Vitamin D, part 3 – The Evidence • Hacker News Board

Re: Vitamin D, part 3 – The Evidence

#191

Post by tchaffee » Tue, Sep 08, 2020, 9:29 PM UTC

leftyted wrote: post #188

tchaffee wrote: post #144

Earlier quoted context omitted.

> A change like the loss of melanin requires selective pressure It does? What about genetic drift, random mutations, and artificial selection, where humans select based on qualities not necessarily conducive to survival? There is also some evidence that this change in skin color was only widespread as recently as 8,000 years ago [1]. > which in this case was likely furnished by less vitamin D How likely? > The pressu…

> It does? What about genetic drift, random mutations, and artificial selection, where humans select based on qualities not necessarily conducive to survival? It seems unlikely to be due to these factors since there's a gradient from black to white as you move away from the equator.

> It seems unlikely

That's fairly far from any scientific method I would have confidence in.

Re: Vitamin D, part 3 – The Evidence

#192

Post by baccheion » Tue, Sep 08, 2020, 9:34 PM UTC

dolguldur wrote: post #173

baccheion wrote: post #84

Earlier quoted context omitted.

RDA is 400 IU. It's actually the food RDA, with 20% expected from food. Overall RDA (sun + food) is 2000 IU. Therapeutic vitamin doses are 10x the RDA. 6x is elevated while doing "nothing" and 20x is full saturation ("but why"). 2x and 4x for minerals. For vitamin D, that would then be 20,000 IU or roughly 300 IU/kg/day. No need to take that much or be outside the 40-60 ng/mL range for no reason. On the other hand, m…

Thanks for the info! I’m taking 400mg - 800mg magnesium daily, recently added K2 (100 mcg MK-4) together with 2000 or 3000 IU D3. What would you change? Get my blood levels first and then increase D3? Increase my magnesium supplementation? Don’t take calcium at all? How did you find your own doses and what else are you supplementing?

Use CRON-o-meter. Meet all RDAs with just a variety of whole quality foods, get more magnesium than phosphorus (and 1/3rd-1/2 as much as calcium), ensure alkaline PRAL score, and ensure sufficient quality sleep.

Higher amounts of D3 aren't necessary, but there are therapeutic effects. The idea is to somewhat mimic hGH/IGF-1, DHEA, and melatonin of youth while lowering stress hormones.

As a male, ZMA is a good way to improve sleep and move closer toward meeting the magnesium requirements.

Maintain a lower/normal amount of D3, clear all nutrient/sleep deficiencies, and then start increasing 25(OH)D if necessary. D3 sometimes isn't even needed until older, unless trying for the therapeutic effects I mentioned.

Such a combo works even better with resistance training to stimulate bone.

I stated minimums for MK-4 and MK-7. I like the effects of higher amounts of MK-4. 5-10 mg.

I'm currently taking: 60,000 IU D3, 15 mg MK-4, 1.35g magnesium, and 2 Naturelo One Daily capsules (provides 240 mcg MK-7).

Re: Vitamin D, part 3 – The Evidence

#193

Post by throwaway6000 » Tue, Sep 08, 2020, 9:49 PM UTC

bad_user wrote: post #164

JPLeRouzic wrote: post #114

Earlier quoted context omitted.

> RCTs are high quality, because they are done in a controlled setting I have a personal interest in Amyotrophic Lateral Sclerosis, so I am reading patients' Internet forums since two years. Several patients report participating in trials but they also tell that they take other drugs without telling doctors (they do not want to be expelled from the trial). Those drugs could be whatever they fancy, and they change oft…

Those are anecdotes, the question is how often does it happen? Sure, it's possible, which is why we have reviews aggregating the findings of multiple studies. The results of one study could be an anomaly, which is why replication is important in science. But when those results get replicated in tens or hundreds of such studies, we can start trusting those findings (although when surrogate markers are involved, their…

People who boost their vitamin D levels with supplements reduce their risk of respiratory tract infections, such as the flu, by up to 12%, according to a new systematic review and meta-analysis study of 25 randomized controlled trial (RCT) studies published in The BMJ.

https://bcmj.org/news/vitamin-d-effective-reducing-flu-and-c...

Harvard Gazette: Study confirms vitamin D protects against colds and flu

https://news.harvard.edu/gazette/story/2017/02/study-confirm...

WebMD: Vitamin D May Cut Risk of Flu

https://www.webmd.com/cold-and-flu/news/20100616/vitamin-d-m...

Vitamin D protects against colds and flu, finds major global study https://www.sciencedaily.com/releases/2017/02/170216110002.h...

Re: Vitamin D, part 3 – The Evidence

#194

Post by neetdeth » Tue, Sep 08, 2020, 10:04 PM UTC

tchaffee wrote: post #144

api wrote: post #25

The most obvious evidence to me has always been that Europeans are not black. A change like the loss of melanin requires selective pressure, which in this case was likely furnished by less vitamin D as we migrated away from the equator. The pressure must have been significant since being white carries a big downside: higher vulnerability to sunburn and skin cancer. When I lived in Cali I always envied my darker skinn…

> A change like the loss of melanin requires selective pressure It does? What about genetic drift, random mutations, and artificial selection, where humans select based on qualities not necessarily conducive to survival? There is also some evidence that this change in skin color was only widespread as recently as 8,000 years ago [1]. > which in this case was likely furnished by less vitamin D How likely? > The pressu…

One aspect of sexual selection is that a disadvantageous trait needn't kill to cause differential outcomes in reproduction. If a deficiency results lower hunting success, diminished fighting prowess, loss of mental acuity etc. the individual will be disfavored in mate selection. Iterated over generations, this eventually extinguishes some genes.

There's also the aesthetic aspect, where some traits seem to be favored simply because they are attractive to the opposite sex, which can be justified because offspring will have more favorable opportunities for reproduction, but only because the trait is well liked. A strange attractor in the genetic code, if you will. This happens across species, so I wouldn't call it artificial selection - artificial selection applied to humans is also known as eugenics.

Re: Vitamin D, part 3 – The Evidence

#195

Post by ajhurliman » Tue, Sep 08, 2020, 10:13 PM UTC

mola wrote: post #94

This is wonderful scientific writing; approachable without being condescending or over simplifying, without a trace of sensationalism. Really beautiful.

I thought the opposite: It campaigns against vitamin D as if it were a wolf in sheep's clothes. I've seen the author (and her partner) post and link about the dangers of vitamin D for a while now and it seems very unscientific to come at a subject with your mind already made up.

The author has clearly made up their mind about vitamin D and now they've made it duty to lobby on behalf of that belief, but I don't think they're capable of honest, unbiased science regarding this subject anymore.

Re: Vitamin D, part 3 – The Evidence

#196

Post by 0-_-0 » Tue, Sep 08, 2020, 10:27 PM UTC

tchaffee wrote: post #190

0-_-0 wrote: post #160

Earlier quoted context omitted.

I read the article but failed to see what doubt it sheds on the idea that light skin evolved to increase vitamin D production. Could you help me find it please? You asked for evidence of causation, which I provided. Correlation of latitude with skin colour is evidence of causation. Light skin colour providing vitamin D while increasing skin cancer risk is evidence of causation. No other known advantage of light skin…

> Correlation of latitude with skin colour is evidence of causation. Correlation is not causation. I'm sorry but I don't think you have any evidence at all that lighter skin was caused by a need for more vitamin D. It's just an educated guess on your part. Lighter skin could have just as easily been an adaptation related to less visibility to predators and prey in snow. Like the article I cited said "researchers are…

Correlation is not causation, but you didn't ask for proof, you asked for evidence, and correlation is evidence. For example, do you know whether smoking causes cancer? Because all the evidence we have that it does is based on correlation. Or you're happy saying "I don't know" and asking more questions? How would you show a causal link between vitamin D deficiency causing the evolution of light skin colour without being able to conduct a double blind study? It's fundamentally impossible to prove, all we have is evidence, which is this case is sufficient to say as the first sentence in Wikipedia [1]: "An abundance of clinical and epidemiological evidence supports that light skin pigmentation developed due to the importance of maintaining vitamin D3 production in the skin"

[1] https://en.wikipedia.org/wiki/Light_skin#Evolution

Re: Vitamin D, part 3 – The Evidence

#197

Post by hessp » Tue, Sep 08, 2020, 11:16 PM UTC

devaboone wrote: post #125

dcx wrote: post #92

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…

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 m…

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/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

Re: Vitamin D, part 3 – The Evidence

#198

Post by pcvarmint » Wed, Sep 09, 2020, 1:18 AM UTC

I don't really care what RCT trials show.

I have suffered from bone fractures 3 times, 2 spontaneously, and I was eventually diagnosed with osteomalacia at age 46.

I therefore take Vitamin D and Calcium supplements regularly.

My Z score was -5.0 four years ago, but after taking supplementation and Fosamax for several years, it was raised to -2.0.

Re: Vitamin D, part 3 – The Evidence

#199

Post by devaboone » Wed, Sep 09, 2020, 1:22 AM UTC

gambler wrote: post #158

This picture in the article is misleading: https://static.wixstatic.com/media/3e0600_a25ba8bbf26b47a096... At the very leat, vitamin D does seem to prevent respiratory infections. The article even admits as much later on. There are several RCTs that verify this. So why put a red cross next to "prevention of respiratory infections"? Also, worth reading: "Why randomized controlled trials of calcium and vitamin D someti…

The chart is only regarding RCTs. In the best individual trials that we have, it does not show a benefit for respiratory infections. But we do see some suggestion of benefit in meta-analyses. In general, if the meta-analysis shows something that is not seen in RCTs, then we probably need more evidence. But it does seem to be a real effect.

Re: Vitamin D, part 3 – The Evidence

#200

Post by leftyted » Wed, Sep 09, 2020, 3:47 AM UTC

tchaffee wrote: post #191

leftyted wrote: post #188

Earlier quoted context omitted.

> It does? What about genetic drift, random mutations, and artificial selection, where humans select based on qualities not necessarily conducive to survival? It seems unlikely to be due to these factors since there's a gradient from black to white as you move away from the equator.

> It seems unlikely That's fairly far from any scientific method I would have confidence in.

You could have responded to my post but instead you did this. Why?

There are more than two skin tone phenotypes. It's a gradient that gets lighter as you move away from areas of higher UV radiation to areas of lower UV radiation.