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The Big Vitamin D Mistake (nih.gov)
756 points by pacaro on Dec 7, 2017 | hide | past | favorite | 441 comments

Anecdotally, I had this discussion with a cardiovascular interventionist specialist about seven or eight years ago when I was managing a team of cardio theatre orderlies in a private hospital. He made the comment, "mark my words, in about five to ten years time there will be a major scare about needing to absorb more vitamin D".

His opinion was that the increase in sunscreen usage and the push to avoid skin cancer by staying covered up was likely to blame. I find it interesting when articles such as this pop up, because it directly reflects his concerns from those years ago.

For reference, this was the late Dr Geoffrey Mews (who I only just realised has passed on while I was looking for a reference to post. That's made me a bit sad now)

The NIH guys also did a study that said that even in tropical countries, Vitamin D absorption has fallen dramatically because of lifestyle changes. One of the probable factors is the lust for fair skin. I routinely see people covered from head to toe to help them stay fair skinned, even kids are sent to play covered in full sleeve clothing.


When the burn time is less than 10 minutes, you need to cover them up or have them play in the shade. The UV index for tomorrow is just shy of 14 and we are a month or two from the time of year when it’s highest, you would need medical treatment for a child who played in that and was uncovered all day.

Related: I found the old measure (burn time) much easier to use than the new UV index, and while having it standard across countries is good, it’s not straight forward to convert.


That UV index stuff is no joke. My girlfriend spent an hour "sunbathing" in the canary islands and came back with the most incredible sunburn I've ever seen. I'm mega paranoid (SPF 50 all the time in hot countries) and didn't notice anything damaging but she had to be covered in aloe vera creams to numb the pain.. it affected her sleep, it must have been unbearable.

Not sure what the health qualms are with lack of Vitamin D bit I'm certain I don't want to advocate in favour of potentially harming people as much as my girlfriend experienced.

> Not sure what the health qualms are with lack of Vitamin D

Rickets and Osteomalacia are the big ones, I think. Both are a form of softening of the bones. Vitamin D apparently helps regulate the absorption and use of calcium, magnesium, and phosphate in the body.

Ouch! I've gotten a few bad sunburns in Los Angeles, but that sounds like something else.

My sunbathing policy is to go without sunscreen but only for 20-30 minutes daily around noon.

I never took the time to investigate how accurate this site is, but it seems quite nice since it has uv index, time to skin redness and time to sunburn:


> One of the probable factors is the lust for fair skin.

I think this must be cultural. Certainly in my experience in the United States, the lust is for tanned skin. There are even tanning salons, where one can lie down in a machine which floods one's skin with UV.

Now, I personally love fair skin, and have never understood why others seem to love a tan so much.

It's a cultural thing, and directly related to wealth (or class, if you prefer).

If most people work outside for a living, then the sign of wealth is that you don't have a tan. If most people work in offices, then the sign of wealth is that you have a tan, implying that you went on vacation or otherwise have the available leisure time.

When most people do manual labor, having impractically long fingernails demonstrates that you don't have to do that.

When most people have two or three sets of clothing, changing clothes several times a day demonstrates your wealth.

When most people eat a subsistence diet, being fat is demonstrating wealth. when most people eat fast food, being thin demonstrates your superior resources.

If most people need to pay attention to what they are wearing at their jobs, dressing in a way which signals that you don't have to pay attention is a status marker.

If everybody drives a car, picking an unusual vehicle can be a status marker. What's the difference between a Chevy Silverado 2-door and a Ford F-150 SVT Raptor? They demonstrate different spending priorities.

Tanning salons are on a steep downturn [1] (at least the UV ones, spray tans are a different thing).

1 - https://www.bloomberg.com/features/2016-tanning-salon-indust...

1 - https://www.bloomberg.com/features/2016-tanning-salon-indust...

Fathers family was Irish, Mothers Scottish.

I burn in front of a monitor, I have fair skin because factor 50 and covering everything I can are simply required.

And in Asia they sell skin-whitening lotions.

I live in southern Brazil (one of these tropical countries), where sunlight is not that easy to get; also people dress up and cover themselves much more than in other regions due to not only the weather but also for cultural reasons. In fact, the city where I live (Curitiba) has a huge portion of people who need vitamin D supplements, to the point this deficiency became folkloric. I was quite "happy" to learn last year that after a full decade here my blood exam showed for the first time in 35 years that now I need vitamin D supplements too.

Fair skin is a lot better than skin cancer!

Sure, but higher melanin (ie, darker skin pigmentation) is correlated with lower cancer rates [1][2]. So the point is that cultural changes are causing people who were previously were at lower risk of cancer due to their skin pigmentation/higher melanin, to now have reducing melanin/pigmentation, therefore increasing rates of skin cancer.

[1] https://www.cancer.org/cancer/skin-cancer/prevention-and-ear...

[2] https://www.cdc.gov/cancer/skin/statistics/race.htm

Aren't those links about "people with naturally darker skin"? I'm not sure how cultural changes can affect that. Rich people may eat caviar, but eating caviar won't make you rich...

> The tan is caused by an increase in the activity and number of melanocytes, the cells that make the pigment melanin. Melanin helps block out damaging UV rays up to a point,

It's not particularly clearly worded but to me that seems to suggest that tanning increases melanin and that melanin helps prevent cancer regardless of whether your dark skin is natural or tanned.

But if tanning also produces cancer it remains to be determined which effect dominates (unlike for people with naturally dark skin, where the effect can only go in the beneficial sense).

Every source I've seen clearly states tanning always increases your chance of skin cancer. Tanning does provide a small amount of protection against burning (around 3 SPF worth), but no protection against cancer.


They studied based on 2 weeks of tanning which is very minimal.

You clearly get more than SPF 3 with a deep tan as you can spend 8 hours in direct sun without obvious problems. Without any tan you get a burn in under an hour suggesting ~SPF 10+.

Broadly, my understanding is that a major change in skin tone is 'worth' about 15 SPF, so tanning would fall somewhere below that.

For a fixed amount of sun exposure, spreading out the duration is better both to establish a tan and to allow more time for skin recovery. But there isn't really a case where tanning increases safety, because you get the tan via exposure.

It's like saying pilots who practice a lot are safer; for any given flight it might be true, but cumulative risk can only rise.

I thought it was burning that was associated with an increased cancer risk, not just tanning in general?

Indoor tanning is associated with higher rates of skin cancer: https://www.cdc.gov/cancer/skin/basic_info/indoor_tanning.ht... I suspect outdoor tanning is as well.

We know that genetics and environment both play a significant role.

So think about it this way:

If you're genetically predisposed to having very dark skin, you will be able to tolerate more UV exposure without significantly increasing your risk of cancer. And by continuing to be exposed to high UV levels, your body will continue to produce melanin to keep you protected. It's a feedback loop.

If you're genetically predisposed to having pale skin, but then expose your skin to higher levels of UV than your low melanin levels can guard against, you will sustain significant sunburn, and if you do this repeatedly you'll significantly increase your risk of skin cancer. But if you gradually expose yourself to moderate levels of UV you can gradually increase your melanin levels more safely, but only as far as your genetics allow. (This is theoretical of course; we know very well that it's very hard for fair-skinned people to expose themselves to UV light from the sun or tanning beds without overdoing it, hence the widespread occurance of skin cancer.)

My educated guess about the notion that dark skinned people are experiencing higher levels of cancer would be that if a dark-skinned person keeps avoiding UV for long enough, their melanin levels start to decline (due to it not being an optimal use of resources), but then if/when sun exposure happens, the protection isn't as strong and the risk of cancer is higher.

The notion of 'building up a tan' is dangerously wrong advice. Even for people with darker skin it is unwise to have significant bursts of UV exposure.

I'm curious as to whether your educated guess derives from a clinical background, or reddit?





The notion of 'building up a tan' is dangerously wrong advice.

I know, I acknowledged that in my comment.

My main point was only about the extent to which people with genetically high melanin levels are at much lower risk of cancer (which your first link confirms), but how their risk might increase if their melanin levels drop.

I don't dispute that it's a complex and dangerous topic. And as someone with genetically very pale skin, I most certainly steer well clear of direct sunlight and make no efforts to develop a tan.

I'm curious as to whether your educated guess derives from a clinical background, or reddit?

That's a low blow :)

I rarely go anywhere near Reddit, certainly not for anything to do with health. I have spent 10+ years researching health topics for reasons to with serious, chronic, illnesses I've endured, and have now largely overcome thanks to what I've learned.

It was a low blow. Sorry. I've been watching my uncle and father die slowly from melanomas, chunk by chunk cut out of their faces, their backs. My uncle still has a healthy deep tan.

And even last year I heard girls talk about building up a 'base tan' before summer. Roasting like rotisserie chickens under the solarium lamps.

That's what the above poster already said.

> people who were previously were at lower risk of cancer due to their skin pigmentation/higher melanin

Unless the above poster means “due to their [acquired] skin pigmentation” I don’t see how the comment can make any sense. Why would their rates of skin cancer be higher now?

Maybe OP is referring to spray tans? That's my best guess.

I've known about the sunscreen misinformation for a long time.

My dad died of malignant melanoma. He wore sun screen all the time. He didn't swim. He would wear sun hats. He was paranoid, and likely had premonition of it. Unfortunately, his prevention methods might have actually exacerbated his odds even further because he was depriving his skin of one of its few natural healing modalities.

I'm sorry to hear you dad died of melanoma. But I can guarantee that reducing his UV exposure did not increase his risk. It's possible that intense and closely repeated sun exposure as a child had already caused DNA damage.


Anyway, please wear shades and a hat.

You're right, my father had bad sunburns as a child. Shades and hat are a good tip, as is reducing UV over-exposure.

My point is that moderate sun exposure is healthy and good melanoma prevention. From what I've seen, there is quite a bit of research to back this up.

I think that better education about this would encourage people to develop healthy relationships with the sun at a young age. Right now the conventional wisdom seems to be "just throw sunscreen at it" / "stay out of the sun unless you are wearing sunscreen" and I think this totally misses the point.

My caution is that it's unwise to tell people to avoid sun exposure in total. While sunscreen does seem to be helpful in slowing sun damage, it'd also be unwise to suggest that sunscreen will protect people from overexposure, there isn't really evidence for that. There is a whole body of research. Take a look at some of the studies cited in this article http://m.jabfm.org/content/24/6/735.full

What does that have to do with the price of tea in China? Not smoking doesn't mean you will not get lung cancer.

I know you probably meant that as a comment about correlation vs. causation, which is understandable. I agree that this is a complex issue, and that there are more factors than just sun exposure. But just so you're aware, your analogy rubbed me the wrong way. My father's death was definitely related to sun exposure in some way or another, and probably other factors like diet (he ate a lot of sugar), psychology/hormones (he experienced a lot of stress), and yes, genetics.

it's not misinformation. one anecdote in one direction does not counter thousands in the other direction.

Talk to some people in the southern hemisphere (australia and nz). There is a LOT of awareness of sun damage in these countries.

There is misinformation about sunscreen. I'm not going to go and advocate that people don't use sunscreen, rather, for my own self, I've decided that it's important to have positive, moderate exposure to the sun in order to develop a healthy tan, to avoid overexposure, and to use sunscreen and protective clothing if I'm sure to be out in heavy sun.

It's a complex, dynamical issue and there is conflicting evidence about the effectiveness of sunscreen to just blanket reduce melanoma: https://www.ncbi.nlm.nih.gov/pubmed/22994908

Not only that, there have been some controversies about sunscreens themselves containing questionable ingredients, some of which might actually be carcinogenic. If you're going to market your product as cancer preventative, but go and put carcinogens into that very same product, my trust level in your industry has been reduced by somewhere in the range of 25%-75%.

Somehow, in all this, there are people who think any raw sun exposure is going to cause cancer. That's actually misinformation. Melanin is known to be a protective. How can one go about increasing melanin? By tanning in moderation, letting your skin adapt to the sun. Of course there are people who simply don't tan easily, and yes, they should be cautious. But I'm fortunate to have skin that tans, and I'm going to let it do that!

You are misrepresenting the studies findings. It did not show that sunscreen itself is ineffectual, but that as a population measure for children that it's effectiveness was variable. Anyone who has children will attest to the difficulty of applying and maintaining the required level of sunscreen, especially as it is invisible.

If you have concerns about the chemical sunscreens, please use zinc oxide. It is totally non reactive.

Sun damage is cumulative, a tan is a reaction to damage. People with a tan have sun damaged skin.

Naturally very dark skinned people are different, and also have enhanced mechanisms to allow damaged cells to self-euthanize.

Not quite right? A tan is a reaction to sunlight, independent of damage.

Ah! Research, gotta love it. UVA darkens directly as a result of action on the melanin. UVB damages DNA resulting in long-lasting production of more melanin.

Right, it concluded "there is still no evidence of a protective effect of sunscreen against MN development in children". Melanocytic Nevi are precursors to melanoma, and childhood sunburns give people an early start in developing them.

Here's another study arguing that sunscreen might inhibit the inflammatory response without actually reducing the burn. Their abstract concludes "As such, sunscreens might promote instead of protect against melanoma." : http://journals.lww.com/melanomaresearch/Abstract/2005/02000...

SPF is actually measured by reduction of redness. That study points out that reduction of redness doesn't necessarily come with a reduction of damage!

If people are preventing their body from expressing its natural sun defenses and going out and overexposing themselves to the sun, believing themselves to protected... If that protection is illusory, that's kind of a recipe for disaster. People could be getting burned and not even know it... They won't even know to put aloe on.

Take that one with this one, which postulates that sun exposure isn't what causes malignant melanoma, sunburns are:

> Although there is convincing evidence that nonmelanoma skin cancer is related to cumulative sun exposure, there is less evidence of that association with CMM. If CMM were related to cumulative sun exposure, one would expect that outdoor workers would have a greater incidence of CMM than indoor workers. However, that is not the case. The incidence of CMM is actually increasing among indoor workers who receive three to nine times less solar UV radiation than outdoor workers. Furthermore, there is a higher incidence of CMM among whites living in northern states such Delaware, Vermont, and New Hampshire (>30 per 100,000), which enjoy less year-round sunlight and UV radiation than southern states such as Texas, Florida, Arizona, and New Mexico (<25 per 100,000). In California, whites living in San Francisco had a CMM incidence of 30.5 per 100,000, whereas those living in Los Angeles had an incidence of 24.9 per 100,000. There are a few studies that suggest that chronic, low-grade exposure to sunlight may be protective against CMM. In one Austrian study, those with chronic sun exposure without sunburn had a reduced incidence of CMM compared with those with recreational sun exposure. In Germany, outdoor activities during childhood, in the absence of sunburn, were associated with a lower risk of melanoma. Chronic, repeated sun exposure may allow the skin to accommodate to UV radiation by increasing melanin production, thereby reducing the risk of sunburn. An English study published in 2011 showed that regular weekend sun exposure had a protective effect against CMM, and the researchers postulated that this may be mediated by photo-adaptation or higher vitamin D levels.


It's going to take a lot to convince me, at 56 and very aware of sun damage to the skin of my friends who spend more time in the sun than I do, that "healthy tan" isn't an oxymoron.

"Tan" doesn't necessarily mean that someone got that tan through healthy sun exposure.

Check out JoeAltmaier's comment.

If you spend some time in the sun without getting a tan, it's still good for you even if you don't tan, as long as you're not burning.

gah! yes there is misinformation everywhere but 99% of it doesn't come from experts.

do some product research and pick a reputable brand. but don't try to scare people off sunscreen by implying that it causes cancer!

Sun exposure != skin cancer.

It's like avoiding eating food altogether because you might became obese, or worse (given the odds) choke on it.

When the time it takes to get a burn is 10 minutes or less, you might as well treat it as exposure = burn.

After I met an albino woman travelling I really appreciate my very-white-but-not-albino-skin.

Sun lotion can only prolong your safe time, but 0 times whatever is still zero, as in her case. So there is a difference.

That's when sunbathing on Venus. Or if you're a ginger or similar.

On good old Earth, one can sit in the sun for hours on end without a burn. In fact people frequently do, like all the time.

With some SPF30 sunscreen, or sufficiently dark skin, sure. I'm not especially pale, but I'll start burning in under an hour of direct sunlight. "Hours on end" would be a recipe for painfulness.

It depends where you are and what time of year it is. Go to Tasmania in summer and give that a shot. Ozone layer depletion is no joke.

Where do you live? I suspect it isn’t in the South Pacific.

In Southern Europe and SE Asia. Does that count?

No for Europe but closer for SE Asia. The South Pacific is worse due to the ozone hole which mainly effects regions below the equator. It has a savage effect on UV that gets through. Obviously a bad year, but check the below image and you’ll get the idea of the pattern.


Nothing in the world is binary/yesno/truefalse!

More exposure to UV (eg sun exposure) leads to a greater chance of developing skin cancer.

People who work outside don’t get skin cancer. People who cook themselves for fun do.

If they did, we would know, because workers compensation would be paying for it.

> People who work outside don’t get skin cancer.

Yes, they do.

> If they did, we would know, because workers compensation would be paying for it.

While state workers comp laws vary in ways which make this different from state to state, workers comp is paying for it for some subset of people who work outside.


Many of them (like my uncle a few years ago) don’t last very long, so it isn’t workers comp that you should just look at. It is definitely something that happens.

Yes, they do. My father, a life long outsdoorsman and forest ranger for many years regularly had/has skin cancers removed once he got into his 70's. The cancer causing sun damage from your youth/working years doesn't tend to catch up with you until you're older I believe.

Don't they?

"However, compared with the general population, the rates for certain diseases, including some types of cancer, appear to be higher among agricultural workers, which may be related to exposures that are common in their work environments. For example, farming communities have higher rates of leukemia, non-Hodgkin lymphoma, multiple myeloma, and soft tissue sarcoma, as well as cancers of the skin, lip, stomach, brain, and prostate."


Ag workers were routinely exposed to ridiculous levels of dangerous pesticides for most of the 20th century.

This is a pretty well-known anecdote: men in drive-on-right countries tend to get more skin cancers in their left sides than their right sides.

This is believed to be due to sun exposure of the left side while driving.

See: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3117975/

Cancer is a complex, heterogeneous disease caused by varying degrees of interaction between inherited and exposed risks. It's just not as simple as you make it out to be.

My electrician father who spent several years working on rooftops in Houston and developed skin cancer on his hand at 51 would beg to differ.

Antidotes are not data. We have no reason to believe from your story that your would not have got skin cancer if he had spent all his time in a cave. Or maybe he wouldn't have, because he would have died of something even worse at 45.

Science is trying to work this out, it is complex. We know that sun exposure both protects from and causes skin cancer depending on the study. This is a complex subject, the only thing I think I can safely say is don't get a sunburn.

You're completely incorrect:


It is estimated that around 200 melanomas and 34,000 non-melanoma skin cancers per year are caused by occupational exposures in Australia.[1]


The 2006 Report on indicators for occupational disease highlights there was an increase in skin cancer claims per million employees/persons over a six-year period to 2004. The report says that given the long latency period associated with exposure and the onset of skin cancer, it is also likely that compensation claims greatly understate the real incidence of occupational skin cancer6 .

In this case his one point of data would be enough to refute the original claim.

> People who work outside don’t get skin cancer.

That's a bit of a blasé thing to say... I have lost direct family members through melanoma due to their work requiring them to be in the sun all day, and clearly many other people here have too. I can't fathom how you would form such an opinion.

People who work outside generally do not do it in bare skin unless they are idiots (of which we have many, many, many examples). You don't typically see military folks wearing shorts and t-shirts even in the hottest weather unless they are out doing PT because the work they do can be harmful and so they use clothing to protect themselves. This used to be common sense. Why do bedouins wear long, flowing robes in the desert? Same reason.

My father, who worked outdoors most of his life, always wore long pants and long sleeves even on the hottest summer days. I did not understand why when I was younger. I now get it.

Because surely all of those farm hands will be able to prove that it was their outdoors work that caused the cancer 30 years later! And surely the insurance will pay to right those wrongs!

> [...] even kids are sent to play covered in full sleeve clothing.

Which is good because if I remember correctly the human skin has quit a bit natural sun protection, but is only fully developed in the twenties.

If I got that mixed up with something else please correct me if I'm wrong.

Henry Osiecki in his book The Nutrient Bible, I own the 9th edition published in March 2010, recommends 2000-8000IU for three weeks to reestablish sufficient levels, and a supplementary rage of 400-3000IU a day for maintenance.

I obtained this book while studying clinical nutrition in Australia in 2005.

Clinical nutrition as taught by at least a handful of teaching practitioners in Australia that I'm aware of has been using mega-dose therapy to re-establish nutritional deficiencies since at least before I became aware of it twelve years ago.

What dose is recommended for adults and what is the best way to get it into your system?

From the last couple sentences of the abstract:

This could lead to a recommendation of 1000 IU for children <1 year on enriched formula and 1500 IU for breastfed children older than 6 months, 3000 IU for children >1 year of age, and around 8000 IU for young adults and thereafter. Actions are urgently needed to protect the global population from vitamin D deficiency.

So 8000 IU for adults

I was already taking 10.000IU a day (in winter) to battle Seasonal Affective Disorder. I live above 51N latitude though, so I practically don't see the sun in winter.

This is per day?

I have been deficient for a few years now and I take ~6000 IU per day, but it doesnt seem to make a big difference in my blood tests. I already thought 6K was a lot...

Are you taking it with food? I think it dissolves in fat, so you might want to take it with some oil for better absorption.

Yup - it's a fat soluble vitamin - this is a very good point to bring up. I made the "taking it with my low fat meal of the day" (breakfast) and made a change to correct that.

I've been told I should be taking it in the morning though, because it can affect sleep if you take it in the evening - anyone know differently?

Gwern ran a self-experiment finding that it did affect his sleep: https://www.gwern.net/zeo/Vitamin-D

eat bacon.

I didnt know that - I usually take it shortly after breakfast, but ill try this - thanks!

My doc prescribed me 25,000 IU once a week for 8 weeks then 10,000 IU daily thereafter. The kicks of 25k were what made the diff for me. YMMV

holy smokes, thats a ton. Are there any effects of too much?

Yeah, it's fat soluble so you can take too much (but you'd have to take a ridiculous amount).

The normal doctor prescription to increase levels is a 50k pill once a week for a couple months. The previous recommended level was 20ng/ml, but they increased it to 30ng/ml.

When I got tested mine was 11ng/ml (and this is in the sunny bay area). To have the recommended value from normal sun exposure you'd need face/legs/arms exposed to sunlight for ~30-45 minutes a day which most people don't get. It's very hard to increase D from food.

I'm also not sure how they determine the recommended amount and there seems to be a ton of pseudoscience around all of this stuff so it's hard to tell what's true.

Yah like doing 25k a day. That could cause problems.

Surprisingly few problems. Wife has been doing 80k a day for the past few years and have help tremendously with her auto immune decease.

If you're going to do high doses, stay away from anything with significant amount of calcium in your food (dairy, nuts etc)

80,000 IU is a terrifying number for daily intake. Did you mean 8k and not 80k?

I meant 80k. See studies from Dr Cicero Coimbra for more background if you're interested.

Interesting. I started taking it since I've started working inside for my day job. Apparently I should be upping my dosage. I take a multi and one or two D tablets and probably get a max of ~5600 from that outside of any absorbed from foods.

I also eat a lot of eggs. My girlfriend will be pleased to know that I'll be upping our egg intake!

> Apparently I should be upping my dosage.

Get your current nmol/L value and decide based on that data.

In Germany, you have to pay around €30 for that test. It's not covered by insurance for some reason. Anyhow, if they ask for significantly more than that, they are ripping you off.

I'll be booking my yearly physical soon, so I'll ask for a test then.

edit: Just having checked I misread the dosages completely. Right now it's much less.

    Multivitamin  - 400IU
    D3 Supplement - 400IU
I thought the multi was 4000 and I occasionally take 2 of the supplements, but usually 1. Maybe the double strength next time...

Better watch out with egg intake upping, check your cholesterol and trigliceride levels. Anyway good to consult with professional nutrituonist.

Ask your doctor, really. When I got diagnosed with vitamin D deficiency (inside on the computer all the time, I'm quite pale) a few years ago the prescription I got was for pills that had 50,000 IUs each and I was to take one twice a week. I recently got a new doctor and was getting bloodwork done and she saw the mention of the deficiency and she asked if I wanted that tested for... she said she usually doesn't bother because everyone in my state (West Virginia) is deficient, she just recommends people take 1000 IUs a day or so. Personally I take 10,000 IUs about every other day. At least assuming the stuff I ordered off Amazon is at all legitimate (vitamins and such things are such a super sketchy market, companies get busted selling sawdust pills all the time).

One thing that I was not expecting, when I was on that prescription at first I noticed a marked improvement in my hearing (which I had not noticed being degraded at all previously...). I thought I was imagining it but upon doing some research it turns out that hearing loss is one of the possible complications of vitamin D deficiency.

you could also investigate in vitamin D lamps (Sperti, for example), they are not cheap though

an hour of sunshine a day?

Except during the summer months, the skin makes little if any vitamin D from the sun at latitudes above 37 degrees north (in the United States, the shaded region in the map) or below 37 degrees south of the equator. People who live in these areas are at relatively greater risk for vitamin D deficiency.

Check out the map: https://www.health.harvard.edu/staying-healthy/time-for-more...

I saw the quoted text, but missed any explanation. I would love a clarification on whether they claim the skin is not getting exposed to sun or, even when exposed, does not make any vitamin D, which is how I read the above.

This is an honest question -- if it is the first, I am not too concerned. I grew up in a colder climate and, while living far in the shaded area today, routinely wear short sleeves and walk a lot outside from early spring to late fall. If it is the second, I would love to learn the underlying causes at least as a scientific curiosity (and start thinking about vitamin D supplements).

The sun is too low in winter and the atmosphere blocks the UVB rays our skin needs to produce Vitamin D. The same thing happens around sunrise and sunset even in summer. Here's a good explanation from HN's favorite site:


BTW, here is the equivalent South Parallel: https://en.wikipedia.org/wiki/37th_parallel_south

Argentina and Southern Chile in it. Buenos aAires looks ok. Bu

That line was a lot lower than I imagined! Surprised that Denver is “too far north”.

It is silly to go through the trouble of including a map, only to reinforce the imprecision of the parallel approximation. Obviously People in Denver get more sunlight than e.g. people in Nashville, given the altitude and weather patterns. More detailed maps don't limit themselves to drawing a straight line.

That's me. Any idea how well supplements are absorbed? Which are better or worse?

Get a blood test first so you know your Vitamin D level (they're cheap: https://news.ycombinator.com/item?id=15869485), maybe you already get enough from your diet.

If you do need supplementation, then Vitamin D3 (specifically Cholecalciferol) is vastly better absorbed than Vitamin D2. If you want a specific recommendation, buy this: https://www.amazon.com/gp/product/B07234TTCC and take it twice per week (Sunday & Thursday for example), that'll average to about 1400 IU per day.

According to the article, it is safe and recommended to take one of those 5000 IU capsules per day.

I see 8000 IU for adults:

This could lead to a recommendation of 1000 IU for children <1 year on enriched formula and 1500 IU for breastfed children older than 6 months, 3000 IU for children >1 year of age, and around 8000 IU for young adults and thereafter.

Supposedly this is why Northern Europeans evolved lactose tolerance. Asians got the D they needed from the sun and leafy veggies.

Seems odd, considering cow milk contains virtually no vitamin D. It is often enriched with vitamin D, but that practice likely does not predate the evolution of lactose tolerance.

When it comes to nutrition, the majority of unsourced information on web forums is made-up nonsense. Perhaps not maliciously in bad-faith (i.e. maybe OP really has heard this before)... but usually someone repeating something they heard 3rd or 4th-hand without any real fact-checking.

Milk is high in vitamin D because it's intentionally added. Like iodine in table salt, or fluoride in drinking water. Obviously these things had no role in human evolution before they started in the 20th century.

Vitamin D is only absorbed in the presence of fat in the intestine. Milk is a source of fat. Of course it isn't the only source of fat, but the hypothesized explanation is more plausible than you might think.

I have observed 'seanmcdirmid to be a thoughtful commentator. It would be uncharitable to suggest that he thinks that USDA has regulated milk drinking for millennia.

Most "1st-hand" nutritional research is also wrong. That has been the case for decades, which explains the field's relative lack of progress. The reason is that most nutritional research is funded by large commercial food interests.

Oops. You are right, I was thinking of calcium, which you can get from green veggies as well. I get confused because we had to deal with them all at once when my wife was pregnant.

I know the subthread went in another direction, but: vitamin D increases the absorption of calcium. With minimal vitamin D synthesis from sun exposure in northern Europe, it makes sense that extra dietary calcium would be an evolutionary advantage. Hence, lactose tolerance. So OP's comment made sense even while confusing vitamin d and calcium.

Hah, that's a direction I hadn't considered. That is indeed exactly why vit D is added to milk in the first place. The milk industry claims it's a good source of calcium, but fails to mention it's generally a poorly absorbed source of calcium. Hence the addition of vit D.

Hard cheeses are generally very low in lactose, by the way, but I guess lactose intolerant societies are unlikely to discover this on their own.

Lactose intolerant societies generally have cheese and other forms of curd. Also, babies are generally lactose tolerant regardless, losing this tolerance later.

Lactose tolerance evolved in several different populations independently (including African populations), so I think Vitamin D can only be part of the story. Lactose tolerance gives you access to nutrients from milk, which has a huge impact.

I don't know any of the history, but I would wager high protein content as that's also the huge benefit meat-eating brought humans.

You would need 1) the sun to actually be shining, 2) no cloud cover and 3) probably be naked. Most of us won't get enough vitamin D from being outside for an hour.

1. The key UV for vitamin D production by our skin are UVB rays, optimal between 10am and 2pm, except in the winter at 40+ latitude when the rays travel longer through the atmosphere due to the low solar angle. For instance in Washington state your skin cannot produce vitamin D from November to February.

2. UVB do pass through clouds. (But not through glass windows.)

3. Arms and face exposure are sufficient if you spend 10, 20, or 30 minutes a day depending on UV index of the day (the higher the UV index the less time you need to trigger vitamin D production) and on your skin color. There is some kind of "reservoir" effect that limits production of vitamin D to a maximum, so sun exposure time beyond the above does not have any benefit in terms of vitamin D production.

That's easier said than done for some. A couple of years ago we had an exceptionally bleak November here, with one city for example having only 12 minutes of sunshine in the whole month of November. (I'm not talking about places within the Arctic Circle, although relatively speaking they could almost seem that way for some, of course.)

The average where I live for Nov is about an hour of sunlight per day, but to catch that you'd have to spend all the light hours of day outside (and for sure, November sunshine isn't quite the same as summer sunshine).

UVB rays do pass through clouds.

It is more complicated than that. A dark cloudy day (no gaps to sky) will not have much UVB. A day with thin high clouds won't block much, and may make it worse (reflecting or scattering).

And here's a calculator:


They calculate to 1000 UD if I see that right, I assume it's linar over time so just multiply that.

This article from the NYTimes (paywall) caught my attention many years ago. Turns out it's from 2010 so about the same time as Dr. Mews prediction. http://www.nytimes.com/2010/07/27/health/27brod.html

Related to this topic, if you have IBS/IBD, some interesting research been coming out in the last couple of years indicating that low vitamin D may play a role in this issue as well. This [1] 2015 study found 82% of people with IBS had low vitamin D levels relative to 31% in the control group. This [2] 2016 one proved causation of vitamin D supplementation improving symptoms, by randomly splitting into two groups and treating only one. This [3] speculative writeup by the Vitamin D Council in 2014 discusses some possible mechanisms of action.

This seems like such low-hanging fruit that it was extremely surprising to me that this is at the cutting edge. Causes and cures for IBS are not clear and one third of patients find current treatments unsuccessful [4]. But the above doesn't seem to be well known in online discussion because it's so new, and my gastroenterologist didn't bring it up at all either.

[1] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4412886/

[2] https://www.ncbi.nlm.nih.gov/pubmed/27154424

[3] https://www.vitamindcouncil.org/health-conditions/inflammato...

[4] https://www.vitamindcouncil.org/study-finds-high-dose-vitami...

Anecdotal: nothing helped my IBS. Dietary changes, exercise, nothing. Drs said nothing looked wrong. By the time I was 26, it was so bad I would stay home and not socialize often. I would need immodium like candy just to get through a social function. It was truly a nightmare. I was ready to give up.

4000 UI vitamin D a day, and about four weeks in it magically goes away 90%. I've gotten thanks from other people I passed the tip to.

Incidentally, the symptoms started abruptly about a year and a half before my diagnosis of melanoma; another disease with a vitamin D link.

A common type of IBS is actually caused by an autoimmune condition whereby the body begins to attack the protein vinculin instead of attacking camplobacter cdtb. There's a blood test you can now get which tell you if this is going on in your system.

What's the test called?

Anecdotal: I have Chrohns and take 2000 UI Vitamin D everyday. I've been prescribed the lowest dosage anti-inflammatory (Mesalamine) for years and rarely had a flare up. My Vitamin D blood tests always come back in the normal level.

Another anecdote... I also take mesalamine (as Delzicol in my case), and take 3000 IU of Vitamin D (along with supplements of calcium, B-complex, and some others). I almost never have flares.

However, I can't get a good colonoscopy - my GI doc says the prep is always bad, even if I extend it for an additional day. He attributes that to a chronic simmering inflammatory state preventing things from cleaning out well. That puts me at a much higher risk of colon cancer, and so I'm also doing Entyvio infusions prophylactically.

Have you tried going to a different doctor?

What's 'normal' at your lab? My lab says 50 ng/ml is normal, but my experience with antibodies says it should be between 70 and 100 to see an effect.

My lab shows anything over 30 ng/ml as "optimal" (looks like 30 to 100 on the chart). My values the past 2 years have been in the mid 50's.

Thanks for this. I have IBS and began taking a 2000 IU supplement of Vitamin D awhile back for unrelated reasons. Maybe I'll bump it up to 3000 to see if it helps.

No worries at all! I'm in the same boat. FYI some patience is needed as it apparently takes 3-6 months for changes in vitamin D input to make its way into the bloodstream and show effects [1]. I've just started supplementing 5000 IU as I get very low levels of sunlight. Fingers crossed that this helps the both of us.

[1] http://www.vitamindandms.org/faq/index.html#How%20long%20wil...?

That seems to be too low to have an effect if you are actually deficient according to the study.

This article seems to be a low quality review of other research with a clickbatey title (full text here: https://www.jpmph.org/journal/view.php?doi=10.3961/jpmph.16....).

Pubmed is sort of like arxiv.org and the fact this has an nih.gov base url should not be taken as an endorsement of it by the NIH.

That said I do actually believe that more then the recommended amount of vitamin D can be beneficial and the recommendations are in need of reevaluation.

Just to back this up: the journal it's published in has a very very low impact factor of 0.235 (i.e. it publishes 4x more papers that it gets citations, probably most of it's papers are never cited by anyone) [1]. If this paper was considered a big a deal by the wider research community you would expect it to be published in a high profile journal.

[1]: https://journal.komci.org/ViewJournalInfo.php?JID=109#Impact...

This sounds extremely low to me, but looking at the list of top journals sorted by Impact Factor on https://journal.komci.org/SearchJournal.php (you have to choose "Impact factor" in the "Sort results by" dropdown, as it does not generate a useful URL), the top journal only has an IF of 0.791.

I don't really know anything about the medical publishing world, but I would have expected a top journal to be cited much more?

If most papers have dozens of citations, shouldn't each paper on average be cited dozens of times? Obviously with massive skew.

Do you know why this is the case? Is there some flaw in their methodology?

Good question! The scientific method does not include references to "impact factor" :)

I mean, it does. The "fairy tale" that one hears in high school doesn't, but we put aside fairy tales when we became adults.

If you are done with the "undergrad level" of Popper and Kuhn it is worth reading Imre Lakatos's work on philosophy of science. It contains a moment where one realizes that research programs live or die by this "impact factor" and that this living or dying is a key part of the overall methodology of science. The gist is that science is actually participating in a survival-of-the-fittest evolution with certain foundational ideas as the "genes" which "reproduce". So scientific ideas are actually good or bad in no small part due to their ability to create further scientific research along similar lines. A low impact-factor therefore directly says "along this particularly important-to-science axis, this journal sucks."

You are right that "the impact factor of a journal is meaningful and provides a simple/preliminary heuristic for measuring up _some_ aspects of a paper published in it" - but this is not what you wrote.

1. Imre Lakatos and maturity are great, both implying that you should not apply the aforementioned rule of thumb to an individual paper - an individual in the population - whether it was published in Nature or an insignificant contender.

2. Your memetic approach is also good, but incomplete: the objective function in case of these journals is maximizing the impact factor - so we can conclude that "PrevMed is less successful in maximizing the impact factor than some competitors, or it is a younger journal, or ..." Yes, imact factor and quality correlate in the long run, but we are not at undergrad level.

3. "A low impact-factor ... directly says" - Not directly. Also, most of the journals - not to mention conferences - do not even have an impact factor.

4. "...this journal sucks" - Most of the people writing in these kind of journals have given up a lot to contribute something modest. The editor of this journal is probably emailing with reviewers at 1am or so. Just saying...

But to stretch the analogy a bit further would it be fair to say that impact factor is very like sexual selection for extreme display traits that otherwise are detrimental to the wellbeing of the species?

Yes impact factor matters to current science as practiced but there is plenty of good criticism to show (at least as it is currently calculated) that it is a lousy measure of what is likely to end up being true, reproducible and useful.

> would it be fair to say that impact factor is very like sexual selection for extreme display traits that otherwise are detrimental to the wellbeing of the species?

If I read every PoS article vaguely related to my research, I'd never get anything done. In practice, I don't pay attention to impact factor. But I do pay attention to who's publishing. And that's basically the same as impact factor, in practice.

> that it is a lousy measure of what is likely to end up being true, reproducible and useful.

I don't think so.

High impact factor publications are MUCH more likely to be quality science than low impact factor publications (at least in my area).

The major venues would have to get at least two orders of magnitude worse before they became bad indicators of quality.

Of course, and obviously, that does not entail that all work published in high impact factor journals is high-quality.

I think the fundamental problem is just that you vastly under-estimate the enormous volume of utter crap there is out there.

Thanks for the recommendation - I've never heard of Lakatos and have only read Popper and Kuhn. Do you have any other recommendations?

They didn't seem to do any novel work. Just cite the work of others without even doing a meta analysis of statistical significance.

its papers

>>Pubmed is sort of like arxiv.org

What? It's nothing of the sort. Pubmed is not a preprint server. The paper in question was accepted by a journal. The quality may not have been great - I agree - but it is not like the archive at all.

He means it’s a resource for finding any/all articles, irrespective of source journal or quality - specifically pointing out that people shouldn’t infer anything from the NIH url.

It’s very much like arxiv in that regard.

Seems that way, I know, to some of my friends who don't work in the same field as me (health research), but pubmed doesn't include all biomedical journals, and it's not a place where anyone can archive papers independently. Which isn't to say that everything in pubmed is high quality or that it's a great gatekeeper, but yeah, it definitely excludes material.

If taking EPIC series morbidity and mortality endpoint analysis at face value, best outcomes on average are around 2500 IU/d intake. (In generally healthy individuals.)

So this recommending 4000 IU/d is not too far fetched.

Yeah to be clear I think there is lots of good science supporting increased vitamin D intake possibly including some of the work cited/described here. This article just doesn't seem notable, novel or particularly well written beyond the grabby title.

I logged in just to downvote this. PubMed is an aggregator, closer to Google Scholar than the arXiv.

Fair enough. I was just trying to make the point that something being on pubmed doesn't mean its anything close to an NIH recommendation and chose arxiv as it would be familiar to a CS audience.

Lots of people in health research do treat pubmed as a gatekeeper though (sometimes foolishly imo). It is more exclusive than both Google Scholar and arxiv -- but also like you say, not a guarantee of quality + not the kind of resource where you can read one article and be like "here's what NIH says."

So semantics, I guess. Just felt compelled to mention it, probably more because it frustrates me to see health researchers use pubmed as their only gateway to scholarly lit.

vitamin D testing was a huge money maker to labs. the EU cut this test from its health plans and a few equipment makers (in labs, equipment works like big iron, you get it leased for free while your reagent subscription is active) are bankrupting.

This supports my lived experience. Found to be incredibly low in vitamin D, and diagnosed with autoimmune thyroiditis. Doctor said to supplement with 2000 IU being the max per day.

After seeing no improvement whatsoever in vitamin D levels, and after talking with others with the same issue, I self medicated to 10000 IU / day.

Lo and behold my vitamin D levels went back up and my auto-antibodies went back down.

Interesting to hear of a connection between this, type 1 diabetes and autoimmune thyroid disease (Hashimoto's?). I have celiac, also an autoimmune disease, and one of the symptoms is tingly and numb extremities, peripheral neuropathy. I think that's related to the ataxia side of celiac and nerve degeneration from nerves losing their sheathing.

Prior to diagnosis, I learned that the numbness is also a symptom of Vitamin D deficiency and found that taking supplements helped.

Have you ever taken a fluoroquinolone antibiotic at any point in your life?

Look into r-lipoic acid, low dose 100mg (take one per day, with food), from the Doctor's Best brand (available on Amazon). You might consider that for the peripheral neuropathy, it does wonders for some people.

Well, shoot. I just took ciprofloxacin for a week following a minor surgery, and noticed that I've lost some of the sensation in my upper right leg. I assumed it was caused by the surgery, but in six weeks, it hasn't improved. Not exactly life-altering, but it does feel pretty weird when scratching an itch and I'll get odd tingling there sometimes while trying to sleep that feels more warm than painful.

> Nearly all quinolone antibiotics in modern use are fluoroquinolones ... One example is ciprofloxacin (Cipro), one of the most widely used antibiotics worldwide.

Cipro and fluoros in general can be extremely dangerous (and Cipro is the light-weight among the class, the others are truly terrifying). It's now carrying two black-box warning labels from the FDA, which they slapped on it after dragging their feet for over a decade about several well-known and horrific side effects, including causing nerve damage.

If you've taken it in the last year or two, I'd suggest taking high absorbtion magnesium (citrate etc). Some of the particularly bad effects from Cipro seem to be caused - if not entirely, at least in part - by low magnesium levels. It strips magnesium out of various tissue and leaves it necrotic, which is how it destroys tendons for example (one of the FDA labels is for spontaneous tendon rupture). If you had low magnesium levels before taking it, the concern is that much greater. The earlier you take the magnesium after completing Cipro, the better.

The other compounding action on fluoros, including Cipro, is NSAIDs and steroids, they dramatically increase the damage from the antibiotic (the instructions you get with Cipro properly warn against taking NSAIDs with it, but how many people don't realize how dangerous taking Advil around the same time might be?).

Cipro is being implicated in all sorts of interesting things:



If you spend even a few minutes digging, you'll find a large array of high quality sources now discussing it. 20 years ago it was mostly fringe sources discussing it. The FDA though, was warned as far back as the early 1990s, for example by a paper out of UCLA med circa 1994 that perfectly laid out how dangerous it was. The FDA's behavior was either malicious (protecting pharma revenue), or they were scared to pull such a valuable broad spectrum antibiotic.

Cipro was force fed to soldiers during the first Iraq Gulf War (on a non-proven claim that it could protect against anthrax). The last few years, since the FDA slapped a warning on it for peripheral neuropathy (and seeing as it's being implicated in two dozen other major health problems), veterans groups have been looking into it as a possible source of gulf war syndrome. [1]

There are increasing links suggesting the huge increase in women being diagnosed with Fibromyalgia, may in fact be effects due to how common Cipro has been prescribed for things like urinary tract infections. If you get injured by Cipro, doctors will often immediately jump to diagnosing you with one of three things (typically ignoring the blatant Cipro tie): lactic acidosis, rheumatoid arthritis, or fibromyalgia.

It's merely my opinion, but I think Bayer is probably due a trillion dollar lawsuit. Anyone that has ever taken Cipro has likely suffered serious damage from it, which may not show up for many years (the FDA says the damage from Cipro may continue for several years). At least in the US, millions of people are prescribed it every year.

[1] https://www.militarytimes.com/2013/11/01/new-fda-warnings-on...

Sounds awful. I had a girlfriend who took Cipro repeatedly for urinary tract infections. Another, fibromyalgia - I wonder whether she had taken those drugs. Most likely.

Fucking tendon ruptures. My girlfriend is a runner and she had a tendon rupture in her knee that was caused by cipro. Fucking nasty and immoral what the regulators and drug companies have done with this antibiotic.

Thanks, I'll check out that supplement.

I looked up the list of those drugs (-floxacins?) and I don't recall having taken one of those. I was actually prescribed Ciprofloxacin earlier this year, merely as a prophylactic after a very minor surgery, and after looking into it I decided to not fill the prescription.

Yes, Hashimoto's. All auto-immune diseases are linked. If you have one, you have a higher chance of having another. This doesn't mean you will have the other, just that the number of people with T1D among hashimoto's patients is higher than the number of people with T1D among the general public, and vice versa.

This is similar to my lived experience. I was diagnosed with Hashimoto's 3 years ago. I was lucky to find a great doctor that specialized in it. He put me on 15000 IU / day for 3 months because I was so severely low in addition to having high antibodies. Within 3 months my levels were so much better. I still take 10000 IU / day along with selenium, iron, fish oil and good diet/exercise and all my levels have been in check for 2 years :)

Selenium has done wonders for me too. It's sad that so many patients have to find this information on their own. Glad to hear your doc is on top of it.

Could you write a bit about the role of selenium in your treatment? Thanks.

Sorry just now saw this. The article here goes into things pretty well for my situation at least http://www.lifeextension.com/protocols/metabolic-health/thyr...

I don't want to give any kind of medical advice especially without knowing the situation of others. If you are concerned though, it doesn't hurt to get blood work done. Following are the common things to test for if you think you may have Hashimoto's or thyroid issues.

Vit D, Ferritin, Thyroid peroxidase antibody (TPO), Thyroglobulin antibody (TGAb), Thyroid-stimulating hormone (TSH), Free T4 Test

Did you experience any other benefits from that regimen of supplements?

Yes it completely changed my entire well being. Muscle twitching stopped, major back aches and leg cramps went away, headaches went away, brain fog went away, concentration went up, sleep improved, skin improved. To be fair, I made other lifestyle changes too in addition to the regimen of supplements.

I've got a nice doctor. I was also incredibly low (getting muscle twitches) and he put me on 15000 IU a day. Did wonders. :)

Can you explain muscle twitches vs Vitamin D?

Could it also cause cramps?

> incredibly low in vitamin D

How much low, in ng/ml or nmol/L?

Not GP, but my level was 8 nmol/L in the middle of summer. No medical explanation could be found for why I was so deficient, and I get at least 1hr sunlight every day during my daily cycle commute (UK). Symptoms were depression, tiredness and disturbed thinking.

I was prescribed vitamin D3 10,000 IU/day.

This is extremely low. And what about now, after the 10,000 IU/day supplementation?

I was around 15 nmol/L (I think). 20 was the minimum. I checked a few months after starting my new regime, and it had gone up to about 50. I then tried backing down to 4000 IU a day and it fell back to around 40, so I went back to 10000, and I haven't checked since then, but I do know my antibody counts are down.

I'm under close supervision for vitamin D levels. Previously, I was taking 100,000IU D3 (50k 2x daily). I'm not taking any right now but my next panel is in a few weeks so we'll see if I get back to taking it.

If you're taking little green footballs of oil-based D2, I suggest dry D3. I had much better response.

Could someone help me understand this?

>it was found that 8895 IU/d was needed for 97.5% of individuals to achieve values ≥50 nmol/L. Another study confirmed that 6201 IU/d was needed to achieve 75 nmol/L and 9122 IU/d was needed to reach 100 nmol/L. The largest meta-analysis ever conducted of studies published between 1966 and 2013 showed that 25-hydroxyvitamin D levels <75 nmol/L may be too low for safety and associated with higher all-cause mortality, demolishing the previously presumed U-shape curve of mortality associated with vitamin D levels.

What is IU/d? What is nmol/L? Could someone ELI5 the entire abstract for me? Well, maybe a little more than 5, I get that there was an error estimating recommended levels and we're not getting enough.

IU/d = international units per day (a measure of vitamin D intake)

nmol/L = nanomoles per litre (a measure of resultant blood concentration of vitamin D)

The ELI5 is:

1. Trials indicate that vitamin D deficiency (possibly below a blood concentration of 75 nmol/L) is a bad thing and is associated with a higher risk of death (from any cause) and also other health problems (risk of development of type I diabetes is given as an example)

2. The current recommended daily allowance (RDA) of vitamin D (https://ods.od.nih.gov/factsheets/VitaminD-HealthProfessiona...) is currently lower than the intakes that studies have found are needed for most people to provide the blood concentrations which may be needed for good health (possibly due to a previous calculation error in determining the RDA)

3. Therefore, the author recommends to increase the RDA for vitamin D

The generally accepted goal by both the researchers and the US RDA is to reach 50-75 nmol/L blood levels, using however many IU that takes.

IU/d is "IU per day of Vitamin D", and nmol/L is "nmol per liter of blood". Vitamin D is measured in IU rather than grams like most other supplements for medical reasons I'm not familiar with. nmol is an unfamiliar unit, but I can help clarify why this paper is so stunning anyways.

https://ods.od.nih.gov/factsheets/VitaminD-HealthProfessiona... is a summary of the NIH's position on Vitamin D for US citizens. The research linked by this post differs in two key ways, approximately:

First, "<75 nmol/L may be too low for safety", vs. the NIH statement ">50 nmol/L generally considered adequate" (for adults).

Second, "8895 IU was needed to reach >50 nmol/L", vs. the NIH statement "600 IU sufficient with minimal sun exposure" (for adults).

So, in summary, for healthy adults, they assert that 10-20x the current RDA-indicated IU of vitamin D consumption is necessary to achieve the recommended blood saturation level of 50-75 nmol/L in all adults.

Two notes: These precise figures are for grown adults, NOT children; and, I strongly encourage getting a vitamin D blood test before starting or modifying your vitamin D supplement intake, especially if attempting to reach the 15x RDA levels described here.

IU are used whenever a particular vitamin has multiple forms with varying levels of efficacy [0]. Or it may be used when the typical quantities are measured in inconveniently small units.

1 IU of cholecalciferol is 0.025 micrograms. If you supplement vitamin D at hogh doses, make sure you use cholecalciferol rather than ergocalciferol. The former is naturally synthesized in your own skin, whereas the latter is produced mainly in mushrooms, and can result in unpleasant side effects. Maximum-dose recommendations from nutritionists may include the assumption that the consumer does not know the difference, therefore reflect the highest safe dose of the least-safe vitamer.

It is similar to the issues with vitamin A, when someone may safely supplement with carotenes and unsafely supplement with retinol. You can eat sweet potato and carrots until you turn orange, but you cannot eat a single bite of polar bear liver. But because we are mostly idiots, nutritionists cannot recommend a high-dose supplement for vitamin A, with carotene in mind, because someone will inevitably overdose themselves with retinol. So if you can certify yourself as not-a-moron, you will be able to figure out when those recommendations may be safely ignored.

[0] https://en.wikipedia.org/wiki/Vitamer

Where can one go to learn about different forms of vitamins and the safe&recommended doses for each?

The other reply to your comment is entirely valid and I encourage you to read it in full.

That said, the only way to measure a safe dose of a vitamin is to perform medical tests before and during a dosing regimen to ensure that you are neither under nor over the target levels of the vitamin in your body.

Medical science is not yet reliable when it comes to defining target levels of vitamins in any individual's body.

In general, for all body dosing regimens, the goal is to survive the dosing changes without dying first, and to produce the desired result second. If you are not treating a specific symptom and instead wish to simply calibrate your blood levels to "optimum", be warned: There is no optimum, period full stop.

For example, if you increase your vitamin D levels precisely to a target amount with careful blood testing and supplement regimes, then your risk of death from sunlight exposure may increase if/when the levels of sunlight you're exposed to shift significantly (due to work, weather, or travel). Some will immediately object that the increase in risk is vanishingly small. You are irreplaceable. What level of risk of death of acceptable to you?

Soylent calibrates their food product to 100% of all doses specified by the US RDA for healthy adults. It's generally assumed to be a safe set of targets, though some would say that it is too low in many respects (while missing the bigger picture of the 'pick one' conflict between society-level dosing and individual-specific dosing), and others would say that it is too high in many respects (while missing the bigger picture of the 'pick one' conflict between increased risk of side effects vs. increased risk of malnutrition).

There's a good reason why everyone ends up at the same sentence, and I'm going to provide it now:

Seek advice from a medical professional before consuming supplements. If you are unwilling to do so, get a med-alert bracelet and keep a summary of the past year of dosing changes in your wallet. It may someday save your life. If you are unwilling to wear a med-alert bracelet and keep a log of your self-alteration efforts, consciously accept that you risk death if unintended consequences occur.

Unfortunately, most of the sites that claim to aggregate such information are heavily incentivized to misrepresent or falsify information in order to sell you supplements, either directly sourced or through affiliate programs.

Many of the remainder are constrained by politics or medical malpractice law. For instance, USRDA recommendations and USDA gimmicks like the food pyramid are heavily influenced by agricultural businesses. Minimum daily requirements are mostly based on the amounts needed to avoid showing symptoms of known deficiency diseases, rather than to actually be healthy.

The actual scientific research is rather sparse. I am aware of a study performed in the 1960s that completely replaced all meals with a nutrient slurry with the texture of corn syrup, which was partially spoiled because subjects were convincing accomplices to smuggle real food to them. Thanks to subject compliance issues, most long-term research is done on analysis of food-diary observations and surveys. Short-term research, such as for satiety and glycemic response, is more controllable.

You will have to do a lot of your own digging.

Start with professional athletes like swimmers, cyclists, and bodybuilders, but beware the "broscience". Look at the life extension people that use caloric restriction and intermittent fasting. Check out the Soylent people. Look at the practice of geophagy. Listen to some vegans. Study some biochemistry, especially the Krebs cycle and the known DNA repair and disease-fighting mechanisms. Do a lot of Wikipedia walks.

Be aware that your nutrient requirements will vary from others as a result of your personal genetic quirks, but mostly can be expressed as a ratio of mass to ingested kcal.

Learning the biochemistry is key. You have to know that omega-3 and omega-6 fatty acids use some of the same enzymes at particular steps in their metabolic chains, so those fats will compete with one another in your body, meaning that those nutrients must be in a balanced ratio to each other, regardless of your absolute consumption. What's the best ratio? I don't know. Cursory analysis suggests that 6 parts omega-6 to 1 part omega-3 is too high. Supplementing with krill oil, algae oil, chia seed, or flax meal would therefore be as warranted as cutting the amount of omega-6 from vegetable oils.

If you look at Na+/K+-ATPase, it actively transports sodium and potassium across the cell wall until the interior is mostly K and the exterior is mostly Na. Your dietary requirements are likely related to the homeostasis mechanisms for regulating the ionic concentrations. What's the best ratio? I don't know. Cursory analysis suggests that your body requires overall 2.25 times as much K+ as Na+ at any given time, but the K+ is more strongly conserved, being mainly inside your cells. So you should probably eat a ratio similar to that found in your extracellular fluid, which is 33.5:1 Na+:K+, which indicates that your table salt should probably be at least 1:24 KCl:NaCl by mass. Sea salt provides some K, but not that much--about 1:200. And it also shouldn't be more than 3:1 KCl:NaCl by mass, even if you are severely deficient, because your body needs the Na+ to be present to pump K+ into the cells.

It's all guessing, and the signal-to-noise ratio is very low.

Both IU/d and nmol/L are measurements of molecules. nmol/L is "nano-moles per liter", and is a measure of concentration: https://en.wikipedia.org/wiki/Molar_concentration

"IU" is a measurement common in pharmacology, and has to do with trying to standardize how much mass/volume of a substance will give a particular biological effect. The "/d" is per day.

In summary, the article is saying that, based on a meta analysis[1] of previous research, we have misunderstood or misreported some of these measurements. They suggest both the safe dosage and the effective dosage for Vitamin D should be much higher, and argue that this is a cheap and effective way of treating problems associated with Vitamin D deficiency.

[1] https://en.wikipedia.org/wiki/Meta-analysis

(edited for spelling)

IU/d International Units per day

nmol/L Nano Mols per liter.

The abstract is basically saying previous work was mistaken and we need to take a lot more vitamin D than we've been suggesting, and calling on regulatory authorities to change their guidelines.

I have been taking 5000IU Vitamin D for the past 7 years, with a little more over the winter months. It's stupidly cheap, I get 360 5000IU capsules for $13, so it has cost me less than $100 over that period.

Anecdotally, it was a game changer for me personally. I got less sick during the winter, and my overall wellbeing improved greatly.

A word of advice, increase Vitamin K intake aswell. Vitamin D helps calcium absorption, but Vitamin K directs it to where it needs to go (skeleton).

Word of advice: don't take vitamins ADEK without advice from a physician for extended periods or in high doses. These are fat soluble so you can have too much of them.

This should be reiterated: Please consult a professional before drastically altering the chemical composition of your ephemeral body.

I know it sounds downright crazy, but it's possible that someone who's studied medicine and practiced it for years, actually knows better than random anonymous forum users.

>>I know it sounds downright crazy, but it's possible that someone who's studied medicine and practiced it for years, actually knows better than random anonymous forum users.

As the link in the OP actually denotes, no, that's not always the case.

Bodybuilders and performance trainers - as well as Soviet Union sports scientists - have known for decades that Vitamin D supplementation is vital. This has been rejected by a significant number of general practitioners and other medical experts who are and were anti-supplement simply out of rote thinking.

Yes, people should be tested for their levels. But this simply isn't feasible for poor people, and telling them to get serum tests for Vitamin D before taking a lower-bound amount of the cheap supplement from the grocery store is ridiculous.

I don’t think that the drug regimes of the Soviet Olympic Teams should be held up as a good example to follow - a lot of damage was done to a lot of people. On a related note, the Russian team just got banned for trying that crap again.


That was mostly political decision, many American/Norwegian/... are legally taking performance enhancing drugs.

This is what's known as an ad hominem argument

That literally has nothing to do with whether or not Vitamin D is useful.

The difference is that when medics suggest a certain amount of vitamin D as optimal, they do it because they have done the research. When bodybuilders do it, it's just an article of faith for them and not something you should follow.

It is always possible to arrive at a correct conclusion through entirely incorrect reasoning.

Or, as the saying goes, a broken clock is right twice a day.

No, this line of thinking leads people to blindly trust the peer-reviewed process, which is fraught with plenty of political landmines and corruption.

Homeopathy is crap. But bodybuilding/powerlifting/athletic training often finds the answers well ahead of peer-reviewed science.

That's why doctors recommend that people get adequate sunlight every day. Of course paler people need to find a safe balance.

For most of the U.S. population, sunlight isn't enough: https://news.ycombinator.com/item?id=15869454

Unfortunately very few doctors keep learning and try to be up to date with the current research (I don't blame them, they are extremely overworked). Especially their diet advices are so laughable.

I had a friend 10 years ago, diagnosed with lupus (living in the NYC/Tri-state area). Her doctor told her, "Don't take supplements. Just eat a balance diet and you will be alright. Supplements interfere with your body's chemical balance." So patients have to read up on and talk with others to avoid quacks like that one.

Dermatologists still prescribe antibiotics for acne. For some specializations, it's all about the maintaining the status quo.

Truth be told, doctors still don't know much about IBS and/or Crohn's. Or even conditions like rosacea and/or dermatitis. Mark my words, better gut flora/microbiome will be the cure for these conditions in the near future and doctors will contest this up until the evidence is too loud to ignore.

"The best way to get vitamins is to eat better." -Every physician ever.

Unless you have your own organic garden this is a pipe dream.

A fruit or vegetable that have traveled thousand of miles before being delivered to you has almost no vitamins left in it and probably didn't have much to start with considering soil depletion.

I believe (emphasis on believe) that supplementation is necessary even if you "eat right".

This study is only about vitamin C and doesn't mention transportation. This is a bit light imo.

This advice is not useful when physicians exist that will tell you a non-useful thing--or even a wrong thing--according to current consensus among nutrition specialists, because nutrition is not their specific area of expertise.

For instance, overdose quantities may be different among the various vitamers of a specific vitamin. Your physician will advise you not to supplement ADEK because people have overdosed on retinol or ergocalciferol, whereas you can eat carotene until you literally turn orange, and 15-30 minutes of daily midday sunlight can make 10000 to 20000 IU each time.

The danger of vitamin D oversupply (even as cholecalciferol) is calcium related, which is why you have to balance it with vitamin K (as menatetrenone), but it's called vitamin K from the German for "clotting factor", so then your doctor worries about clots. But vitamin E (as RRR-alpha-tocopherol) is also an anticoagulant. It's almost as if you have to consider every vitamin as just one part of a balanced system of nutrition...

So in order to give you good advice, your doctor would have to have detailed and intimate knowledge of your current nutritional state and your physiology, but we only have 15 minutes and I don't want a malpractice suit for giving you the wrong advice, so just f' it and give 'em the boilerplate: "You don't need to supplement. Just eat a balanced diet with plenty of dark green vegetables, and get some exercise."

So there you go. I just saved you a copay, unless your particular physician has an interest in nutrition-based medicine.

Don't get your vitamins from the corner pharmacy or the grocery store. Most of them will use the cheapest chemical that technically qualifies as a particular vitamin. You need specific vitamers if you intend to exceed the general recommendations. Do your own research, and remember that you can damage your own body by doing something stupid with it. If you consult a physician, make sure they have enough training and education to be credible with respect to nutrition and biochemistry before you fork over money for an office visit. You can read the same articles and papers that they read, if you are motivated enough to do so.

Yes they can check some of your vitamin levels with a periodic blood test.

Vitamin K can be dangerous for a not insignificant part of the population, many of whom don't realize they might be sensitive to it. It is a very strong addition to the body and affects blood clotting and interactions with many medications.

If you want to safely increase vitamin K, just eat more dark green vegetables like spinach. There's no need to overdo it with K or it could be a regrettable error.

The best „normal“ dietary source is Gouda cheese, and almost an order of magnitude better, Natto (though that’s hard on the taste buds).

Gouda is important for my health? Thanks, that's the best news I've heard all week !

It'll do you a lot of Gouda.

False. The best "normal" source is foie gras.

Natto is not "normal". It is an acquired taste. The acquisition of said taste is a difficult, nauseating, and extremely stinky path. Besides that, most of the vitamin K from natto is as MK-7.

Animal-sourced vitamin K is mostly menatetrenone (aka menaquinone MK-4) whereas vitamin K from fermentation bacteria is various lengths of menaquinone, of which only MK-4 and MK-7 have good vitamin K activity in humans, and the MK-4 form is usually nearly absent. Plant-sourced K is as phylloquinone, which has to be converted to menatetrenone in the body.

So also-good sources are egg yolks from free-ranging, pastured laying hens and butter from free-ranging, pastured dairy cows. Basically, you need to eat parts of animals that were raised by traditional, non-battery farming, particularly the livers and adipose tissue. Poultry animals such as geese, chickens, and ducks are good for this. Apparently, the oil from rendered emu fat is also high in vitamin K.

Cheeses have some MK-4 from the milk and some MK-7 from the bacteria, but a lot of their K is in less easily assimilated forms. That's probably good enough unless you have some rare and nigh-undetectable enzymatic deficiency that interferes with conversion of MK-9 to MK-4, or something.

I suppose that if you force-fed some geese a bunch of natto, and then mashed up their livers into a paste, that would be a great vitamin K pate. I think I'd rather just swallow a pill.

Foie gras is not "normal", because it's very expensive and its production inhumane. And I did not call Natto normal, if you read my comment carefully. It's not that easy to acquire, and as you said, it's disgusting.

Most pills/drops you would prefer over foie gras are mostly made from Natto (MK-7) btw.. there are some supplements with MK-4 but those are rare and quite expensive.

I meant "normal" in the sense that it contains the animal form of vitamin K (K2 MK-4) rather than bacterial (K2 MK-7) or plant (K1) vitamin K.

Foie gras is nauseating for a completely different reason than natto. As actual food goes, I'd rather eat the pastured eggs and butter, even though they are also rare and expensive in US supermarkets.

It doesn't help that the supplement industry is loaded to the rafters with hucksters and scammers, but you can get a year's supply of pills labeled as 5 mg MK-4 for $90. It'd be hard to tell whether that's really what's in them without engaging a testing lab at additional expense.

What is Natto?

Fermented soybeans, a japanese dish. It's a bit smelly. I had no issue with it when I went to japan, but I really enjoy somewhat aged cheeses.


You may not like the taste, but trying it is an interesting experiment.

Boiled soybeans served in mucus

> I got less sick during the winter, and my overall wellbeing improved greatly.

Just out of curiosity, did you work out regularly in a gym before taking those pills?

Not the GP, but: While I discovered in the last years that I absolutely need to work out regularly or risk getting depressed, it is especially hard in the winter months. It seems that my body is preparing for hibernation and all I want to do is sleep and eat (preferably with lots of carbs and fat).

I think I will talk to my doctor about trying some Vitamin D supplementation in the next months. Generally I try to avoid supplements, but in this case I don't know what else to try.

It is very easy to fall to low levels of Vitamin D even with supplementation (you need an abnormally high dose at times to get to 'normal'). So, please do check with your doctor. If you do have a deficiency and get supplements, it makes a lot of difference.

In winter you probably also get less sunlight. I'm under the impression that most people would benefit from bright daylight during the day -- I have some LEDs in the daylight/6000K spectrum on a timer at my workstation -- even if you aren't diagnosed with SAD.

Remember to keep them on during the _daytime_ only, though, to keep your body clock on the appropriate schedule!

This is not necessarily the same issue as you're talking about, but I feel like in the winter, doing your workouts outdoors in the daytime can be a good thing.

Some people (including me) find that they stay indoors most of the time in the winter. Doing your workout outside gets you out there, which gives you not only sunlight (speaking of Vitamin D) but also a change of scenery that can cut down on cabin fever.

With the proper gear, the cold is tolerable (except maybe in extreme climates). And, especially if the exercise is vigorous, it's more tolerable being outdoors in the cold than it would be if you just went stood or sat around outside.

Vitamin K is found in very high concentrations in almost any leafy green vegetable or tomatoes and countless other vegetables. You won't have any problem getting enough vitamin K.

Just take half a pound of spinach and boil it, when you eat it, it'll be about the size of a medium bowl. That will be about 50 calories and contain 1200% of your daily vitamin K needed!!

>...Just take half a pound of spinach and boil it, when you eat it, it'll be about the size of a medium bowl. That will be about 50 calories and contain 1200% of your daily vitamin K needed!

It really isn't that simple. One issue is that it doesn't matter how much is in spinach if you don't absorb it.

>...Circulating phylloquinone levels after spinach with and without butter were substantially lower (7.5- and 24.3-fold respectively) than those after taking the pharmaceutical concentrate. Moreover, the absorption of phylloquinone from the vegetables was 1.5 times slower than from Konakion.


And while those vegetables will get you some K1, they won't get you K2 which is important for how calcium is handled in the body.

>...We examined whether dietary intake of phylloquinone (vitamin K-1) and menaquinone (vitamin K-2) were related to aortic calcification and coronary heart disease (CHD) in the population-based Rotterdam Study.

>...The relative risk (RR) of CHD mortality was reduced in the mid and upper tertiles of dietary menaquinone compared to the lower tertile [RR = 0.73 (95% CI: 0.45, 1.17) and 0.43 (0.24, 0.77), respectively]. Intake of menaquinone was also inversely related to all-cause mortality [RR = 0.91 (0.75, 1.09) and 0.74 (0.59, 0.92), respectively] and severe aortic calcification [odds ratio of 0.71 (0.50, 1.00) and 0.48 (0.32, 0.71), respectively]. Phylloquinone intake was not related to any of the outcomes. These findings suggest that an adequate intake of menaquinone could be important for CHD prevention.


>and my overall wellbeing improved greatly.

Just a counter-point. Vitamin D didn't help me with SAD. SAD seems only addressed for me by a proper full spectrum lamp for 30 minutes a day in the winter.

I haven't heard this about vitamin K before - please correct me if I'm wrong, but I don't think we know how the mechanism through which vitamin K reduces skeletal fractures.

Here you can find all info you want: https://examine.com/supplements/vitamin-k/

Search on that page for: "Skeleton and Bone Metabolism". K1 and K2 work differently. We know a lot but there is still a lot more we don't know. Hell, looks like even different versions of K2 (from MK-4 to MK-13) works for different stuff in body. Only because MK-7 stays in blood for longer than MK-4 doesn't mean that it better. It could also mean that body is better in utilizing MK-4, or even that it's using it for different stuff.

More here: https://chrismasterjohnphd.com/2016/12/03/start-here-for-vit...

Both of those sites appear to be money-making ventures that sell vitamins; I wouldn't consider them reliable sources.

Here is a university page with information:


Examine.com does NOT sell vitamins/supplements.

They collect and analyze available research, and the result of that process is their product (in the form of guides etc).

Thanks for noting this. Their web site design (as well as the use of a dotcom domain) gives a misleading impression

And Chris Masterjohn, PhD is also working with them, example http://v6.examinecdn.com/erd/chrismasterjohn2.pdf

Personally I don't know better source with information about different supplements than examine.com, more how they are working here: https://examine.com/about/ If you know better source point it to me, please. This university page you provided is short and old.

Just one question: what's wrong with using dotcom domain?

If examine.com's metaanalsyses are based on legitimate research papers -- and you've read some of the papers yourself and find that they indeed provide support for the article citing them -- then i'd say yeah, use the site.

i guess to respond to your question: most biomedical research today is eminating from universities and university-affiliated entites. page for page, i generally wouldn't expect a .com web site -- the majority of which are probably just attempting to generate advertising revenue -- to be on par in terms of accuracy etc with a .edu site. generally, I've found one of the best ways to improve the signal-to-noise ratio is to filter to a specific set of domains (e.g., ,edu, .gov) when searching online.

Indeed we don't, plus the two forms of vitamin K (phylloquinone and menaquinone) have different mode of action.

They are important cofactor for many proteins, including one called osteocalcin, needed for bone calcification.

It looks like Vitamin K also inhibits arterial calcification.[1]

1. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4052396/

Correct; see my other comment as well. Vitamin K supplementation should not be casually added to anyone's diet without careful evaluation.

D3 is the more active form, agreed on adding K too. Worth paying a bit more for higher quality controls.

Has anyone had experience ordering blood work (e.g. the vitamin d 25 hydroxy test) without visiting a doctor? I've seen very few references to the set of sites that pop up first online [0, 1, 2, 3] when I've gone looking for reviews in the past. Any suggestions? I'm in CA.

[0]: https://www.privatemdlabs.com [1]: http://www.directlabs.com/ [2]: https://www.walkinlab.com/ [3]: https://www.health-tests-direct.com/

I've tried DirectLabs, WalkInLabs, and Life Extension, and have been happy with them all. All of those companies are basically just "doctor ordering resellers" for the two big test labs (LabCorp and Quest), so you generally don't have to worry about the quality of the testing.

I specifically use Life Extension for vitamin D because they're the cheapest one I'm aware of.

Can you tell me which one of those uses Quest? I used Life Extension as well for vitamin D but had to go pretty far to get to a LabCorp facility. I've got a Quest facility a few minutes away I'd rather go to.

Sure, here's the ones I know of:

Quest-only: DirectLabs, Personalabs

Choice of Quest or DirectLabs: Walk-in Lab (switch the radio button to Quest on the category pages, and make sure a "QD" icon shows up next to it in your cart), TrueHealthLabs (make sure the tests you look at say Quest is an option), HealthTestsDirect (make sure the test list page is toggled to Quest at the top)

DirectLabs and Walk-in are generally cheaper than the others I mentioned.

You can try labespy.com. It will search for the lowest price amongst all these sites, amongst many others. You can find vitamin d for $33.

In case you have a health insurance - many plans provide a free yearly preventive care doctor visit, which include basic blood lab work. I took advantage of it many times with different insurance companies.

I'm not sure it applies to US where Health Insurance is rather russian roulette when you need coverage. Not sure about Aetna, but BlueCross is pretty clear: "BCBSNC will provide coverage for testing serum vitamin D levels when it is determined to be medically necessary because the medical criteria and guidelines noted below are met." https://www.bcbsnc.com/assets/services/public/pdfs/medicalpo...

I just recently have been struggling with coverage of Vitamin D test for kid with Celiac.

When I asked my doctor (in the US) for a vitamin D test earlier this year, he told me he would be happy to write the prescription but my insurance would most likely not cover it. He said so many people are getting it that insurance companies have started denying the claim unless there was a genuine medical need. I went elsewhere for it, see my other comment: https://news.ycombinator.com/item?id=15869485

I've used Direct Labs multiple times over the years (including for 25 hydroxy) and I've always been perfectly happy with them.

I self-paid for a handful of labs a few months ago, including Vit D (and thyroid, and blood related stuff, and cholesterol, and a few other related things).

I went in, the nurse drew some blood and charged me $150. A week later, they mailed me the results.

None of this was done online, and insurance never was involved. I found a lab in town, asked their cash price, and they told me, and it was fine. Specifically the lab was associated with a larger medical facility, so call around to any local hospitals to see what they quote you.

I got a Vitamin D test a few months ago via http://www.lifeextension.com/Vitamins-Supplements/itemLC0819...

The "Vitamin D 25 Hydroxy Blood Test" was $47. I got a blood draw order signed by a doctor that I had to take to a LabCorp - so make sure you've got one near you.

I joined one medical in sf and while I did meet with a doctor, you can also do walk-ins for blood tests. It was fast. There is a yearly fee to be a member and they have offices all over CA. https://www.onemedical.com/blog/health-guides/lab-test-guide...

Bloodwork is a core utility of naturopaths so one would probably know the best place to visit. You don't have to be incredibly lucky for your preventative plan to cover the visit.

I've had great experiences with http://discountedlabs.com

In CA, Quest Diagnostics requires a doctors note for the tests I've taken. Other providers or other tests may be different.

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