The Science Behind Vitamin D, Our Rampant Deficiency, And Its Harmful Impact On Our Health

Coming up on this episode of the Doctor's Pharmacy.

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Since 2010, AG1 has led the future of foundational nutrition, continuously refining their formula to create a smarter, better way to elevate your baseline health. I drink AG1 every morning and I consistently feel more energetic throughout the day. I even recommend it to all my family and friends because of the results I've seen myself. If you want to take ownership of your health, it starts with AG1. Try AG1 and get 10 free AG1 travel packs with your first purchase. go to drinkag1.com/hymen. That's drinkag1.com/hymen. Check it out. And now let's get back to this week's episode of the Doctor's Pharmacy. Welcome to the Doctor's Pharmacy. I'm Dr. Mark Hyman, and this is a place for conversations that matter. And I wanna welcome you to my new podcast series called Know youw Numbers, designed to help you understand your health. through the lens of your own biology and your lab tests, looking particularly through the lens of functional medicine. Now, for too long, healthcare has required you to go to your doctor to access your own blood tests and your biology and then rely on your doctor to guide you. But you are now entering an era where each of us can access and understand our own biological data and become the CEO of our own health. Know youw Numbers will help you understand what lab tests are the most important to get, and what traditional medicine often misses. You will learn what the results mean, the optimal ranges, how they relate to other important lab biomarkers, and how to optimize your health based on your own lab data. And you will learn when it's important to see your doctor for further testing and treatment, because not everything is something you can deal with on your own. Now, in a perfect world, I'd have the chance to see millions of patients, but the truth is I'm just one doctor. But in over 30 years of seeing millions of biomarkers in tens of thousands of patients, I've come to understand that much is being missed by conventional healthcare. We often wait until we have symptoms or diseases and then get tested. But the transition from wellness to illness can often be detected decades before any symptom or diagnosis. Now, I want people to have access to their own health data and the ability to engage in self-care and in lifestyle practices that can optimize health and reverse the trajectory of chronic disease that now affects six in 10 Americans and accounts for over $4 trillion a year in healthcare costs. And that is why I recently co-founded Function Health, a revolutionary new way to understand and manage your health through lab testing and lab tests that you're not necessarily getting through your own healthcare system. All the results are delivered to you in an easy to use dashboard that tracks your numbers over time, and gives you actionable insights for every biomarker. We're building function to democratize much of what I do, to give you the keys to your health and to put control of your health firmly back into your hands. Now, this podcast is separate from my clinical practice at the Ultra Wellness Center, my work at Cleveland Clinic and Function Health. The podcast represents my opinions and my guests' opinions. Neither myself nor the podcast endorses the views or statements of my guests. This podcast is for general information purposes only. It does not establish a doctor-patient relationship. And because everyone has unique life circumstances, the content in this podcast should not be taken as personal medical advice. Consult with a qualified healthcare professional with any medical questions or concerns. Keeping this podcast free is part of my mission to bring practical ways of improving health to the general public. And in keeping with that theme, I'd like to thank those sponsors that made today's podcast possible. and now let's get started with Know youw Numbers. We're starting first with vitamin D, which is a massive problem both in terms of its impact on our health, its lack of understanding by traditional medicine, the lack of proper testing, diagnosis and treatment. It's just a mess out there. And this is one of the most important biomarkers you should know about yourself. So why does it matter? Well, vitamin D deficiency is a big problem. It affects over a billion people worldwide. In the US alone, 70% of Americans have either insufficient or deficient or suboptimal levels of vitamin D, increasing the risk for cancer, obesity, diabetes, high blood pressure, heart disease, depression, fibromyalgia, chronic muscle pain, bone loss, autoimmune diseases like MS and lots more. And the truth is, it's probably one of the most important biological compounds in your body because it affects so much. So what is vitamin D and what does it do? do in the body? Well, it's a fat soluble vitamin, meaning you have to eat it with fat to be absorbed, but it's more like a hormone than a vitamin. It regulates over a thousand genes. So it affects the gene expression of over a thousand genes that affect almost everything in your body. Now you can get it from your diet and you can get it from the sunshine because your skin converts the UV radiation into vitamin D in your skin. but there's some problems with that. One, it's really hard to get enough from your diet. And two, unless you're running around half naked south of the Atlanta latitude between 10 and two in the afternoon for half an hour every day, you're probably not going to get enough vitamin D. Now, what does vitamin D do? It regulates a lot of things. It regulates calcium in your body and phosphorus levels. It supports the functioning of your immune system. And we're going to talk about specifically how it affects your risk of cancer and your risk infections, particularly COVID. It protects against getting sick all the time from things like colds and flus and other infections. I mean, the data from COVID is quite striking. We're going to cover that in a little bit. And it's so important to keep your vitamin D levels up to prevent serious complications from COVID and even prevent getting COVID. Obviously, you know, vitamin D is good for your bones. Now, just so you know, people say drink milk to get your vitamin D. There ain't no vitamin D in milk naturally. It's added as a supplement to vitamin D. And it was done so because rickets was so rampant and people thought that people drink vitamin D a lot. So, the public health officials added it to milk, but it's not naturally in milk. It also supports healthy hormone health, including sex hormone production. It supports your muscle strength and function, really important for muscle health. Supports your brain health, your mood, cognitive function, neurotransmitters like serotonin, dopamine, cognitive function in terms of neuroprotection against things like Alzheimer's and Parkinson's. It also helps your oral health, your dental health, obviously your gut health. It prevents chronic disease, almost every kind of chronic disease you can imagine, because it's one of the most important regulators of your biology. Now, where does conventional medicine miss the mark here? Well, first of all, it's not part of your routine lab test, and it needs to be. It should be. Everybody should get their vitamin D tested. Often we wait until things are bad and then test, oh, you have osteoporosis. Let's check your vitamin D level. Well, that's kind of too late. I believe in testing not guessing. So I test, I don't guess. And what we look at is the reference ranges when we test the vitamin D levels. But it's important to understand that most reference ranges are based on the average in a population. I just want to kind of give you a background a little bit on optimal ranges. When we look at a lab reference ranges based on the average in a population. So, for example, it looks at what is the reference range based on the levels in the current population. Now, if you were an American, your average weight is high because 75% of us are overweight. If you landed on the Earth from Mars, you would think it's normal, quote, normal to be overweight because 75% of Americans are overweight. That doesn't mean it's optimal. So because we have such a rampant level of vitamin D deficiency or insufficiency, the current reference ranges are far too low on the bottom level. They're about 30, some are even 20. That's a disaster. Your reference range really should be what's optimal, not normal. And what's optimal is probably 45 nanograms per deciliter, not 30 or less. Most of traditional medicine also focused on disease treatment, not prevention. Now, there's a great article I read by one of the scientists who really was a pioneer in vitamin D, who wrote a paper called Long Latency Deficiency Diseases. And what he was talking about was the difference between a deficiency disease of a vitamin that causes acute effect versus a long-term effect. For example, if your level of vitamin D is acutely low, you can get rickets. But if it's kind of marginally insufficient, it may not cause rickets. but it actually can cause osteoporosis later in life. So what we wanna focus on is preventing these long-latency deficiency diseases. And the dose you need, for example, to prevent rickets, it might be 30 units a day, which is not very much. The amount you might need to prevent osteoporosis might be 2,000 to 5,000 units a day. Also, most doctors are not up to date on the latest research. It takes about 17 years for the average scientific discovery to be implemented in medical practice. And also, there's a bias against prevention, there's a bias against testing, It's how we're trained. Don't test. Just make sure you do your diagnosis by history and then test it confirm, but you should not be using testing to screen people. Also, most doctors don't even know how to diagnose vitamin D deficiency clinically and what the symptoms are. There's an actually an easy at home test. If you take your thumb and you push it against your shin, the bony part of your leg at the lower part of your leg, and you push the bone in. It shouldn't be tender. If it's tender, it's because you have some level of vitamin D insufficiency or deficiency. It's called osteomalacia. It means softening of the bones and that hurts. So you can just do that test at home. Then you should definitely go get your test done. Also, there's often lack of clear guidelines in medicine for what the optimal levels of nutrients are and what the optimal levels of supplementation are. And also requires personalization because we're all different and we're all genetically different. Some people might need a thousand units a day. Some people might need 4,000. 5,000 units or 5,000 or even 10,000 units a day and we'll talk about that. Also, people say, oh, it's going to cost so much to do this. But what is the cost of these untreated diseases like cancer or heart disease or diabetes or autoimmune diseases or chronic infections or COVID for God's sake? You know, how many people end up in the hospital from COVID because they were vitamin D deficient? You know, it's hugely expensive. Also, one of the things that drives me crazy is this whole kind of mantra of evidence-based medicine. Well, clearly we need to use evidence in medicine, but often the evidence is not looked at carefully. Often it's not interpreted properly. Often the science is misunderstood and it can be from poorly designed trials. And for example, you know, I always say if you take an aspirin and if you don't have a headache, it doesn't do anything. So for example, one of the vitamin D studies that was considered a landmark trial in 2022, the VITAL trial by Manson was published in New England Journal of Medicine, said that, well, you know, giving 2,000 units a day of vitamin D had no effect on fracture risk in healthy people 50 years and older. Well, that is not the right way to do the study. You have to look at who's deficient. If you give vitamin D to people whose vitamin D levels are good, of course it's not going to reduce fracture risk because they already are protected. But if you give it just to the people who are deficient, you can see a big change. So the participants in this study, which was a very important study, were not selected based on vitamin D deficiency or low bone mass or osteoporosis. So it's kind of crazy, you know, it's the same thing as I said, if you have an aspirin trial and you give it to people to see if it will cure headaches, well, if nobody has a headache in the population you're giving the aspirin to, you're not gonna see the effect. And what the results showed in the study, there was really no difference in fracture risk after five years, but it didn't actually look at vitamin D supplementation in those with vitamin D deficiency. And so it kind of, you know, kind of questioned the justification for widespread testing and treatment to certain levels, but I think it was really a poorly designed study and actually didn't answer the question to which it was focused on. What about functional medicine? How do we look at things differently? We take a much more proactive approach, a much more personalized approach, an approach that actually digs into what's going on with your biology and it's an individual. So we test, we don't guess. We want to test vitamin D in every patient. Now, maybe if you're a lifeguard, I know you're and you're tan all the time. I know your vitamin D level is probably okay. And I have a friend who's a surfer who lives in Mexico, and his vitamin D level was optimal. But I almost never see people with optimal levels unless they're supplementing, particularly in our modern world. So you want to make sure you detect this early because the longer you let it go, the longer it goes on in your life, the worse health outcomes you're going to have. And I'll get into some of the complications of long-term vitamin D deficiency or insufficiency. but you also have to personalize it, right? So not everybody gets the same amount. Everybody's different. Age is different. Sex is different. Where you live is different. Your genetics are different. For example, there's a whole bunch of vitamin D receptors that are regulated by genetics. And if you have vitamin D receptors that may not work as well, you might not be able to absorb as much or actually have the best function for vitamin D. So you may need a higher dose where somebody else might have different genetics. That means they'll do really well on a lower dose. So the dose ranges really probably should be between 1000 to 5000 a day. The safe levels according to the government, the Dietary Reference Intake, is 4000. So up to 4000, the government says it's safe. Now, what are most recommendations for? About 400 as you get older, maybe 800 units a day. Not real ideal. And they don't even recommend the right vitamin D form. It should be vitamin D3, which is the active form, not vitamin D2. And there's often poor conversion. The optimal reference range, is probably 45 to 75, up to 100 is fine as well. In fact, levels up to 250 have been shown to be very safe. Now, if you look at one study they did of healthy young adults who took 10,000 units a day for three months, there were no adverse effects on these people. Lifeguards have levels of over 200 nanograms per deciliter. So, I like to get my patients probably around 50 or so, 50 to 75, and that usually is a good optimal level. for blood level. But you can't know based on supplementation. You have to actually test your blood level to know where you're at. Also important to look at your kidney liver function which influence vitamin D effects. Also, vitamin D deficiency can often be missed because people think they have a parathyroid problem which is a hormonal condition that can occur where you get bone loss and muscle cramps and all kinds of symptoms and osteoporosis. but it's actually because you have low vitamin D levels and it's called secondary hyperparathyroidism. If you take too much, it's not good either. So you gotta be careful. It is a fat soluble vitamin. It does get absorbed in tissues and you can get high calcium levels, for example, if you're taking too much and that could cause kidney stones, kidney damage and other things. But I've never seen that personally. The other thing to know though is if you're overweight, you have much higher body mass and you need a lot more vitamin D to fill up the tank. so people who are obese are often very vitamin D deficient. So what are the root causes of abnormal levels or low levels of vitamin D? Lack of sunlight. You know, we all live and work inside. Americans spend 94% of their time inside. We use sunscreen. If you use SPF 15, it reduces the absorption of vitamin D by 95%. This is a study by Holick. And by the way, all the things that I'm talking about, all the scientific references are going to be in the show notes. You can look it up yourself. I'm not making this stuff up. So this is very well researched. Topic and I'm just giving you the highlights, but I want you to know that if you want to go deeper, there's a lot more in the show notes that can help you go deeper on this topic. Also, people use clothing or covered from head to toe. I remember one study that found that Muslim women who lived in Scandinavia were fully covered head to toe and they had severe seasonal affect disorder and fibromyalgia and muscle aches and muscle pains. And it was because they were all vitamin D deficient. If you live in cities and urban areas, you don't get as much sun. There's poor air quality might affect vitamin D absorption. If you live in northern latitudes, you might not get good sun exposure, particularly at certain times of the year, like in the winter. If you live in Portland, Seattle, London, and a lot more low vitamin D levels there. If you look at MS, for example, people who live in northern latitudes have much higher risk of multiple sclerosis, and that's been linked to vitamin D deficiency. Other things can affect your vitamin D status. For example, you have chronic kidney disease or liver failure that can impair the activation and conversion of vitamin D. so you kind of have to be paying attention a little more carefully. Medications can interfere with your vitamin D absorption and utilization. So a big study showed that US and US kids and adults that were taking oral steroids, which are used for autoimmune disease, all kinds of different conditions, were two times as likely to have severe vitamin D deficiency than non-steroid users. If you use long-term antibiotics, if you're on chemo, If you seize or preventing drugs, if you use certain kind of drugs that lower cholesterol that bind your bile, certain blood pressure pills, antacids, all affect your ability to absorb vitamin D. So they can cause vitamin D deficiency. We talked about the obesity issue. If you have a big body and a lot of body mass and fat, you actually just it's a fat soluble vitamins but stored in fast. So you basically have a big reservoir and your levels tend to be lower. So you need more vitamin D. Also, if you had weight loss surgery, gastric bypass, you know, it reduces absorption of nutrients across the board, particularly vitamin D. Not a good thing. As you get older, also older people tend to have thinner skin, it loses elasticity, and your skin actually can make vitamin D when exposed to sunlight, but as you get older, it just doesn't work as well. So, as you get older, you get more vitamin D deficiency, and you actually need more vitamin D. more important as you get older for preventing infections and immunity and cancer and things we'll share in a minute. If you have chronic kidney disease, also that affects vitamin D status. Also, as you get older, we lose stomach acid. So, your stomach acid is low. That can reduce vitamin D absorption as well. So, it can reduce it both from food or supplements. So, you just might need more. Now, people with gut issues also have trouble with absorption. People with, for example, celiac or Crohn's or ulcerative colitis or irritable bowel syndrome often have inflamed guts and that affects your vitamin D absorption. Also our diet, you know, most of us, and why didn't, you know, think, why did we need vitamin D? You know, we were, why did we need supplements? We all were out there living for hundreds of thousands of years as human beings. We didn't need vitamin D supplementation. What's the big deal? Like, why do we need it? Why can't we get it from food? And when you look at the data on this, it's really interesting. First of all, most of us lived in equatorial regions, and we were out in some of the most areas. I was just out in Africa. and was visiting the Hadza tribe, which was one of the last hunter-gatherer tribes out there in Africa. And, they basically had no clothing. They were out there basically with a little bunch of leather covering their private parts and otherwise they were naked. And so, they were running around outside all day naked in an equatorial region and they're getting enough vitamin D. Those populations that lived, for example, in northern latitudes, they lived on the coastal areas. And one of the best sources of vitamin D is fatty fish. And that was a big part of our diet. In fact, fatty fish in the Northwest, in the Pacific Northwest in the United States, I forget the name of the actual fish, but it's a tiny little fish that was so valuable because it was so oily and fatty that it was used as currency. In other words, as to trade as money. So it's such a valuable commodity and, and mackerel, herring, sardines. Cod liver oil, cod liver oil is a great source of vitamin D. Egg yolks, beef liver, mushrooms, things that we eat also, it was interesting when we visited the Hadza, it was so interesting as part of their tribal initiations. Again, this is one of the last hunter-gatherer tribes. They actually get to eat if you become a man and you go through the rituals of becoming a man and kill a big animal, then you get the privilege of eating the organ meats first. the liver, the heart, the kidneys, the testicles, right? So all these things have much higher levels of nutrients and most people don't eat this stuff. Also wild mushrooms, porcini mushrooms are the highest. So we see a lot of foraged food, wild food, coastal areas with fatty fish. So we did get a fair bit of vitamin D even if we lived in northern latitudes. But for most part today, we don't eat those things and people don't run around half naked most of the year in Equatorial regions anymore. There are fortified foods but they're most mostly fortified with vitamin D2 milk, you know, OJ, cereals, plant-based milks. But you want to eat a food that's naturally nutrient dense, not something that's nutrient poor that you have to add stuff to enrich it. And they don't actually don't use the right vitamin E. They use vitamin D2 with not vitamin D3, which is the one that actually works for you. So, you know, vitamin D3 fortified products tend to work better vitamin D2 fortified products and that's the studies are in the shown as we can share what those are so you can learn about it. Most people are not meeting the minimum amount. Now, when you understand what the RDAs are, these were developed, this is a recommended dietary allowance where they call them the dietary reference index. Now, these were levels that were established in an era where there was massive nutritional deficiencies, lots of vitamin deficiencies, mineral deficiencies and diseases that were resulting from those like rickets or scurvy, right? so they establish these levels to be the minimum amount you need to prevent a deficiency disease. So not how much is for optimal health, right? How much vitamin D do you need to not get rickets? 30 units. How much vitamin D do you need to not get osteoporosis? Probably four or five thousand units, right? How much vitamin D do you need to not get the flu and COVID and cancer? Probably three to five thousand units, right? So it's literally 10 times the dose. So the RDA is like 600 for adults, 800 if you're over 70 years old. But that's for preventing Rickets, not for optimal health. And I think we talked about the long latency concept, very important concept. Also, people just aren't aware, right? People don't know they haven't been tested by their doctor. Their doctor never checked it. It's not in the regular annual lab panel. They don't think about it. And the winter people go, oh, I'm depressed in the winter. You know, why? well, it's not just because it's cold out. I love the winter, actually. If you get adequate vitamin D, you're not going to get what we call seasonal effective disorder. You're not going to feel better. Also, your race matters because melanin in the skin blocks absorption of ultraviolet light, right? So if you're African-American or we were in Africa, I mean, they had very dark skin, Asian, Native American, you tend to actually absorb less vitamin D. and produce less vitamin D through your skin because of the blockage of the ultraviolet light by melanin, which is a good thing because it prevents cancer and other things. But it's a bad thing if you're living in a modern world and you're not living your traditional life that you evolved to eat to live. Genetics play a role as well. As I mentioned, you know, there's a gene that metabolizes vitamin D, converts the inactive form to the active form of vitamin D3. It helps break down excess vitamin D. It may actually cause increased metabolism called a gene called CYP2-4-A-1 doesn't really matter. But the point is that there's genes that regulate metabolism vitamin D absorption vitamin D and often we use gene testing to customize our prescriptions depending on what we see in the patients. A lot of other things also affect vitamin D levels like your calcium level, magnesium level, which are often part of the functional health testing. Vitamin K, zinc, vitamin A, phosphorus, all really important and conventional medicine just doesn't check it. I see a lot of people getting their doctor checking vitamin D2. Well, that's not even worth checking. You want to check hi 25 hydroxy vitamin D3. That's the test you want 25 hydroxy vitamin D3. And again, that's in the show notes. We're going to write all down. It's part of the function panel. You don't even think about if you get that test. Okay, so we've got through all the background on this. What symptoms will you get if you are low or are deficient or insufficient in vitamin D? you'll get inflammation because it's important in regulating immunity. You'll get more suppression of your immune system. My niece, for example, was constantly getting sick with colds and flus and having to, you know, leave work 25 years old. You know, she's an artist. She spent a lot of time inside or works at, you know, inside. And I checked her vitamin D, and she was very vitamin D deficient. And I gave her high-dose vitamin D, and now she's not getting sick at all. So it's very effective. If you look at, for example, the data on flus, if your vitamin D level is adequate, it creates a 75% reduction in your risk of getting the flu. So you really make sure you're getting that for immunity, particularly in the year of COVID and so forth. We'll talk about that more. Also, bone and joint pain and achiness and fractures all linked to often low vitamin D mood. If you're depressed, if you have seasonal affective disorder in the winter, you could have vitamin E deficiency. hair loss. Nobody wants to lose their hair, but another it's another symptom of low vitamin D. Lack of appetite, fatigue, fibromyalgia, muscle cramps, weakness, spasms, twitches, tremors, all can be related to low vitamin D. Now, what are the diseases that you might get if you don't have adequate levels of vitamin D? Now, this is where it gets a little scary, but the good news is it's such an easy fix. I mean, vitamin D supplementation is safe, it's effective, and it costs literally pennies a day. so we're not talking about some super expensive intervention. This is one of the most important things that I do in my practice is get people's vitamin D levels up to an optimal level. So what kind of diseases are we seeing correlated with or associated with or proven to be caused by low vitamin D? The first is cancer. Now what's the mechanism? Well, vitamin D is anti-inflammatory, which cancer is an inflammatory disease. Vitamin D is anti-angiogenic, which means that it prevents the growth of new blood vessels, which is exactly how cancer grows. And a lot of the new cancer therapies are anti-angiogenesis therapies. It also affects your cell cycle regulation. So it inhibits tumor growth. It inhibits tumor cell division. All good. Also, you have these things called natural killer cells, which are super important and just like what they sound, they're like special forces of your immune system. They go around and they find and seek and destroy cancer cells. And they're critical in what we call immunosurveillance, which is recognizing and getting rid of cancer cells. So you wanna make sure you have great natural killer cell function. And in fact, vitamin D boosts your natural killer cell function. Let's look at specific cancers now. What about breast cancer? Well, if you're looking at people who have higher vitamin E levels in one 2008 analysis published in PLOS ONE, there was a lower risk of breast cancer in those who had higher levels of vitamin D. There was an 82% lower risk of breast cancer in women with vitamin D levels. They were over 60 nanograms per deciliter compared with women who had levels of less than 20 nanograms per deciliter, which is very, very low. Now, sufficient levels also affects your treatment outcomes. So if you're getting breast cancer, if you have breast cancer, you better get your vitamin D level up. Why? So in a 2021 prospective cohort study published in the Journal of Clinical Oncology, women who had invasive breast cancer whose vitamin D levels were over 30 nanograms per deciliter had a 27% lower risk of death compared to women with vitamin D levels that were really low, like under 20. In another study, a 2014 meta-analysis that was published in anti-cancer research, it showed that higher vitamin D levels over 30 upon diagnosis of breast cancer, if you made, in other words, we had high, higher good levels of vitamin D when you got diagnosed, there was a 44% reduction in the risk of breast cancer related death than those who had the lowest vitamin D levels, which were, let's say, under 17. What about other cancers? Well, prostate, lung, colorectal cancer, ovarian cancer, A big study in 2022, published in the Journal of the National Cancer Institute, showed a 17% lower cancer mortality among men and women in the highest category of vitamin D versus the lowest category. Now, there's a lot of research outcomes that are variable and not all studies show the same thing. And, you know, we can cherry pick studies, but the weight of the evidence is overwhelming that vitamin D is a good idea. And, and not every study shows a benefit. There's differences in study design and the dose of supplementation. the cancer type, the progression, the vitamin D level at baseline, you know, the effects on different sex, male or female, the failure to control for genetics, diet, lifestyle factors. These are all things that really are often not looked at properly in studies. So there's a lot of mixed variables, but on the whole, having higher levels of vitamin D is a good idea to prevent cancer and if you get cancer to prevent dying from cancer. what else is important to think about in terms of vitamin D? Well, autoimmunity and infectious disease, because cancer is one part of your immune system, but also autoimmunity and infections are another part of your immune function and how we regulate that. So when you look at vitamin D, what it does, it helps basically regulate your immune system. It helps balance your immune system. It activates what we call T-cells and B-cells, which are your immune cells that fight cancer and infection. It also boosts another category of your white blood cells called macrophages, which are like Pac-Man that hunt and destroy. So these identify and neutralize viruses, bacteria, other pathogens, and it basically enhances our ability to fight infection. It also regulates something really important because, yes, we want to be able to fight infection, but we don't overactivate our immune system and actually fight ourselves, which is called autoimmune disease, where we're attacking our own tissues. And there's something called T regulatory cells, which basically regulate your T cells, your lymphocytes, your white blood cells, and it allows tolerance to yourself. So you don't want to be attacking yourself, right? And what we find is that it prevents your immune system from attacking its own tissues. And low vitamin D levels is a big risk factor for autoimmune disease, including multiple sclerosis, rheumatoid arthritis, lupus, fibromyalgia, psoriasis, and type 1 diabetes. And basically studies show that there's an inverse relationship between vitamin D levels and clinical biomarkers of autoimmune disease. In other words, a higher vitamin D level, lower the biomarkers of autoimmunity and vice versa. Let's look at multiple sclerosis and a few other things just specifically because it's really important. In 2020 in frontiers of neurology, patients who had relapsing remitting MS, with a baseline vitamin D status that was greater than 30, had far lower lesions in their brain, we call white matter lesions. They basically damage from inflammation in the brain than people who had and lower disability scores than people who had lower levels of vitamin D. In another study in 2021, they showed that if you had higher levels of vitamin D who had lower risk for rheumatoid arthritis and lower likelihood of having a positive biomarker or rheumatoid factor. Another study showed, for example, at a birth study looking in Lancet, one of the top journals in the world, showed that just giving kids 2000 units of vitamin D from age one years old was associated with an 80% decreased risk of type 1 diabetes. That's amazing, right? This is a very serious disease if you get it. And just simply giving kids vitamin D can reduce the risk of getting type 1 diabetes by 80%. Now let's talk about COVID And this is the one that I think is really important. You know, when you look at the data, it was really compelling. if you were vitamin D deficient, you were more likely to get severe COVID, you're more likely to get complications, you're more likely to be in the hospital, you're more likely to have bad outcomes and death. In a 2020 study, they found that in 200 COVID patients that were hospitalized, vitamin D was reported to be deficient in 80% of those patients. and when people had very significant vitamin D deficiency, which was very low levels, they had higher levels of heart damage, more inflammation. They were in the hospital longer. They had more risk of heart effects. And, and those who had levels of over 20 had lower risk of these problems. And men typically had lower levels than women. In another 2022 study in nature, we have over 450 adults with COVID if your levels were very low under 10, you were at a 50% higher risk of severe COVID. Another study in 2022 that looked at a large population of US veterans, they found that vitamin D supplementation, so giving vitamin D was associated with a 33% reduction in death within 30 days of your COVID infection. So if you get COVID and you then start taking vitamin D, your risk of death is a lot lower. There was another large study that showed in Israel that there were no deaths if your vitamin D level was over 50. Another study showed if you had low level vitamin D, your risk of ending them on the hospital having severe COVID and dying was 70% higher than if your levels were good. So COVID is another good reason to take a vitamin D. What about your brain? Your brain also is very influenced by vitamin D and your vitamin D status. So, you know, mood disorders are a big factor. I mean, we see rampant depression, mood disorders in our country and maybe some of it is due to vitamin D deficiency. or I would say insufficiency, because, you know, when you look at deficiency, it depends on the cutoff level, right? So, I think the probably optimal levels are 45 to 50 or more normal cutoff levels are 30 or even 20 on some labs. But, if you look at what the role of vitamin D is, it plays a big role in the production of the feel good neurotransmitters like serotonin and low levels of vitamin D have been linked to depression, to anxiety, to bipolar disease, to schizophrenia, and even obviously seasonal affective disorder. Also, people who tend to be sicker with things like diabetes or Alzheimer's colitis, they actually see a lot benefit when they take vitamin D, particularly in terms of mood. Postpartum depression is a big issue as depression after women give birth. We know that postpartum depression has been linked with very low levels of vitamin D. What about other functions of your brain, like your cognitive function? Well, the studies on Alzheimer's and dementia showed that vitamin D may help reduce neuroinflammation. And we know that Alzheimer's and dementia are diseases of inflammation in the brain. It may help clear the amyloid plaques that clog up the brain. It helps promote new brain cell growth like neurogenesis. It protects against oxidative stress and it even helps make new connections between brain cells. In 2022, in the American Journal of Clinical Nutrition, they looked at over 427,000 white European participants and you had a 54% higher risk of dementia with vitamin D levels of under 25, which is 10 in our units in the US versus levels of 20. Now, I think your level should be much higher, obviously, but I think that's a very impressive result. I wonder what the data would have shown if your level was not 10 or less or 20 or less, but maybe 50 or more. So it probably would have been even a bigger effect. Also, sex hormone function also is regulated by vitamin D. Infertility is a big issue and so are menstrual issues. And it turns out that if you give vitamin D to women who have infertility, often caused by insulin resistance or PCOS, and they had vitamin D deficiency, you will significantly improve the rate of in vitro fertilization outcomes and clinical pregnancy rates and embryo quality. So basically, if you're having trouble getting pregnant, you need vitamin D because it helps with getting pregnant and keeping your quality of your embryos and doing all the things you need to do if you want to have a baby. Also, bone issues, as we know, we probably are aware of that. It's one of the things most people know that vitamin D is important for your bones, but it bone bone issues are huge. You know, women get osteoporosis, men get osteoporosis. And if your vitamin E levels are low, you don't absorb calcium as well. It's one of its main functions. so if you have low vitamin D, it reduces your bone density, increase risk of bone fractures. Obviously, if you're very, very low, you get rickets. But even if you're not very, very low, you get osteomalacia. As I mentioned before, the softening of your bones, and you get osteoporosis. So we see that there's real benefit in those who take vitamin D. Calcium may actually really be as effective as we once thought, but it really works. if you're low in vitamin D, it's one of those long latency deficiency diseases. Now, if you get too much vitamin D, it's not good either. So it's really finding that nice balance. What about your heart and your metabolic health? Again, another big factor to consider when you're looking at vitamin D. If you have type 2 diabetes, you're likely to be vitamin D deficient. And vitamin D deficiency link is linked to higher levels of insulin resistance, higher blood sugar levels, and giving vitamin D supplements actually helps show improvement in the markers of insulin resistance, prediabetes, and diabetes. So high dose of vitamin D2, for example, 50,000 units a week for eight weeks in those with diabetes, improve their fasting blood sugar, improve their insulin, improve their insulin resistance markers after treatment with vitamin D. Another study looked from NHANES data, which is a huge government database, found that insulin resistance was dropped by 18% for each additional unit of vitamin D3 intake, which is pretty amazing. Also obesity, a new study in 2023 just published in November 7th, 2023, showed that poor vitamin D status was associated with increased total and appendicular body fat. That means, you know, arms and legs and so forth. So really, the lower vitamin D level you have, the higher risk you have of being overweight. So forget about Ozempic, Trulicity, vitamin D. Cardiovascular disease. Also another big factor, if your level was less than 15, you had a 62% greater risk of heart attacks compared to if your level was higher than that. Also, if your levels were really low, like less than 10, you had an 80% increased risk of bad cardiac events. Also high blood pressure. High blood pressure is controlled by something called the renin-angiotensin-aldosterone system. and a deficiency in vitamin D can lead to an overactive system leading to hypertension. So if you have high blood pressure, again, another reason to take vitamin D. Also, cardiovascular disease. If you have low levels of vitamin D, it leads to inflammation, vascular dysfunction, and may cause the progression of hardening the arteries, atherosclerosis, and damage to arteries. It also seems to cause more calcium deposition in the arteries, and if you have low vitamin D levels. Also, what about gums? Another part of your bone health. But gum disease really is rampant and it leads linked to heart disease. It's linked to Alzheimer's, many other things. So you wanna make sure you get the anti-inflammatory properties of vitamin D that helps promote oral immunity. If you tend to have gum disease, we call periodontitis, you have lower level vitamin D typically. And if you take vitamin D, if you have gum disease, it actually improves your outcome. So good idea. Also, it's important to remember you wanna probably take vitamin D with some vitamin K2, which also helps bone health. as well as heart health, helps prevents cavities as well. So really important. Also helps with antimicrobial properties. So that's a lot, right? A lot of things that can go on with your health that can be linked to low vitamin D levels. Everything from cancer to autoimmunity to infections, dementia, hormonal disorders, infertility, heart disease, gum disease. I mean, the list goes on and on. So It's such an easy thing to fix, but you have to know your level. You can't just guess because some people are okay and some people aren't. And some people need a thousand units a day. Some people need 10,000 units a day. And the only way to know is to check and recheck and see your levels and what they show over time. So what can you do to optimize your vitamin D levels? Well, you can eat vitamin D rich foods, right? Fatty fish, herring, mackerel, sardines. All the stuff people love, right? Cod liver oil, not so many people are eating that stuff. Personally, I love that stuff. But fatty fish is a great source of vitamin D, but you're not going to get that much. Egg yolks, beef liver and mushrooms, particularly porcini mushrooms. Again, you can barely get porcini mushrooms. When I go to Italy, I love to eat those. Now, there are fortified milks, but I don't really recommend that, both regular and plant milks. But there's a lot of, if somebody calls them nut juices, I mean, they're, they're not really the best things to be consuming on, on a regular basis. But they're really not enough to optimize your levels or to prevent deficiency. Now, you could also say, well, I want to take supplements. I want to be in the sun. Well, you should probably be careful of your face because you don't want to get wrinkles. But sun exposure on your skin can be helpful probably between 10 and 2 in the afternoon when the UV index is highest. But you have to be at a latitude below Atlanta. And if you're in the north during the winter, forget about it. People say, oh, I'm taking I don't need vitamin D in the summer. Well, actually, often, unless you're out there as a lifeguard or surfing all day, you're likely to need a lot of vitamin D supplementation. But generally, about 20 minutes of sun exposure every day without clothing, without sunscreen, is enough to get your vitamin D levels up if you're below the latitude of Atlanta and it's in the summertime, which most of us can't do. Now, you can use light box therapy. 10,000 Lux light therapy 30 minutes a day, that also helps. But the easiest way is just take Vitamin D. It's cheap, it's easy to take, it's no side effects, and it's easily available. The range I usually recommend is 2,000 to 5,000 units a day. Higher doses you can take if you're very low, you can take, it's like filling up your gas tank. You can just go full bore, take 10,000 a day, 20,000 a day, and do that for a month or two, and you'll be okay. You want to fill up the tank because it's a fat soluble vitamin, but you want to be careful to check. And it takes about three to six months to correct deficiencies. Make sure you take it with food, particularly fat, which helps absorption. Also, you want to take it with other supplements, magnesium, which is important for vitamin D3 activation, K2 also important, which activates something called osteocalcin. So make sure the calcium gets absorbed and stored in your bones and your teeth. But you should check it initially every three months if you're low. once you're at a baseline level, probably twice a year is a good amount to check and see where you're at. And you can fine-tune your dose, fine-tune your levels, and make sure you're in the optimum range, which I think is probably about 50 to 75, and then you adjust accordingly. So that was vitamin D, guys. I know it was a lot, but all the references, all the science in the show notes, there's a transcript there as well if you want to dig in with what I said. But this is an example of why knowing your numbers is so important. It's one of the most important tests I do, and really a critical number to know. Now, as I said, if I could, I would see millions and billions of patients, but I can't. There's just one me. But with Function Health, we're aiming to democratize much of what I do, offering you the keys to your own health. We're in a new era of medicine. It's a democratized, data-driven system that gives each of us the access to our own health data, and it's informed by the latest science and the science of functional medicine. there is nothing more important than taking ownership of your health. And it starts with a set of over a hundred lab tests ranging from full hormone testing to deep cardiometabolic testing to nutritional assessment, including vitamin D3, heavy metals, and lots more. Now, many of these essential tests are not measured in your typical annual blood panel. And there's no more navigating burdensome insurance. There's no more having to wait for a doctor's appointment. There's no more need to consult Dr. Google. to figure out what they mean. 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