7 ms·

The association between Vitamin D deficiency (VDD as referred to in this article) and increased risk of respiratory infections is well-known. Mild to moderate V

The association between Vitamin D deficiency (VDD as referred to in this article) and increased risk of respiratory infections is well-known. Mild to moderate Vitamin D supplementation, especially during winter or in those with subpar dietary habits, is a good idea. However, I've noticed that Vitamin D has been garnered an almost cult-like following on parts of the internet in recent years. Some of the health claims around Vitamin D are getting out of control, and the recommendations for Vitamin D supplementation are far too high in certain circles. I have to admit that I fell for this to some degree. I started supplementing 5000 IU/day after reading all of the writings about Vitamin D deficiency, the health benefits of Vitamin D, and the arguments that current Vitamin D supplementation recommendations were far too low. But that 5000 IU/day put me near overdose territory when I got my serum levels checked. Even my doctor, who is very pro-Vitamin D supplementation, warned me to significantly cut my supplementation. The scary part is that I see recommendations for significantly higher Vitamin D dosing all over Twitter and health forums lately. There's a growing idea that more is better, amplified by health influencers trying to stand out from the crowd and the growing cult-like status of Vitamin D as a wonder vitamin. I think encouraging mild vitamin d supplementation (or improved dietary patterns with more Vitamin D) is a good step in the right direction, but I'm also worried to see how much of this is being exaggerated and taken to unhealthy extremes. When in doubt, get a blood test.

spamizbad 5y ago
My understanding is Vitamin D stays in your system a while. It’s one of the reasons why I believe Vitamin D deficiencies tend to be treated with 1-3 very large doses of Vitamin D, separated by weeks, with what I assume are blood tests in between.
- PragmaticPulp 5y ago
  Yes! The half-life of Vitamin D in the body is very long. Toxicity can build over many months of supplementation, which is why it's important to get a blood test after around 6 months of starting supplementation.
  - DantesKite 5y ago
    What's interesting: There doesn't seem to be toxicity associated with Vitamin D produced by sunlight. The body seems to have mechanisms that prevent overdose, even if you're constantly in the sun.
    - szundi 5y ago
      There was a lady on a reddit sub who claimed she is working in a hospital and having cases of people overdosed with vitamin D that causes calcium to build up in the blood vessels.
- saila 5y ago
  Data point: I recently found out my vitamin D levels were extremely low and was prescribed 1 50,000 IU tablet a week for 8 weeks. Halfway through the course I'm already feeling much better.
treeman79 5y ago
A year before covid I was in diagnosed with low vit D and a host of other ailments. Spent a year stuck in bed; then started Vit D among other things. Following summer I spent kayaking. It was one of several things, but my life completely changed.
- PragmaticPulp 5y ago
  > I was in diagnosed with low vit D and a host of other ailments. > then started Vit D among other things > It was one of several things, but my life completely changed. Very glad to hear you improved, but your comment is a perfect example of the powerful aura developing around Vitamin D. By your own admission, you were diagnosed with a host of ailments and implemented several other changes, but the only one we're hearing about is Vitamin D. There are stories like this all over the internet, where people receive a low Vitamin D diagnosis as part of a broader workup for serious ailments and they start Vitamin D supplementation as a part of a multi-pronged treatment approach, but when the anecdotes are distilled online Vitamin D is the only part of the equation that gets noted. You genuinely had a vitamin D deficiency as diagnosed by blood test, but many other people with as-yet-undiagnosed illnesses might read your comment and assume that excessive Vitamin D supplementation is something they should try. After all, who wouldn't want such a life-changing turnaround? But like I said, it's important to close the loop with blood tests. Vitamin D deficiency can't be diagnosed by symptoms alone, and high Vitamin D deficiency can be a risk for Hypervitaminosis D, which brings its own set of symptoms. Mild Vitamin D supplementation is low risk, but Vitamin D isn't going to be life-changing for anyone but those with severe deficiencies.
  - friedman23 5y ago
    > but Vitamin D isn't going to be life-changing for anyone but those with severe deficiencies. Given modern diets, I'd suspect many people have deficiencies in one or more key micronutrients. Given how low risk supplementation is, I think overdoing it and losing out on a bit of money is safer than under doing it. Of course be moderate in the amount you supplement by but the argument that it's just a waste of money never resonated with me. I'd happily sacrifice money on the off chance that I'm actually saving my health.
cosmiccrisp 5y ago
I jumped on the train recently after the wife suggested it. And have heard some promising info from watching some John Campbell's videos and a bit of googling around about it. Been taking 4000/day since August and do feel better overall. Haven't caught any colds yet (knock on wood). From what I had read, 4000 was the max suggested amount to be safe. I'm hoping that I won't get any bad colds this winter by doing this.
- PragmaticPulp 5y ago
  > I'm hoping that I won't get any bad colds this winter by doing this. Unfortunately, I was still getting colds regularly while my blood levels were around 100ng/mL. This is the type of magical Vitamin D thinking I was talking about: Fixing a vitamin D deficiency is a positive improvement, but it's not a miracle vitamin.
  - cosmiccrisp 5y ago
    >Fixing a vitamin D deficiency is a positive improvement Apparently, quite a lot of people are vitamin D deficient. As a computer nerd, I'm pretty sure I was.
    - PragmaticPulp 5y ago
      As a fellow computer nerd, I bought into the same narratives. That's how I ended up approaching Vitamin D toxicity as I mentioned above. That's my point: The narratives around Vitamin D are getting greatly exaggerated. Mild supplementation is usually fine, but this idea that we're all deficient and we all need to be taking huge doses is getting out of control on social media.
      - cosmiccrisp 5y ago
        >but this idea that we're all deficient and we all need to be taking huge doses is getting out of control on social media. Agreed!
      - sekathlon 5y ago
toolz 5y ago
You didn't mention any negative effects of approaching vitamin D overdose, did you experience any or was this simply a concern of your doctor?
- PragmaticPulp 5y ago
  Some of the worst effects aren't immediately obvious, such as metastatic calcification of tissues over time. Long-term effects aren't fully elucidated because high Vitamin D doses weren't common until recently. However, there is growing evidence that excess Vitamin D can contribute to worsening cardiovascular disease and premature aging of cells. You won't necessarily feel the effects of too-high Vitamin D levels right away, but years or decades of excess Vitamin D could do a lot of hidden damage without any benefit over moderate levels.
  - vixen99 5y ago
    > there is growing evidence Since you don't say what 'excessive' is, we don't know whether your comment is significant or not. Can you please avoid making statements like this without adding a link to a peer-reviewed paper so that we can assess it. EU study from 2012: https://efsa.onlinelibrary.wiley.com/doi/pdf/10.2903/j.efsa.2012.2813 https://efsa.onlinelibrary.wiley.com/doi/pdf/10.2903/j.efsa.... As to excessive dose: " Without calcium supplementation, even very high vitamin D3 supplementation does not cause vascular calcification, especially if another important finding is included. Even when calcium blood levels are high, the culprit for undesirable vascular calcification is not vitamin D but insufficient blood levels of vitamin K2". COVID-19 Mortality Risk Correlates Inversely with Vitamin D3 Status, and a Mortality Rate Close to Zero Could Theoretically Be Achieved at 50 ng/mL 25(OH)D3: Results of a Systematic Review and Meta-Analysis: Front Public Health. 2021; 9: 624559. Just found this (staring me in the face, a pdf link) https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7973108/pdf/fpubh-09-624559.pdf https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7973108/pdf/fpu...
    - sowbug 5y ago
      A suggestion: your otherwise helpful reply might be more effective without upbraiding the commenter you're replying to. (Yes, irony noted that I'm upbraiding you.)
null_object 5y ago
I’m getting the feeling that you don’t live somewhere like Scandinavia, where we are barely exposed to sunlight for 6 months of the year.
winternett 5y ago
I started moderating my vitamin D intake a little last year too, the blood test is a good idea, but during the initial parts of the outbreak, everything was closed, and rightfully so, so I was relying on gut instincts and luckily didn't overdose. I'm not a doctor, but I have read that Vitamin D also benefits bone health, especially in people of color. The price of the supplement went up dramatically last year, a $2.50 bottle of 1,000 IU pills here (East Coast US) costs now anywhere from $5.45-$15.00 now in retail stores. It's sad that opportunism is usually always the first move in health care in the US now. It's a shame how much better health (and even proper education on it) depends so much on income/wealth here in the US.
- mixmastamyk 5y ago
  $4.99 for 1k or 5k at Trader Joe's.
- fragmede 5y ago
  Why, it's almost as if some sort of central planning would be a better way of planning healthcare for a nation!
ravenstine 5y ago
I think the cult-like following for Vitamin D is an inverse of some of the cult-like following for the vaccines. (VACCINES ARE GOOD, FOLKS, DON'T REPLY SAYING I'M AN ANTIVAXXER) There are people who believe that the vaccines are much more capable than they are, and go as far as lionizing Pfizer in the form of things like tattoos, Fauci fan art, and so on. Yes, they are a very small segment of the population, but I've run into these people in real life. One of my best friends has a faith-like belief in the vaccines to such a point that he totally clams up if I show a shred of skepticism. This was a guy who practiced formal debate and we used to have many intellectual discussions despite our differences. The people who believe Vitamin D is their Lord and Savior are reacting to the fact that the establishment has almost entirely abandoned the pretense of "diet and exercise" in favor of pharmaceuticals to the exclusion of almost anything else. Vitamin D isn't a cure, but it is very underappreciated, and when the entire medical system not only fails for decades to solve obesity but then fails to tell people to take action in their own lives to get themselves fit and healthy, it's cause to raise an eyebrow no matter what you think about Vitamin D. Both are a result in a division caused by a system that fails to explain its own legitimacy. I think it's great that we have the vaccines. I think Vitamin D is great. I think both are imperfect. But I can't blame people for attaching themselves to either one as if they are separate churches to attend; what have the establishment done to establish our trust? > But that 5000 IU/day put me near overdose territory when I got my serum levels checked. Even my doctor, who is very pro-Vitamin D supplementation, warned me to significantly cut my supplementation. That's interesting. It's been a really long while since I looked at research papers around Vitamin D, but my conclusion was that what was thought to be a daily limit for Vitamin D wasn't entirely justified for the average healthy person, but I'll have to check that again. I've been either getting some sunlight every day or taking 5000 IU supplementally every day and haven't suffered any obvious consequences. Sunlight really is the best though, and you don't need that much sunlight to get a sufficient dose. It also raises levels of nitric oxide which has its own benefits.
- gameswithgo 5y ago
  Vaccines are probably 3 orders of magnitude more effective at reducing the spread of covid than vitamin d. Not 3 times, 3 orders of magnitude, probably more than that really. Imperfect as they are it is still an amazing and wonderful thing we were able to create and get them out so quickly, likely millions of lives saved and millions more would have been if not for morons spreading lies
Strom 5y ago
> But that 5000 IU/day put me near overdose territory when I got my serum levels checked. I need to consume 4000 IU/day just to keep my serum levels acceptable. I do agree though that blood tests are necessary. When I started getting into the vitamin D supplements, I had my blood levels tested every 3 months for a few years. I started out dangerously deficient and even 8000 IU/day was barely moving the needle in the beginning. However over a longer period 8000 IU/day ended up being too much, so I cut it down to 4000 IU/day where I've been for years now. There are a lot of factors going into this and everyone's circumstances are different. Frequent testing to verify assumptions is a must. I spend a good amount of time outside, going running regularly, and am in decent shape. I also eat 250g of salmon weekly, which contains about 1000-2500 IU. However at the end of the day I live in the north (59 deg lat) and the sun here is of limited impact.
- hinkley 5y ago
  The mammalian liver stores vitamin A and vitamin D (polar bears store so much of the former that polar bear liver will give you vitamin A poisoning, even in small quantities). If you are deficient that usually means low reserves, so some or most of what you take will go into your liver instead of your blood. Over time your serum levels climb on the same dose, which is why you have to keep testing. It’s also why therapies for vitamin D deficiency can include prescription ultra high dose pills taken once a month for a few months, rather than (or in addition to) daily supplementation.
  - Scoundreller 5y ago
    Body fat also stores Vit D (and A, E and K), so you also need to consider how much has been deposited there and how much of one’s body fat turnsover.
spfzero 5y ago
The group https://grassrootshealth.org https://grassrootshealth.org sells an inexpensive at-home test kit for D3 serum levels. IIRC it includes two tests so that you can make changes if needed then check to see how much they helped, and back off on supplements if desired. I had also been taking 5000 IU/day with K2, which helped me get up to 50 ng (starting from 39). I stopped taking the supplements because I felt sun exposure was probably the better way to approach it. For one thing I live in a sunny place, and I enjoy the relaxation. Also, my guess is that D3 levels may be a proxy for things like sun exposure, and that the health benefits might derive from those instead, and might be more complex than just one compound. If I can't reliably get sun exposure though, as in the next three months when my local UV index gets pretty low, I'll go back to supplementation.
- genewitch 5y ago
  I'll attempt to cite this before the edit timer expires. If you live above 35° North, a full day of sun is not enough to get all the vitamin D you need. There's a reason foods (like bread, milk, cereal) are fortified.
pdonis 5y ago
> When in doubt, get a blood test. Definitely. I would say get one regularly anyway, Vitamin D levels are important enough that they should be part of routine blood work done during a regular physical. Then, if you're supplementing, you can adjust your dosage accordingly based on the results so your blood levels stay in the desired range.
legulere 5y ago
The association between Vitamin D levels often breaks down in interventional studies which points to common causes for both susceptibility for respiratory disease and low Vitamin D levels (For instance Winter both lowers Vitamin D levels as well as increases respiratory diseases).
dominotw 5y ago
in my circle it was the joe rogan podcast with dr rhonda patrick during the height of covid mania, that set off the craze for vitamin d obession.
SergeAx 5y ago
It is quite difficult to overdose vitamin D: "... healthy adults in a clinical setting, receiving 50,000 IU of vitamin D2 once every 2 weeks (equivalent to approximately 3,300 IU/day) for up to 6 years, maintained 25(OH)D concentrations of 40–60 ng/ml (100–150 nmol/l) without any evidence of VDT [vitamin D toxicity]. Those findings were consistent with the observation by Ekwaru et al. (17) that Canadian adults who ingested up to 20,000 IU of vitamin D3 per day had a significant increase of 25(OH)D concentrations, up to 60 ng/ml (150 nmol/l), but without any evidence of toxicity" https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6158375/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6158375/

spamizbad 5y ago

My understanding is Vitamin D stays in your system a while. It’s one of the reasons why I believe Vitamin D deficiencies tend to be treated with 1-3 very large doses of Vitamin D, separated by weeks, with what I assume are blood tests in between.

PragmaticPulp 5y ago
Yes! The half-life of Vitamin D in the body is very long. Toxicity can build over many months of supplementation, which is why it's important to get a blood test after around 6 months of starting supplementation.
- DantesKite 5y ago
  What's interesting: There doesn't seem to be toxicity associated with Vitamin D produced by sunlight. The body seems to have mechanisms that prevent overdose, even if you're constantly in the sun.
  - szundi 5y ago
    There was a lady on a reddit sub who claimed she is working in a hospital and having cases of people overdosed with vitamin D that causes calcium to build up in the blood vessels.
saila 5y ago
Data point: I recently found out my vitamin D levels were extremely low and was prescribed 1 50,000 IU tablet a week for 8 weeks. Halfway through the course I'm already feeling much better.

treeman79 5y ago

A year before covid I was in diagnosed with low vit D and a host of other ailments. Spent a year stuck in bed; then started Vit D among other things. Following summer I spent kayaking. It was one of several things, but my life completely changed.

PragmaticPulp 5y ago
> I was in diagnosed with low vit D and a host of other ailments. > then started Vit D among other things > It was one of several things, but my life completely changed. Very glad to hear you improved, but your comment is a perfect example of the powerful aura developing around Vitamin D. By your own admission, you were diagnosed with a host of ailments and implemented several other changes, but the only one we're hearing about is Vitamin D. There are stories like this all over the internet, where people receive a low Vitamin D diagnosis as part of a broader workup for serious ailments and they start Vitamin D supplementation as a part of a multi-pronged treatment approach, but when the anecdotes are distilled online Vitamin D is the only part of the equation that gets noted. You genuinely had a vitamin D deficiency as diagnosed by blood test, but many other people with as-yet-undiagnosed illnesses might read your comment and assume that excessive Vitamin D supplementation is something they should try. After all, who wouldn't want such a life-changing turnaround? But like I said, it's important to close the loop with blood tests. Vitamin D deficiency can't be diagnosed by symptoms alone, and high Vitamin D deficiency can be a risk for Hypervitaminosis D, which brings its own set of symptoms. Mild Vitamin D supplementation is low risk, but Vitamin D isn't going to be life-changing for anyone but those with severe deficiencies.
- friedman23 5y ago
  > but Vitamin D isn't going to be life-changing for anyone but those with severe deficiencies. Given modern diets, I'd suspect many people have deficiencies in one or more key micronutrients. Given how low risk supplementation is, I think overdoing it and losing out on a bit of money is safer than under doing it. Of course be moderate in the amount you supplement by but the argument that it's just a waste of money never resonated with me. I'd happily sacrifice money on the off chance that I'm actually saving my health.

cosmiccrisp 5y ago

I jumped on the train recently after the wife suggested it. And have heard some promising info from watching some John Campbell's videos and a bit of googling around about it. Been taking 4000/day since August and do feel better overall. Haven't caught any colds yet (knock on wood). From what I had read, 4000 was the max suggested amount to be safe. I'm hoping that I won't get any bad colds this winter by doing this.

PragmaticPulp 5y ago
> I'm hoping that I won't get any bad colds this winter by doing this. Unfortunately, I was still getting colds regularly while my blood levels were around 100ng/mL. This is the type of magical Vitamin D thinking I was talking about: Fixing a vitamin D deficiency is a positive improvement, but it's not a miracle vitamin.
- cosmiccrisp 5y ago
  >Fixing a vitamin D deficiency is a positive improvement Apparently, quite a lot of people are vitamin D deficient. As a computer nerd, I'm pretty sure I was.
  - PragmaticPulp 5y ago
    As a fellow computer nerd, I bought into the same narratives. That's how I ended up approaching Vitamin D toxicity as I mentioned above. That's my point: The narratives around Vitamin D are getting greatly exaggerated. Mild supplementation is usually fine, but this idea that we're all deficient and we all need to be taking huge doses is getting out of control on social media.
    - cosmiccrisp 5y ago
      >but this idea that we're all deficient and we all need to be taking huge doses is getting out of control on social media. Agreed!
    - sekathlon 5y ago

toolz 5y ago

You didn't mention any negative effects of approaching vitamin D overdose, did you experience any or was this simply a concern of your doctor?

PragmaticPulp 5y ago
Some of the worst effects aren't immediately obvious, such as metastatic calcification of tissues over time. Long-term effects aren't fully elucidated because high Vitamin D doses weren't common until recently. However, there is growing evidence that excess Vitamin D can contribute to worsening cardiovascular disease and premature aging of cells. You won't necessarily feel the effects of too-high Vitamin D levels right away, but years or decades of excess Vitamin D could do a lot of hidden damage without any benefit over moderate levels.
- vixen99 5y ago
  > there is growing evidence Since you don't say what 'excessive' is, we don't know whether your comment is significant or not. Can you please avoid making statements like this without adding a link to a peer-reviewed paper so that we can assess it. EU study from 2012: https://efsa.onlinelibrary.wiley.com/doi/pdf/10.2903/j.efsa.2012.2813 https://efsa.onlinelibrary.wiley.com/doi/pdf/10.2903/j.efsa.... As to excessive dose: " Without calcium supplementation, even very high vitamin D3 supplementation does not cause vascular calcification, especially if another important finding is included. Even when calcium blood levels are high, the culprit for undesirable vascular calcification is not vitamin D but insufficient blood levels of vitamin K2". COVID-19 Mortality Risk Correlates Inversely with Vitamin D3 Status, and a Mortality Rate Close to Zero Could Theoretically Be Achieved at 50 ng/mL 25(OH)D3: Results of a Systematic Review and Meta-Analysis: Front Public Health. 2021; 9: 624559. Just found this (staring me in the face, a pdf link) https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7973108/pdf/fpubh-09-624559.pdf https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7973108/pdf/fpu...
  - sowbug 5y ago
    A suggestion: your otherwise helpful reply might be more effective without upbraiding the commenter you're replying to. (Yes, irony noted that I'm upbraiding you.)

null_object 5y ago

I’m getting the feeling that you don’t live somewhere like Scandinavia, where we are barely exposed to sunlight for 6 months of the year.

winternett 5y ago

I started moderating my vitamin D intake a little last year too, the blood test is a good idea, but during the initial parts of the outbreak, everything was closed, and rightfully so, so I was relying on gut instincts and luckily didn't overdose. I'm not a doctor, but I have read that Vitamin D also benefits bone health, especially in people of color. The price of the supplement went up dramatically last year, a $2.50 bottle of 1,000 IU pills here (East Coast US) costs now anywhere from $5.45-$15.00 now in retail stores. It's sad that opportunism is usually always the first move in health care in the US now. It's a shame how much better health (and even proper education on it) depends so much on income/wealth here in the US.

mixmastamyk 5y ago
$4.99 for 1k or 5k at Trader Joe's.
fragmede 5y ago
Why, it's almost as if some sort of central planning would be a better way of planning healthcare for a nation!

ravenstine 5y ago

I think the cult-like following for Vitamin D is an inverse of some of the cult-like following for the vaccines. (VACCINES ARE GOOD, FOLKS, DON'T REPLY SAYING I'M AN ANTIVAXXER) There are people who believe that the vaccines are much more capable than they are, and go as far as lionizing Pfizer in the form of things like tattoos, Fauci fan art, and so on. Yes, they are a very small segment of the population, but I've run into these people in real life. One of my best friends has a faith-like belief in the vaccines to such a point that he totally clams up if I show a shred of skepticism. This was a guy who practiced formal debate and we used to have many intellectual discussions despite our differences. The people who believe Vitamin D is their Lord and Savior are reacting to the fact that the establishment has almost entirely abandoned the pretense of "diet and exercise" in favor of pharmaceuticals to the exclusion of almost anything else. Vitamin D isn't a cure, but it is very underappreciated, and when the entire medical system not only fails for decades to solve obesity but then fails to tell people to take action in their own lives to get themselves fit and healthy, it's cause to raise an eyebrow no matter what you think about Vitamin D. Both are a result in a division caused by a system that fails to explain its own legitimacy. I think it's great that we have the vaccines. I think Vitamin D is great. I think both are imperfect. But I can't blame people for attaching themselves to either one as if they are separate churches to attend; what have the establishment done to establish our trust? > But that 5000 IU/day put me near overdose territory when I got my serum levels checked. Even my doctor, who is very pro-Vitamin D supplementation, warned me to significantly cut my supplementation. That's interesting. It's been a really long while since I looked at research papers around Vitamin D, but my conclusion was that what was thought to be a daily limit for Vitamin D wasn't entirely justified for the average healthy person, but I'll have to check that again. I've been either getting some sunlight every day or taking 5000 IU supplementally every day and haven't suffered any obvious consequences. Sunlight really is the best though, and you don't need that much sunlight to get a sufficient dose. It also raises levels of nitric oxide which has its own benefits.

gameswithgo 5y ago
Vaccines are probably 3 orders of magnitude more effective at reducing the spread of covid than vitamin d. Not 3 times, 3 orders of magnitude, probably more than that really. Imperfect as they are it is still an amazing and wonderful thing we were able to create and get them out so quickly, likely millions of lives saved and millions more would have been if not for morons spreading lies

Strom 5y ago

> But that 5000 IU/day put me near overdose territory when I got my serum levels checked. I need to consume 4000 IU/day just to keep my serum levels acceptable. I do agree though that blood tests are necessary. When I started getting into the vitamin D supplements, I had my blood levels tested every 3 months for a few years. I started out dangerously deficient and even 8000 IU/day was barely moving the needle in the beginning. However over a longer period 8000 IU/day ended up being too much, so I cut it down to 4000 IU/day where I've been for years now. There are a lot of factors going into this and everyone's circumstances are different. Frequent testing to verify assumptions is a must. I spend a good amount of time outside, going running regularly, and am in decent shape. I also eat 250g of salmon weekly, which contains about 1000-2500 IU. However at the end of the day I live in the north (59 deg lat) and the sun here is of limited impact.

hinkley 5y ago
The mammalian liver stores vitamin A and vitamin D (polar bears store so much of the former that polar bear liver will give you vitamin A poisoning, even in small quantities). If you are deficient that usually means low reserves, so some or most of what you take will go into your liver instead of your blood. Over time your serum levels climb on the same dose, which is why you have to keep testing. It’s also why therapies for vitamin D deficiency can include prescription ultra high dose pills taken once a month for a few months, rather than (or in addition to) daily supplementation.
- Scoundreller 5y ago
  Body fat also stores Vit D (and A, E and K), so you also need to consider how much has been deposited there and how much of one’s body fat turnsover.

spfzero 5y ago

The group https://grassrootshealth.org https://grassrootshealth.org sells an inexpensive at-home test kit for D3 serum levels. IIRC it includes two tests so that you can make changes if needed then check to see how much they helped, and back off on supplements if desired. I had also been taking 5000 IU/day with K2, which helped me get up to 50 ng (starting from 39). I stopped taking the supplements because I felt sun exposure was probably the better way to approach it. For one thing I live in a sunny place, and I enjoy the relaxation. Also, my guess is that D3 levels may be a proxy for things like sun exposure, and that the health benefits might derive from those instead, and might be more complex than just one compound. If I can't reliably get sun exposure though, as in the next three months when my local UV index gets pretty low, I'll go back to supplementation.

genewitch 5y ago
I'll attempt to cite this before the edit timer expires. If you live above 35° North, a full day of sun is not enough to get all the vitamin D you need. There's a reason foods (like bread, milk, cereal) are fortified.

pdonis 5y ago

> When in doubt, get a blood test. Definitely. I would say get one regularly anyway, Vitamin D levels are important enough that they should be part of routine blood work done during a regular physical. Then, if you're supplementing, you can adjust your dosage accordingly based on the results so your blood levels stay in the desired range.

legulere 5y ago

The association between Vitamin D levels often breaks down in interventional studies which points to common causes for both susceptibility for respiratory disease and low Vitamin D levels (For instance Winter both lowers Vitamin D levels as well as increases respiratory diseases).

dominotw 5y ago

in my circle it was the joe rogan podcast with dr rhonda patrick during the height of covid mania, that set off the craze for vitamin d obession.

SergeAx 5y ago

It is quite difficult to overdose vitamin D: "... healthy adults in a clinical setting, receiving 50,000 IU of vitamin D2 once every 2 weeks (equivalent to approximately 3,300 IU/day) for up to 6 years, maintained 25(OH)D concentrations of 40–60 ng/ml (100–150 nmol/l) without any evidence of VDT [vitamin D toxicity]. Those findings were consistent with the observation by Ekwaru et al. (17) that Canadian adults who ingested up to 20,000 IU of vitamin D3 per day had a significant increase of 25(OH)D concentrations, up to 60 ng/ml (150 nmol/l), but without any evidence of toxicity" https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6158375/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6158375/