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Comment by jesalg | Hacker News Reader

This is interesting, my wife experienced something exactly the opposite. She started taking Vitamin D couple of years ago since she was quite deficient just like you. After a year or so of 5k IU daily, she started experiencing severe eye issues, including daily crust buildup, irritation, redness, and blepharitis.

We tried all sorts of drops and cleaning regimes to no avail. She went for another blood test and learned her Vitamin D levels were through the roof (somewhere around 90+). She immediately stopped the Vitamin D supplements and after a few weeks, all her eye issues were gone!

Goes to show we definitely need some good studies examining long-term Vitamin D intake.

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5,000 IU per day is an excessively high dose.

4,000 IU is the upper limit. 2K is high.

https://en.wikipedia.org/wiki/Hypervitaminosis_D

I read that people get 10,000 - 20,000 IU from 30 minutes in sun. With that, wouldn't that make the upper limit dangerously low?

4,000 IU per day is the recommended supplement limit.

You can synthesize 1000 IU from 10 minutes in the sun if... you're young, have light skin (of which most is visible), don't wear sunscreen, it's the middle of the day & summer, and you're lying down to get roasted.

4,000 IU is equivalent to getting burnt to a crisp.

This is off by a factor of 10. You get between 10,000 and 25,000 IU in just a little under the time your skin takes to burn. https://www.vitamindcouncil.org/about-vitamin-d/how-do-i-get...

You are very unlikely to develop excess vitamin D unless you supplement more than 10,000 per day for months, and typically not even then unless you exceed 40,000 per day via supplements. https://www.vitamindcouncil.org/about-vitamin-d/am-i-getting...

Additionally, if you supplement or take K2 with vitamin D, the risks are substantially mitigated (Vitamin D adds calcium ions to things, K2 takes them out).

There are already good studies and it is well known that Vitamin D is toxic if too much quantity is taken over time. 5K IU is 5x more than the recommended daily limit. She should have dropped to 1K IU after 4 months of taking 5K IU, that is, if she continued not to get regular sun exposure or eat food rich in Vitamin D. The problem lies in the prescribed amount and the duration and not because of lack of studies. Did a doctors advise 5K IU without a time limit?

Yeah, that's the weird thing about Vitamin D, every single individual metabolizes it differently.

Some people get adequate amounts just from "regular food", others (like me) need extra large doses to keep up, especially during the winter months.

And then there's people like your wife who go through the roof if they see a supplement at the store :D

> Goes to show we definitely need some good studies examining long-term Vitamin D intake.

Goes to show that the recommended level of it are about right.

No, one person needing support at 2.5-5× the recommended upper limit and another person experiencing problems at half the low end of that range doesn't shown that the recommended level is about right.

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