Vitamin D supplementation and incident dementia | Hacker News Reader

Vitamin D supplementation and incident dementia

alz-journals.onlinelibrary.wiley.com

186 pointsbookofjoe131 comments

Like all studies into Vitamin D supplementation that aren’t randomized controlled trials, it’s very hard to tell apart cause and effect. Vitamin D naturally occurs when people go outside and get exposed to the sun, and going outside is correlated with all sorts of healthy traits. Also, publicity of the association of vitamin D with good health has led people who care about their health or who have access to good medical care to supplement vitamin D. Studies that look at the health of people who choose to supplement vitamin D are examining the overall health of those people and can’t specifically measure the effects of the vitamin D supplementation. That’s one of the problems randomized controlled trials are designed to solve.

The study mentions these limitations:

> Considering that sun exposure is the most important natural source of vitamin D, the lack of information on participant-level exposure to sunlight can be considered another limitation of the present study.

> While we included education in our models, the NACC dataset has a dearth of information related to SES and therefore, SES differences could not be accounted for in our study. Future studies using cohorts with more comprehensive data on SES and other social factors would certainly provide valuable information on the associations of SES with exposure to supplementation and risk of dementia.

For what it’s worth, controlling for a variable like education can only partially remove related bias from a result (you don’t have a perfect measure of how a person decided to take vitamin D).

When evolution molds a genepool it does so with inbuilt assumptions, one the assumptions is exposure to some level of sunlight. Deviating from these assumptions would result in undefined behavior (in the CS sense) for individuals.

If an individual cannot or will not expose themselves to sunlight, taking D3 is probably the best option they have.

In my opinion, these are the best options if you want to be healthy like people who get sun exposure (in order from most to least likely to work):

1. Act like a person who is exposed to sunlight. Walk, run, don’t spend every day at a bed, couch, or desk.

2. Expose yourself to sunlight.

3. Supplement vitamin D.

The last time I took a casual glance at studied, it seemed that vitamin D deficiency was correlated with multiple health conditions; however, vitamin D supplementation had not clearly prevented or reversed those conditions. That is, this isn't like scurvy.

A common hypothesis was that vitamin D status was a proxy for sun exposure and not a complete explanation for those health problems.

> Vitamin D naturally occurs when people go outside and get exposed to the sun, ...

Not sure where you are living? If I go outside in winter (+2 months around) I need gloves, cap, scarf. Literally only a little portion of my face gets some sunlight until 5pm. Then it is dark!

I live in Germany!

So, this isn't an argument for a lot of people in cold countries or dark countries. Mostly both..

Exposing to the sun is very hard here around the year.

It's hard to find good answers on actual timelines, but vitamin D is fat soluble and you don't become insufficient after just a week of sitting in the dark.

More like six months.

I am talking about months of actual lack of sunlight, not a week.

I for myself know 2 friends which diagnosed with vitamin D insufficiency. Because we are relatively young this lead to bone problems while doing sports. Without sports it wouldn't be recognized.

Interestingly, this was a bit over-diagnosed maybe 10ish years ago. Not saying this was the case, but some doctors were ordering VitD tests, getting results that said below average or below normal and interpreting it as insufficiency.

You sure do by February or March though, if the last time you spent an afternoon at the park (or the beach) was late August.

I had thought that it was possible to get vitamin D from moderate sun exposure in the winter and went looking for info to refute your post. Turns out you are right and I was wrong: https://www.nytimes.com/2022/12/06/well/live/vitamin-d-defic...

People living above the 37th parallel, basically the tropics, may not be getting enough in the winter, because the sun isn't strong enough to provide it.

It’s brutal, I live near Toronto and not only is the winter sun quite weak but sunny days are quite uncommon. Almost every day is grey and overcast. Combine that with short daylight periods and winter becomes quite the gruelling challenge in terms of mental health especially.

Weeeellll :)

Toronto Harborfront Center is at 43.6397877,-79.3836877,17.12z according to Google. If I look for the southern most part of Germany, that seems to be Oberstdorf which is at 47.3997083,10.2805651,14.08z ;)

Or in other words, Germany in terms of natural sun light exposure in winter is way worse than Toronto. In fact, in Germany its dark much earlier and sun comes up much later for longer. I hear cloud cover is very comparable to the Toronto weather you describe so aptly.

One of the most populated areas of Germany is at around 51.5, if we wanted to "guess" where aldipower might be from. Going mostly straight up from Toronto, if you want to hit "civilization" at that level, that's Waskaganish, QC or Moosonee, ON a bit more south, right on our beautiful Hudson Bay.

I complain less and less about our beautiful country, the more I compare it w/ the world ;)

Wow, TIL. That’s kind of nuts, I just looked at latitude lines because I was sure you had to be wrong but it looks like where I live (which is actually Hamilton) is the same latitude as northern Italy. In fact, it’s almost exactly the same as Florence, where the forecasted highs over the next week are in mid- to high-teens (C). We have a blizzard and most days next week the high is 1 degree. I honestly didn’t realize how much climate is not strictly determined by latitude!

Wind and ocean currents make Western europe way warmer than Canada for a given latitude. Ottawa is only about 45 degrees north, same as Paris. Most of England is further North than that.

Minneapolis is also at 45 degrees; in fact there's a plaque in a public pathway that marks the exact spot. We just recently started getting sunlight at 5 PM again, but that will change soon once DST takes effect.

Europe is going to be in big trouble if the gulf current ever stops flowing.

Paris is almost 49 degrees north. Even Ottawa is closer in latitude to Milan

Not just England, try Scotland and some of its Islands.

Not much chance of Vit D from sunlight for almost half the year.

Penzance 50.1 N London 51.5 N Berwick 55.8 N

Edinburgh 56.0 N Aberdeen 57.1 N Thurso 58.6 N

Kirkwall 59.0 N Lerwick 60.1 N Haroldswick 60.8 N

Cries in Nordic

I take 30 minutes longer lunch breaks in winter the days the sun is out, just to be able to get outside.

It's more or less impossible to get natural Vitamin D otherwise -- any spare time will be during the dark hours.

You're welcome.

Also: Look up New York City ;)

And even then, Toronto gets about 2000 hours of annual sunshine, while London (a D swathes of Northern Europe) get about 1600 hours :(

Yes, thank you for this. I would additional repeat myself to say a very simple thing. If you have to wear clothes over your skin, because it is cold, no sun at all helps you out. I do not go out in a t-shirt when it is snowing..

BTW Inuit getting there vitamin D from fatty fish and other animals, not from the sun.

Yes, this is the reason people further from the tropics tend to have lighter skin and are more likely to have genetics allowing for lactose tolerance throughout life. They're natural adaptations by the body, in response to being in an environment which sunlight (and therefore vitamin D) is more scarce.

The lactose tolerance part doesn't really make sense because dairy products are not naturally high in vitamin D. Companies add the vitamin D to milk. Butter is an exception because it is nearly all fat, so it has a lot more vitamin D. But, because butter is nearly all fat, it also doesn't contain much lactose and is usually well tolerated by people with lactose intolerance.

I have read that the correlation of latitude and lactose tolerance has to do with the fact that milk was less prevalent in warmer climates because it did not store or travel well. So unless you grew up right around milk producing cattle, your gene pool had little exposure too it and thus little evolutionary pressure to continue to tolerate milk after infancy.

By contrast, Europe has a much colder climate and was well suited to dairy cows and storing and shipping dairy products.

So you're saying darker skin prevents the body from producing vitamin D? (Not saying it doesn't, I just didn't know.)

Also, what does lactose (in-)tolerance have to do with… anything? To my knowledge, the fact that lactose tolerance is that common among Europeans is largely a result of thousands of years of domesticating dairy animals. Not all light-skinned people in the world are automatically lactose-tolerant (or "are more likely to have genetics allowing for lactose tolerance throughout life" as you say).

Wikipedia agrees:

> Lactase persistence evolved in several populations independently, probably as an adaptation to the domestication of dairy animals around 10,000 years ago. Today the prevalence of lactose tolerance varies widely between regions and ethnic groups. The ability to digest lactose is most common in people of European descent, and to a lesser extent in some parts of the Middle East and Africa.

https://en.m.wikipedia.org/wiki/Lactose_intolerance

Also see the map on https://en.m.wikipedia.org/wiki/Lactase_persistence .

Seems like skin color is a trade off between protection from skin cancer and getting enough vitamin D. People in areas with abundant sunlight can get all the vitamin D they need from the sun with dark skin while being protected from cancer. People in areas with lower levels of sunlight don't need as much protection from skin cancer caused by the sun but their lighter skin does permit more vitamin D collection from that weaker sunlight.

For europeans - you'd have to go to southern Greece islands like Crete to get below 37th. Even Athens is 37.59 and northen Greece is 40 and above. So basically most of the Europe won't get enough during winter.

Even if there is no sunlight for half the year (and this completely equalizes vitamin D levels in winter), various confounders of sun exposure will still affect a study on vitamin D levels, assuming the study collects some samples during the period when there is sunlight and vitamin D levels vary.

Also, the confounders of vitamin D supplementation I mentioned would apply even if you never get exposed to the sun.

I think your comment is assuming the vitamin D supplementation is effective, when that hasn’t really been established. We don’t even know that vitamin D has a direct effect on most of the correlated health measures.

Our bodies can store enough to make it through the winter if you are replete at the beginning.

That, of course, assumes you don't wear sunscreen during the summer/fall, which I do

You might enjoy this article:

https://www.outsideonline.com/health/wellness/sunscreen-sun-...

That is kind of beside the point. You would have to prove that people in cold countries never get any vitamin D from the sunlight throughout the entire year to eliminate it as a factor.

You would also have to be able to prove that people people with vitamin D Rich diets are identical to those without them.

Without a randomized controlled trial of vitamin D intervention, there is no way to say for sure that people with more or less vitamin D are seeing a benefit from the vitamin itself, and not some other hidden Factor.

Of course it is possible to give a randomized portion of subjects additional vitamin D and the rest a placebo and see if one portion is less likely to develop a disease than the other.

Of course, which is the point that I am making as well as the grandparent post.

Studies which have not done this should be taken with a grain of salt.

Recommend to adults vitamin D intake of 4000 IU (100mcg) daily (or at least 2000 IU) in the absence of testing. 4000 IU is widely regarded as safe.

https://vitamindforall.org/letter.html

It is not limitations. It is just that the findings should be presented truthfully and the authors should not try to suggest more than can actually be inferred from the data.

Correlation between facts is interesting in itself, but to general public it should be clearly presented that "although we can prove these things are correlated, we don't know why and how and whether one causes another or vice versa or there is something else causing dementia as well as making people more likely to supplement with vitamin D".

Without putting this warning label I treat it as kind of "scientific clickbait"

I'd also mention this isn't the only study with this sort of problem. Any health study looking at things that push people out of the house have this problem. People that can leave their homes tend to be in better health than people that can't.

I think the influence on this study is probably inverted though as supplementation could be based on a recommendation to compensate for lack of outdoor time as opposed to a study that measured levels.

>Vitamin D naturally occurs when people go outside and get exposed to the sun, and going outside is correlated with all sorts of healthy traits.

And also increases the risk of skin cancer and Parkinson's!

You what? Sun gives you Parkinson's now?

If you have limited melanin where does it go, your sun tan or substantia nigra?

I make melanin in my melanocytes.

> I make melanin in my melanocytes.

It's a finite rate, which means there's a useful limit of production.

I don't think the ones in my meninges are making it for my skin.

> Vitamin D naturally occurs when people go outside and get exposed to the sun, and going outside is correlated with all sorts of healthy traits.

There is a difference between studying the effects of vitamin D and the effects of vitamin D supplements though. I agree with you on the "general health" variable, because I think it's likely there is some correlation between being somewhat health-conscious and taking vitamin D supplements (unprompted).

However, there is no correlation between going out in the sun and taking supplements. (There might actually be a slightly negative one as some people might start taking them in winter when they don't get a lot of sunlight).

So if you see a strong correlation between taking vitamin D supplements and reduced prevalence of dementia, I don't think this could be caused by sunlight exposure.

It's possible that all these studies are wrong and that Vitamin D supplementation is pointless. Information is never perfect.

But at this time, on the balance, vit D supplementation seems like a pretty sensible bet for anyone living in far latitudes during winter, especially people with more pigmented skin. It looks like there's very little risk of harm, and it's cheap stuff.

I’ll try to get 15-30 min of sun exposure without sun screen in the warmer months each day. Feel immensely better during then, to a point where I’ve seriously considered moving somewhere warmer without real winter months.

Same here, hello from the Space Coast!

Even during winter I try to get some exposure on rare sunny days. The other day we had a very clear day so I sat out on the porch facing the sun for fifteen minutes... in -5c.

Is UV the sole reason for the generation of Vitamin D?

Vitamin D is found in fish, and milk usually has added vitamin D (so you can use the calcium). If you eat 20 eggs you can get 100% of your daily value of vitamin D from that, but I don't recommend it.

Besides dietary sources you need UVB to make vitamin D: https://en.wikipedia.org/wiki/Cholecalciferol

Doesn’t sound like a good idea to forego the sunscreen…

He's probably in a colder climate with minimal UV given his/her reference to "in the warmer months"

Why not?

Perhaps not many in this audience are dealing with having to mitigate the prospect of dementia. How about something close to the horizon for almost all of us?

> Vitamin D deficiency can cause over‐activation of the pulmonary renin‐angiotensin system (RAS) leading to the respiratory syndrome. RAS is regulated in part at least by angiotensin‐converting enzyme 2 (ACE2), which also acts as a primary receptor for SARS‐CoV‐2 entry into the cells. Hence, vitamin D deficiency can exacerbate COVID‐19, via its effects on ACE2.

— Vitamin D and COVID-19: Role of ACE2, age, gender, and ethnicity. J Med Virol. 2021 https://pubmed.ncbi.nlm.nih.gov/33990955/

> Angiotensin-converting enzyme 2 (ACE2), a part of the renin-angiotensin system (RAS), serves as the major entry point into cells for SARS-CoV-2 which attaches to human ACE2, thereby reducing the expression of ACE2 and causing lung injury and pneumonia. Vitamin D, a fat-soluble-vitamin, is a negative endocrine RAS modulator and inhibits renin expression and generation… Therefore, targeting the unbalanced RAS and ACE2 down-regulation with vitamin D in SARS-CoV-2 infection is a potential therapeutic approach to combat COVID-19.

— A brief review of interplay between vitamin D and angiotensin-converting enzyme 2: Implications for a potential treatment for COVID-19. Rev Med Virol. 2020 https://pubmed.ncbi.nlm.nih.gov/32584474/

Here’s a caveat to remember when taking vitamin D:

> Majority of the adults are deficient in both vitamin D and magnesium but continue to go unrecognized … Mg is essential in the metabolism of vitamin D, and taking large doses of vitamin D can induce severe depletion of Mg. Adequate magnesium supplementation should be considered as an important aspect of vitamin D therapy.

— Magnesium Supplementation in Vitamin D Deficiency. Am J Ther. 2019 https://pubmed.ncbi.nlm.nih.gov/28471760/

Infrared is the missing part: https://youtu.be/wadKIiGsDTw Especially for covid, dementia, autoimmune diseases

https://vitamindforall.org/letter.html

I've been taking 1000 IUs daily, for the last 20 years, skipping summers (during which I would attempt sun exposure), while continuously being within acceptable medians for my age. I sure hope what I am typing now makes sense :-)

Any chance you have an identical twin who has not?

Older folks can't make D naturally, so you may want to skip your summer skipping soon.

For all we know they are only 20 years old.

People haven’t been doing things since birth, obviously and especially taking pills. Also this is a thread on dementia, not typically indicated in young adults.

I’d get a cold at least once a year and the flu every few years. I started taking 5K IUs of D3 daily in 2019 and haven't had a cold or flu since then.

Flu spread among all humans (not just those supplementing vit D) was massively reduced in recent years because of a little thing called COVID-19 and all the social distancing/lockdowns that led to...

I live in a household of 4, everyone has continued to get colds at least once a year including covid but I have not had any symptoms of infection and attribute that to my daily intake of D3.

4000 daily during flu winter seasons. It probably works.

https://vitamindforall.org/letter.html

Broke my ribs here due to dangerously low Vitamin D. Was already on Vit D supplements. Later learnt about the entire stack of

Vitamin D + Magnesium + Vitamin K2

Vit D 60k IU once a week, Magnesium Glycinate 350mg every night, Vitamin K2 100mcg per day

The enzyme that converts Vit D into its active form, that enzyme requires Mg for its activation. I was previously taking Vit D for 1 year with almost 0 movement in my blood levels. Magnesium changed that.

I had healthy blood levels of Calcium. Yet my ribs cracked. The problem was lack of K2. But I eat enough meat mainly chicken, then why? Turns out chicken need to be fed grass (contains Vitamin K1) which their bodies convert to K2, so if I eat grass-fed chicken my body would get K2. Chicken are mass produced and fed some grain whatever is probably the cheapest food required to make them grow. No K1 for Chicken. No K2 for me. Welp.

Started taking the combination above. Went from Vit D level of 20ng/ml to 135 ng/ml in a matter of 3 months. Have dialed down the supplements in order to stabilize at a healthy level (aiming for 70-80ng/ml).

I’d like to supplement but every time I take one I get muscle cramps. I suppose it’s just pulling all the magnesium out of my body or something?

I tried magnesium supplements with it but it didn’t help.

Maybe 5000IU is just too much?

From what I understand, vitamin D causes calcium to be released into the bloodstream which can cause cramps. Are you taking vitamin D with vitamin K (MK-7)? Taking MK-7 ensures calcium is deposited in your bones, not your arteries.

I take mk7 with it too. But perhaps it’s a lack of calcium that’s the issue.

It is important to co-administer Vitamin K-12 with the D due to its effects on calcium.

K-12? Do you mean K2?

Id suggest you get a couple vitamin d tests in different seasons and also consider your latitude. i was taking about 4000iu + natural sources in the winter and i still tested low and had to increase my intake. If you dont test you're sorta just guessing.

take with meal or fats.

cramps could also be from low potassium.

my natural sources i use are - whole fat yogurt - pastured eggs (way higher in vit. d than grain fed) - kippers/hering fish in can (no oils)

oh and like someone else said. i do this too. i take my vit d and k2 mk7 at the same time - with a meal or fatty food always.

How much K2 do you take? 100mg? And do you vary the time of day that you take it?

ill take 100mcg mk7 + i eat mild kimchi once a day which is also a source. as for timing i just take after my meal. i eat one meal a day or two meals a day (and zero snacks), but my timing of those meals always varies a lot but it's always after ive had my fats and proteins during my meal.

i am (was?) someone who gets plaque build up in their teeth quickly if i dont brush morning and night every day. once i started k2 that completely stopped. i was shocked at the difference. of course i stil brush in morning and after my last meal but the feeling in my teeth of plaque building up just vanished with daily k2.

i use the now foods brand, its not expensive and I think its made from commercially grown natto. you should not have to pay more than around $10-15 for one month supply.

this cardiologist has a nice short lecture on k2 that really opened my eyes to it. https://www.youtube.com/watch?v=z3njgh2nFRk - he recommmends 200mcg per day

I do 8k but combine with K2

This is a very neutral headline. But for the tl;dr crowd:

> Across all formulations, vitamin D exposure was associated with significantly longer dementia-free survival and lower dementia incidence rate than no exposure (hazard ratio = 0.60, 95% confidence interval: 0.55–0.65). The effect of vitamin D on incidence rate differed significantly across the strata of sex, cognitive status, and APOE ε4 status.

You can get your APOE ε4 status, which is a marker for Alzheimer's and dementia, from any DNA test like 23AndMe. To protect your privacy: use a fake name, new email address, and get a temporary UPS Store mailbox address for the kit to be mailed to. Use a Visa gift card for payment. Yes, it can be done and it works.

>To protect your privacy...

You can't really expect too much privacy with a DNA type test, right? Since it knows all of your relatives who have also (or will ever) taken the test.

Even if they correlate your test results to your relatives, so what? If you’ve used a fake name and mailbox, they can’t know who you are. You’re just a set of AGCT encodings.

The paper this article discuss is already more than 4 years old:

https://www.smithsonianmag.com/smart-news/you-could-be-ident...

...the odds of being positively identified by your DNA is or soon will be almost certain.

You’re missing a key part of that article:

> a good sleuth could construct a family tree and then conduct more targeted research that might lead to someone who had never submitted his or her DNA for testing, as was the case with the Golden State Killer

So this assumes the sleuth does “targeted research”. That’s only going to happen in things like criminal cases or other cases of big interest. It’s not going to happen to someone like me, an average Joe who has no one looking for him but is looking to protect his privacy by attaching a fake name and address to a DNA sequence.

It ought to be enough for the company to make a credible promise to send you the data and delete their copy. Is there really nobody who does that?

You can never have DNA privacy because you leave it behind wherever you go. It's also probably not worth anything.

Here's a link to that page on 23AndMe: https://you.23andme.com/reports/ghr.alzheimers

In essence, this gene controls the levels of cholesterol and fats and the blood. If you're prone to high cholesterol and triglycerides, you can mitigate it with a low dosage statin or through diet modifications.

About ten years ago an article on supplements was followed by a list of what the doctors took personally. They didn't take much but 4 out of five took 2000iu of vitamin D a day. My experience is, if you have gout start taking vitamin D.

Natural Vitamin D level is a marker of sun exposition, not the effective part of the sun.

Infrared is the important part, it is necessary for our system to control inflammation in mitochondria.

Already ton of research on this, but still completely neglected.

Hey people who follow the science: As an “indoor human”, how much should I be taking? (TIA!)

I wouldn’t say I have followed the science but my doc prescribed 2000 IUs daily and it definitely makes a noticeable difference in a gloomy winter

What kind of a difference have you noticed? I also take 2000 IUs, but I haven't noticed any significant difference in how I feel since I've started taking it.

How are feeling generally? It's possible you didn't have a deficiency to start with. I went from being completely depressed, barely able to get out of bed to mostly functional (although still not quite as chirpy as I am in summer) when I started taking a vit d supplement in winter.

you might want to check on your Vitamin D receptivity. For example, I took a DNA test, and it indicated my Vitamin D receptors weren't as efficient as normal so I should take higher doses than other people.

I personally just felt a little sadder and lower energy in my first winter in a gloomy climate. The vitamin D just made me slightly more chipper and energetic.

I didn’t do a blood test pre vitamin D but tested recently and my levels look good, so my doc said to just keep on it.

Wouldn’t say the difference is transformative but it’s helpful.

Up to 4,000 IU is generally recognized as safe. If you take a multivitamin, there is some in that that you should subtract.

https://www.health.harvard.edu/staying-healthy/how-much-vita...

Test your current level, ideally in the winter or early spring. If it’s low or low-normal[1], start with 2000 IU/day. Wait 6-9 months, test again. If it’s still low, increase to 4000 IU/day.

The comments on this submission have more: https://news.ycombinator.com/item?id=34634977#34635562

[1] If it’s really low, see a doctor

Some might not like this answer but the best course of action is still some sun exposure. As for the actual answer, someone correct me if I'm wrong but there there are multiple 'variants' of vit. D and the vast majority of "vit D" supplements most likely don't include the complete formula (which is arguably the best way in order to also assimilate it "fully"). The daily recommended dose is fine unless you're deficient.

There are places where it is impossible to get the recommended amount of sun exposure, even if you were to spend most of your day outside.

There's an app called Dminder that notifies you when the sun is in the optimal position (highest point in the sky) to generate Vitamin D based on your location.

Where I live, there is no optimal position for 8 months of the year.

Older folks most at risk can't make it naturally. D3 is the best bet and complete.

If you consider yourself too old for getting outside than you are having too bad quality of live to have a reason to keep care on your health.

Nope, older folks can’t make it—period. Not even sitting in a bikini at noon at the equator. We lose the ability as we age.

Where I live, it is impossible to get strong enough sunlight for 8 months of the year. Everyone here is deficient without supplementation.

I would advise taking a K2 MK7 supplement with D3, or get a supplement that contains both. Personally, I take one capsule a day that contains both 3000IU of D3 and 100μg of K2 MK7.

D3 by itself can cause high calcium levels, to the point of toxicity in very high doses. The K2 moves the calcium from the blood to bones.

I take LifeExtension K2 MK7. It's quite inexpensive and LifeExtension is reputable brand.

> Personally, I take one capsule a day that contains both 3000IU of D3

Not sure how much D3 you're getting (though starting with 3K IU is a lot) because it's not clear how much gets through the gut. You might want to take some cod liver oil (Ω3 capsules) at the same time -- the fat is believed to improve the still mysterious absorption process.

Typical dosage is a drop of cholecalciferol suspension under the tongue for direct absorption.

The Japanese recipe for fermented soybean, called Natto is an abundant natural source. Not easy to find in the US though. I've found it offline at Japanese groceries and one boutique grocer at an exorbitant price so far.

Rather an acquired taste though. I don't mind it (though have never gone out of my way to find it); my Japanese partner can't stand it.

I had heard that myself but was a bit disappointed in the very mild flavor and coffee-like smell. Needs a bit of soy and mustard to give flavor. Not as odd as people said imho, and more accessible than kimchi. It is gooey however.

Possibly good for prostate health as well. Another reason to try I forgot to mention.

Can't we just get D3 without calcium?

>D3 by itself can cause high calcium levels

I developed a calcification in my arm due to this. My wrist was in pain and I couldn't bend it. Got an x-ray, and boom: what looked like a little ball of bone had appeared.

Stopped taking D3 immediately and my body reabsorbed it, never had it again.

Funny enough, it happened when I was visiting Paris. Got to use Google Translate to explore the French medical system. Fantastic service, people aren't joking! :)

Something between 2k-10k should be fine.

Talk to your doctor. Probably nothing. See my root-level comment.

First get tested to see how deficient you are. I was prescribed 50,000 IU a week for 8 weeks because I have 12 ng/mL. Standard range is 30 to 80 ng/mL.

Not science person but I took some and I was too sleepy, all day. Also there are about 4-5 hours until it promotes the production of melatonin and so you have to time it right. Also it is fat soluble, you need to take it with your (fat?) meal.

Easiest to just take it in the form of fish oil capsules.

Though you can't take larger doses like this, because fish oil also contains vitamin A which can be toxic in higher doses.

What problem is it solving? curious.

later edit: ahh, oil, fat :)

Vitamin D is fat soluble like you said. Vitamin D dissolved in fatty oils from fish should be more easily absorbed, which means you could take it without a meal.

Also, the omega-3 fatty acids in fish oil are good for you, and it provides vitamin A and E.

It's a win-win-win-win!

If you are truly an indoor human, start with 10k iu daily and possibly titrate up from there based on bloodwork. Absorption can differ significantly between individuals

test first, supplement with test results

The most important first step is to test your current levels. Then you can use a Vitamin D calculator[1] to help get you a starting point for how much to supplement based on your desired target level -- recommended target range is 40-60 ng/ml (100-150 nmol/L). Then re-test in 3-6 months to check levels and adjust supplementation as needed.

[1] Vitamin D calculator: https://www.grassrootshealth.net/project/dcalculator

You need infrared also, vit-D is only part of it.

https://youtu.be/wadKIiGsDTw

Science allows you to get your Vitamin D tested, otherwise you're just guessing.

I dove deep into Vitamin D supplementation research during Covid. The tl;dr as I understand it - and bear in mind I'm a layperson in this - is that while Vitamin D deficiency correlates to many bad things, taking Vitamin D doesn't help. It does raise your level as it shows up in blood tests, but the bad things still happen.

Except for some very specific issues.

I have a mild deficiency and used to take Vitamin D. I stopped taking it after consulting with a doctor on the meaning of the VITAL study results [1]. I also recommend [2], from a practicing surgeon who deals with Vitamin D related medical issues in patients.

[1] https://pubmed.ncbi.nlm.nih.gov/35939577/ [2] https://www.devaboone.com/post/vitamin-d-part-3-the-evidence

Thank you for this. I've heard that it's not so much the Vitamin D itself that may be beneficial, but rather the process whereby Vitamin D gets produced that results in the benefits.

The tapestry of cells in our bodies has evolved over millions of years to function in a way that is most favorable to propagating themselves in the context of the environment in which they underwent natural selection. It seems we've removed ourselves from that environment in a lot of ways and then have been trying to compensate for that by micro-managing telemetry that we're able to easily or cheaply observe. However the underlying complexity is far, far beyond what we see as the end result of the cellular processes.

For those of us with winter to deal with the better approach might turn out to be judicious use of UV tanning beds.

>while Vitamin D deficiency correlates to many bad things, taking Vitamin D doesn't help.

Your links state the exact opposite and it's important to get wording right here. If you have a tested vitamin D deficiency (and it's not "mild", as Deva Boone highlights), there are CLEAR benefits to supplementing.

It's only in healthy individuals where the benefits are tiny (like the cancer testing 0.9% v 1.2%) or non-existent.

I should have been clearer.

The way I understand it, for healthy people, a low Vitamin D result on a blood test doesn't merit supplementation.

For various specific illnesses, diagnosed separately, addressing Vitamin D deficiency through supplementation could help.

(Not a doctor, don't take medical advice from HN comments)

There have been many other studies on vitamin D and COVID-19. Recommend reading them all before forming a conclusion.

https://vitamin-d-covid.shotwell.ca/

FWIW, I think the article agrees.

> vitamin D effects were significantly greater in females versus males and in normal cognition versus mild cognitive impairment.

> vitamin D effects were significantly greater in apolipoprotein E ε4 non-carriers versus carriers.

Translation: If you’re already cognitively impaired, vitamin D can do little to fix that. Same goes for if you’re at high risk for Alzheimer’s genetically (ApoEε4), or generally at higher risk for neurovascular diseases (male).

However, as I’m sure others in the comments will point out — supplementing vitamin D will at least ensure you’re not getting cognitive impairment due to vitamin D deficiency, which seems to absolutely be a thing.

The reason is because vit-D is a marker of sun exposition but the the important part.

Infrared is: https://youtu.be/wadKIiGsDTw

TLDR: get some real sun, if you can’t infrared light.

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