Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

Vitamin D, part 3 – The Evidence

devaboone.com

Post reply on HN
Print view View original

51–60 of 218 posts

Re: Vitamin D, part 3 – The Evidence

#51

Post by coldtea »

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…

>I gotta say though... the world would have far less race problems had that odd little quirk of photosynthesis of a key nutrient not existed.

It's not so much about the race, but about the exploitation. Blacks and whites co-lived without racism for millenia, back when anybody could become a slave.

When around the 16th century the Europeans started to exploit latin americans, indians and blacks as slaves, they spread the various theories of racism to justify the practice (both the advance of christianity and englightenment meant that such a thing should now be justified, whereas in the ancient/pagan world just being more powerful was enough to justify making slaves of the less powerful, you didn't need an excuse).

So, if Europens where also blacks, the exploitation would just have found some other justification than skin color (kind of how Hitler didn't have much issue to discriminate against the also-white Jews).

Re: Vitamin D, part 3 – The Evidence

#52

Post by scott_s »

dcolkitt wrote: post #44
m12k wrote: post #2

So Vitamin D deficiency is linked to cancer, heart disease, respiratory infection, stroke, diabetes, and death. But taking it as a supplement helps with none of the above. What is a reasonable hypothesis then? That having an active lifestyle that brings you outside in the sun both causes your Vitamin D to go up, and is correlated with better physical health in general?

> What is a reasonable hypothesis then? The logical conclusion is that vitamin D, as we measure it, is proxying for another factor that we haven't yet detected. This X-factor is heavily influenced by sun exposure, but at most weakly influenced by vitamin D supplementation in its current form. Analogously imagine that we had no concept of the health benefits of exercise. We detected that people with gym memberships we…

You're still assuming that Vitamin D is involved in some interaction that itself is the cause of people being sick. Your reasoning is not allowing for the simpler possibility: sick people have less Vitamin D because sick people are too sick to go outside.

Re: Vitamin D, part 3 – The Evidence

#53

Post by Nursie »

goda90 wrote: post #38

It seems like its easy to identify the harms of extremes. Too little of X causes Y and too much of W causes Z. But with so many variables affecting the human body(nutritional, genetic, environmental, microbial, mental, etc) how can we even approach being certain about optimal levels in the middle? I don't see how we could control for enough variables for long enough to know how much vitamin D is best for the body, an…

But we can see how supplementation affects outcomes, and it turns out that so far the results on that are pretty 'meh', unless you're supplementing specifically for severe vit D deficiency.

Re: Vitamin D, part 3 – The Evidence

#55

Post by mekoka »

My main dissatisfaction with Vitamin D studies is the fact that they usually try to isolate it as a self-contained factor that you can simply raise or lower and observe effects, while neglecting the complex system it is normally a part of.

How about instead treating it as a simple block of that complex system? What I mean is that Vitamin D typically correlates with sun exposure and a healthy outdoorsy lifestyle (i.e. the system). I would think that if you want to understand how its presence affects an individual, you would try raising/lowering it specifically on subjects whose lifestyle guarantees the presence of that system.

Re: Vitamin D, part 3 – The Evidence

#56

Post by ComputerGuru »

I don’t want to be the contrarian that persists in the face of scientific evidences, but I will point out that none of the RCTs listed combined Vitamin D with supplementation of Vitamin K, which several studies suggest plays a synergistic role when it comes to the health benefits. This OSU link covers a number of such studies: https://lpi.oregonstate.edu/mic/vitamins/vitamin-K

Re: Vitamin D, part 3 – The Evidence

#58

Post by chmod600 »

Don't over-think (unless you're a researcher, in which case that's your job). It's pretty simple:

Low levels are bad. If your levels are low, supplement.

Err on the high side because the risks are low, but don't go crazy for long periods of time without testing.

Re: Vitamin D, part 3 – The Evidence

#59

Post by andi999 »

m12k wrote: post #2

So Vitamin D deficiency is linked to cancer, heart disease, respiratory infection, stroke, diabetes, and death. But taking it as a supplement helps with none of the above. What is a reasonable hypothesis then? That having an active lifestyle that brings you outside in the sun both causes your Vitamin D to go up, and is correlated with better physical health in general?

Its probably same reasonwhy there are some correlations with alcohol intake and health, real reason probably: sick people dont drink wine.

Re: Vitamin D, part 3 – The Evidence

#60

Post by tboyd47 »

m12k wrote: post #2

So Vitamin D deficiency is linked to cancer, heart disease, respiratory infection, stroke, diabetes, and death. But taking it as a supplement helps with none of the above. What is a reasonable hypothesis then? That having an active lifestyle that brings you outside in the sun both causes your Vitamin D to go up, and is correlated with better physical health in general?

Perhaps it's just more complicated than the prevailing paradigm of "have problem -> take drug -> problem go away." It could be that Vitamin D deficiency is itself a symptom of an array of underlying problems, or that it is one factor among many leading to a pathology, or that various levels of Vitamin D have various effects among different patients, or all of the above.
Post reply on HN