The Warning Signs and Symptoms of Vitamin D Deficiency | Dr. Mark Hyman

If your level of vitamin D was over 50 nanograms per deciliter, your risk of death from COVID was zero. Like zero. That's amazing. And if your vitamin D levels are low, you are 70% more likely to end up in the hospital, end up in the ICU, or die from COVID For me, starting the day with AG1 is like having a cup of energy. but without the caffeine crash. One scoop gives me a powerful blend of vitamins, minerals, prebiotics, probiotics, and adaptogens. Since drinking AG1, my energy levels have been more consistent and my digestion has dramatically improved. AG1's prebiotics and probiotics support a healthy gut and studies show that 97% of people see improved digestion after 90 days. Now, I love that AG1 uses bioavailable ingredients so my body can actually absorb the nutrients. plus its non-GMO and contains no added sugar. So start with AG1 and see how it can benefit you. Try AG1 and get a free bottle of vitamin D3, K2, and 10 free AG1 travel packs with your first purchase at drinkag1.com/hymen. That's a $48 value free at drinkag1.com/hymen. Before we jump into today's episode, I'd like to note that while I wish I could help everyone via my personal practice, there's simply not enough time for me to do this at this scale. and that's why I've been busy building several passion projects to help you better understand, well, you. If you're looking for data about your biology, check out Function Health for real-time lab insights. If you're in need of deepening your knowledge around your health journey, check out my membership community, Hymen Hive. And if you're looking for curated and trusted supplements and health products for your routine, visit my website, Supplement Store, for a summary of my favorite and tested products. Welcome back to another episode of the Doctor's Pharmacy and Health Bites, where we take juicy little bites into current health topics. I'm Dr. Mark Hyman, and today we're diving into a topic that's really essential for your overall health and yet mostly overlooked in medicine, vitamin D. Now we hear about it all the time and all the benefits of vitamin D, but what exactly is vitamin D and what does it do in our bodies? Because you should know, it's really important. As a fat soluble vitamin, vitamin D needs to be absorbed with fats from our diet and then stored in our body in our fat tissue in our liver, similar to other fat soluble vitamins like A, E and K. This episode will help you understand the crucial role that vitamin D plays in our health and why maintaining adequate levels is super important. Now, vitamin D is best known for its critical role in bone health and in immune system function. It enhances calcium absorption, which is really important. That's how calcium gets in your body with the help of vitamin D. And that's why a deficiency in vitamin D leads to bone deformities and things like rickets in children and osteoporosis adults. But vitamin D does so much more than just support our bones. It's a powerhouse for our immune system. It helps fight inflammation. It helps reduce the risk of all chronic diseases which we suffer from, from obesity, type 2 diabetes, to heart disease and dementia, and autoimmunity. And I could go on and on, mental health, depression, I mean, the list goes on. Now, it even plays a role in lowering the risk of autoimmune conditions and reduces your risk of infection. and this is really crazy data, but the COVID pandemic highlighted the importance of vitamin D and immunity with many studies showing that low levels of vitamin D increase the risk of severe infection, hospitalization, and death. In other words, if your vitamin D was low, you are more likely to end up with a severe infection in the hospital or die. Now, beyond bone health and immunity, vitamin D has a lot of jobs, including thyroid and many, many other things. It affects the expression of over a thousand genes. It's more like a hormone than a vitamin. And it supports the brain really critically by aiding in cognition, helping with memory, mood and depression. And it also helps protect against really bad things like neurodegenerative diseases like Alzheimer's and Parkinson's. Vitamin E is also critical for hormonal balance, fertility and gut health. Literally everything, okay? Everything. Vitamins are not like drugs that have a single action on a single receptor with a single effect for a single disease. Vitamin D and other vitamins are what we call pleomorphic. They have many, many, many effects in the body. And that's what makes them so amazing. And they're very safe and effective and they have no side effects because they're the things your body uses to do its job. And so you just need to have optimal levels, not overdose obviously, but the optimal levels. Now, despite its importance, many people are really deficient or insufficient in this vital nutrient and they miss out on many of the protective benefits. so let's explore why vitamin D deficiency is so common and how it impacts our health and also what we can do to ensure we're getting enough of this essential vitamin. Now we all hear about the benefits of vitamin D, but what exactly is it and what does it do in our bodies? Well, as I mentioned, vitamin D is a fat soluble vitamin, which means it must be absorbed with fats from our diet, like other fat soluble vitamins like A, E and K, and it's stored in our body's fat tissue and liver. Let's dive into bone health and immunity, which are the most well-known effects, but there's many, many more. Vitamin D is obviously known for its critical role in bone health and supporting immune function. How does it work? Well, it enhances the absorption of calcium, which is why deficiency is linked to all kinds of bone deformities like rickets and osteomalacia, which is bone softening and osteoporosis in adults. In fact, if you want to do a cheap vitamin D test, you just stick your thumb on your shin. and push in hard. And if it hurts, you are likely either insufficient or vitamin D deficient. So just try that now, but not if you're driving. Okay. In addition to bone health, vitamin D is a super Powerhouse when it comes to supporting our immune system and fighting inflammation. And that's why having sufficient levels is associated with low risk of so many chronic diseases that are all inflammatory diseases, things like obesity, type 2 diabetes, heart disease, and so and also diseases like autoimmune disease, which includes multiple sclerosis, rheumatoid arthritis, type one diabetes. But that's not all. Vitamin D is also a key player in reducing the risk of infection. In fact, if your vitamin D level is adequately elevated, it means in the high normal range, not like what the reference range is, but optimal levels. Your risk of getting the flu is 75% lower. That's better than the flu vaccine, guys. So this is really cheap, really inexpensive, and it's really safe. It also helps support our immune system and it protects us from just getting sick and colds. And I I get my vitamin D levels up and I never get sick. I really, I don't remember last time I had a cold because I just take my vitamin D every day and it just does its job and I'm good to go. Now it does this by modulating the production of immune cells and immune molecules or messengers like cytokines. It regulates T cells and B cells. T cells are your immune cells like your lymphocytes and natural killer cells. B cells make antibodies and these play a critical role in our innate and adaptive immune systems. The ancient immune system, which is the innate immune system, has been there forever and is sort of a general all-purpose but not specific immune system. And the adaptive immune system is really the specific targeted immune system. That's sort of makes laser-guided bombs. Like you get antibodies to COVID. Well, that's a target against COVID. That's what your immune system does. Now, the COVID-19 pandemic shined a very much needed light on the impact of vitamin D on immunity. We learned from countless studies that low vitamin D levels increase the risk of severe infection, hospitalization, and death. And this is just scratching the surface. If you look at the data, it was quite striking. So out of Israel, if your level of vitamin D was over 50 nanograms per deciliter, we're going to get talking about what the level should be. That's probably the optimal level. If your level was 50 or more, your risk of death from COVID was zero. like zero. That's amazing. And if your vitamin D levels are low, you are 70% more likely to end up in the hospital, end up in the ICU, or die from COVID Now, what else does vitamin D do for the body? Well, it's an incredibly powerful vitamin that affects, as I mentioned, over a thousand genes. We're gonna put all the links and the references of everything I'm saying in the show notes, so don't worry. Now, most people agree it's actually more of a hormone than a vitamin. It impacts all kinds of cellular functions across all of our organs and tissues. For example, the brain uses vitamin D to support cognition, to mood and mental health. You've heard of seasonal affective disorder or SAD or the winter blues. Well, that's vitamin D deficiency, folks. That's why they say use a UV light, 'cause UV light makes your body make vitamin D. But you can also just take vitamin D. It also protects against neurodegenerative diseases like Alzheimer's and Parkinson's. It also plays a role in hormone health and fertility and our gut health is also affected by beneficially modulating the gut microbiome and enhancing overall digestive health. And just more, there's just more. It's a long list. I could just be a 10 hour podcast. There are whole books written on this, but I encourage you check out Michael Hollick's work and his book. He's quite good on this topic. And Robert Heaney, they were both really profoundly deep vitamin D researchers. So if you want to get geeky on it, you should go check that out. Now, the problem is that many people are deficient or insufficient. The difference is what's the reference range of the lab versus what's the optimal range, right? So if you take a bunch of Americans who are all working living inside, who put on sunblock all the time and who don't really get much sun exposure, the quote normal level in the population of vitamin D will be on the low side. like 20 or 30. That's not the optimal level. What if we were all running around like hunters and gatherers and our loin cloths and out in the sun all day and we're getting all the vitamin D we need, we'd probably be like 50 to 100 lifeguards who are sitting out on the beach all day. They get levels of up to 250 and it's safe for them. That's just from the sun, not from taking vitamin D supplements. So when you're insufficient or deficient, you're missing out on all the protective benefits. Exactly how many people are really deficient? Now hang on your hats folks, because I think it's about a billion people. Now the references are in the show notes, but a billion people, that's a lot of people. In the US alone, 70% of people have suboptimal levels, which is a lot of people. That's seven out of ten people. And I think partly that's probably why COVID hit us so hard, aside from the fact that we're all metabolically unhealthy and have chronic disease, which didn't help, but all that partially is linked to vitamin D insufficiency or deficiency. Now this widespread deficiency highlights just how important it is to ensure that we're getting enough vitamin D for optimal health. So what are the symptoms? How do you know if you're deficient? Well, there's some clues, right? You might get sick a lot. You might have muscle aches or joint pain. In fact, one of the things that vitamin D deficiency can cause is fibromyalgia or muscle aches and pains, not just soft bones or painful bones or aches. but actual painful and impaired muscle function. You might have a history of fracture, osteoporosis or brittle bones, right? That can be a clue. You might have things like depression or anxiety or mood or memory issues. Maybe you'll have also hair loss, fatigue, hormonal balances like PCOS. In fact, vitamin D is so critical for thyroid function. Without vitamin D, you can't actually bind the thyroid hormone to the receptors on the nucleus of your cells to do what it's supposed to do. and so you end up with poorly functioning thyroid. So the list goes on and on. Now, if any of these symptoms sound familiar to you, you might want to get your levels checked. In fact, scratch that. Everybody should get their vitamin D level checked. Just baseline. It's like your blood pressure or your blood sugar or your cholesterol. You got to know your vitamin D level. But for some silly reason, I don't know, because maybe nutrition is considered a for stepchild of medicine. Vitamin D is not included in your regular routine lab test, so you're probably going to have to ask your doctor for it. Now, this is partly why I started function health. Now, this is a company I co-founded, which is a health platform that allows people to get access to their own lab data. We test vitamin D and lots of other biomarkers, over 110 biomarkers, to give you a full picture of your health. We look at nutrients, not just vitamin D, but lots of nutrients, hormones, cardiometabolic health. and we can see where you're out of whack. We see that 67% of people are deficient in one or more nutrients at the minimum level for deficiency disease, not the optimal level for health. So when we broaden the aperture and we look at what the optimal levels are, it's probably like 90% or more. Now conventional medicine just doesn't look at this. They look at biomarkers in isolation. They don't do a full workup of your hormones, your lipids, your autoimmune markers to get a deeper look at what's going on beneath the surface. so that's really why I co-founded function health to help you get access to your own lab data. So to get your vitamin D levels checked and start becoming the sea of your own health, just go to functionhealth.com forward slash Mark to skip the 300, 000 person wait list and learn more. All right, so let's talk about vitamin D and diseases. What chronic diseases are associated with vitamin D deficiency? Now, there's this really important concept that I learned from Dr. Robert Heaney, who was one of the leading vitamin D researchers. And he wrote an article, you can look it up, and we're going to put it in the show notes, called Long Latency Deficiency Disease. And let me just explain this for a minute. These are nutritional diseases that don't occur in the short run but occur in the long run. For example, if you are vitamin D deficient in an acute way as a child, you get rickets. If you have chronic low levels of vitamin D, not enough to get rickets, but you might need 30 units a day to not get rickets. You might need 5,000 units a day to not get osteoporosis. You might need more than 10 times the dose. And in the case of vitamin D, the long-latency deficiency disease is osteoporosis, or it could be even things like heart disease or cancer or diabetes or dementia, right? These are long-latency deficiency diseases. They develop over a long period of time due to chronic nutrient deficiencies, not just vitamin D, but all kinds of nutrients. Now, these might not show symptoms right away, but over time they lead to serious health issues like osteoporosis, cardiovascular disease, cancer. So maintaining adequate levels of your nutrients is really key for long-term health and disease prevention. So let's discuss a few of these chronic diseases and their association with these suboptimal levels. And I'll go through the reference ranges. I'll explain all that in a minute, but I want you to just this is, no, no, there's a reference range, which is what's normal for a population. If you were a Martian and landed in America today, it's normal to be overweight, right? Because 75% of us are overweight. It's not optimal, it's just normal. It's just, it's a statistical calculation based on two standard deviations from the mean in the population. It has nothing to do with those optimal or biological optimization. It just has to do with what's normal in a population, right? So vitamin D helps protect against cancer, which is a big one. It does this by regulating the growth, division, and killing of bad or damaged cells. We call this apoptosis or programmed cell death, basically where cells sort of have a self-destruct button, which is good. You don't want your old decrepit cells around. You want to get rid of the old ones and recycle the parts and build new ones. It also enhances immune function and it helps reduce inflammation, which is decreasing the likelihood of all sorts of things. including cancer, which is inflammatory disease. And because of this, not having enough vitamin D is associated with certain cancers like breast, prostate cancer, ovarian and lung and pancreatic cancer, and even skin cancer. On the other hand, that means that adequate levels of vitamin D are associated with protection, which is supported over and over again in the research. For example, a study in 2018 found that women with vitamin D levels of over 60 nanograms per milliliter Just to be clear, most reference ranges on labs out there are 20 or maximum 30 nanograms per milliliter. We're talking about double that, right? At least double or even triple that number. If they had a level over 60, which is where I think most people should be, they had an 82% lower risk of breast cancer incidence compared with those who had a level of under 20. nanograms per milliliter. That's a big deal. In another study, breast cancer patients who had a higher vitamin D level at the time of their diagnosis had a significantly lower risk of death related to their cancer than those with lower levels. So even if you can get cancer, your likelihood of dying from it is lower if your vitamin D level is adequate. I'm just talking about COVID-19, but I'm just telling you, this is anything, any infection, any virus, any bacteria, whether it's the flu or a cold or COVID-19 or monkeypox or whatever the latest and next variation of a virus that we have to deal with, the next pandemic, you gotta get your vitamin E levels up. This is life and death, folks. This is literally life and death. If your risk of dying from COVID-19, which killed a lot of people, was zero, if your level was over 50 nanograms per milliliter, you better get your level up over 50. Now, you probably figured out by now that I'm super passionate about getting regular deep, restful sleep. It's a foundational piece for optimizing metabolism, brain function, and pretty much our health as a whole. One hack that has made such a huge difference in my own sleep quality was keeping my bed nice and cool. That's one of the reasons I love the Pod from Eight Sleep. For me, the most common reason for waking up in the middle of the night is It's getting too hot. In fact, it happened often. Even with the AC crank, sometimes my bed just gets really warm from my own body heat, making it impossible to sleep well. But ever since trying the Eight Sleep Pod, I haven't had that problem and I sleep soundly all night long and wake up feeling rested and energized. The Pod can go on your existing mattress and it pairs dynamic heating and cooling thermal regulation with biometric tracking, so it actually adjusts to my needs throughout the night and gives me interesting data to learn from the next day, like a sleep score and heart rate variability. So whether you sleep hot or cold, the Pod is so smart, it will actively account for your unique needs to keep your bed just the right temperature. A Sleep has even found their products to help people fall asleep 32% faster and reduce waking by 40%. None of us can afford to lose out on high quality sleep. If you're ready to take your nights to the next level, check out a sleep.com/mark and you can save $300 off Pod 4 Ultra and $200 off the Pod 4. That's a sleep.com/mark. E-I-G-H-T-S-L-E-E-P.com/M-A-R-K. Now we learned that early on that vitamin D deficiency had an insufficiency, increased the risk of COVID-19 infection and severity and mortality, as I mentioned. And I kind of alluded to this before, but a study published in JAMA found a 77% increased risk of a positive COVID test in those who had vitamin D deficiency. Another study reported a 59% increased risk of severe infection in people with vitamin E levels of less than 30 nanograms per milliliter. And this was the one from Israel, a large scale study in Israel found a 14 fold. Okay, folks, that's 1400%. Okay, this is not trivial. You know, we say, oh, it's correlation, whatever. If you see a result like that, that's like smoking and cancer. This is a highly predictive result. a 1400% or a 14-fold increase in severe COVID in patients with vitamin D deficiency less than 20 nanograms per deciliter compared to those who had levels of over 40. That's remarkable. Vitamin D also played a major role in protecting against COVID by enhancing immune cell function and inhibiting some of the inflammation or that thing we used to call the cytokine storm that made COVID-19 so bad. So, my advice is slather up your face with sunscreen, the right kind that's non-toxic, you can go to Skin Deep from the Environmental Working Group, ewg.org, you're going to kind of look at what are safe sunscreens without all kinds of crap in them. But, definitely cover up your face because you don't want skin cancer on your face. But, you should not cover your body and get some sun exposure when you're out there in the sun. Or, on the other hand, just don't worry about it and take vitamin D, which is what I do. For too long, the focus has been on the sunlight causing skin cancer, but research shows that low vitamin E levels at the time you get diagnosed with melanoma, which is the deadliest skin cancer, are actually linked to higher mortality. So you want your vitamin E level up by hook or by crook. I wonder if focusing too much on the dangers of sun exposure could be causing more harm than good. Maybe, I don't know. overlooking the health benefits we get from the sun. I think we are. So how do you get safe sun exposure? How can you get the benefits of vitamin D from sunlight exposure safely? Well, here's a few here ideas. First of all, the sun exposure guidelines should be personalized. The current recommendations for public focus on wearing sunscreen and staying out of the sun to reduce skin cancer risk. However, the science doesn't actually support this. In a large cohort study, researchers analyzed 29,000 women in Sweden and found that avoiding sun exposure actually led to higher what we call all-cause mortality rates. That means death from all causes. In fact, among avoiders of the sun, their risk was almost twofold or 200% higher compared to the sun exposure group. That's a big deal. you're twice as likely or more to die if you don't get sun exposure, right? This teaches us that sun avoidance is not necessarily a good thing. We need to reach a happy medium where we're not getting burnt, but we're being exposed to sunlight and we want to avoid obviously the burning and be careful, but it's really important to get sun exposure. Now everybody's different and we all have different kind of skin types and different color skin, which is why the amount of sun should be personalized. If you're darker skin, for example, you have more melanin, which prevents their skin from burning, but it also means they need more sunshine to produce the same amount of vitamin D as someone with fairer skin. That's why African Americans have the lowest rates of skin cancer, but the highest risk of vitamin D deficiency, which puts them at risk for all these other cancers and heart disease. If you have fair and olive skin tones, which are more likely to burn when exposed to sun for longer than a few minutes, then that can be a problem because most people get their sun light only in bursts or intermittently, like during the summer or on a vacation. And going from no sun to exposure to a lot of sun exposure all at once can cause our skin to burn, which then damages our skin and that does increase our risk for cancer. So you don't want to burn. So we should aim for a little unprotected sun exposure every day to gradually build up our tan and protect us from burning. And those with fair skin who burn easily, who are out for longer periods should definitely wear a mineral based sunscreen. Now go outside, get sunshine on your skin between 10 a.m. and 3 p.m. on your arms, back and legs and your trunk. Probably not your face. You can use sunscreen there. The key is not to burn, but to gradually build up a little color in your skin. And people with lighter skin tones should aim for maybe 10 or 15 minutes. People with darker skin tones, they can go 25 to 40 minutes. Also, you got to consider latitude and the time of year. Where are you? you know, Greenland in the middle of winter, well, that's not going to work, right? Or are you in like, you know, Costa Rica, probably, you know, it's very different. Some areas are exposed to less sunlight year round due to where they're located. In winter, for example, the sun is higher in the sky and it's, and much of the UV be light is filtered out by the atmosphere. And so we need to take supplements or try light therapy or do both. And bottom line, you know, we really should probably be just taking supplements and not to worry about it. Now, if you if you have a light or fair skin tone, use a non-toxic mineral based sunscreen to help you avoid burning. If you're out in the sun for longer than a few minutes in the spring and summer. Now, the problem with many sunscreens is they're full of toxic chemicals. They can get in your bloodstream and they mess with your hormones. My basic rule for anything you put on your skin is if you wouldn't eat it, you shouldn't put it on your skin because everything gets absorbed through your skin. That's how we deliver medicines. When someone comes into the ER with a heart attack, the first thing we do is we take a tube of nitroglycerin paste, like a toothpaste tube, we squirt it on the chest, we put a cover over it and that nitroglycerin goes through your skin and saves your life. Or hormone patches or fentanyl patches you've heard of, right? We can get a lot of things through our skin. So just because you think it's a sunblock, it's not getting through your skin and it is. Even makeup, all that. That's why the Skin Deep database from the Environmental Working Group is so good because it helps you figure out what you should use and which you should avoid. These chemicals are in most sunscreens are bad for your skin, they're bad for the environment, they're bad for your health, and they also block vitamin D production. So use a mineral-based sunblock. That's great. The Environmental Working Group actually has a guide to sunscreens, which is really great. It's a great resource, helps you find clean, non-toxic sunscreen. And if you use sunblock all the time, you might want to consider supplementing with a vitamin D all the time. Or basically, I think everybody needs vitamin D. So you know, what am I saying? It's kind of bottom line. It's like, it's like, you know, taking vitamin D, fish oil, just should be basic health practice for everybody. Now, who else is at risk for vitamin D deficiency that should consider being on vitamin C? We already talked about how people with darker skin tones, like African-Americans, Hispanic Asians are at higher risk because they have darker skin, more melanin, which reduces the skin's ability to produce vitamin D. And people who live in northern latitudes, with northern latitudes, you know, like above Atlanta, I would say, and have limited sun exposure, maybe the Pacific Northwest, Seattle, Salt Lake City, Chicago, Boston, Europe, all are at risk. Also, who else is at risk? Well, the elderly. Why? Because their skin doesn't work so well at producing vitamin D. And people who are obese or have chronic illnesses also need a lot more vitamin D because they don't spend a lot of time outdoors and also because body fat holds onto vitamin D, so you need a lot more to fill the tank. People with gut issues also may need more vitamin D because some gut issues can affect fat absorption and then vitamin D absorption. If you have celiac, Crohn's, colitis, irritable bowel, all of those can affect your absorption. There actually are vitamin D shots too. You can take, believe it or not, gallbladder problems if you're a gallbladder issue. Well, why? Because bile is needed to absorb fat soluble vitamins and that's important. and also certain medications, if you're taking medications, they can deplete vitamin D levels like steroids or glucocorticoids, acid blockers like Prilosec or Nexium or acid effects, these are called PPIs, blood pressure medications, the diuretics, particularly thiazide diuretics, certain anti-convulsants, and a medication that was used for weight loss called Orlistat, which I don't think is used anymore. So how do you know if you should take a supplement? Well, Spoiler alert, folks. Everybody should. I'm gonna say that again. Everybody should. But there's a few people who really have to make sure they do, right? Unless you're a lifeguard, you need to take vitamin D. As a recap for people who should take it, one, if you have darker skin tones and have a lot of melanin, if you have fairer lighter skin and wear sunscreen all the time and spend your time indoors, if you're older, if you live in the north, latitudes with less sun exposure. If you have a chronic disease, if you're on certain medications, or if you have all kinds of other stuff like high blood pressure, mood issues, hormone balances, or you get sick a lot, pretty much this describes everybody. You should consider taking a vitamin D supplement that helps get your levels to the optimal range. And this is key. You will not know how much you need unless you test, right? Some people might need a thousand units a day. Some people might need 10,000 units a day. How do you know? You have to test. Don't guess. That's my motto. Test, don't guess. Know your baseline. So measure your serum 25 hydroxyvitamin D. That's the right test to do. Again, many lab orders, many requisitions that doctors use are old and outdated, and they don't actually measure the right vitamin D. They might measure vitamin D2 or 125 vitamin D, you got to measure 25 hydroxy vitamin D. And then you monitor your levels over time to see what's happening and how much you actually need a supplement, and then you adjust your dose. So you want to get your level between 45 to 75 nanograms per milliliter. But like I said, over even 100-150 is safe, but 45 to 75 does the trick. The dose can range, as I said, from 1000 to 5000, even up to 10,000 depending on your levels. There was the one study where they gave healthy young men vitamin D 10,000 units a day for three months and there were no adverse effects at all. So make sure when you supplement, make sure you take it with a food that has fat because that's how you'll absorb it. Now, to know if your dose is working or whether or not you just need to adjust it, it's really important to check your levels every three to six months. if your levels don't get better, you might need genetic testing because there are variations called SNPs or single nucleotide polymorphisms. It's sort of a variation in your gene that affects certain vitamin D related genes and can affect absorption and many other things. Well, folks, that wraps up today's episode of Health Bites. I hope you found enlightening and full of actionable insights about the incredible importance of vitamin D. We've uncovered how this fat soluble vitamin plays critical role in all sorts of bodily functions, from bone health and immunity to brain health and hormone balance, and understanding the science behind vitamin D, I believe, can help empower us to make informed decisions about our health and take proactive steps to maintain optimal levels. We also learned that vitamin D deficiency is really common, and insufficiency is even more common, affecting a billion plus people worldwide. Now, this deficiency can lead to a range of health issues, as I mentioned, from frequent illnesses and infections and fatigue to more serious things like osteoporosis and all sorts of chronic illnesses, autoimmune disease. Remember, get your levels checked regularly. Be mindful of supplementation to make sure you're getting enough of it. Probably about 2 to 5,000 a day is the dose for most people, but you got to check your levels. Remember, you can't manage what you don't measure. So staying informed about your health metrics is important. test, don't guess, right? Keep tuning in for more insights into how you can take control of your health in ways that empower and rejuvenate. If you enjoyed this episode, don't forget to rate, review and follow wherever you listen to Health Bites. Your support makes all the difference. So thank you. And thanks again for joining me today and see you next Friday for another juicy episode of Health Bites. Thanks for listening today. If you love this podcast, please share it with your friends and family. Leave a comment on your own best practices on how you upgrade your health and subscribe wherever you get your podcasts. And follow me on all social media channels at Dr. Mark Hyman. And we'll see you next time on the Doctor's Pharmacy. For more information on today's episode, please check out my new video and audio podcast, Health Hacks. It airs every Tuesday and includes a more detailed breakdown of these Friday Health Bites episodes. I'm always getting questions about my favorite books, podcasts, gadgets, supplements, recipes, and lots more. And now you can have access to all of this information by signing up for my free Mark's Picks newsletter at drhyman.com/marks-picks. 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