Source? There have been many articles on HN showing the RDA to be ~10x too low (something like 5,000 IU) and that the daily safety limit to be significantly higher than that (something like 30,000 IU).

Edit: for clarity I am not saying it is impossible to overdose on oral tablets, but rather that with most tablets 400 IU to 1000 IU and the safe limit so much higher than these, it seems like it would be extremely unlikely for someone to be taking 30+ tablets daily. Not impossible, but not easy either.

▲

moritzwarhier 9 hours ago | parent | next [-]

> Source? There have been many articles on HN showing the RDA to be ~10x too low (something like 5,000 IU) and that the daily safety limit to be significantly higher than that (something like 30,000 IU).

First: the RDA and the safety limit are not the same, and an RDA in a country being too low does not mean that the maximum safe dose is wrong.

And it certainly does not mean that there is a higher risk in under-dosing than overdosing when taking the RDA (which already includes recommendations for supplementing if you spend most of your time indoors).

I'm not a scientist, so I only know what physicians told me and what's explained in news publications or by consumer advocacy non-profits.

Here are a study (which I didn't read) and the NHS's advise on Vitamin D toxicity:

https://www.ncbi.nlm.nih.gov/books/NBK557876/

https://www.nhs.uk/conditions/vitamins-and-minerals/vitamin-...

The study says:

> Most cases of vitamin D toxicity resolve without serious complications or sequelae. However, in some instances, severe hypercalcemia can lead to acute renal failure requiring hemodialysis. Cases of permanent renal damage due to vitamin D toxicity are rare.

Which sounds good, but I don't think it supports that there is no risk of oral Vitamin D overdose.

▲

neRok 8 hours ago | parent [-]

The first link makes the problem sound like it can happen to anyone, but then when you tease out the details;

* Toxicity resulting from lack of monitoring is frequently seen in patients requiring high doses to treat ailments like osteoporosis, renal osteodystrophy, psoriasis, gastric bypass surgery, celiac, or inflammatory bowel disease.

* Patients who are on high doses of Vitamin D and taking inadvertently increased amounts of highly fortified milk are also at increased risk for vitamin D toxicity.

* According to the latest report from America's Poison Centers (APC), there were 11,718 cases of vitamin D exposure recorded in the National Poison Data System. More than half of these cases were in children younger than 5 years.

* The clinical signs and symptoms of vitamin D toxicity manifest from hypercalcemia's effects.

* Clinical management of vitamin D toxicity is mainly supportive and focuses on lowering calcium levels.

* Isotonic saline should be used to correct dehydration and increase renal calcium clearance.

A lot of those point to people drinking too much milk! (enriched milk)

* People with osteoporosis thinking "I better drink more milk for strong bones" when they are already on supplements/medicine.

* Kids drinking lots of milk and presumably not drinking any water - hence the dehydration.

PS: There are a lot of people out there that don't drink any water, and stick to juice or milk or soda, etc. They are not always fat, but that doesn't mean they don't have issues.

	▲	moritzwarhier 6 hours ago \| parent [-]
		I've read the article by now and I like it. It's balanced, more so than the comment section made me think. And my takeaway is not that everyone should be taking 10k IE, but it's a great reminder to be more consistent in taking my Vitamin capsules in winter. I'm still standing by my point that it's "easy" to overdose on Vitamin D. Like the article already mentions, one should remember possible kidney issues and not take insane doses of it. What the recommended daily intake should be, I don't know. The whole reason I'm commenting on this is I used to take one of the "top" antidepressants on this list. And I am a skeptic of antidepressants, that doesn't mean I deny all positive effects in people who are prescribed them, of course. For what it's worth, it's also easy to overdose on Venlafaxine. It's still considered safe. Just an example to make clear that my comment was not a critique of taking Vitamin D in general. I don't find the article's main point surprising though. That's the reason I'm taking Vitamin D, too. Doesn't mean that it's impossible to overdose, and this point is also important, because many people still think that it would be impossible to take too much of an vitamin or mineral. Thankfully, high-dose Vitamin A / retinol supplements are not as widespread.

▲

ifwinterco 8 hours ago | parent | prev | next [-]

Why would you not be able to overdose orally? It's not like it stops absorbing past a certain dose, and there is such a thing as too much (especially if vitamin k2 is lacking)

▲

perching_aix 9 hours ago | parent | prev | next [-]

That's a bit of a non-sequitur, isn't it? The debated point is how oral intake as a delivery method can pan out specifically (and its limits), not the dosage limits of Vitamin D in general. Think consuming a drug vs injecting it.

▲

bulbar 8 hours ago | parent | prev [-]

I do know somebody taking way more than 30k/day though.

Seems to be a thing in conspiracy theories "they try to hide those simple tricks from you (drinking bleach, ivamectin, 100k D3, ...)