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Comment by amanaplanacanal | Hacker News Reader

I suspect that blood vitamin D is mainly a marker for how much outdoor exercise people are getting, and that it is the exercise rather than the D which is causal.

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My life changed after I got tested for vit D and started talking supplements. I was severely deficient. I am now sufficient and everything changed for me.

What exactly changed?

In December by chance I put a pack of Vitamin D into my shopping basket. I did not think much, thought to take 1000IE but then decided that for the first week I take 3000 to catch up. Muscle pain went and control over eating improved. I did not expect any changes based on past experience with 1000 but this time I could not ignore it (age can play a role) and I stayed on 3000. Tests a month later showed I was just not deficient any-more. I continued on the regime and started having improvements in long running skin issues to the extent my dentist noticed. It may not be a miracle drug but one should not underestimate cumulative impact individual factors, age and lifestyle changes (less sun) that may change levels and demand.

I do think this is worth emphasising: the article only focuses on mortality. Not quality of life. Vitamin D makes me not feel like crap, it's cheap, and effectively zero risk. I'm not expecting it to make me live longer, I like that it makes me live better.

That doesn't undermine OP's point. Being deficient is unhealthy. But that doesn't mean an overabundance makes you healthier.

I used to take 4k IU + K² and think that I'm covered, since 4K units was a lot.

I landed on just above deficient when tested.

My wife was on kind of same regime, but didn't follow it very strictly. She was deficient, but not extremely.

It was quite surprising, because I got warned when buying 4k unit tabs that they were quite strong and pharmacy clerk suggested taking less.

Have you looked into UVB lamps?

Had a friend talking about them, but they seem to be prohibitively expensive. Do you have positive experience using such lamps?

I tend to have some eczema on my scalp that sun really helps with.

Maybe a lamp that costs the equivalent of a week of holidays in a warm place could be justified after all.

I don't have any experience myself but they do seem to be effective. Yeah, I think you'd have to compare it to a holiday, or how much time that would mean in a Solarium.

I am deficient, too, and take supplements (rare liver disease).

I wonder if taking mushrooms soaked in the sun improves absorption compared to supplements?

Make sure those mushrooms are prepared well though because as I understand it, the human digestive system has a hard time breaking down chitin cell walls, so without proper preparation, the mushrooms may pass through mostly undigested.

The point about letting the mushrooms soak up sunlight to boost their vitamin D content is totally true and absolutely fascinating though!

> When commonly consumed mushroom species are exposed to a source of ultraviolet (UV) radiation, such as sunlight or a UV lamp, they can generate nutritionally relevant amounts of vitamin D. The most common form of vitamin D in mushrooms is D2, with lesser amounts of vitamins D3 and D4, while vitamin D3 is the most common form in animal foods. Although the levels of vitamin D2 in UV-exposed mushrooms may decrease with storage and cooking, if they are consumed before the ‘best-before’ date, vitamin D2 level is likely to remain above 10 μg/100 g fresh weight, which is higher than the level in most vitamin D-containing foods and similar to the daily requirement of vitamin D recommended internationally.

Source: https://pmc.ncbi.nlm.nih.gov/articles/PMC6213178/

How do you know the changes aren’t placebo?

Because I was suicidal, had extreme mood swings and all of the muscle pain and instability.

I didn't even know about vit D, didn't research it. I just got a panel done to get an idea of what's going on with me and discovered I was severely deficient on vit D

2 years ago i caught some repeated strep throat infection, repeated like 6-8 times - because my original general doctor said that with low CRP there is no way i have bacterial infection... before i found a doctor who finally did proper swab and ABTs - but i was so far gone that i got horrible headaches, muscle pain, stinging, absolute weakness... on top of that i cought covid and proper flu. Totally crazy, when they did mi vitamin D it was at 10% of minila recomended value. I god vit D and some immunity pills(pigs blood cells - this is questionable). I was slurping the vitamin D every day and in couple of weeks I was almost back to normal.

I have seen neurologists, imunologist, infection diseases specialist, everything is boreliosis qack and even somatic doctor...

Funny thing is before i got sick i spent 3 months on tenerife, so no reason for me to have low vit D. But it was probably depleted by immunity trying to fight the repeated infections.

so yeah, get your vitamin D checked if you feel weak, low on mood or anything out of zen

Keep in mind vitamin D is really, among other things, an immune signaling molecule.

So, we know the mechanism, and it's quite plausible that supplementation works.

In other words, as an skeptic, I don't think it's just an epidemiological correlation.

Bingo. Obviously being deficient is bad, but the reason supplementation seems unimpressive is this is one of those proxies for healthy lifestyle. Kinda like how grip strength is correlated with longevity but banging out tons of hand gripper sets isn’t going to do much for you health.

Maybe this is true if you’re only considering white people. Brown people can spend a lot of time outdoors and still be deficient, especially if their ancestry is from much a much sunnier region or lifestyle than the one they’re currently living in.

Indeed: “Vitamin D deficiency in western dwelling South Asian populations: an unrecognised epidemic” … “27–60% of individuals, depending on season”

https://pmc.ncbi.nlm.nih.gov/articles/PMC7663314/?utm_source...

It has never been established that darker people require the same amount of D as lighter. The supplement industry plays on these fearmongering to boost sales.

I also suspect that the frequency of outdoor exercise matters even if the total duration of outdoor exercise remains the same. Subjectively, I feel much healthier when doing thirty minutes of outdoor exercise six times a week, than when doing one hour of outdoor exercise three times a week. But then of course, all the causal effects could have been caused by a different factor (say dopamine release) than vitamin D.

But then why do we see improvements in people that get vitamin D + K2 supplements and not exercise?

As the article mentions, we pretty much don't see improvements with supplementation.

From the article:

> the balance of evidence tips pretty clearly in the direction that people with low-ish levels would be wise to supplement

I don’t think there’s anything definitive. 400IU/day from one study is nothing if you’re deficient. 2000IU from another study is better, but even then we don’t seem to know much about absorption from these studies. For example, did it actually raise serum levels by 10ng/ml after a year, and how did THAT correlate to positive or negative health outcomes? K2 also seems to play an important symbiotic relationship with D, and seems notably absent from these studies.

if supplements don't absorb and therefore don't affect health, there's no reason to take them.

You missed the K2 part of his comment though. Both my mother and I have chronically tested incredibly low for vitmain D, both always taken supplements, both never had improvement. A couple years ago, my mom texted me saying she tried a D3+K2 supplement and for the first time in her life tested in range for vitamin D on her panel. I was skeptical but tried it, and have tested in normal range since.

Yeah, I wish the article had brought Vitamin K2 into the mix since that seems trendy to pair with your D3 these days.

It depends on one’s whereabouts and kind of exercise. Exercising in a gym or outside with all your skin covered won’t make much vitamin D.

Ding ding ding.

People who are drawing blood and trying to find some correlation between vitamin presence and health at this point are just practicing divination. The fact that it can be published in a scientific journal without any sort of RCT to back it up is palpably unscientific.

The customers of these studies are the supplement companies looking for another product to sell.

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