion podcast. I'm your host, Dr. Melanie Jackson. And this week, I'm again joined by Dr. Max Galhain, who spoke to us last week about circadian rhythms, healthy sleep patterns, and how that can impact upon our blood sugar levels, but also our hormone levels in all stages of life. But we did speak specifically about pregnancy. and this is the next piece of the puzzle that we want to speak about today and that's the impact of light and sunlight on the health and well-being of our bodies and on our physiology. We're also going to talk about the nutritional value of a sun on our skin, on our eyes and how to use the sun for optimal health. This episode is sponsored by my dear friend and birth prep extraordinaire Poppy Child from Pop That Mama. She's a doula and hypnobirthing practitioner and her online hypnobirthing course called The Birth Box has already helped thousands of women get ready for labor. Listen to this recent review of The Birth Box. The woman says, I'm a first-time mom and I gave birth to my beautiful baby boy yesterday. I've been listening to The Birth Box on repeat for the past few months, including the day in which I went into labor. And I had the most empowering birth experience. And I can honestly say that listening to the birth box was a huge part of this success.
Mel:
[1:53] Reframing the pain that you experienced during labor can be a purposeful pain instead of a harmful pain. And that really helped me to know that. And just being able to surrender to the wild ride that birth is and let my body take over was the most incredible thing. And this is coming from a pelvic floor physiotherapist based here in Australia. She says, I will recommend it to all my patients. And you know me, I'm so picky about what I will endorse, but I do get behind the work that Poppy is doing. And in the birth box, you'll learn tools to help you manage pain and how to stay steady when labor gets intense. It's all about giving you knowledge, confidence, and a mindset that actually works when the big day comes and for the big days that will follow. BirthBox is rated five stars across the board. And with my code, Melanie, you'll get 25% off. So if you're preparing for birth, go to the checkout.
Mel:
[2:54] You'll be so glad you did. The link is in the show notes. Use the code Melanie to get your 25% off. Welcome back, Max, to the Great Birth Rebellion podcast.
Max:
[3:05] Thank you, Mel. Looking for something.
Mel:
[3:08] And I will just say before we start, I feel like the last week's episode was a prerequisite. It's kind of pre-listening to what we're going to talk about today. But for those who are not prepared to go back to that episode, can you give us a quick summary of the circadian rhythm? Because it's important as we understand the importance of daily exposure to rhythm-based sunlight, which is the topic that we're going to cover today.
Max:
[3:34] Yeah, so humans are massively reliant still. We haven't become immune or independent from that requirement to respect the natural 24-hour solar cycle, which is full-spectrum sunlight during the day and darkness at night. And what we discussed last episode was this conceptual idea of the requirement as being like a yin and yang symbol with a clock face around it. And the yin and yang symbol
Max:
[4:08] Implies an equal and opposite reliance on both parts. It's essential. The key part of half of the circadian story is nocturnal darkness so that the body can make a robust amount of melatonin to orchestrate repair of all the body's physiological processes. What we're going to talk about today is the yang, is the light, and how important full-spectrum sunlight is for human health and for health of pregnancy, of the infant, and into the rest of life. There's many ways to approach this. I think probably the most useful way is to talk about the spectrum of natural sunlight. So sunlight is emitted. So the sun is a star. It's an equilibrium state and essentially, not to get into the physics of it, but it emits energy on this electromagnetic spectrum. That energy...
Max:
[5:10] Hits planet Earth, having been filtered by the ozone layer and by atmospheric gases. And what the ozone layer does is actually filters the most high energy or what we call short wavelength UVC life. So anything under UVB light, which has the power to do a lot of damage, gets filtered out. So when we stand on Earth, we have this spectrum. It turns out that our visual system is only tuned to see a narrow part of this electromagnetic radiation from around 400 to around 700 nanometers. Below that, we have this UV light, and above that, we have light in the infrared. It turns out that each part of this solar spectrum is providing a unique value to human physiology and in that way could be thought of as these are all essential light nutrients in their own way.
Max:
[6:15] The nuance that we have to make, specifically with respect to ultraviolet light, is that we just have to be smart about exposure habits based on our ancestry, our skin type, and the amount of UV light in the environment because the photons are higher energy and they have the power to move electrons around it, to change and potentially do a little bit of damage. Nevertheless they're essential and it's essential to have ultraviolet light in our life and i guess the physiological evidence for that is the vitamin d system and all the physiology that is downstream of having enough vitamin d and and vitamin d is a is a sunshine hormone it's uh it's it's more than that it's what we call it's a it is a psychosteroid hormone with with pleiotropic effects essentially meaning it's a hormone that regulates a whole bunch of diverse ranges of human function, of which skeletal health, calcium phosphate absorption is only the beginning. We can definitely expand about ultraviolet light and all the nuances around that. Light in the visible spectrum is mostly important, especially the blue light for circadian rhythm entrainment. And as we mentioned last episode, the body needs blue
Max:
[7:42] Blue in the context of solar blue, not isolated alien refined blue from your device, from your LED downlights, or from any kind of man-made artificial source. It needs blue from the sun because the presence of that blue is always balanced by longer wavelength light in the red, in the near infrared. And the stimulatory effects of blue light on the body and on the circadian system become balanced by the reparative, restorative effects of the longer wavelength, red and near infrared light, which is now and has been for the past three decades, harnessed in the field of photobiomodulation and low-level light therapy for a bunch of therapeutic and cosmetic effects. So that's visible light. And then as we go into the near-infrared, it turns out that the dominant or the most amount of light by photon count that hits Earth is in this non-visible near-infrared band. So over 50% of light that's hitting Earth we can't see, but it's not useless.
Max:
[9:01] It's far from useless. It's actually essential. and turning out and it's taken research by astrophysicists, optical engineers, people that aren't anchored to traditional potential biomedical thought paradigms to put their intelligence into these areas and finding out that the body is using near-infrared light that we can't see to help run mitochondrial metabolism so essentially run the state of existence and everything that enables the steel cells to work is running on or assisted by near-infrared and if we're inside all day we're not going to get we're not going to get any of those and we're going to get obviously excessive of narrow blue so Each one of those from the ultraviolet at 280 nanometers all the way past 1500 nanometers in the infrared, they're all light nutrients that the body needs. And that all makes up part of the healthful effect of being outside during the day. And when I say outside, I don't mean being beaten down by unrestricted daylight all day.
Max:
[10:21] I mean being in an ambient environment that contains full spectrum light.
Mel:
[10:25] Okay, so what I'm hearing, because last episode we talked about the importance of seeing daylight on our circadian rhythms, now we're talking about actual physical exposure to light outside through open windows, through basically bathing our bodies somehow in the light, because there's a spectrum of light that we can see, there's elements of light that we can see, but there's also light spectrum. Spectrums that we can't see but that have positive and beneficial effects on our health. Can you tell us why do humans need sun on their skin or to be outside and bathing in light, not just actually seeing light?
Max:
[11:10] The effect of light hitting the skin triggers a whole bunch of very, very interesting chemical pathways, both biochemical and biophysical effects.
Max:
[11:22] What happens is that when the photon actually hits the skin, depending on the wavelength, it gets absorbed. It either gets absorbed or it hits and gets scattered. So in the shorter wavelength, which means ultraviolet light, the body has developed or adapted a bunch of defenses to benefit from, but also protect against this ultraviolet light. And to color in what you said earlier, the crux of the issue here in Australia is that we have a bunch of Northern European explants, people of Northern European descent, who instead of adapting to the massive solar yield and ultraviolet intensity, arrived via ships, that's insufficient time to essentially adapt. So what we can know, we'll realize by the difference in melanin levels in the skin, which is this pigment that exists in the top layer of our skin, is that there's a difference and there's an appropriateness of exposure depending on ancestry and skin type. So where we live in Australia, where it gets up to a UV index of 14, which is a measure of ultraviolet B intensity, the people were the darkest shades of melanin. They're the darkest photo types, the indigenous Australians. That gives us a clue about what kind of defenses are required.
Max:
[12:49] We'll talk about this a bit more, but essentially, if we have lighter skin than the people who adapted to this area over multiple thousands of generations, then we need to essentially be very careful about how we dose that shorter wavelength, that UV light. And we can do that in a number of ways.
Max:
[13:11] The crux of it is either covering up or simply avoiding being in direct sunlight during peak UV periods and simply get our light needs met earlier in the day. How you can do that is because the amount of ultraviolet light is changing throughout the day based on the sun angle, the zenith angle. So as the sun rises, the amount of atmosphere that the light penetrates through is more. So all that UV can't get through. It gets absorbed and attenuated. As the sun rises more and the angle becomes more acute, more overhead, then all that UV can get through. And that's why there's this peak UV period during the middle of the day. So where people are at highest risk of burning, but they're also at the period where they can generate the most vitamin D. So what happens when ultraviolet light, and we'll start here,
Max:
[14:06] Hits the skin is that it kicks off a reaction that converts cholesterol, which is sitting in the cell membranes, into vitamin D. It breaks a bond in the chemical structure and then the vitamin D can form. We as humans have used and repurposed vitamin D to basically run a whole bunch of important programs in the cell and body. So what is happening is that when your body makes vitamin D, it goes through various stages of activation in the liver and the kidneys, and it helps your body to absorb vitamin D
Max:
[14:45] Calcium and phosphate from the gut and help retain it at the kidneys. The way we found out about this problem was in the early 1900s, late 1800s, during the industrial revolution in Europe, where they were pumping out all this coal-fired smog in the cities. What that did is it acted as a barrier or an absorber to prevent the penetration of ultraviolet light into the cities. So what happened is the children who were not getting any UV light at all developed this bone condition called rickets. And it was vitamin D deficiency because they weren't able to generate enough vitamin D. They weren't ingesting enough food sources of vitamin D. So they got this bow-legged appearance, which is essentially inadequate development of the long bones because of the vitamin D deficiency. And there were some very fascinating experiments done, even just observations done, that the farming children in rural areas of California,
Max:
[15:48] I believe it was Poland, perhaps, and they didn't have the same problem. So the question was, what is it about this inner city living was able to mitigate this effects of rickets? And as they progressed, they realized that if you purified cod liver, cod livers, the fish, then that could essentially prevent this vitamin D deficiency rickets. Again, they didn't know it was vitamin D. and then as we went further along in the scientific process you know we realized that this was a hormone that you could ingest if it's preformed in in certain foods because it's fat soluble or you can make it yourself and you can make it but you need ultraviolet light and there's these key factors that affect how much vitamin d that can be made and and environmentally they're the season, the latitude.
Max:
[16:40] Because in Northern US, Europe, there's months of the year where there's minimal ability to make any vitamin D in this seasonal absence of UVB light. And then there's also factors related to us as individuals. How much skin pigmentation do we have? What are our personal habits? Do we go outside and expose our skin to the sun or not? So all these things affect how much vitamin D we make and therefore influence at the basis bone health. As it relates to pregnancy, the pregnant woman has to mobilize and use a massive amount of these products in calcium phosphate to essentially ossify a fetal skeleton to make a baby's bones. It's a massive demand. There's probably multiple pathways that ensure that that baby gets those factors
Max:
[17:36] Potentially even at the expense of the mother. It highlights how important it is for the mother to get sufficient vitamin D because the baby can't generate its own yet. So it's reliant on maternal intake of vitamin D or maternal sunlight exposure to make enough so that it can grow its own skeleton. But it turned out, and this is research more in the past probably 20 years, that the vitamin D was having way more effects than simply just the skeletal system. As it specifically relates to pregnancy, because that's what we're interested in at the moment, it seems to control inflammation, the inflammatory system, but also neuroinflammation and brain development.
Max:
[18:26] So vitamin D is a brain essential nutrient and without it, you're not going to get the proper formation of the baby's brain.
Max:
[18:34] But it also influences, and essentially the vitamin D serum level can be thought of metaphorically as a switch that influences the immune inflammatory state of the body. If you're in a state of vitamin D deficiency or insufficiency, then you're potentially activating a bunch of pathways that predispose the body to a pro-inflammatory state. This seems to have relevance for neuroinflammation in the baby and actual epigenetic imprinting for that baby going forward. But not only that, it's critical in correct placental function, in the function of the placental vessels, and therefore deficiency is a risk factor for preeclampsia. Other than preeclampsia, it's also associated with failure to progress because vitamin is also necessary for muscle muscle function and the myometrium needs an adequate vitamin D to essentially provide the contractive force to facilitate birth. So there's all these fascinating aspects to vitamin D but whenever you hear about vitamin D, whenever you read the literature about vitamin D, I want you to think about ultraviolet light because ultraviolet B light is how we get 90% of our vitamin D needs met.
Mel:
[19:56] And as you were talking about vitamin D being anti-inflammatory and how that relates to preeclampsia, because there's some inflammatory processes, you know, there's inflammatory processes to do with preterm birth, with preeclampsia and yeah, with poor placental function, they all have an inflammatory element. As I checked the bloods of all of my clients, I can see really, I think, I reckon 85% of them are vitamin D deficient. And I'm talking to everybody about, okay, got to get your vitamin D levels up. Part of that is appropriate sunlight exposure. And as you already said, the darker your skin is, the more sun exposure you need in order to feel the impact of that because of the high level of melanin. But the flip side is if you've got fair skin, you could get your vitamin D and sun exposure in faster, particularly if you're in an environment that has high UV index. So what you're saying, so in places where they see a lot of rain and overcast, you would do better to live there as a fair-skinned person than in Australia, obviously, because of the less sun, but actually you need less sun because your skin's fairer.
Mel:
[21:21] So there's that part of the conversation. How does supplementation fit into this? Because if a woman was to go to her GP or doctor with a vitamin D deficiency, the remedy probably wouldn't be sun exposure.
Mel:
[21:38] There would be an element where they're like, yeah, go and get your skin into some sun, but not too much sun. They would recommend supplementation. And you mentioned actually that there is vitamin D in some food. So we can consume vitamin D, we can absorb it, or we can get it from the sun through various physiological processes. How do those two go hand in hand? Because can you fix a deficiency... With just regular daily sun exposure or is supplementation needed in that moment?
Max:
[22:14] Okay. Yeah. Great questions. The way, and maybe we need to define what is vitamin D deficiency because there's actually even discrepancy in the literature here. The unit that we measure when you get your blood taken from your doctor to measure a vitamin D level, it measures a circulating form of vitamin D called 25-hydroxyvitamin D. This is essentially a storage form, which then gets activated through enzymatic steps in the tissues where it's needed, but it's a good proxy for your vitamin D status. So in Australia, the lower limit of deficiency here is defined is 50 nanomoles per liter. In the early two 2010s, the US Endocrine Society, in recognition of these massive number of effects and benefits or associations of vitamin D deficiency with cancer, with autoimmune disease incidence, with infectious diseases susceptibility, with metabolic and cardiovascular disease susceptibility, with even all-cause mortality in these observational studies, they revised their recommendation and called 75 nanomoles deficient, anything below 75 nanomoles deficient.
Max:
[23:29] Interestingly, if I see patients in general practice, the endocrinologists, they treat all their osteoporotic patients, they need them above 75. The neurologists, when they treat MS, they want everyone to be over 100. So these other medical specialties are providing hints at understanding the importance of vitamin D, but again, they default to supplementation. I think what we should aim for at a bare minimum is repletion by those criteria from the US Endocrine Society headed by Professor Michael Hollick, which states anything under than 75 is undesirable. And look, they've established that in a number of ways, basically looking at inflection points of disease incidence, but also biochemically, but with things like the changes in the parathyroid hormone.
Max:
[24:21] The point is, you can build up the vitamin D through supplements and through natural exposure. The massive controversy with respect to vitamin D in medicine and science is anchored in the following, and it is extremely controversial. Because what occurs through vitamin D supplementation is a purified D3 is not the same as generating vitamin D through the skin. It's not the same. So what we can do to raise the level through supplements will obviously will prevent the frank complications. And anyone under 75, I recommend that they supplement at least up until that level. But beyond that, there doesn't seem to be benefit in these interventional trials from supplementation. So a lot of researchers have taken that as, okay, nothing to see here about this whole vitamin D story. But really, we need to take a step back and think about this problem a bit harder. And it turns out that the vitamin Ds aren't the same. When you generate it in the skin, it essentially gets bound to a vitamin D binding protein and provides this really consistent release throughout for the next three, four, five week. It's got a longer half-life. When you take it orally, it binds to the lipoprotein fraction. It's less specifically delivered to where it needs to go.
Max:
[25:49] What also is happening here is that the serum vitamin D level is actually a proxy of for someone's sun-seeking exposure and sun-seeking behavior. So it's almost a way of measuring or understanding not only how much ultraviolet B light they've gotten, but how many healthy circadian signals they've got, how much near-infrared light they've had, how much time that they've spent outside in nature. What it means is that wherever possible, we want to build and generate our vitamin D through natural exposure, through sunlight. Keeping in mind everything that we talked about with respect to dosing, which needs to be done depending on skin type and depending on latitude. To be clear about the number of pregnancy-related complications that can be avoided, can be prevented with vitamin D repletion, I'll reference this study. It's a meta-analysis from 2024, the effects of vitamin D in pregnancy on maternal and offspring health, umbrella review of of systematic review and meta-analyses. And they obviously went through 16 eligible systematic reviews and meta-analyses, including 250,000 women, and the results demonstrated that vitamin D deficiency in pregnancy is associated with an increased risk of preterm birth, small for gestational age,
Max:
[27:09] Recurrent miscarriage, bacterial vaginosis, and gestational diabetes mellitus. And vitamin D supplementation in pregnancy increases birth weight and reduces the risk of maternal preeclampsia, miscarriage, vitamin D deficiency,
Max:
[27:23] Fetal or neonatal mortality, as well as attention deficit hyperactivity disorder and autism spectrum disorder in childhood. Conclusion is that we need to be avoiding vitamin D deficiency. So,
Max:
[27:35] How we do that, I think, now is the key point. And what I would advise is to, again, supplement if we're under 75 at the same time as getting an appropriate skin-type appropriate amount of sunlight to generate it in our skin. So the question is, how much sunlight is enough? And that is a pretty important question when it comes to dosing this. And Michael Holick, Professor Holick, who, again, was an endocrinologist in Boston and discovered the active form of vitamin D, he did studies and basically found that if you give people whole body exposure with enough UVB light to just about develop some redness,
Max:
[28:21] Then you're generating about 20,000 units of vitamin D. So that is that's a massive amount if you think one pill contains a thousand units you can generate 20 times that by essentially just getting up into the the the burning stage which is obviously not what i we don't advise to go to burning but what it shows is how efficient the body can be to make this compound in in the skin so again and that is the the good form that's the great pathway because it provides a really slow release form of the hormone and it helps it keep releasing it and getting it to exactly where it needs to go. What we should aim for if, again, we're potentially over the frank deficiency threshold and we're above 75 nanomoles, is working on potentially getting 10 minutes, 15 minutes of exposed skin. Potentially on our abdomen, on our whole body per day without burning. And what time of the solar day we do that is going to depend on how much skin pigmentation we have. If we're from Somalia originally, and we have this Fitzpatrick 6 skin type, then you can safely go out in UV indexes of 12 and close to the midday. It's not going to be a problem. You're not going to burn. And those women have an abundant amount of an extremely protective form of melanin,
Max:
[29:51] Eumelanin, which is 99.9% efficient at dissipating ultraviolet light and converting it to heat. If we're of Northern European, Scottish descent with red hair, and we're living here in Northern New South Wales, then maybe you're only going to need 15 minutes from 8am till 8.30 till 8.40. It might be as short as that to get our knees met and then when UV index climbs, we go inside. So I guess the key point here is we're going to dose our ultraviolet light so that we build up a healthy vitamin D and hopefully prevent this raft of pregnancy complications.
Mel:
[30:33] So what I'm hearing is that the supplementation and sun exposure are two different kinds of vitamin D, use them together to remedy a deficiency, but then once you get over the deficiency threshold, you can maintain your vitamin D levels with a relatively short amount of exposure at an appropriate time of day for your skin type. And because we can move all over the world now, we can live in a place that's not appropriate for our skin type. So possibly my husband would not get vitamin D deficient if we moved to London, whereas I would be more likely to because I need more sun exposure for my skin type. So what we do know is that, Pregnant women are perpetually deficient of vitamin D and everybody's trying to get their vitamin D levels up. I think you're right about the thresholds. A lot of the blood test thresholds are like, this is how much you need to be not dead. And then it's kind of like, but it's not the optimal healthy levels. It's just, hey, you're not going to die with a level of this.
Mel:
[31:42] So with a lot of things, the levels for health are actually higher than the clinical thresholds that are offered in the blood tests. But vitamin D seems to be the same.
Mel:
[31:52] Are you getting ready to have a baby? And if you are, what are you going to do about the pain of contractions? There are lots of things you can do. In fact, I'm going to tell you about them because I've been watching women give birth without pain relief for over 18 years. I'm Dr. Melanie Jackson and I'm a home birth midwife. I had my own babies at home without pain relief and I've been helping other women do the same for my entire career. If you want the top tips and tricks that I recommend to help women give birth without pain medication, it's all here in the link below in my guide to giving birth without pain relief. You can do it. Give it a go. Why not just prepare?
Max:
[32:33] Can I make a point about another key difference between supplementation versus sunlight-derived vitamin D? To get what we call hypervitaminosis D, to get excess, you need quite a heroic doses. You need probably more than 50,000 units a day for quite many, many months to get what we call hypercalcemic hypervitaminosis D and the serum calcium rises.
Max:
[33:03] You get a Frank syndrome of hypervitaminosis D. that takes a massive amount of vitamin D supplementation, which most people don't come anywhere near to. However, interestingly, so if we're generating it in our skin, there's actually no physiological possibility of becoming toxic in vitamin D. And that's because what the body does is if you continue to irradiate with more ultraviolet light, then the body just shunts these vitamin D into other pathways. So it breaks the compound down into these related psychosteroid compounds that
Max:
[33:43] Essentially, again, prevent the body from getting in excess. But obviously, we don't necessarily need to or want to be roasted to a crisp at all, but we want to play with an appropriate amount to get these needs met to generate well-being. A related pathway to vitamin D with respect to is stimulated by ultraviolet light is this peptide pro-hormone. It's called pro-opilomelanocortin. It's a bit of a handful. But what women need to know and what I think everyone should know is that it's stimulated by ultraviolet B light as well. And it mediates both the pigment response, so making more melanin in the skin, and it also cleaves off an endorphin, which is called beta endorphins. So the body rewards you for generating vitamin D by being an ultraviolet light, by making some of this opioid that can be thought of as, again, the body rewarding you for giving it what it needs and what it wants.
Mel:
[34:50] So basically you're saying when our skin is exposed to sunlight, it activates an endorphin reaction and we feel good. And people do. If you go outside and you're in the sun, universally people go, that's nice. Like that was nice to go outside. That's your endorphins telling you, Hey, this is good. So I am way back a long time ago. I read somewhere that if, so that the impact of sun on your skin, and I could be completely wrong, but it needs to settle in. So we're in a society that's obsessed with hygiene and daily showering and soaps and products and things on our skin. Is it true that if you like wash and shower daily with soap that you like, for lack of a better explanation that wash off the vitamin D that would have otherwise soaked into your skin and that this kind of over use of products and hygiene products is getting in the way of our body being able to benefit from the sun exposure?
Max:
[36:00] It's an interesting question and I think it was originally proposed because non-human mammals like primates they generate vitamin D in their fur their exposed fur, and then they lick the fur to essentially get their vitamin D. What happens in the human skin is that when this cholesterol gets turned to vitamin D, it seems to get immediately ejected into the intracidial space and into the capillary beds, and then it binds. So Hollick did some research that suggests that this wasn't significantly affecting absorption, whether or not you immediately wash off, which is a good thing.
Mel:
[36:41] Those are the questions I had about vitamin D because I don't want women to be frightened of exposing their skin to the sun because of the pervasive messages
Mel:
[36:50] about, you know, the potential dangers of extended sun exposure. But we've got to remember that we actually need sun exposure to maintain our health. And during these extenuating times of being pregnant and feeding and caring for our babies, We want to do everything we can to be nutrient abundant instead of deficient.
Max:
[37:13] Absolutely. There's a couple of points I'll make. There's some data to suggest that potentially 6,000 units a day is the threshold to ensure enough is being passed through into the breast milk.
Max:
[37:26] There was a study done by Hollis 2011, I believe, showed that 4,000 units was more than completely safe in terms of tolerance during pregnancy and with no adverse effects. I think what you generate from natural exposure, 15, 20 minutes in the way that we've discussed, you're going to make a lot more than that. And you're going to probably do the best thing to ensure that there's enough being put into the breast milk. That's UVB light. And really, maybe the last thing to say about it is that in medicine, we make a determinant of risk versus benefit for basically every intervention, whether it's a drug, whatever we're recommending. And I really think that light and short wavelength light, UV light falls into that category. The long-term risks of potentially photoaging, solar elastosis, skin cancers, they are modulated by lots of things, oxidative stress, circadian rhythm disruption, particularly with respect to cancer. But the point here is that where there's a benefit phase, there's a benefit spectrum that is happening during pregnancy. And we just need to be smart about balancing those risks and benefits so that we're giving us the best chance of having a healthy birth and having a healthy child and baby. So if you don't have any more questions about vitamin B, maybe we could briefly touch on some of the visible light pathways.
Mel:
[38:53] We could. I also had one other question that occurred to me. What are the foods, if we wanted to eat vitamin D, what are those foods?
Max:
[39:01] The richest sources of vitamin D are going to be found in things like sardines, in some of these cold water, fattier fishes. I'm talking about naturally occurring, not fortified, because in many places of the world, they actually fortify foods with vitamin D. So that would probably be my pick. And I really like sardines and those fatty fish because they also contain DHA, iodine, zinc, selenium, all these brain essential nutrients that can only be found in abundance in the marine food web.
Max:
[39:36] So eggs, and they've done studies comparing the vitamin D content of fully pastured eggs that hens have been grazing or foraging on open pasture exposed to sunlight. But they have a greater vitamin D level than the hens that are shot up in a confined fed factory operation, which shouldn't be surprising at all. So if you need another reason to spend an extra $4 on the fully pastured eggs, you're getting more nutrition in addition to the choline and And the B vitamins you're getting from your eggs, you're also going to get more vitamin D. So those would probably be my pick. There's other foods that also contain vitamin A. So cod liver and bovine liver, I'm not going to comment on that. I think you've probably had other guests to discuss that, the nutritional aspects, only to suggest that they are also a rich source if some women are choosing to eat their mid-pregnancy. and obviously Lily Nichols I think has got some really good results.
Mel:
[40:38] Yeah, Lily Nichols is excellent for that. I'm so glad you said that about the chicken eggs because I'm actually writing a book at the moment called A Guide to a Great Pregnancy and one of the – I just can't get away with it but I'm away from it but I'm putting kind of a list of things that I think everyone should do. I mean regardless of if they're pregnant or not, And one of the things I was suggesting to people is buy four chickens. Like that's on the list of things to do because eggs are so full of nutrition, but actually the food production line for eggs is so devastating in terms of how they treat the chickens and how healthy the chickens are versus how healthy the egg is. And the fact that they're yet confined and not exposed to sunlight. And you're saying the ones that get to roam free, of course, if they're exposed to more sun, their eggs are going to have more vitamin D. It's a no-brainer. But that reminds me to just keep that in the book because
Mel:
[41:38] I keep looking at it going. You can't tell people to buy chickens, you know, if they want to have a great pregnancy. But I feel like I can actually. Definitely. All right. So you were going to say, if we're finished with the vitamin D conversation, what next did you want to tell us about sun exposure for health?
Max:
[41:58] So if we're progressing along the spectrum from shorter to longer wavelength light, and we've got our UV or we've dosed our UV, what it seems like was one of the most important ancestral and evolutionary environments was the tree, or interestingly, the peak of visual human discrimination is actually in the green. The rainforest has some really interesting effect on the natural light spectrum. It actually blocks, prevents the penetration of lots of UV, but it allows for this massive amount of red and more near-infrared, so in that non-visible. And this gets to the point that I mentioned in our first episode, which is that this optics engineer kind of analyzed the human body and realized. And has found that we're designed to harvest near-infrared photons and concentrate them into really sensitive areas like the brain and like the uterus, the fetus. And what is happening, the near-infrared light is actually stimulating the production of melatonin, the same melatonin
Max:
[43:08] But melatonin being made on site in our mitochondria during the day.
Max:
[43:12] So it's a way that the body is actively mitigating oxidative stress and generating beneficial tissue healing effect throughout the day. So what I guess I'm saying here is that part of this idea of optimizing our health with respect to sunlight is dosing our UV is discussed, but trying to spend as much time simply outside but potentially undercover surrounded by greenery and surrounded by bushes because the the other thing that was was discovered is that plants use a whole bunch of red and blue light to photosynthesize and they reflect the near infrared to the environment because they don't want to overheat they're very very efficient in that so this is where we come in you know walking through the forest is we're collecting all this waste energy which is sunlight being reflected by the leaves and the plants that they don't need for photosynthesis but we use essentially photometabolism in our mitochondria this is like a you know mind-blowing moment when you realize the healthiest place to be during the day is surrounded by plants in the shade,
Max:
[44:25] In greenery, and that's creating all this massively benefit antioxidant effect that so vastly outweighs the dietary antioxidant formulation. It's simply natural antioxidant generated by being in a healthy full spectrum daylight.
Mel:
[44:44] So basically, what we really already know about that science is catching up is that humans need to be outside in nature with nature. So do our animals. Anything that's producing our food needs to be outside to optimize the quality of our body's functions and of the food system. It really isn't rocket science, Max, but we unfortunately have to have conversations with people in these modern lifestyles to say, hey, you actually just have to go outside for a little bit for the sake of your own health. And all of those needs are accentuated in pregnancy because of the extra work that we're doing. But also, and in the conversation we had last episode about the circadian rhythm and about habits of going outside and sun exposure, if we are doing these things as parents, if that's how your lifestyle revolves, and that's certainly what's happened in our family, is the kids are all aware that at nighttime, the orange lights come on. And, you know, sometimes we've done wild things like done a flight overseas and the lights are intense. And so, and I'm putting red light glasses on all the kids and my mom and myself and going, righty everybody. And, but they're learning, okay, this is important for us. This is what we do in our family.
Mel:
[46:07] So not only are you teaching them, but also you're protecting them. But same thing with the sunlight exposure. If you're doing it, you're immediately going to entrench this culture of being outside and with nature into your children. So this is generational health. You know, we talk about generational wealth. It's the things that we do impact the wealth of our next generation. But this is generational health.
Max:
[46:30] Absolutely. And look, it's no different to developing or fostering, promoting healthy eating habits. Just like a family makes a conscious choice to not buy processed foods and not bring in McDonald's into the house or excess chocolates and lollies and soft drinks, we so can put in place these healthy light habits, which is we don't turn on overhead downlights after dark. That's not something our family does. There are a whole number of little tricks or habits that you can employ to help everyone get these healthy kind of signals.
Max:
[47:04] So going straight outside when everyone wakes up is a really good one. The goal is to everyone go outside, we stand on the grass, we play, we're engaged outdoors. And although they don't realize it, they're actually checking a whole bunch of boxes on the circadian requirements. They are moving their body. So we didn't talk about movement, but physical movement is another zeitgeist to help entrain the circadian rhythm. They're getting this bright morning sunlight. We're getting light potentially on the body. And the body is completely permeable to light. This near-infrared passes all the way through the body eight centimeters, meaning that Younger children are potentially more impacted or more influenced by their light environment than adults, and they're more susceptible to or potentially beneficial from these light photons. So getting everyone outside, it can be anything. It depends on where you live, but you can all walk towards to the local hill, see the sunrise come up if everyone's up.
Max:
[48:07] I recommend that, and maybe this is the deeper cuts of the circadian lifestyle, but if for those who are really committed getting up and watching the sunrise together is is a extremely powerful way of of entraining the circadian clock because it's the brightest amount of it's the biggest change delta but from from darkness to bright it's an amazing signal to cut off melatonin production start uh ramp up healthy cortisol and get the day going so you can all walk together i mean there's so many different ways of doing it you can you can set up a playground outside facing the east so all the kids just play and they're getting that east you can you know put people in put them in a little beach cart and you know walk to the corner where you can see where the sun comes through the trees there's there's so many ways of doing it but it whatever however use your imagination just just try and build in healthy light habits into your daily routine in a way that that's going to work for for everyone in the family and and then become second nature because Because again, it's about sustainable and long-term lifestyle change rather than doing this for a week because I'm pregnant.
Mel:
[49:17] And the other thing I've noticed is if you get in the habit of it, you actually feel the impact of not having it when you don't do it. And you think, oh my gosh, I feel, why do I feel this? And you think, oh, that's right. Something just changed, you know, maybe they're changing your routine or something. And you can feel when you don't do it. The other question I wanted to ask is if you're in a privileged position where natural light comes into your home and you can see the sunrise from a window in your house, for example, how do you optimise that opportunity? Because I have heard that having the windows closed versus having them open changes the impact again on the benefit of the sunlight.
Mel:
[49:59] So, for example, I've got these big windows at the back. We intentionally put them at the back because that's where the sun rises and we thought, wouldn't it be great to watch the sunrise? But if they're closed, there's a different impact if they're open. Can you talk to us about that? How do we optimise light? If we're inside.
Max:
[50:17] So anytime you filter light with a car window, with windows of your house, with sunglasses, depending on the structure of that surface or that window, you are going to change the spectral composition of the light that gets transmitted. And therefore, you're going to change the photobiological response because the body is tuned to signature of light exposures, which is always anchored or dictated by what natural unfiltered sunlight is doing. So anytime you change it, you're going to change the message. So therefore, the goal, wherever possible, is to get unfiltered light into the eyes and obviously on the skin, depending on time of day and UV index. So what does that look like? It looks like opening windows because the physics of light ensures that you don't need a massive amount of opening to get photons through there. So you can even crack the window a little bit on the car. You open one louver, open the sliding doors.
Max:
[51:28] That's much preferable to filtering the light. Is filter light better than plain artificial light? Absolutely. And you're still getting brightness. So there are shades of optimal here and obviously just do what you can. To make maybe a quick revisit to ultraviolet is that because ultraviolet is short wavelength, it will get readily attenuated by clothing
Max:
[51:52] So it doesn't take a lot to still be outside, but to cover up. And that's kind of what I recommend after we've dosed ourselves appropriately is to cover up and preferably what they've found is that the natural fibers like a linen particularly
Max:
[52:08] Protects against or prevents UV penetrating, but is very permissible to those near infrared longer wavelengths that have such a massive and beneficial health effect. So that needs to be taken into account. And sunscreens are by definition ultraviolet blocking. So they are going to inhibit the photochemical conversion of 7-D hydrocholesterol to vitamin D. The significance of that for vitamin D status is minimized by current recommendations. It's my personal opinion that that is an important factor. So use that information with do with that what you will and potentially also of relevance with respect to exposure and sunlight is the link between the eye and the skin and what we know and what we discussed last episode is that what is happening through the eye the light through the eye affects the systemic endocrine system one of those endocrine functions is the tanning response So whatever we want to do when we're outside is to make sure that the signal is congruent between the eyes and the skin. So if we are in extremely bright light, you know, in the midday UV, we're in the midday
Max:
[53:32] You want to be covering up both your skin and your eyes. Conversely, if you're trying to build your vitamin D level earlier in the day, you don't want to be wearing sunglasses if you've got your skin exposed. So there needs to be congruence there because there is this neuroendocrine effect from the eyes, from the retina, that will influence the tanning response. And you're potentially going to increase or reduce your ability to respond to this UV light if you're covering up the eyes because the eyes think that you're in a low UV environment.
Max:
[54:06] The final interesting anecdote maybe that I'll mention is this idea that dietary factors affect photosensitivity. And we know in medicine that drugs affect photosensitivity. Doxycycline antibiotics and the tetracyclines cause photosensitivity. Isotretinoin, the acne medication, absolutely makes people more photosensitive. Certain chemotherapeutic drugs affect the body's ability to deal with the stress or the temporary hormetic stress of ultraviolet light. So what we've also noticed anecdotally is that if you're consuming or stop consuming dietary sources of omega-6 fatty acids, which is commonly found, abundantly found in refined restaurant oils and the like, then that seems to reduce photosensitivity to ultraviolet light. So that's just an interesting anecdote. There needs to be more data and more research done about that, but it's potentially affecting, again, what the body's doing or how the body's responding to that light. And the body ancestrally had a much higher proportion of omega-3 polyunsaturated fatty acids and omega-6 polyunsaturated fatty acids.
Max:
[55:29] So that's no doubt part of probably the formulation of what's going on there.
Mel:
[55:33] I feel like we have gone through, Just partway through a lot of avenues with regards to sun, vitamin D, nutrition, how we perceive it and its impact on the body. But I do think that if everybody listens to the circadian rhythm episode that I did with Max last week and this one, you're going to get a general picture of the importance of the basic things that we spoke about for good health and for a healthful pregnancy. Thank you so much for your time and wisdom, Max. In the show notes, we're going to put all of Max's details there. If you want to look further into the work that he's doing in these areas, you can explore all his offerings online as well. Thanks, Max. That has been this week's episode of the Great Birth Rebellion podcast and I'll see you in the next episode. To get access to the resources for each podcast episode, join the mailing list at melanethemidwife.com and to support the work of this podcast, wear the rebellion in the form of clothing and other merch at thegreatbirthrebellion.com follow me mel @Melaniethemidwife on socials and the show @thegreatbirthrebellion all the details are in the show notes.
This transcript was produced by ai technology and may contain errors.
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