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Comment by cloudhead | Hacker News Reader

So 5000 IU is the recommended amount?

This was linked on here a couple of months ago: [The Big Vitamin D Mistake [2017]](https://pmc.ncbi.nlm.nih.gov/articles/PMC5541280/)

> 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.

> 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.

> ...

> Since 10 000 IU/d is needed to achieve 100 nmol/L [9], except for individuals with vitamin D hypersensitivity, and since there is no evidence of adverse effects associated with serum 25(OH)D levels <140 nmol/L, leaving a considerable margin of safety for efforts to raise the population-wide concentration to around 100 nmol/L, the doses we propose could be used to reach the level of 75 nmol/L or preferably 100 nmol/L.

Multiple previous discussions:

https://hn.algolia.com/?q=vitamin+d+mistake

Vitamin D is a favorite topic around here:

https://hn.algolia.com/?q=vitamin+d

It depends. I have MS and I take 10k IU. My cousin who also has MS takes 20k but gets regular blood tests for it.

According to what I read in a newspaper article, the recommended dose is much lower, at 800.

According to the internet, it is way higher, probably over 9000.

Edit because the comment might be to shallow for HN: I sympathize with the struggle against depression and, after first-hand experience, share the skepticism against the widespread prescription of antidepressants and the methods of evidence presented for it.

Very serious and important topic.

Regarding Vitamin D, I am also supplementing in the Winter, but I have not read the article, which says it has an estimated reading time > 10min. I use one 1000IE (0.025mg according to the package) tablet a day max.

I'll bookmark this discussion page to read TFA later maybe.

It’s important to take Vitamin D, as a fat soluble vitamin, with dietary fat during a meal. Something about bile production and absorption.

Also important to take it with Vitamin K.

Yes, I remember that and have Vitamin D+K combo tablets with calcium.

Seems like it would be best to increase time spent outdoors though.

There's likely significant individual variation in bioavailability. I would start with 2-5K/day, then measure and iterate.

I was taking 2x2000 IU with almost no sun exposure and then did bloodwork. My level was 77.8 ng/mL. The lab's reference ranges listed 30-50 ng/mL as optimal, 50-100 as high, over 100 as potentially toxic, and over 200 as toxic.

I don't know why this is downvoted, I had a very similar experience a while back. I took 4000 IU/day for about 4 months, insignificant sun exposure and ended up at 60 ng/mL (lab listed normal range as 30-40).

My starting levels were unknown but I assumed they were low given my usual sun exposure and some low-energy symptoms (which resolved a couple of weeks after I started taking it). I discontinued VitD then and now I only take 1000 IU/day in the winter.

With K3! Otherwise you're fucking yourself up.

Oh dear, here we go again.

IU, not mg.

K2, not K3.

5000 IU is very high, might be beneficial during the winter for folks with very fair skin. but most probably shouldn't take that much every day

You mean very dark skin?

It's my understanding that northern Europeans evolved fair skin in order to cope with the lack of vitamin D in their diet.

yes, i had it backwards - thanks for the correction.

You got it backwards, it would be more beneficial in areas with few hours of sun for darker skin folks, since they do not absorb as much Vitamin D as fair skin folk do.

absorb or create?

i understand it as: absorbing is in the intestine, generating D happens in the skin when exposed to the sun

Correct, what I meant was absorbing UV light, that then as you state creates D.

That's equivalent to about 10 minutes of sun exposure. Not very much when you look at it that way.

That comparison doesn't work. Only 10-20% of the vitamin D we intake is delivered through food and the body cannot process more sourcing from food. Even if you take more you will not benefit in an unlimited way, processing more. The skin is much better at generating/making/doing it.

The skin is definitely much better, but a higher than "recommended" dose is definitely (anecdata) effective at bringing up and maintaining the measureable Vitamin D3 level in your blood if you are under the recommended range. It's an important metric to track in your regular blood tests.

I think you mean for those with very dark skin, not fair?

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