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Comment by hammock | Hacker News Reader

Reminder that the FDA recommended daily allowance of vitamin D is 10x lower than it was supposed to be, because of a math error, and they have never corrected it.

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

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The abstract wasn't clear to me, but looking it up FDA recommends 20mcg = 800 IU, and the paper recommends 8000 IU. It seems like others are more conservative (7000 IU).

I don't think I've ever seen the 20mcg rec, everywhere I've seen was something like 2000 (and that's what the supplements come as), but P appears correct.

What was the math error that led to this? And I'm curious now how to get 8000 IU. Just take a bunch of pills all at once in the morning?

The paper referenced Finland, which seems like a strong confirmation of safety, but the best information I could find was https://www.ruokavirasto.fi/en/foodstuffs/healthy-diet/natio... . What effective IU dose are people getting in Finland with these changes?

> I don't think I've ever seen the 20mcg rec

The 20mcg rec (the wrong rec) is quite literally on every single nutrition label in America that has Vitamin D. Maybe you haven’t noticed it. Surely you’ve seen it if you’re in the U.S.

https://www.fda.gov/food/nutrition-facts-label/daily-value-n...

> What was the math error that led to this? And I'm curious now how to get 8000 IU. Just take a bunch of pills all at once in the morning?

Read the paper I posted. And it is easy to find 5000iu and 10000iu capsules at a drug store.

> it is easy to find 5000iu and 10000iu capsules at a drug store

Not in Canada!

Good to know. Guess there are still a few good things about American healthcare system

What I don't understand is how it's possible for 90% of people to have a vitamin D deficiency, or whatever that crazy number was. Surely by that point it's just normal?

Its also normal to be overweight and need glasses, doesn't mean that it isn't a problem.

I don't know how it was approached for vitamin D, but it's all about the model they choose, which in the first instance is just something they pull out of thin air. For many water soluble vitamins and minerals the model is based on a threshold for urine excretion; up the dose until the study group is excreting as much as they take in. Until someone figures out otherwise--i.e. that it's too little, too much, or that other considerations need to be made--that's the basis for the RDA.

> What I don't understand is how it's possible for 90% of people to have a vitamin D deficiency

If everyone is being told to get 10x less vitamin d than they really need, seems easy

What does "low vit D" mean when there aren't any negative effects of it?

Most people arent supplementing Vit D, so the recommendations are not relevant to deficiency status.

Set aside pills.

Vit d deficiency is a known problem because of our indoor lives and sunscreen culture, so FDA requires by law supplementation of foods. Like milk. But because the RDA is wrong, these foods get supplemented with insufficient amounts.

Case in point, seasonally adjusted the typical American gets in a day average ~1800iu from the sun and ~200iu from supplemented dietary intake (2000iu total, deficient). If we were to acknowledge the RDA is wrong then milk etc could have 30x more supplementation bringing the average up and filling the gap better

Modern life is spent indoors whereas historically during our evolution it was outdoors

People use clothes now.

I remember this article about Vitamin D says nobody is certain whether it actually does anything:

https://www.nytimes.com/2022/07/27/health/vitamin-d-bone-fra...

Between the vitamin D error (this affected US and Europe and probably more places) and the sodium/blood pressure study that was misleading if not outright false, it's amazing how a few data points can become widespread advice without much verification and follow-up.

I'm sure there's tons more cases that we don't even know about, not in the conspiracy sense, but more in the sense that there's some issues with how carefully these claims are validated before they get put out there as a rule to be followed.

One of the big issues is the momentum. Even long after these misstakes have been found doctors still give advice based on the error.

Doctors giving advice based on mistaken or otherwise bad data and outdated guidance is a pervasive problem

Let alone meddling vested interests, e.g. with RDA for sugar.

Those are two recommendations out of how many? And how many years? How many errors do police make? Actuaries? Security researchers?

Vitamin D and sodium are examples out of a couple core nutrients, and I could list other nutrients such as sugar or fat too. So the rate is not excellent.

> How many errors do police make? Actuaries? Security researchers?

They make plenty of mistakes too. What's your point?

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