166 | Miracle Molecules: Vitamin D (Part 2) - Sunlight, Urbanization, and Why Your D Levels Might Be Lower Than You Think

Ever wondered why sunlight is essential for your health, yet many of us remain vitamin D deficient? In this eye-opening episode, we trace the impacts of urbanization from the Industrial Revolution and how pollution led to widespread vitamin D deficiencies. Uncover the science behind vitamin D synthesis and why even people in sun-drenched areas struggle with low levels. Explore natural food sources rich in this crucial nutrient, from fatty fish to red meats, and learn the critical differences between vitamin D2 and D3. We emphasize the importance of testing your vitamin D levels regularly rather than assuming you're in the clear.

We also demystify the complexities of measuring vitamin D, focusing on why clinicians prefer the 25-hydroxy form over the active 1,25-dihydroxy version for reliable results. Understand the intricate regulation of vitamin D in your body, and why the 25-hydroxy form is the gold standard for assessing your vitamin D stores. Finally, we touch on the principles of functional medicine and how lifestyle modifications can support overall wellness. Remember, our podcast is your guide to health education, but always consult healthcare professionals for personalized advice. Join us for this insightful journey into the world of vitamin D and take control of your health today!

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Transcript

Speaker 1 0:02

Hey everyone, welcome to the Inflammation Nation podcast. I'm your host, Dr Steve Noseberg.

Speaker 2 0:08

One of the greatest obstacles to crafting health and wellness is identifying and controlling inflammation. It's at the core of all complex and chronic diseases and it's the driving mechanism that underlies the most common symptoms that people like you struggle to overcome. Join us as we explore cutting-edge science and research to give you the information and tools you need to create the quality of life you want and deserve. And now here is the host of Inflammation Nation, dr Stephen Noseworthy.

Speaker 1 0:37

Hey guys, we're back with part two of our discussion about vitamin D as the next miracle molecule in this little mini-series, and in part one you might want to go back and listen to that if you're just jumping into this episode we talked about, you know, what is a vitamin, what is a hormone? And is vitamin D a vitamin or is it actually a hormone, like many people say? And the answer is it's both. If you look at the definitions of those compounds, it's clearly can be classified as either one, and we talked about some of the differences between vitamin D2 and vitamin D3. And we also made a distinction between the 25-hydroxy version, which is the one that we're all measuring or at least we should be which is actually a precursor hormone, and that has to be converted into the 125 dihydroxy version, which is the active metabolite, and we'll come back to that.

Speaker 1 1:36

But I want to tell you just a little bit of history, like we can go back in what we know, for example, back in the let's say it was the advent of the industrial revolution, say a couple hundred years ago. What ended up happening with, with the evolution of industry and machinery and standardization of manufacturing facilities? Um, what happened was people who lived in the rural, in the country settings, started in in the European communities. They started moving into cities to get jobs and as more and more people came into these cities, the cities built more houses or housing complexes for the increasing population. They also started making manufacturing facilities and plants that used machinery that burned fuel sources that increased the level of pollution in these communities. And all of these things had the effect of like, for example, taller buildings that were crowded close together with a pall of smog or pollution in the air basically filtered out the sun and as a result, shortly after the onset of the Industrial Revolution, there was a massive increase in vitamin D-related diseases, particularly rickets, which is a bone-related vitamin D disease where calcium doesn't go into the bones, bones become soft and they bow under the weight of someone's body. So I think it's kind of important to recognize that number one. We can make vitamin D from sun exposure, but we need to have adequate sun exposure.

Speaker 1 3:18

Now I've been measuring vitamin D with my clients as a routine part of my initial analysis and subsequent follow-ups for a couple of decades now. It's just part of how I assess somebody's fundamental physiology, and I have a lot of clients in very sunny areas and they tell me yeah, I spend plenty of time outdoors, but routinely the only people that I do my initial vitamin D assessments on that actually have adequate levels of vitamin D are people who are taking supplements, even though they might live in sunny places and spend what they think is an adequate amount of time outdoors. And so I want you to consider that if you live in a sunny place and you spend time outdoors, you may or may not have adequate vitamin D levels. Don't guess, always check. I mean that's kind of a catchphrase in our levels. Don't guess, always check. I mean that's kind of a catchphrase in our world. It's like, let's test, let's not guess. But estimates are that, all other things being equal meaning say, no interfering factors, that we can or have the potential to make about 90% of the vitamin D that we need just from the sun.

Speaker 1 4:24

We also get vitamin D from our diet, and so vitamin D occurs naturally in fatty and oily fish such as, say, trout, salmon, swordfish, sardines, mackerel. You can also find vitamin D in egg yolks and most of your red meats, and particularly in organ meats, specifically liver, and there are plant sources of vitamin D, but this is mostly the vitamin D2 version, which is less bioavailable, less absorbable than the vitamin D3. That comes from the animal sources right, and you can again, you can get vitamin D from fungi and algae, but it's just not as good as the stuff that you're going to get from the animal sources. A vitamin D is one of four different fat-soluble vitamins right, vitamins A, d, e and K and while vitamin D absorbs passively from your gut into the bloodstream, it tends to work better when you take vitamin D with fats. So if you're eating fatty foods that have vitamin D in it, absorption happens very easily. If you're taking it foods that have vitamin D in it, absorption happens very easily. If you're taking it with a supplement, then it helps to have it with a fatty meal, for example. We'll come back to this towards the end of the episode, but the main way that we get vitamin D is through adequate sun exposure. At least that's the way it's designed to be.

Speaker 1 5:40

And, again, assuming no interference, your skin can make upwards of about 10,000 IUs of vitamin D every day, and that's a decent dose, right, but that's without any interfering factors. For example, if your skin tone is lighter, you will likely make more vitamin D from the sun than if you are darker complected, people with darker complexions need more time in the sun than if you are darker complected. People with darker complexions need more time in the sun to get the same amount of vitamin D production that someone who has fairer skin. If you live in a higher latitude, if you live in more northern climates, you're going to make less vitamin D from the sun. So if you live near the equator, it's easier to make vitamin D than if you live, say, in Sweden or Norway. And also the time of day a sun exposure can make a difference, like the optimal time to get vitamin D from your skin is between 10 am and 3 pm, which, of course, is the very time that dermatologists warn that we should stay away from the sun.

Speaker 1 6:42

So how do we actually make vitamin D from the sun? Well, it's a multi-step process that requires, number one, adequate sun exposure. Number two, adequate cholesterol as a base molecule, as well as healthy liver and kidney systems. So here's the process in a nutshell when you have adequate sun exposure, it triggers your skin cells to trap cholesterol and then use an enzyme to convert cholesterol into the parent vitamin D called calciferol. So the first thing to remember is that vitamin D number one is made from cholesterol and step number one happens in the skin when we expose our skin to adequate sunlight. Step number two, then, is where we take this parent form of calciferol, the parent vitamin D, and we move that to the liver, where the liver uses another enzyme to convert this parent calciferol into the pro-hormone, the 25-hydroxyvitamin D Now remember, this is a pro-hormone. The 25-hydroxy vitamin D Now, remember, this is a pro-hormone, it's not biologically active and it has to be converted in one more step to the 125-dihydroxy version, and this happens in the kidneys.

Speaker 1 7:57

So, if you flow through the process, here is what you need to make most of your vitamin D. Number one adequate sun exposure at key times of the day, and what is adequate is going to depend on your skin tone, where you live relative to the equator, how much time you spend in the sun, the time of day you spend in the sun, and whether or not you have enough cholesterol. To begin with and this is potentially a problem with people on statin drugs, where their cholesterol levels go too low they start to run out of material to make vitamin D and other hormones like cortisol and reproductive hormones. So adequate sun exposure is key. Then you need a healthy liver to take that parent cholesterol compound called calciferol and then convert that into the 25-hydroxyprohormone. And while most of your cells have a small capacity to make 25-hydroxyvitamin D locally, the vast majority of this does come from the liver.

Speaker 1 8:58

And once you create this 25-hydroxy second product, or the prohormone, then you need a healthy kidney system to make the final end product, which is the biologically active 125-dihydroxyvitamin D that binds to the vitamin D receptors in your cells. Now remember, these vitamin D receptors live in all of your cells. They live inside your cells' nuclei, in the very same place where you have receptors for thyroid and reproductive hormones. And when the active form of vitamin D binds to the vitamin D receptor, it turns on and off specific genes in different patterns to modulate and control how your vitamin D gets expressed, to modulate and control how your vitamin D gets expressed. And so vitamin D functionality is critical to core cellular function and to control your genetic expression. And again, this process is sun to skin, to liver, to kidneys. And then the active form goes into your cells, binds to the vitamin D receptor in the nucleus and controls your genes. That makes the proteins, that allows your cells to do their jobs.

Measuring Vitamin D

Speaker 1 10:08

And if we want to know what our vitamin D status is, the best option is to actually measure the 25-hydroxy version, the pro-hormone, which tells us more about deficiency or insufficiency than if we were to measure the active 125-dihydroxy version. We get more information from measuring the pro-hormone than we ever could from actually measuring the active metabolite. So let's talk about optimal levels and intake. Since there are two metabolite forms of vitamin D the 25 and the 125, there are two tests to measure vitamin D status. So we can either measure the 25-hydroxyprohormone or the active 125-dihydroxyversion, and there's some disagreement as to whether to test just one or the other or both, and people have their favorites.

Speaker 1 13:00

Of course, some providers will say that well, since the 125 version is the active metabolite, then that's the one that we should be looking at, and you know there's some merit to that thought. After all, like when I look at someone's thyroid, I want to see the whole picture, but ultimately I want to focus on what's called free T3, which is the hormone that acts on the thyroid receptors inside the nucleus to create thyroid function. And I don't mean thyroid gland function, I'm thinking cells, how they function in response to thyroid hormone exposure. But the problem is in measuring the active 125, there's some limitations here. One of the main issues is that this active 125 version has a much shorter half-life than the precursor 25 hydroxy version and, as a general rule, labs like to measure things that are more chemically stable, things that have longer half-lives, which allows them to give docs like me more accurate and more reliable assessments, which is what I like as a clinician so, and I'm not going to spend too much time on this. But here's a quick list of why measuring the active 125 vitamin D version is perhaps not the most useful thing to do.

Speaker 1 14:15

Number one the 125-hydroxy version. The active metabolite is found in blood in very, very low concentrations, which means that labs need even more specialized technology and measurement strategies to measure them accurately. Like if we compare the size of how much 25-hydroxy pro-hormone is circulating in the blood compared to the amount of the 125-dihydroxy, the pro-hormone pool is roughly 2,000 times larger than the size of the active 125 metabolites. Than the size of the active 125 metabolites, it's simply harder to measure things that are present in only such small quantities. So that's a problem, and we know from studies that different techniques measuring even the same blood samples when they're measuring the 125 version will actually give us different results and unfortunately, the available techniques we have are known through research to suffer from poor sensitivity and specificity. And, to add insult to injury, we don't even have standardized reference materials to really establish what we should be comparing these numbers to anyways.

Speaker 1 15:34

Another problem and this gets a little bit more sciencey, but the 125 biologically active version is what we call lipophilic, meaning it mixes with fat. It doesn't mix well with water. Technically, that makes it more difficult to measure, and on top of that, the active 125 version has a very short half-life of only a few hours, versus the 25 hydroxyprohormone, which has a half-life of several days. It's just easier to measure things that hang around longer. And so, and finally, let me just kind of put this to rest here Since the active metabolite, the 125 version, these levels are very tightly regulated by parathyroid hormone levels, which in turn is regulated by calcium and also the parent vitamin D, calciferol. The active metabolite, the 125 version, the levels that we can measure actually has little or no relationship to our stores of vitamin D and therefore we can't really use the 125 version as an accurate way to determine whether or not we have a vitamin D deficiency, sufficiency, or whether or not the levels are optimized.

Speaker 1 16:52

Now, having said that, if you're interested in measuring your 125 active vitamin D, there's nothing wrong with that, but you should never do that without also checking your 25 hydroxy pro-hormone levels. It's not an either or do it this one or that one. It always starts with measuring the 25 hydroxy pro-hormone version, and if you want to then add the 125 active metabolite version, there's nothing wrong with it. Here's an illustration of why it would be wrong to just measure the 125. If you measure the active 125 version alone and let's say you decide that you can trust the number the lab gives you and the reference range that they're using, you don't know if that low active level is because the precursor pool of 25-hydroxy is too low and you simply don't have enough of what you should start with to make what you're measuring. Or you don't know if you're vitamin D sufficient, meaning you have a lot of 25-hydroxy available, but the problem is with how your kidneys are converting that into the active form. You can't tell if all you're measuring is the active metabolite, and I think that the only utility in measuring the 125-hydroxy vitamin D is when you do it in conjunction with the 25-hydroxy precursor pro-home version, pro-hormone version, and, ideally, when you're also checking it with your labs, looking at liver function and kidney function, then, and only then, do I think you start to see the whole picture.

Speaker 1 18:32

Now there's one final issue to sort out before we close this episode, and that is what are the optimal levels of vitamin D and how do you get there if your levels are too low? Well, if you compare what most labs say or what they define as vitamin D deficiency, and if you read the medical research, and then if you ask clinicians who actually have experience testing and supporting vitamin D with real people who have real problems, you start to see some disagreement and discordance. Most labs use the levels reported in research done many years ago by a guy named Grant Hollick, where he said that deficiency doesn't happen until the 25 hydroxy versions go below 30. Yet a quick search of PubMed and the National Library of Medicine will easily show more updated research says that anything below 50 is a deficiency, and most functional medicine practitioners that I know that I consider to be good clinicians. As a group we kind of think that optimal levels for the general population should be somewhere between 70 and 90.

Speaker 1 19:42

And again, this is the 25 hydroxy version being measured in standard units of nanograms per milliliter, not metric units of nanomoles per liter, and you can count. You can go online and just convert them between the two. But very simply, you can go from US units to metric units by multiplying by two and a half. So, for example, if your vitamin E level is 10, your metric versions would be 25. If it's 100, it would be 250. Or you can go the other direction you can take your metric units and divide it by two and a half and you'll get the US standard units.

Speaker 1 20:19

But this guideline of vitamin D being between 70 and 90 changes when someone has an active autoimmune issue or if they're chronically ill, chronically inflamed. In those cases, I and other like-minded docs like to see the 25-hydroxyvitamin D version closer to 100. And listen, it's okay if your levels go above that, as long as your calcium levels stay normal. And in fact, let me address this crazy notion that if your vitamin D is like 103 or if it's barely just a smidge above the lab range, that your vitamin D toxic and you need to stop taking it or else something bad is going to happen. Like my personal coaching clients hear this nonsense from their medical doctors all the time and it just tells me that these MDs don't understand vitamin D at all. So let me be very clear.

Speaker 1 21:12

What is vitamin D toxicity? It is hypercalcemia period, like anyone who takes way too much vitamin D and ends up in the ER because they've had some kind of a toxic reaction. It's because massive amounts of vitamin D can cause calcium to go too high, which won't kill you, but you're going to feel like you're dying and you're going to call 911 and end up in the ER. And the ER will either tell you just simply stop taking vitamin C, drink plenty of water and you're going to be fine, or, if your calcium is high enough, then they'll give you some medications to bring it down further and faster until you stabilize. And in fact, there are a handful of case reports in the medical literature that address this and in every single case report, people who are quote unquote vitamin D toxic were taking millions of IUs of vitamin D because of a product mislabeling. And that's what got them into trouble, because they were taking like literally millions of IUs of vitamin D when the RDA is like 400 IUs. These people were taking millions every day and in every case they were hypercalcemic, their calcium went too high and their symptoms resolved once their calcium levels came back to normal. So unless you're buying your vitamin D from a spurious or a non-trusted source, and as long as your intake isn't in the sky high range and, most importantly, as long as your calcium levels are normal, then you're not vitamin D toxic, even if your lab says that your 25 hydroxy is above the lab range.

Speaker 1 22:51

It's just that simple, all right, two final points. First, I mentioned this earlier. Since vitamin D is a fat-soluble vitamin, we know that its absorption is enhanced either by taking a vitamin D supplement with a fatty meal or, perhaps better yet, using a supplement where the vitamin D is in some kind of a fat or an oil base. The one that I use with my personal coaching clients is in a base of MCT oil, which is derived from coconuts. In this case, I also like to use a liquid form that can be used sublingually under the tongue, and the combination of vitamin D in a base of healthy fat like MCT oil and being held under the tongue before swallowed, will typically help improve vitamin D status more than a poorly formulated product and not taking it with some kind of a fat.

Functional Medicine and Wellness Support

Speaker 1 23:46

So how much do you need? Well, honestly, it depends, and I'm sure you probably knew I would say that, but I can't give you a vitamin D dose that's going to work for everyone. In fact, I can have two clients starting with the same low level of vitamin D. Give them the same dose of the same formula and measure their vitamin D levels eight weeks later, and one will have their vitamin D levels improve dramatically and the others will have barely moved. And so proper dosing depends on where you're starting from. How low is your starting point depends on what your target is, of course, combined with other factors like how much you might store in body fat or how active your immune system is.

Speaker 1 24:31

So it's easier to raise vitamin D levels in leaner people, who have less body fat, who have more stable immune systems, who are less inflamed, as compared to someone, say, with Hashimoto's or any other autoimmune reactivity, who has more body fat and is more immunologically unstable, who's always getting flared up and they're always inflamed. Immunologically unstable who's always getting flared up and they're always inflamed. Those people are going to have two very different responses to the same dose of the same supplement, but I'll say that as a general rule, once you get your vitamin D levels to where you want them to be. You can generally keep them there with a daily intake of anywhere from 6,000 to 10,000 IUs per day. Again, it just depends on their metabolic state and other factors. Some people we can keep their levels normal or optimal with 6,000. Others they have to go to 10. Everyone's a little bit different. And ignore the 400 IU RDA. That's ridiculous. In fact, we often joke that RDA stands for the ridiculously dumb amount and maybe I'll do a separate podcast on that someday. All right, that's it for vitamin D. I'll be back soon with our next miracle molecule, right here on the Information Nation podcast.

Speaker 1 25:51

This podcast is for general informational and educational purposes only and does not constitute the practice of medicine in any form or capacity. No doctor-patient relationship is formed. The use of the information in this podcast or any materials associated with or linked to the podcast is at the listener's own risk. The content of this podcast is not intended to be a substitute for professional and personalized medical advice, diagnosis or treatment, and listeners should not disregard or delay obtaining proper medical advice when a health condition exists and warns them. And finally, functional medicine is not intended or designed to treat disease, but rather is a natural approach to support restoring health and wellness. The use of diet and lifestyle modifications and nutritional supplementation is supportive for adjunctive care.