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So there is such a thing as "knowledge". Learning problem solving skills in the absence of subject-matter knowledge is simply a Markov walk exercise.

edit - corrected spelling


This is the central claim of E.D Hirsch's Why Knowledge Matters[1] book on educational reform. Hirsch is perhaps best known for coining the term "cultural literacy" in his book of the same name.

A little while back I wrote about cultural literacy in the software industry, following the lead of Hirsch's book.[2]

1. https://hep.gse.harvard.edu/9781612509525/why-knowledge-matt...

2. https://thundergolfer.com/software/culture/2024/01/14/comput...


I was in high school when calculators arrived on the scene. I still have several slide rules (one was circular so it would be more accurate :-) ). In the space of one year, slide rules completely disappeared. I stopped trying to show my kids how to use one when they kept looking at me like I was a caveman......


In about the mid-70s, electronic calculators went from something that was $100 for a very basic maybe 5 function calculator (and hundreds of dollars for an RPN HP) to maybe $100 for a functional TI scientific calculator in about a year. And that's mid-70s dollars. I got a discontinued HP maybe a couple years later for about the same amount of money.


>one was circular so it would be more accurate :-)

I have never used a slide rule, and I am missing the joke. Is that true? My assumption would be that humans are better manipulating a linear device than angles.


The longer a slide rule the more precise it is - you get mode decimal places. But it also become less convenient to use. That's where the circular slide rule comes in: a 4 inch diameter circular slide rule has the scales on its rim, which are 4 * 3.14 = 12.56 inches long, so it's equivalent to a 12.5 inch linear slide rule but more compact. That's how a Breitling wristwatch can include a usable slide rule - it's equivalent to a 6 inch linear slide rule on your wrist.

Also, in a linear slide rule you have to move the center scale left or right: to multiply 2 * 4 you move the slide to the right, but to multiply 3 * 4 you need to move it to the left (it "overflows"). With a circular slide rule you don't have that problem.


To build on the other answer. Precision is the word you want, not accuracy. My mother had an extra-long slide rule which sadly disappeared in some cleaning/move. But a circular slide rule can mimic linear length to some degree while staying fairly compact.


I have not used either but I assume it is possible due to it being easier to manufacture a pivot point with tight tolerances so there isn’t much play in the slide.


It's not really an accuracy problem AFAIK. But the precision (i.e. number of significant digits) is limited by the effective length of the scale (whether linear or circular) even if the manufacturing accuracy is perfect.


Seems like a pretty reasonable analysis of what is going on. I'd be interested in hearing any rebuttals.


He’s comparing a very narrow range after listing but you can buy crypto at anytime using DEXs. He compares it to an IPO but it’s easy to buy crypto before it’s listed on a centralized exchange and much harder to buy equity in a private company.

So yes, retail had its shot before a major CEX listing.

If you bought Solana or Cardano in the bear market you are outperforming Bitcoin.

Solana was a few bucks in 2020 and close to $260 in 2021.


The average Coinbase retail investor is not going to use a DEX. In fact I would be surprised if over 50% of their users have ever transmitted coins away from Coinbase a single time. Sure the first users were obtaining BTC for productive purposes like buying from darknet markets, but the majority of their users have come during the investment booms. From their S1 they are holding $90 billion in cash and fiat. $44 billion of that is for institutions, but the rest is from retail investors who are buying what Coinbase makes available to them and letting it sit in the app while they wait for it to go up.


The study conditions are so artificial (very slow), that any potential efficiencies would likely be negligible. My son, who ran track in college used to tell me that it was harder to run at a 7 minute mile pace than 6 minute mile pace, because they were doing all their training to run at sub-5 pace. My experience on the bike is similar. AS for the author's comment about how easy the neuromuscular coordination to bike is, he probably hasn't tried to consistently maintain a cadence of 110-120 rpm. It takes practice to be able to do that smoothly, and improves your technique when you're going at a slower pace.


I would guess they evaluated it at 8 min/mile pace because a more typical speed for evaluating running economy (e.g, 16 km/h or ~6:00 pace) might be a bit tough for cyclists who don't run. Especially since you'd need to do 5 minutes or more at said pace to make a meaningful determination of RE.


Most of what is stated is simply not true. I am a physician, not a member of the AMA. They have absolutely no role in the selection of medical students, training of physicians, or their licensing. I have no particular love for the AMA. But lets keep the criticisms accurate.


The AMA lobbied in the 90s to limit federally funded residency slots. This served to restrict supply of doctors because medical schools base acceptance on available residency slots. The AMA has pushed for more funding of residency slots in more recent times, but their lobbying behavior in the 90s clearly shows they have an interest in controlling the supply of doctors.


The AMA was founded to get control of the "snake oil salesman" problem in the 1800s, and their stated method was lobbying to get licensing laws passed in every state. Controlling who gets to be a doctor was unambiguously the central function of the organization. Along the way, they were no doubt approached with a lot of other suggestions about how they could help and once they outlived their original purpose, have carried on as a zombie improving their ability to profit from all the little suggestions they got along the way.


To (mis-)quote Eric Hoffer, “Every great cause starts off as a movement, turns into a business, and ends up as a racket.”


Is that misquoting? I think that's almost verbatim the quote.


I believe the AMA is responsible for accreditation of medical schools. Without accreditation, they can't make doctors, thus the AMA controls the supply of doctors.


^ Yeah that's directionally accurate. The AMA is one of the two funders of LCME, the accrediting agency of medical schools for MDs (outside of the med school trade association itself). While they do not run medical schools, they have enormous power over training standards, who should be a physician, how medicine should be practiced, and who shouldn't practice. As an example, they lobby pretty regularly against the expansion of the role of RNs/NPs (https://www.ama-assn.org/press-center/ama-statements/ama-sta...). Much of this derives originally from the Flexner Report which created the current system of US medical education, which is still based on old sensibilities that physicians should be professional gentlemen and "proper" (and perhaps fueled by cocaine -- no seriously, google "halstead cocaine").

I am not a physician, but I have been in the guts of healthcare for quite a while, and the AMA continues to pop up as the man behind the curtain surprisingly often.


They're all connected in some capacity, but AMA does not accredit medical schools.

* LCME accredits M.D. Schools

* D.O. Schools have their own accreditation (not sure what it is)

* AAMC runs the racket of "MATCH" to appoint graduating medical students to programs (and strip most of their rights as employees).

* ACGME accredits Residency Programs.


What a great story and an amazing person. It's always nice to read about someone who was genuinely a good person. I especially liked the quote: “Every man’s life ends the same way. It is only the details of how he lived that distinguish one man from another.”


Fully agree. What an amazing read :)


While hypervitaminosis D is a real syndrome, as evidenced by this story, low Vitamin D levels are endemic in temperate and northern latitudes. We did a study several years ago ( Vitamin D Status in an Elective Orthopedic Surgical Population. Foot Ankle Int. 2016 Feb;37(2):186-91. doi: 10.1177/1071100715609054) in Vermont among healthy folks who were going to get surgery and roughly 2/3 had low vitamin D levels (<30ng). Low vitamin D is a significant risk factor for fractures, such as hip fractures in the elderly which is a major cause of mortality. So please don't interpret this story as a reason to avoid any vitamin D supplementation. 1-2000 IU/day has been shown to be safe with long term use, but if you have any questions, you should absolutely talk with your primary care provider. PS - Yes, I am a practicing physician.


I'm the physician who wrote the article. And I agree with you. Vitamin D deficiency is a problem because it leads to bone loss (see part 1: https://www.devaboone.com/post/vitamin-d-part-1-back-to-basi...). And Vitamin D supplements can be very helpful for those with a deficiency. The point that I am trying to make is that Vitamin D should not be thought of as a dietary supplement. I am seeing more and more people with high calcium levels from being on high-dose Vitamin D. If you treat Vitamin D like the steroid hormone that it is, you will treat it like a medicine, and not take outrageous doses because someone online suggested it. At least, that's what I'm trying to get across.


Thanks for your article. As another physician (hey - three in a row on hackernews, clearly this is the new place to hang out), it's been interesting following the Vitamin D story, and I enjoyed reading your article. I was always a bit skeptical of the data, but then came across the first cochrane review for it, and was surprised to see a general reduction in all-cause mortality in a general population. But looking it up again [1], the conclusion seems far more couched. Do you have any comments on the Cochrane reviews?

[1] https://www.cochranelibrary.com/cdsr/doi/10.1002/14651858.CD...


I really like the Cochrane reviews, and love that they periodically update areas when there is more recent research. And you are correct, their articles on Vitamin D have become less enthusiastic with time. This makes sense I think, since the initial publications on a topic will all be "positive" - they have to find something new to get published (creating a publication bias). And they do try to account for publication bias, but really the best way to fix it is to have more studies. With Vitamin D getting so much attention, you can get published whether you find a correlation or not, so you have a wider range of studies to look at. I wanted to give a summary of the Cochrane reviews and the largest human trials of Vitamin D in the next blog post.


Not a physician, but still following this story closely. Can I ask you docs to weigh in on the recent results regarding the role of vitamin D in covid-19 outcomes?


This is a correlation. There are lots of conditions that are associated with low Vitamin D. Mortality overall is associated with low Vitamin D. But it doesn't mean that the low Vitamin D caused any of these problems. Having overall poor health leads to Vitamin D deficiency. The increase in mortality is more likely related to your overall health status, not your Vit D status.


Do you know anything about the link between schizophrenia and Vit. d?


Don't expect to find anything beyond a correlation between VitD levels and any serious disease. In any study that such is found, the substitution had no effect.


> I will not give any recommendation without first knowing Vitamin D and calcium levels.

This sounds too risk-averse, and I worry that it scares people off taking Vitamin D at all; yet a low level would be good for most people.

I live in a northern latitude, and Vitamin D deficiency is widespread. What should the public health system recommend? It seems there are two choices:

(a) Regularly test the Vitamin D levels of the entire population, and recommend zero Vitamin D supplements for any individual who has not been tested recently.

(b) Find an average "safe" level that will help most and cause damage in very few.

From a perspective of an individual physician I would see how you might want to cover your risk and go for (a), but thinking about it as a whole population, I would think (b) is the best.


Yeah I think it may be a bit overzealous to say that even people who are not supplementing at all, and even in a population where low Vitamin D is common, should wait until they measure k and Vitamin D (which could be not for a long time).

“first, do no harm” seems to be the thread of this caution though, so not exactly unexpected from a doctor.


My PCP tests my Vitamin D levels annually, and it doesn’t cost me anything; it’s just part of the standard bloodwork. It’s always been fine in the past, but the most recent time I was told it was low and was prescribed Vitamin D.

I’m not a health nut, just someone who has annual physicals. Doesn’t it make more sense to encourage people to spend their time and money on annual checkups and tests, rather than encouraging them to buy supplements they might not need—or, worse, that might harm them? Supplements seem cheap at first, but the costs add up over time.

We should be encouraging people to see doctors, not to make uninformed health decisions that might not be right for them.


Here in the United States there are millions without insurance and they're unlikely to be able to afford a doctor's visit - as those without insurance also tend to be the poorest. To be honest, many probably can't afford dietary supplements either but for those who can then a blanket recommendation would be good for them. Either that or we should push for a public health measure ensuring everyone gets a physical, including bloodwork, every 5 years whether you have insurance or not. We need to start thinking through workable solutions for the bottom 20%.


Yeah, I just don’t see this happening across the whole population. Maybe with an expensive campaign to encourage yearly physicals you will get a certain sector of society; but there are going to be millions who haven’t got insurance, worry they would be wasting a doctor’s time, are scared of the authorities, can’t afford the travel time, and so on.

I believe there is a safe level. In Sweden the government recommends everybody to take 10 micrograms daily, with some groups at 20 micrograms, and this advice is very commonly followed. As far as I understand it that advice does an awful lot more good than it does harm.


You're probably right. Public health is a difficult issue.


Thank you for writing and sharing this story!

My mother has been plagued many of the same symptoms that your patient had, and she has been searching for a cure for years. All of her blood levels are "within normal ranges", and doctors always dismiss her as being crazy, so she ends up seeking treatment from various "quack" doctors.

It sounds like you are the kind of doctor that is able to analyze the human body holistically and solve underlying problems that other doctors would miss.

How can I find a doctor like you that I can convince my mom to go to?


I don't think it's necessarily a holistic thing... i think it's more that the doctor specializes in this area and most doctors aren't familiar with it.


This is exactly it. I was able to see it because I deal with this every day. I am not more holistic than other doctors; I just know how to look at calcium and Vitamin D levels.


For folks on supplements should you skip a dose when getting a lot of sunlight or does your body know to produce less when not needed?


Even if you're taking vitamin D supplements, you probably won't get the full anti-covid benefits unless you also get at least 15 (and preferably 30) minutes of direct sunlight exposure each day. My understanding is that vitamin D causes your skin to produce nitric oxide, but this nitric oxide doesn't actually get released into the rest of your body unless you get actual sun exposure.


> get at least 15 (and preferably 30) minutes of direct sunlight exposure each day

This time is directly proportional to how much skin you expose to the sun. If it's only face & hands you need a lot more than if you're in the swimsuit.

It would be interesting to know what clothing the 15-30 min tip assumes.

Also, sunlight through a window does nothing. You need the UV light.


I wonder if incandescent bulbs were better for us in this one area.


Not a doctor or any profession of relevance but I do use tanning lights. Incandescents produce mostly visible light and very little UVA or UVB for those health concerns. Fluorescents tend to produce more UVB in comparison but still very negligible. Tanning lights generally produce the amount of UVA and UVB needed for vitamin D synthesis although you have to use with caution.


No, they don't produce any UV light.

Even if the filament somehow does (I doubt it), it won't make it through the glass of the bulb.


I don't think incandescent bulbs produce any significant UV. The temperature is too low.


Any sources? I've seen much discussion of vitamin D and COVID, and they all appear to imply that supplements would help.



That isn't a source for vitamin D supplements not having an effect on COVID, that's a source saying that sunlight is needed to produce nitric oxide.

Looking online, I see that there is a hypothesis that nitric oxide has a protective effect against COVID, but I don't see that this hypothesis is any better tested than the hypothesis that vitamin D itself has a protective effect against COVID.

So, sunlight will probably get you the best of both worlds, as it would help either way, but there doesn't seem to be real evidence for nitric oxide vs vitamin D.


Yeah I would describe the evidence for both as circumstantial but fairly compelling, and very low risk. Even given the unknowns and potential risks, getting enough sun exposure is probably the best anti-Covid intervention from a cost-benefit perspective.


> the full anti-covid benefits

The alleged anti-covid benefits.

There's been no causal relation established so far.


What about vitamin K2? Will it help to reduce calcium levels back to normal when taken in parallel with D3?


Only if you take K2-MK7. The regular form of K2 will not help much. And you need to take 100mcg of MK7 per 10,000 IU of D. It also helps to build up your potassium levels using potassium citrate or bicarbonate (NEVER potassium chloride) over time. Potassium is critical for cellular mineral transport, and low potassium levels will have an impact on blood calcium.

I know many people on this protocol who have had their blood tested and verified that they have no detectable calcium levels in the blood. And blood testing is key. Anyone on this protocol should be checking their calcium, D, and potassium levels. They should also monitor their blood pressure.


What's wrong with potassium chloride? I've been using lite salt (50/50 sodium chloride and potassium chloride) in my diet to help make sure I get enough potassium, and your comment has me a little concerned.


Potassium chloride is toxic in higher doses, and not tolerated well by the body. If you are using Lite Salt as salt, you probably aren't taking enough to matter. The various studies for potassium toxicity are done using potassium chloride.

The citrate and bicarbonate forms are much better tolerated, and at much higher doses. I take 3 teaspoons a day of potassium citrate, in water, spread throughout the day (I built up to this over time) because I have a mostly meat and dairy diet. This yields approximately 6 grams of potassium a day. For most people building up to 2 teaspoons a day is sufficient. This much potassium chloride would be dangerous.

The primary symptom of too much of the citrate or bicarbonate forms is diarrhea. Also, the metabolic byproduct of citrate is bicarbonate, which has a far greater effect on body pH than taking bicarbonate itself, as the process increases blood pH rather than that of the intestinal tract.


> Only if you take K2-MK7.

Citation? Do you mean MK4?


I believe both forms have similar effects but MK7 stays active in the body much longer.

MK4 is the common one in lots of things. MK7 is the form found in quantity in nattō which is not commonly consumed outside Japan. It can be supplemented.


Is it high or low blood pressure they should be looking out for?


Low. But that usually means that you are not properly balancing your potassium and sodium intake.


That's interesting. I've been taking 5000 IU of D daily since COVID. I get barely any sun though. And I noticed noticed my blood pressure went down by 10/10. 110/70 though so I'm happy lol


I'd like to know that, too. I've been taking one of these a day:

https://smile.amazon.com/gp/product/B0716RWHX4/ref=ppx_yo_dt...

So, 1000 IU.


Thank you for your article. I also had alarming palpitations while on Vitamin D 5000IU, and did not make the connection until months later when I slacked off with taking it and they went away. Started taking them again and the palpitations came back. Went through the full battery of heart tests and everything said I was fine. I posted on here a few months back on another post about Vitamin D, explaining my (admittedly anecdotal) situation, and some commenters seemed not to believe me. Happy to hear that I'm not alone.


Come to think of it, I've had some weird palpitations the last couple of years that have given me a bit of a scare too. I think I started taking Vitamin D supplements around that time (after I had my levels checked). The palpitations seem to happen on and off, and I've also been on the supplements on and off, but I haven't paid attention to if the times match up. I do know I haven't taken the supplements the past few months and it seems the palpitations haven't occurred in that time. I'll probably take the supplements again in the winter, so I'll need to see if the issue returns, and if so, whether not taking them makes it stop again.


Huh. I'll add some more anec-data to this thread: both my mom and myself have had similar issues.

My folks live in WA near Seattle and, while summers are pretty nice, most of the year is crazy dark and gray, necessitating some Vit D supplementation. My mom was pretty diligent about that and noticed heart palpitation on a few occasions, but no actual heart issues.

I live further north and supplement for the same reasons, and have even gone to the hospital thinking I was having a heart attack -- but all the tests came back fine. Those heart issues were after a long period of supplementation + aggressive workouts. If anything, my heart health was probably better then than most times; doctors attributed the issues to stress.


Sorry to hear that. I hope this helps you, as I know how scary and frustrating that is. How many IUs were you taking? I seem to be fine on <= 1000IU taken periodically, but 5000IU daily was too much for me.


I was taking 2000IU daily.

For more details, I'd usually take it late morning with breakfast. I'm a normal weight (155lbs), exercise, eat healthy, low stress, in my 30s, good blood pressure, don't drink coffee. I'd notice the heart issues usually in the evening. Sometimes they would occur almost daily for a week, and then they'd go away for a couple of weeks. Then I'd experience them again one day, and not for another few days. They would occur for about a few seconds or a minute when I was at rest and not doing anything active. It's hard to describe the feeling but it was kind of like a muscle spasm occurring in what I thought my was heart. Or, like some strange beating/squeezing sensation that would occur once, then again 5 seconds later, then a couple of seconds after, then that was it. Or it might return after a few minutes and happen again.

It was an intense and serious enough feeling that it would make me pause whatever I was doing. It would make me think that one of these times it would be a bit worse, I'd end up collapsing, and that would be the end. I'd usually do a bit of cardio for a few minutes because like I said it only seemed to happen when I was at a resting heart rate.

I should probably get my heart checked because there's a good chance the connection with the vitamin D supplements is just a coincidence. Nonetheless, I'll pay attention to see if there seems to be a relation between the two, because although it's unlikely, stranger things have happened.


Interesting. I had the reverse problem. I had lots of random muscle twitches and fatigue. Got my vitamin d levels tested, and they were extremely low (don't remember the exact number). I'm now on vitamin D and the symptoms went away.


Have you come across people that take high levels of vitamin d as well as get plenty of sun, but whose levels are still less than 30? And further, this is happening to both a father and a son?


My doctor told me that abnormally low vitamin D levels can be genetic. Haven't done much research, but looking at my family would agree.


How do you feel about vitamin k2 (and magnesium) for lowering the risk of high calcium?


As far as I'm aware it's only B vitamins that aren't toxic in high volumes. I take 1,500ug of B12 (60,000% nrv - B12 has fairly poor adoption) for a nervous system disorder, seems to stops my toes going purple...


I dose a similar amount of B12 as you and likewise see real benefits, but I recently stumbled across some research that claims vitamin B6 and B12 supplemenation show increased incidence of lung cancer in men [1]. I'm wondering if any of the above physicians can comment on this research.

1. https://examine.com/nutrition/vitamin-b-cancer/


">55 mcg/day [B12] was associated with a 98% greater risk" Wow, that is quite a staggering increase! Luckily it was men who smoke; "As for never-smokers, the paper states they “were excluded from the smoking-stratified analysis because of the low number of participants with incident lung cancer in that group.”

It's interesting how woman weren't affected, but I am all too aware of the link between smoking and lung cancer as the two go hand in hand. My father died of lung cancer and we didn't part on the best of terms as he had a bad cough for a over a decade before being diagnosed, I lacked sympathy as it was virtually a given. Seeing patients needing to go outside to smoke (often with an IV attached) as they are dying is something I'll never get my head. I would name it the Darwin ward, but that is probably insensitive... (ASD)

It makes me angry that medics won't even condon, let along recommend smokers switch to vaping due to politics. They could save 100,000's of lives per year in the US alone (480k smokers die per year).


Works well. I've been taking at least 50,000 IU/day for over 2 years and serum calcium is always in range. I add milligrams of K2 MK-4, micrograms MK-7, and 100s of mg of magnesium (now over 1g).


Wow! Why so much, my dude?


Because...


I walk for 30 minutes a day in direct sunlight. If I do this for a year (been 5 months so far) do I not need to worry about vitamin d intake? I am also a healthy young male in my 20’s


As others have pointed out, it depends on time of year and where you live. Far north, e.g. Canada, the U.K, Scandinavia the sun won't give you any Vitamin D at all for roughly six months of the year.


I’ve been using the DMinder app (not affiliated in any way and it’s totally free) to estimate how much vitamin D I’ve been getting. You input how overcast it is and what percent of your skin is exposed and then it uses your skin tone (input at setup), latitude, altitude, and time of day and it’ll track a rough estimate of how much vitamin D you’ve produced while you’re outside.

There’s also “Quick and Easy Screening for Vitamin D Deficiency in Adults”[1] which has a quick and dirty formula in Table 2 to help assess your risk of deficiency without a blood test.

[1]https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4998626/pdf/med...


is exposed amount of skin an input?


It depends on your latitude and skin color, mostly, and other factors like how much clothing you wear.


Can’t find a citation at the moment, but it also depends on what part of your body is exposed. Just resting your forearm on an open car window won’t do it. You have to expose your torso mid-day IIRC.

https://www.healthline.com/nutrition/vitamin-d-from-sun#time...


Just as a pure speculation (I am not specialized in this area) I find it a little bit odd that forearm is not enough as I find it is the most common area exposed to sun by people at least in the last 100.000 years.

So I am wondering how come in this case selection did not chose those whose forearms can produce a lot of Vitamin D as it was probably the most exposed part to the sun.


Don't forget that many people used to bathe outside for many millenia. But I too would be interested in how clothing through generations have put selective pressures on humans, if any.


It probably depends on how much skin is exposed as well as your genetics.

Getting your vitamin D levels tested is a super simple blood test - you can just ask your doctor and they'll prescribe it.


What latitude?


I have read that vitamin D deficiency can play a role in starting multiple sclerosis. I was years working mostly indoors, not seeing sun much and then one day my eyeballs started flickering and I was diagnosed with multiple sclerosis. Maybe if I monitored vit. D levels and have taken supplements, I could have prevent multiple sclerosis but maybe not. It is not that easy and clear, it seems.


At least 10.000 IU/day are seemingly not a problem [1]. Old recommendations of only 1.000 IU/day are likely way too low as well [2].

[1] https://www.sciencedirect.com/science/article/abs/pii/S09600...

[2] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5541280/


The case mentioned in the article was taking 5000 IU/day, and that proved to be too much. I'm not an expert, but 10000 sounds a WHOLE lot.

I started taking 2000 IU/day because I wasn't seeing much of daylight because of the pandemic. I hope that's a safe amount, but it would be nice to get my blood levels checked.


There are a fair number of clinics that will do blood tests for you. This is the first one that came up on DDG: https://www.everlywell.com/products/vitamin-d-test/ $49 but you have to prick your finger for the blood they need.


It most certainly should continue to be thought of as a dietary supplement by current definitions, or you are on an errand to redefine that term (in the USA, at least).

It is the responsibility of physicians to discuss diet and supplementation with patients, and know that food and supplements have potent acute and chronic effects, and these effects may be on par with prescription medications.


Physicians might know. Quacks don’t. If you simply google for vitamin D, you find so many quack websites as the top result. So your idea of keeping it a supplement is a bit questionable, if it is actually medication and is easily dismissed as harmless by quacks.


Can harmful levels of calcium be present even if Vitamin D levels are measured as within the reference range of 30.0 - 100.0 ng/mL?


This is what happened to Shannon in the story. Her level was 79 ng/ml, but she still had high calcium.


Unlikely with enough vitamin K2 and magnesium, assuming calcium is below the TUL.


Is taking 100mg of chelated magnesium 3-5x a day harmful to by health? I've been taking this for a while now and just found out it can increase calcium to dangerous levels (citation needed). Please advise.


I got this from the doctor:

Magnesium is interesting. A lot of these vitamins and minerals interact, in ways many doctors have forgotten. Magnesium is essential for calcium metabolism, so I often recommend it for anyone who takes calcium. It does help with muscle cramps and many take it for insomnia. Magnesium isn't a miracle drug, any more than Vitamin D, but it is a necessary mineral, and people do really notice improvements with muscle soreness. If cramps are the main issue you have, some people swear by magnesium malate - the malic acid in it may also help with sore muscles.


Could taking calcitriol also lead to overly high calcium levels?


I'm a ~50somethingish white male experiencing bone loss (via DEXA scan). My two doctors (general and specialist) both said: let's try OTC vitamin D, even though it probably won't do anything because you aren't deficient; if that doesn't do anything we'll provide a prescription for actual vitamin D.

We experimented over two years and OTC VitD didn't help, but my point is, I was confused by two types of Vitamin D: the stuff you can by OTC, and the "real" stuff. How does this compare to the VitD you are referring to?

(I cannot take calcium because I have another disease, and "calcium bolus" is a very real concern for me do to another medication i am on.)


Someone tried 300 IU/kg vitamin D3 and 45 mg vitamin K2 MK-4 (15 mg 3x/day) for bone health. 100 mcg MK-7. Magnesium was increased to 1,200 mg.

Use a tool like CRON-o-meter to check diet. PRAL score. ZMA.


try weightlifting - this is the fastest way to increase bone density


just prescribe sunlight


Difficult in places where there is insufficient sunlight for much of the year!


Basic sunlamps aren't expensive. I grow plants in-doors and suppliment w/ them, the bulbs are ~10-15 bucks and fit in any desk or ceiling lamp.

I have a "happy lamp" by a reading chair in my living room, and sit under it in the mornings while drinking coffee and watching the news. Coffee+Sun perks me up in the morning right quick.

I'm in Edmonton, Canada -- look it up on a map, we're far up there -- and it's basically how I make it through the winters here.


So these are UV bulbs? I know bright light is used to combat SAD, but AFAIK that's not about vitamin D, just the light itself having an effect on mood.


i was mainly joking because I think that most of the times when we peal back the layers of research we see that natural systems have adapted over time for certain reasons. Also there should be further research into how native people in northern climates adapt to low sunlight conditions given their location. Perhaps there are areas of the diet we are overlooking instead of just prescribing vit D as the only fix


I've had a deficiency diagnosed, I'm worried about the prescribed integrators, since everyone is suggesting daily doses and I'm taking 15000ui/month in a single dose. what's better?


dunno about difference between effect of daily vs monthly dosage, but 15000IU per month is newborn dosage here in Europe for first year, 1 drop per day = 500IU, so I would not worry too much about such low dosage which is insufficient for adult anyway unless you spend lot of time outside exposed to sun

I'm taking 2500IU daily


This actually reinforces for me the idea that people need individualized expert advice on this. I know that lay people (and I include myself here) tend to think if x is good for you then more x is even better. So you see vitamins marketed with extreme %s over daily recommended levels. Supplementation really seems it should be last resort.

This reminds me somewhat of how people are so concerned about the health effects of too much salt that they end up getting too little, which is also detrimental.


I asked my doctor about getting my levels checked in regards to vitamins, testosterone, etc. She somewhat rudely brushed it off. Is there a good way to ask about this or should I seek out a specialist on my own?


For the basics like this, you can just buy the test online from any of the test vendors like Ulta, LTAPI, etc.


You might want to find a new doctor. The primary care doctors I've had in my life run blood tests for things like vitamin levels (especially B12 and D) annually.


You can just order bloodwork online with no interaction from a doctor and go to a local lab testing corp to get the blood drawn. This is assuming you're in America.

e.g. privatemdlabs.com (I'm not recommending that site, just giving it as an example, though I have used them in the past and everything worked as expected).


If you are a lay person, as I am, you can still make judgements symptomatically. If you have good reason to believe you are probably deficient, you can conservatively experiment with taking supplements and see if it helps. If your status improves, adjust doses downward as needed.

Keep a journal. Keep a journal. Keep a journal.

If you can't manage it yourself in that manner, yes, seek testing and so forth.

Don't ever take supplements of any kind for any reason if you don't have reason to believe you in particular actually need the supplement. Period.


From the article: "It often takes many months for high Vitamin D levels to drop, and it took six months for Shannon’s level to fall into the 50s."

I don't think a journal will help in these circumstances, the time lapse between cause and effect is just too long. Getting tested is cheap and easy (and here I'm thinking of people who are deficient in vitamin D, if the results are too low then it seems that taking a supplement would be a good idea).


This story in specific is being told by the medical specialist who resolved the issue and I was not really trying to give advice for extreme cases where you should pretty obviously be speaking to a medical specialist.

But I've journaled for years and my experience suggests that if you do it regularly, you do get better at noticing things over longer time frames. So, no, it's not useless to journal in such cases.

As with anything, more education and experience with it will get you better at it and how useful it is to you will depend on a lot of factors.


Journal is huge.

I also keep a log of every medication and supplement and notes on how it affects me. Doctors like being handed a 2 Page document with everything listed and the results.

I also got diagnosed with a rare condition from this. Doctor saw more to the reactions then I had.


People don't realize it, but journaling doesn't have to be hard. If you are talking to yourself, really brief notes can help jog your memory about "That was the day I had two eggs instead of one and otherwise did everything the same" and you don't necessary need to write down every single morsel of food to let yourself know next week "That was the day I had an extra egg with that meal." You know what your "usual" is. "My usual, but with an extra egg" is something that will mean something to future you next week, even if it means nothing ten years from now.

Journaling as a health management tool doesn't have to be complicated and burdensome. Write down what you feel you will need help remembering in a few days when you are wondering "What truck ran me over this time???" and as you get value out of it, you may feel like writing more because you can see it isn't a waste of time.

Just start, no matter how pathetically.


I totally agree. Right now I'm actually very vitamin D deficient (10 ng/ml) and on 50,000 IU Rx dosage weekly, and I'm in Arizona! I just don't get enough sunlight and wear sunblock all the time due to being extremely fair and feeling like meat in a frying pan when the sun is on me. Also staying indoors due to Corona! But I wouldn't have guessed Vitamin D deficiency.

I haven't had any bone fracture issues (thankfully) since I'm still young, but low vitamin D levels can also apparently give you brain fogginess and depression, which I'm suffering from.

But it does seem like Vitamin D testing isn't on most normal testing regimes, it was only when I presented with depression that I got tested.


Important news from the future: use shade not sunscreen whenever possible. And, as long as you're not often getting peeling-levels of sunburn, don't fear the sun, or the feeling of the hot sun, so much.

Sun exposure is sufficiently correlated with so many health benefits that it is almost certainly causative for those benefits – especially lower rates of heart disease. Endogenous Vitamin-D production is just one mechanism/signal of the sun's influence, not the full story, so supplementation of Vitamin-D can't reproduce all the sun's benefits.

And, other than preventing sunburns, the health benefits of sunscreen are suspiciously under-proven, and the potential effects of long-term exposure-to/blood-absorption-of their ingredients under-studied. In another decade or two, the current levels of sunscreen use, and recommendation by expert bodies that should know better, will likely be considered a public health failure up there with "use margarine not butter" or "replace fats with sugars" or "masks don't help against respiratory epidemics".

Use shade not sunscreen whenever possible.


I wouldn't be surprised if sunscreen is the next BPA: https://www.cnn.com/2019/05/06/health/sunscreen-bloodstream-...


To help support this, keep an eye on a UV tracker. I used to be terrified of the Australian sun, but with a UV tracker I know when it's safe to be outside for hours with no sunscreen, and when the danger levels are extreme.

https://www.arpansa.gov.au/our-services/monitoring/ultraviol...


I would normally be with you but I burn in just a couple of minutes, and I've unfortunately had some really bad burns in the past (where my skin is still very freckled).

I'm totally with you on shade over sunscreen though, I only put sunscreen on my face, and just try to shade everything else. Sadly my skin hates sunscreen too!


Have you looked into or tried any of the mineral-based sunscreens with zinc oxide or titanium dioxide?


While I agree with many things you said: Unfortunately, any UV light exposure is causing harm not just the exposure leading to sunburn. There is no safe level of tanning. Use the same mental model as with X-Ray exposure.


This isn't a fair analogy since sunlight has many well documented positive effects. Vitamin D production being obvious, but also many understudied effects like nitric oxide release. It's difficult to fully root out confounding effects, but typically people with more sun exposure live for longer, despite having higher rates of skin cancer.


It's very likely the UV is an essential trigger of the benefits of sun exposure – either through supporting chemical processes like internal Vitamin-D synthesis, or simply providing the right amount of chaotic 'eustress' that exercises, without overwhelming, essential self-repair mechanisms. So, I'd strongly disagree that "any UV light exposure is causing harm".

Instead, there's a dose-response curve, as with almost everything else, and some moderate level of UV exposure is almost certainly net-beneficial.

Further, getting a light natural tan from the sun itself, without ever becoming uncomfortably burned, is probably more indicative of that optimal level of UV exposure than remaining ultra-pale from absolute avoidance of all sun-UV.


"There is no safe level of tanning" is misinformation and such confident-but-wrong statements should never be used. It's completely false to state that people shouldn't expose themselves to the sun when it's part of our biology. Overexposure and getting frequent sunburns will add up and increase chances of skin cancer, but to say that no level of sun exposure is safe is wrong.


My understanding is that direct sunlight over a major portion of the body for a full 5-8 minutes around noon can be enough to elevate levels sufficiently. In spreading the exposure in this manner one can avoid burns.


Before adding supplemental vitamin D, first ensure nutrient sufficiency and that all RDAs are being met (with just food). For example, low magnesium impairs vitamin D conversion and is a more common problem. Further, hGH/IGF-1 also pushes for conversion of vitamin D. Insufficient potassium, insulin resistance, and some other things clip hGH/IGF-1.

In some cases, fixing diet and sleep (ZMA for males) normalizes vitamin D. After other steps are taken, then add some amount of D3 if necessary. It's been said it's better gotten from red light (one of those special lamps/light) on the skin, as the body is able to regulate/limit absorption.

Either way, some supplementation is likely to be needed with age. Response of the skin to sunlight declines over time, especially due to rising cortisol.


> low Vitamin D levels are endemic in temperate and northern latitudes

When this last came up, jusssi commented about the actual counter-intuitive distribution of D deficiency:

> under 20% in Northern Europe, 30-60% in rest of Europe, up to 80% in Middle East.

https://eje.bioscientifica.com/view/journals/eje/180/4/EJE-1...

https://news.ycombinator.com/item?id=23255533


We probably wouldn't even expect it to be a straight correlation with "the higher your latitude, the lower your vitamin D."

Skin color is very tightly coupled with latitude, with melanin concentrations evolved to let in a small window of sunlight that (1) allows enough production of vitamin D and (2) prevents destruction of folic acid.

(A few exceptions can be found in communities that have historically eaten large amounts of fish, such as Inuits, who tend to have skin color slightly darker than "expected" because they are getting more vitamin D from diet, and so the the folic acid side of the fitness function "wins.")

Given that, we shouldn't necessarily expect populations whose ancestors have been at one latitude for hundreds/thousands of years, and who get plenty of out-door time, to necessarily be vitamin D deficient.

What is more likely to contribute to higher vitamin D deficiencies in a population would be (1) immigration/expatriation of people to higher latitudes (even over the course of hundreds or thousands of years) and (2) living indoors more.

Naturally, this may result in a hodge-podge of communities with vitamin D deficiencies, which may not be clearly correlated with latitude (although may still show correlation).


Thanks for your input. I think a valuable thing that can be added to the conversation is a rough evaluation of how long vitamin D takes to leave the body.

It's easy for us to look at a bottle and control how much we're putting in, the tricky part is managing that we're only putting in enough to compensate for what has been used or lost since the last dosage. If people were given a vague idea of the Vitamin D "burn rate", and what factors might increase or decrease that number, I believe your and Dr. Boone's points may be significantly better received by others.


What’s your opinion on K2? K2/D3 ratio and how would age affect the ratio?


Funny question I know but how effective are D supplements at improving low D levels?


As I understand it, very effective. But most of the research that correlates low vitamin D levels with various diseases is from observational studies, so there's always a question of whether a low vitamin D level is the causal problem or if it's more complicated, for example maybe lack of sunlight causes other effects in addition to low vitamin D levels and those other effects are the real problem rather than the low vitamin D levels.

IFAICT, most doctors will still prescribe supplements for low vitamin D though. It certainly doesn't seem to hurt, as long as the levels don't get too high as discussed in this article.


There is a site with some data on supplementation's effect on serum D3 levels. Short version, they are effective. https://www.grassrootshealth.net


Explain that: Low vitamin D is also common in Africa!

https://theconversation.com/think-vitamin-d-deficiency-is-no...


Because too much clothes maybe? Western clothing style was introduced by colonization


As a Vermonter, I have to ask - does the locale have anything to do with the low Vitamin D levels, any more than most of the rest of the northern United States?

Would 5000 - 10000 IU/day be toxic?


devboone has previously said that less than 3000 IU per day should be safe, but again this should be determined with the help of a physician, not self-selected. She said she has definitely seen toxicity in some of her patients with doses of over 5000 IU per day.


Thank you very much for the straight answer. I'd prefer not to poison myself via Vitamin D! I worry with COVID-19 other people are going to be overcompensating as well.


The easiest solution is just to be stable at a level of supplementation for a few weeks (even zero), then get a test. They're like $40 for the blood test, and then you can tell if you're in the normal range, high or low.


> seen toxicity in some of her patients with doses of over 5000 IU per day.

I believe she said "per day for years".


Yes, the assumption was that this is a daily supplement, meaning an indefinite period of time.


Your body makes its own vitamin D in response to sunlight exposure.


Not all sunlight exposure works though. It needs to have enough UV-B in it. And that’s dictated by the time of year, the location, and the time of day. In some places, you may only get an hour or so of the right kind of rays.


Well, yes. But does the region have significantly less sunlight than others? Or is it just the people in question didn't get nearly as much exposure?


Latitude, local geography and weather will all play a role in how much sunlight you get. If you're living in a valley you can have much shorter days than your latitude would suggest. And if the weather is shitty enough to keep you inside much of the year that will obviously have an impact.


Yes, age and skin color also have a large influence on whether your body can utilize the sunlight you receive.


Yep, there were studies that Somali refugee populations in MN and Sweden have very low vitamin D levels (and associated high rate of children autism)


How does the autism follow?


while we don't know "how", there is growing body of work showing a correlation between low level vitamin D - in particular winter pregnancies in Northern Europe countries correlate with higher rate of autism as well as the mentioned studies of the 2 clusters of Somali refugees.


Do you recommend vitamin D3 or D2 and why? Please advise.


It's harder to be too high than too low, especially with enough magnesium and vitamin K2. When high, just lower calcium to the 500-600 mg range and use magnesium to eclipse phosphorus.


The sentiment of nutrition hacking with supplements expressed in the parent comment just seems wrong. Not factually wrong, I'm not able to judge, though it could be--one expert says one thing and the other the opposite. It just seems like a dangerous attitude of over-confidence to think you can mix and match supplements based on numbers from blood results. And who has their blood tested so often they can adjust their supplements weekly or monthly--because you wouldn't want to go too long at the wrong level.

There are so many complex systems in the body, and so many interactions such as vitamin D and calcium, that it just seems risky. Some people are knowledgeable about supplements and interactions, others sound knowledgeable but are just selling the next fad. Not to mention that it all depends on the person's specific metabolism and any conditions they might have (such as the patient in the article).

Or do we even need supplements at all if we just ate well and had an active lifestyle? Speaking as someone who just had yogurt and a banana: "Let thy food be thy medicine and thy medicine be thy food."


>It just seems like a dangerous attitude of over-confidence to think you can mix and match supplements based on numbers from blood results.

unfortunately that seems to be the the only option we have - "Let thy be thy doctor" :) From personal experience - thanks to Epic software i was given the total printout of my visit to a doctor few months back - the doctor somehow completely skipped low RBC and other related counts in my blood results which were clearly showing anemia and actually did match my feelings of overall fatigue, especially setting up quickly upon trying to exercise, restless leg syndrome, etc. After looking at those blood numbers myself, i started B12 (B12 deficiency is one of the reasons for iron deficiency, and i have an underlying condition known to cause B12 deficiency which the doctor was actually aware too - though, nevermind, the doctors could do nothing with that condition too) and iron, and the things improved remarkably, in particular RLS is gone and i can exercise without hitting almost immediately that fatigue ceiling.

>Or do we even need supplements at all if we just ate well and had an active lifestyle? Speaking as someone who just had yogurt and a banana: "Let thy food be thy medicine and thy medicine be thy food."

you're enjoying condition which can be summed up as confirmation bias of a healthy person. It is a really great condition - i've enjoyed it myself for about the first 40 years of my life.


There are 2 tests (a few months apart) needed to calibrate vitamin D dose. One could even go through the Coimbra protocol induction (though they don't have MS) to find the optimal amount for them.


I’m thinking of flagging this since it seems to overweight the risk of high vitamin d vs the more common risk of low vitamin d?


I'm the one who wrote the article. I would actually argue that the risk of low Vitamin D has been overplayed. There are very alarmist articles out there about this epidemic of Vitamin D deficiency - which causes people to go out and buy supplements. But there is very little actual data showing that healthy people should take Vitamin D. This is where you get into the large human trials of Vitamin D supplementation, which I want to get into for part 3.


Thank you for writing these articles. Even more thanks for coming here and participating in the discussion.


It came across to me as a warning that we wouldn’t be so cavalier about any other hormone, so we shouldn’t be with Vitamin D either. In that context it’s fine.


Please don't, unless your expertise is comparable to that of the physician who wrote the article.


Your average HN reader has probably seen enough articles posted here about vitamin D deficiency that we are in fact the perfect audience to read about the dangers of taking too much of it.


> So please don't interpret this story as a reason to avoid any vitamin D supplementation. 1-2000 IU/day has been shown to be safe with long term use

I'll give you a more regular story. Some time ago I thought I needed to take D3 supplements after being exposed to all this PR pushing it and given that I don't eat food rich in it, rarely get sunlight, don't go outside in daylight (densely populated area, supermarkets work 24/7, etc.). So I bought some and took 2000 IU/day for a few days. Suddenly I started feeling numbness on the tip of my toes. After a bit of research I attributed it to D3, immediately stopped taking it, but numbness went away only after a few weeks. It's hard to see how taking it longer could have been safe.

So please don't generalize that 2000 IU is safe just because something showed that it was for some people in certain circumstances given certain country-specific lifestyle, foods, etc. I don't think a decent study on D3 safety even exists.


No offense, but this sounds like a bad diagnosis on your part. It takes more than a few days for Vitamin D problems to arise. The fact that the numbness took a few weeks to go away after taking Vitamin D for only a couple of days means it was most probably some other thing causing the problem.


It took a few weeks to go away completely, but got noticeably better just after a couple of days. I'm pretty confident in that diagnosis, as nothing else have changed.


The headlines don't reflect the results reported in the abstract. In particular, a erectile dysfunction rate of 25% at one year is very high. Furthermore, the criteria for cancer oblation seems to be PSA decrease of 75%, which was achieved in 96% of patients. However, one would generally expect a much larger reduction in PSA if the cancer were truly oblated.


The levels of prostate cancer are very much titled toward older males past their sexual prime: https://www.verywellhealth.com/thmb/Imcc48tegbPKpY2cL18sXOIB...

ED may be less of a concern with this group compared to other cancers or diseases. Not to mention the high rates of heart disease at that age in America already causing it.

Plus the rates must be compared to other modern prostate treatment options.


Almost makes me wish I had gone to MIT instead of Harvard....


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