Transcription
Vitamin D toxicity. Is it true or is it fear-mongering? How is vitamin D produced in our body? How much you should take? How much is too much? And what lab exams can you perform to make sure you're in the correct range? Let's get right into it.
Vitamin D toxicity. Is it true or is it just fear? Some say 5,000 international units a day is too much and can be dangerous. Some others will take 20,000 international units per day with no issues whatsoever. And historically speaking, doctors in the United States have used up to 200,000 units up to 600,000 units per day for specific conditions.
So how is vitamin D produced in our body? It basically comes from the sun. UVB lights or rays from the sun hit the skin, impacts seven dihydro cholesterol in our skin, and then it converts into a previtamin D, and with some heat, it interacts and creates vitamin D3 or cholecalciferol. Vitamin D3 is the oral supplementation that we typically take when we take vitamin D. They do prescribe vitamin D2, which you actually cannot make from sunlight. So sunlight does not produce D2. Okay. However, it is prescribed. Sometimes they'll say take 50,000 units of vitamin D2 every single week for maybe four weeks or eight weeks to get your vitamin D levels up. Okay.
So the sun hits the skin, goes to previtamin D3, and then converts to vitamin D3 cholecalciferol. Now cholecalciferol has to convert through the liver to 25 hydroxy vitamin D. This is what they check in the labs. So when you get your vitamin D levels, they're checking for 25 hydroxy vitamin D. In the United States, that range is 30 to 100 nanogs per milliliter. Okay? If you're in a different country and use a different metric system, you want to multiply it by 2.5. So it will be, let's say, 100 nanogs is going to be 250 nanomoles. Okay? So you want to look at that conversion.
So, in order to convert vitamin D, you need to go through the liver and co-factors. And I'll link that video um at the end of the video where we talk about different co-factors. You'll need co-factors like magnesium and boron and other things and vitamin K. Well, you'll convert it to 25 hydroxy vitamin D. Now, that is the storage form of vitamin D. The kidney will convert it further to 1,25 dihydroxy vitamin D, which also can be measured in the lab but is often not measured, and this is the active form of vitamin D. Okay. And you need magnesium and other co-factors to make this happen efficiently.
So how much can we take? So let's look at a few studies. Study number one, they took 60 post-menopausal women, and their vitamin D levels were all below 20 nanograms per milliliter. Okay. In group one, they actually gave them 300,000 units of vitamin D3 in a single dose. Right? What they showed was it increased muscle strength, and at four weeks, it was about 53.9 nanogs per milliliter, and then at 12 weeks, it was 23.1. So at 12 weeks, still above the initial starting range. In group two, they gave them 800 units of vitamin D international units, which is really the recommended dose currently here in the United States. Okay. So they gave them 800 international units per day. They took it continuously. They showed no change in muscle strength, and at four weeks, their levels were 16.9 nanogs per milliliter. Way below that one. And then at 12 weeks, it's still only 19.8 nanogs per milliliter. So what that means is that that large dose, that one single dose, increased the vitamin D level, and they actually had a physiological effect. Granted, this dose is much larger than even at 12 weeks if you just took 800 units. Okay. So but they also noted there was no change in serum calcium or parathyroid hormone. So there was no impact on the calcium levels. And what we think about is with hypervitamin D levels is that it's going to impact calcium. It's going to go into different areas. It's going to cause kidney stones, etc. Okay.
Study number two, they gave 600,000 units of vitamin D2 and vitamin D3 to certain subjects. They gave it both orally and intramuscularly. And what they found was vitamin D3 taken orally had the most impact in raising your vitamin D levels. So you would think that giving it intramuscularly, right, directly with the needle, would have a better effect, but no. Vitamin D3 orally had the best effect, and there was no change in calcium. Okay.
Number three here, there was a study where they took and and uh and tracked these individuals 5,500 international units up to 11,000 international units per day, and there was no change in serum calcium. Okay.
Study number four. This is just on three individuals. These three individuals were taking 20,000 international units up to 60,000 international units for two to six years. Okay? And there was no change in their serum calcium levels. Okay. So there was no toxicity noted anywhere in these studies.
Historically speaking, they started to think about vitamin D when they had rickets developing in urban areas. Okay. So they started using cod liver oil and started recommending sunlight. So to prevent rickets, which is basically a weakening of the bones, in 1920, they started to fortify the foods with vitamin D to prevent rickets, right, especially with milk, right? That's why milk has become so popular is because it's a good source of calcium and vitamin D. However, it was fortified. Now, in the 1930s and 1940s, they started to really use high levels of vitamin D for certain conditions like asthma, psoriasis, rheumatoid arthritis, a lot of these autoimmune conditions. And they were using sometimes from 200,000 units up to 600,000 units for up to 10 days, up to months, and sometimes up to a year or two years. And this is where they start to see some complications where they're taking super physiological doses for long periods of time, months to years, where they start to see complications of hypercalcemia, kidney stones, and other medical conditions that pop up with excessive use of vitamin D. So that's when the different targets came out, different levels came out in terms of what your ideal level should be or dosages should be. Really, the minimum dose or 600 to 800 international units per day is really to prevent rickets. Okay? If you want to have immune response, autoimmune um modulation, if you want to have muscle strength, and you want to improve overall function, now we're looking at different numbers. Okay?
So, for the most part, it's safe at higher levels. So, what is the higher level for you? That's the question, right? We don't know because some people will take 10,000 international units per day. And let's say the husband is taking 10,000 units, and he's been doing it for six months, and his level is 90. His wife's been taking it the same amount of time, 10,000 units, and the number is now 140 on the blood. So you have to be cognizant of individuality. Okay? Even when you go out in the sun, your vitamin D production can be anywhere from 1,000 international units up to 20,000 international units, depending, uh, and that's per hour, depending on latitude, skin color, age, absorption, right? Uh, genetic issues or genetic predisposition or autoimmune conditions. So all these factors come into play. Okay. So, you have to be very careful as to what you think is normal. Okay? And don't worry about like sun exposure. Sun, you're not going to get hypervitamin D levels from sun exposure. It has kind of a self-limiting effect. Okay?
So, when we look at this, they use it for rickets, they use it for all these different conditions. Um, and you use hyperphysiological doses for extended periods of time. That's when they start to have complications. So in our office, when we do our blood work, we like to see patients between 60 and 80 nanogs per milliliter. If you're in a different country, use different metric systems. Just multiply by 2.5. Okay? Whatever that number is. Now, the Endocrine Society has actually come out and said what we see is that we have complications starting around 150 nanogs per milliliter. Okay. So we're well under that number. So if your number, if your blood tests are showing 150 and above, certainly you need to go down. Ideally, you probably want to keep it around 100 or lower to be safe. You have to ask the question, what level is good enough to have that physiological effect that we want? And I believe that number is going to be between 60 and 80 up to maybe 100, 110. If you start to exceed 150 or even 200, you got to be very careful. You may have some complications as a result of it.
All right, so there it is. If you want to know more, I'll link a couple of videos about vitamin D in the corner above. All right, my name is Dr. Jen Sun. We're clinical excellence meets excellent results. And we'll see you guys next week on the healthy side. Have an awesome day.