[gregwebs]

This is really dangerous advice to be peddling on internet forums. Statements 1 & 2 are both misleading.

It is certainly true that a few high dosages of vitamin D are not harmful. The issue is the negative effects of having too high of a vitamin D status.

Anyone taking more than 2k IU/day should do so after consulting their doctor or at least testing of their vitamin D levels.

[semerda]

And your statement is wiser because?

I've been taking vitamin d3 10K IU/day for 10 years and it has allowed my blood V-D3 levels to go from 12 ng/mL to ~50 which is within normal range. The NIH recommended dose has been going up over the last 2 decades starting at 400 IU and now 4,000 IU as we learn more and more about it's effectiveness.

[gregwebs]

The NIH states that 4000 IU is the tolerable upper intake: https://ods.od.nih.gov/factsheets/VitaminD-HealthProfessiona...

If you are rounding down your vitamin D status then it is currently at what the NIH say should be avoided. Have you consulted with a medical professional about your vitamin d status?

10k IU/day can be great when someone's level is 12, but it's not a maintenance dosage once at healthy levels.

[cachestash]

https://pubmed.ncbi.nlm.nih.gov/28768407/

"A statistical error in the estimation of the recommended dietary allowance (RDA) for vitamin D was recently discovered; in a correct analysis of the data used by the Institute of Medicine, it was found that 8895 IU/d was needed for 97.5% of individuals to achieve values ≥50 nmol/L. Another study confirmed that 6201 IU/d was needed to achieve 75 nmol/L and 9122 IU/d was needed to reach 100 nmol/L. The largest meta-analysis ever conducted of studies published between 1966 and 2013 showed that 25-hydroxyvitamin D levels <75 nmol/L may be too low for safety and associated with higher all-cause mortality, demolishing the previously presumed U-shape curve of mortality associated with vitamin D levels. Since all-disease mortality is reduced to 1.0 with serum vitamin D levels ≥100 nmol/L, we call public health authorities to consider designating as the RDA at least three-fourths of the levels proposed by the Endocrine Society Expert Committee as safe upper tolerable daily intake doses. This could lead to a recommendation of 1000 IU for children <1 year on enriched formula and 1500 IU for breastfed children older than 6 months, 3000 IU for children >1 year of age, and around 8000 IU for young adults and thereafter. Actions are urgently needed to protect the global population from vitamin D deficiency."

[gregwebs]

It is pretty easy to cherry pick a paper advocating whatever you want to advocate for vitamin D. The paper you cite is entirely founded on another paper about fixing the daily estimate. That paper states about its improved estimate: "As this dose is far beyond the range of studied doses, caution is warranted when interpreting this estimate."

I have no doubt that the mainstream NIH advice is not optimal. The best thing for everyone to do though is not to recommend high dosages for everyone but instead to recommend getting vitamin D levels tested.

[trevorkoob]

I noted the levels needed to maximize intestinal calcium absorption because this is the best studied aspect of Vitamin D. Rickets was the main reason Vitamin D was discovered and supplemented.

Vitamin D level blood testing is imprecise - I would not consider any one test of Vitamin D levels to be accurate.

This person's cited paper corresponds with the calcium absorption data that suggests around 8,000 IU D3 is where calcium absorption begins to plateau and more vitamin D leads to minimal additional calcium absorption.

Since I haven't been going outside, I take vitamin D 10,000 IU daily. You are correct in that one shouldn't just take the advice of random internet strangers - I should be more careful in posting. My personal experience with Vitamin D has been extremely positive and so I get excited about sharing what I know - of course I had to work and couldn't actively respond to this thread as much as I would like.

[gregwebs]

Its nice to see someone not get upset about the criticism!

Things that work well for one person can be dangerous for others. It's fine to share your positive experiences, but it's another step to be recommending the same to others.

There are a lot of other factors besides calcium absorption to consider. In fact maximizing calcium absorption with vitamin D likely has negative consequences unless there is proper vitamin K intake as well.

[cachestash]

> It is pretty easy to cherry pick a paper advocating whatever you want to advocate for vitamin D.

Which is just what you did before.

[semerda]

I do quarterly blood panels to make sure all numbers are within range. All is good.

[subaru_shoe]

so are you saying that it is not ok to stand naked in the sun at noon for 15 minutes ? our bodies producing 20k IU is harmful? what idiot designed our bodies!

[northern-lights]

Not sure why this is being downvoted. This advice is far more useful than OPs.

Be careful of anyone claiming to be an expert on anything, especially on an anonymous forum - even if that forum has in general higher quality opinion.

And the OP does not mention Vitamin K2 at all. How does anybody who claims to have done a Masters on Vitamin D not mention K2?

[trevorkoob]

I didn't mention K2 because I didn't study it. I make no claim to expertise, only familiarity.

Personally, I eat dark green leafy vegetables every day - one serving of kale contains 443% daily value of vitamin K and I probably consume 2-3 servings a day.

Most food we eat doesn't contain vitamin D. A serving of farmed salmon, for example, contains about 250 IU D3 - 32% of the daily value.

In any case, I highly agree with not trusting anonymous internet opinions.