[redlizard]

Hopped on the last thread a little late and couldn't get a meaningful discussion about this (Perhaps i'm just completely on the wrong foot):

Are these studies just showing that vitamin D is a good predictor of income (because race is a good predictor of income)? Now that the US is starting to have conversations about racial inequality, every time I see a hackernews or reddit post on vitamin D I am asking myself that question. I have read several studies that link low income to higher mortality rates across several different diseases. [0]

And several other studies that link education levels (which are inherently linked to childhood wealth levels) to worse mortality rates as well.[1]

There is a link between lower vitamin d levels and skin color, with an obvious plausible explanation ( Melanin lowers skins ability to produce vitamin D).[2]

In the U.S. at least there is a strong link between income, education levels, and skin color. [3]

While I am hopeful that ongoing research will help us understand the mechanisms by which vitamin-D operates, I really worry that it is somehow a very well dressed red-herring. One one hand a promised panacea: vitamin d supplements, the other a complex economic and political problem that barely anyone can comprehend or are even willing to engage with.

One of the more damning studies shows that vitamin d supplementation is good enough to remove your deficiency, it has reproduced really poorly on any of the other correlated health effects.[4]

Are there any studies that someone can link that would alleviate my concerns? When these kind of population health studies are conducted (I am in no way familiar with how they are actually done), how are factors like income inequality and education level generally controlled for?

And an interesting article related to Vitamin-D health benefits that had a slightly different take on causes for supposed benefits: https://www.outsideonline.com/2380751/sunscreen-sun-exposure...

[0] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4866586/

[1] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4435622/

[2] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5946242/

[3] https://journals.plos.org/plosone/article?id=10.1371/journal...

[4] https://www.nejm.org/doi/full/10.1056/NEJMoa1809944

[devaboone]

Thanks for commenting. These are all great points. For a while I have thought that Vitamin D just became the latest Vitamin C - are people on here old enough to remember when Vitamin C was a miracle drug that treated and prevented cancer? Fortunately you can expel excess Vitamin C much easier than Vitamin D. In my next post on this I really want to go into the human trials. The evidence for Vitamin D supplementation in the general population is just not there. And yes, darker skin color is a risk for Vitamin D deficiency. And the correlations that you mention are all real, which can partly explain the correlations between low Vitamin D and health problems - and then explain why supplementing doesn't seem to help. It's not the Vitamin D causing an increased mortality - it's everything else that might be associated with low Vitamin D and at the same time associated with mortality.

[mrandish]

Deva,

Thanks for your articles (P1 and P2) as well as your posts on HN. I'm happy to hear there will be a Part 3. The topics you describe above will be of interest. I'm a layperson who has read many of the recent papers on D3 and have been supplementing 6k IU D3 with 100mg K2-mk7 (recently increased to 10k D3). My 25-H is 71 ng/mL as of last week (lab 'normal' = 20 - 79 ng/mL). Here are some questions I'd appreciate you considering addressing in Part 3.

* Do you think that some patients (like Shannon) have adverse reactions (and others don't) mostly due to random individual sensitivity or does it seem like there are may be some factors that could serve as indicators? For example, I don't even know if a person's size (kg) 'matters' either in the test result or in absorption.

* I've seen claims that some reasonable UV exposure can A) increase uptake of supplemented D3, or B) Is recommended (if possible) because 'UV-sourced D3' is somehow 'different/better'. Yet I haven't found any published discussion of A or B. I realize the answer is likely both complicated and uncertain, but would love to know if either A or B has been evidenced, is unevidenced but 'seems plausible' or unevidenced and doesn't seem plausible.

To be clear, I'm not asking for personalized advice. Just giving you N=1 context on one reader's questions: I currently have no apparent ill-effects from supplementation. Based in part on your post, I'm now considering dropping back to 5k IU D3 as my goal is really to ensure I'm not D3 deficient (not mega-dose). I started supplementing initially due to diagnosed SAD and more recently went up from 6k to 10k in light of possible CV19 bonus benefit (I'm not at elevated CV risk anyway).