4 ms·

Well, that review is quite old and out of date now. We now know that vitamin D doesn't in fact protect against these diseases (from the results of large vitamin

Well, that review is quite old and out of date now. We now know that vitamin D doesn't in fact protect against these diseases (from the results of large vitamin D supplementation trials). However, a number of large studies show that sunlight itself does give significant protection against cancer and cardiovascular disease, and reduces all cause mortality. It is thought that this effect is due to skin-derived nitric oxide rather than vitamin D. https://onlinelibrary.wiley.com/doi/full/10.1111/joim.12251 https://onlinelibrary.wiley.com/doi/full/10.1111/joim.12251

nradov 2y ago
We still don't know much about vitamin D supplementation one way or the other. Most of those large studies were badly flawed in that they gave rather arbitrary fixed doses to subjects rather than titrating doses to hit target blood levels.
- cpncrunch 2y ago
  There have been a large number of trials now, and I see no mention of the flaws you outline in this review: https://www.bmj.com/content/366/bmj.l4673.short https://www.bmj.com/content/366/bmj.l4673.short Not saying you're wrong, just curious if you can point out which trials were/weren't flawed in this way, and a reference to a review which mentions it.
  - nradov 2y ago
    I spot checked a few of the studies in that meta analysis and they all suffered from the exact same methodological flaw that I pointed out above. They administered fixed doses to subjects rather than titrating the doses up or down to hit target blood levels.
    - deleted 2y ago
      [deleted]
    - cpncrunch 2y ago
      Yes, this is mentioned in the limitations of that review: "The dose of vitamin D used in included trials varied. Our study could not accurately compare equivalent daily vitamin D supplementation dose in the included trials because they all had different treatment regimens and dosing intervals (daily, weekly, monthly, or bolus doses). This might be one of the reasons why this study did not determine an effective daily dose of vitamin D supplementation. Furthermore, the vitamin D status before, during, and after treatment is useful to determine the effectiveness of vitamin D supplementation in improving the actual vitamin D status. Long term vitamin D status is expected to be a much more accurate, reliable, and important clinical parameter compared with a daily dose of vitamin D supplementation. However, previous trials were limited in providing such data. These limitations and uncertainties associated with vitamin D supplementation dose and vitamin D status in treatment and control groups warrant further investigation."

nradov 2y ago

We still don't know much about vitamin D supplementation one way or the other. Most of those large studies were badly flawed in that they gave rather arbitrary fixed doses to subjects rather than titrating doses to hit target blood levels.

cpncrunch 2y ago
There have been a large number of trials now, and I see no mention of the flaws you outline in this review: https://www.bmj.com/content/366/bmj.l4673.short https://www.bmj.com/content/366/bmj.l4673.short Not saying you're wrong, just curious if you can point out which trials were/weren't flawed in this way, and a reference to a review which mentions it.
- nradov 2y ago
  I spot checked a few of the studies in that meta analysis and they all suffered from the exact same methodological flaw that I pointed out above. They administered fixed doses to subjects rather than titrating the doses up or down to hit target blood levels.
  - deleted 2y ago
    [deleted]
  - cpncrunch 2y ago
    Yes, this is mentioned in the limitations of that review: "The dose of vitamin D used in included trials varied. Our study could not accurately compare equivalent daily vitamin D supplementation dose in the included trials because they all had different treatment regimens and dosing intervals (daily, weekly, monthly, or bolus doses). This might be one of the reasons why this study did not determine an effective daily dose of vitamin D supplementation. Furthermore, the vitamin D status before, during, and after treatment is useful to determine the effectiveness of vitamin D supplementation in improving the actual vitamin D status. Long term vitamin D status is expected to be a much more accurate, reliable, and important clinical parameter compared with a daily dose of vitamin D supplementation. However, previous trials were limited in providing such data. These limitations and uncertainties associated with vitamin D supplementation dose and vitamin D status in treatment and control groups warrant further investigation."