4 ms·

This seems like it might be a little selective. What about these [1] [2] randomised controlled trials that show vitamin D supplementation has an effect on IBS

by dcx 6y ago

This seems like it might be a little selective. What about these [1] [2] randomised controlled trials that show vitamin D supplementation has an effect on IBS symptoms? Or this [3] double-blinded trial showing supplementation improved sleep quality in people with sleep disorders? Or this [4] one showing improvements in depressive symptoms in overweight and obese subjects? The study cited in TFA is large but only uses participants aged 50 and above, with a relatively low dose of vitamin D. Also, is it just me or is the line of argument used a little bit weak? You could use the same kind of argument to dismiss the need for dietary vitamin C, as follows: (a) vitamin C deficiency is associated with a bunch of other health conditions (as it's a marker of poor nutrition or socioeconomic status), so (b) let's look at the effects of supplementing vitamin C, which (c) naturally finds that supplementation does nothing for said conditions, and therefore (d) conclude that it is a pretty useless vitamin, while placing minimal focus on the things that it actually does fix, such as scurvy? I am not an academic, so perhaps I am missing some context though. [1] https://pubmed.ncbi.nlm.nih.gov/27154424/ https://pubmed.ncbi.nlm.nih.gov/27154424/ [2] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5900470/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5900470/ [3] https://tumj.tums.ac.ir/article-1-8272-en.html https://tumj.tums.ac.ir/article-1-8272-en.html [4] https://onlinelibrary.wiley.com/doi/full/10.1111/j.1365-2796.2008.02008.x https://onlinelibrary.wiley.com/doi/full/10.1111/j.1365-2796...

ramenmeal 6y ago
I think the article addresses those by saying they are the result of publication bias.
devaboone 6y ago
I wrote the blog post. Unfortunately I was not able to include every study on Vitamin D, and had to pare it back to the largest and/or most significant studies. Most of the studies you mention are small and published in obscure journals. As for my argument, I would never claim that Vitamin D is "a pretty useless vitamin". It is extremely useful, and is lifesaving for people with hypoparathyroidism. But that doesn't mean we should all be taking it. Note that the studies you mention are looking at treating something, not preventing something. Many of the people supplementing are doing it because they believe it will keep them healthy - and this does not appear to be the case. That is more the point of my article. The articles you cite are interesting and hopefully will produce larger trials.
- dcx 6y ago
  > Many of the people supplementing are doing it because they believe it will keep them healthy - and this does not appear to be the case. I agree with much of your thinking - just not this particular conclusion. 1. As you mention, we know that low-to-moderate levels of vitamin D supplementation is safe. 2. We also know that a solid chunk of the population does not get enough sunlight / is vitamin D insufficient. 3. There are no large-scale trials yet for some items where vitamin D is suspected to have good effects. But there are a few nevertheless, which you share within the article itself - cancer, mortality, respiratory disease particularly stand out. 4. There are also a pile of smaller but promising, statistically significant, double-blinded, randomised controlled trials in a bunch of useful areas. 5. So this seems to be a Pascal's Wager type of situation, where supplementation is all upside and no downside, as long as people don't get crazy with it. As you say it's not a panacea, and to cite an old comment, I am aware [1] that there are other benefits you get from sunlight. But even if it doesn't do as much as people think, I don't see why it is bad advice for most people to supplement vitamin D to keep themselves healthy! [1] https://news.ycombinator.com/item?id=19247337 https://news.ycombinator.com/item?id=19247337
- hessp 6y ago
  Would love to hear your take on this study which recently came out and gained some popularity here on HN: https://www.sciencedirect.com/science/article/pii/S0960076020302764 https://www.sciencedirect.com/science/article/pii/S096007602... Speaking solely as a layman, that study seems like it might be extremely relevant to the discussion here. But at the same time I don't have the background necessary to critique or dissect it. HN Post on the study: https://news.ycombinator.com/item?id=24366006 https://news.ycombinator.com/item?id=24366006
fortenforge 6y ago
It's interesting that you mention Vitamin C! Do you know many people who take Vitamin C supplements? Did you know that Vitamin C had its own supplementation hype cycle in the 70s and 80s? It's out of fashion now, mostly because people understand now that it's not a miracle drug. I suspect the same thing will happen with Vitamin D. TFA isn't saying that you don't need vitamin D, or that it can't be used to treat Ricketts or osteomalacia (which, like scurvy, are relatively rare conditions). It's simply saying that widespread supplementation on people who have normal levels or minor deficiencies isn't supported by the evidence.
ljhsiung 6y ago
Did you read the article? > It is an essential hormone, definitely, but not a magical pill that will ward off disease. There are conditions that benefit from Vitamin D supplementation - for hypoparathyroidism, a condition that can cause dangerously low calcium levels, Vitamin D is lifesaving. For otherwise healthy adults, the benefit is less clear. Takeaways: it's not clear what preventative benefits it has. Even to use your vitamin C example, it's also widely touted to take vitamin C for general well being, such as helping colds. But its preventative benefits aren't clear [1]. Nobody has ever said vitamin C is useless, but it's just not a panacea (much like the article claims about vitamin D). [1] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1160577/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1160577/
- deleted 6y ago
  [deleted]
- dcx 6y ago
  Yes. See response to author's comment below. On vitamin C - I stated dietary vitamin C to make it clear I was not referring to supplemental vitamin C. I was hoping to avoid this exact rabbit hole; that example was just to highlight an issue with the argumentation.

by dcx 6y ago

ramenmeal 6y ago

I think the article addresses those by saying they are the result of publication bias.

devaboone 6y ago

I wrote the blog post. Unfortunately I was not able to include every study on Vitamin D, and had to pare it back to the largest and/or most significant studies. Most of the studies you mention are small and published in obscure journals. As for my argument, I would never claim that Vitamin D is "a pretty useless vitamin". It is extremely useful, and is lifesaving for people with hypoparathyroidism. But that doesn't mean we should all be taking it. Note that the studies you mention are looking at treating something, not preventing something. Many of the people supplementing are doing it because they believe it will keep them healthy - and this does not appear to be the case. That is more the point of my article. The articles you cite are interesting and hopefully will produce larger trials.

dcx 6y ago
> Many of the people supplementing are doing it because they believe it will keep them healthy - and this does not appear to be the case. I agree with much of your thinking - just not this particular conclusion. 1. As you mention, we know that low-to-moderate levels of vitamin D supplementation is safe. 2. We also know that a solid chunk of the population does not get enough sunlight / is vitamin D insufficient. 3. There are no large-scale trials yet for some items where vitamin D is suspected to have good effects. But there are a few nevertheless, which you share within the article itself - cancer, mortality, respiratory disease particularly stand out. 4. There are also a pile of smaller but promising, statistically significant, double-blinded, randomised controlled trials in a bunch of useful areas. 5. So this seems to be a Pascal's Wager type of situation, where supplementation is all upside and no downside, as long as people don't get crazy with it. As you say it's not a panacea, and to cite an old comment, I am aware [1] that there are other benefits you get from sunlight. But even if it doesn't do as much as people think, I don't see why it is bad advice for most people to supplement vitamin D to keep themselves healthy! [1] https://news.ycombinator.com/item?id=19247337 https://news.ycombinator.com/item?id=19247337
hessp 6y ago
Would love to hear your take on this study which recently came out and gained some popularity here on HN: https://www.sciencedirect.com/science/article/pii/S0960076020302764 https://www.sciencedirect.com/science/article/pii/S096007602... Speaking solely as a layman, that study seems like it might be extremely relevant to the discussion here. But at the same time I don't have the background necessary to critique or dissect it. HN Post on the study: https://news.ycombinator.com/item?id=24366006 https://news.ycombinator.com/item?id=24366006

fortenforge 6y ago

It's interesting that you mention Vitamin C! Do you know many people who take Vitamin C supplements? Did you know that Vitamin C had its own supplementation hype cycle in the 70s and 80s? It's out of fashion now, mostly because people understand now that it's not a miracle drug. I suspect the same thing will happen with Vitamin D. TFA isn't saying that you don't need vitamin D, or that it can't be used to treat Ricketts or osteomalacia (which, like scurvy, are relatively rare conditions). It's simply saying that widespread supplementation on people who have normal levels or minor deficiencies isn't supported by the evidence.

ljhsiung 6y ago

Did you read the article? > It is an essential hormone, definitely, but not a magical pill that will ward off disease. There are conditions that benefit from Vitamin D supplementation - for hypoparathyroidism, a condition that can cause dangerously low calcium levels, Vitamin D is lifesaving. For otherwise healthy adults, the benefit is less clear. Takeaways: it's not clear what preventative benefits it has. Even to use your vitamin C example, it's also widely touted to take vitamin C for general well being, such as helping colds. But its preventative benefits aren't clear [1]. Nobody has ever said vitamin C is useless, but it's just not a panacea (much like the article claims about vitamin D). [1] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1160577/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1160577/

deleted 6y ago
[deleted]
dcx 6y ago
Yes. See response to author's comment below. On vitamin C - I stated dietary vitamin C to make it clear I was not referring to supplemental vitamin C. I was hoping to avoid this exact rabbit hole; that example was just to highlight an issue with the argumentation.