13 ms·

Vitamin D: the New Covid-19 Chloroquine?

181 points by chl 6y ago

eli_gottlieb 6y ago
Welp. I don't think it's gonna make the difference if I get COVID-19, but I did order some Vitamin D supplements. I live in a low-sunlight area, work indoors, and don't drink a lot of milk. 75% of people in my region are Vitamin D deficient. I can put two and two together.
- api 6y ago
  There's enough evidence for vitamin D being beneficial that it's certainly not likely to hurt anything and is probably a good idea.
- chl 6y ago
  My guess: It might not make _the_ difference whether you _get_ it, but it's not at all unlikely (given all the evidence that has accumulated so far & extrapolation from experience w/ other viral respiratory infections) that it will influence disease severity significantly.
api 6y ago
One difficulty in determining if vitamin D actually helps with COVID is determining if vitamin D levels are directly affecting outcomes or whether they are a proxy for something else. For example: are low levels a proxy for people who don't go outside much and therefore don't exercise? That's a huge problem in medical studies generally.
- chl 6y ago
  There are now 24 trials (of some kind) listed on ClinicalTrials.gov: https://clinicaltrials.gov/ct2/results?term=vitamin+d&cond=COVID-19 https://clinicaltrials.gov/ct2/results?term=vitamin+d&cond=C... At some point, high-quality RCT results will be in.
- OJFord 6y ago
  In other words: establishing causation (or lack of it) is more useful than merely correlation. Yes. But hardly breaking news, or even specific to medicine.
  - antishatter 6y ago
    I mean yes, but OP's comment is especially notable with Vit D because it's deficiency is very common and often a marker for other common age related diseases. It is highly likely that Vitamin D isn't saving these people's lives, it's that the folks without vitamin D are older and/or have disease.
- pjkundert 6y ago
  There is strong evidence of this, summarized: https://www.outsideonline.com/2380751/sunscreen-sun-exposure-skin-cancer-science https://www.outsideonline.com/2380751/sunscreen-sun-exposure... Huge inverse correlation between Vitamin D and all-cause mortality -- but almost complete failure of vitamin D supplementation vs. cancer, heart disease and stroke. What? Turns out that sunlight produces vitamin D -- and a host of other difficult to detect artifacts, which seem to be at the root of the reduction in all-cause mortality. Seems interesting. Or, carry on -- I'm sure there's nothing to see here, and your pasty-white overweight doctor's advice to avoid sun exposure is right...
  - Dylan16807 6y ago
    Doctors advising people to avoid sun exposure? Is that strawman based on anything? I hope you don't mean the advice to use sunscreen when you're going to be outside so long you'd get sunburn without it.
    - jerf 6y ago
      How old are you? I can assure you, whether it was the intent or not, that the message got out in the 1980s and 1990s that all sunlight exposure is uniformly bad and its only effect is to increase your likelihood of skin cancer, so everyone should avoid it and unconditionally use strong sunscreen for any exposure.
    - radford-neal 6y ago
      See https://www.canada.ca/en/health-canada/services/sun-safety/sun-safety-basics.html https://www.canada.ca/en/health-canada/services/sun-safety/s... for one example of an official health authority advising people to zealously avoid sun exposure, with no mention whatever of vitamin D deficiency or other downsides of not getting any sun.
  - pdonis 6y ago
    The studies referenced in the Outside Online article failed to collect a crucial piece of data: what were the actual blood levels of Vitamin D in the participants? Without that piece of data you have no idea what, if any, difference the supplements were actually making vs. placebo.
mcfly1985 6y ago
What does the author mean "the new chloroquine"? No one knows if chloroquine + zinc is effective when taken early. Anyone telling you they know is lying.
andreygrehov 6y ago
I'm surprised the article barely mentions Vitamin K, which is needed along with Vitamin D - D to mobilize the calcium and K2 to put it into the right place. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5613455/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5613455/
- raverbashing 6y ago
  There are some interesting discussions about Vit K and Covid, basically Vit K promotes coagulation but it seems that its deficiency is associated with the coagulation issues seen in Covid patients. And it might as well be that the correlation is inverted (that is, the development of coagulation troubles might cause low Vit K)
  - perl4ever 6y ago
    What is Vitamin K & K2? My associations are (respectively) potassium and the mountain near Everest.
- paulirwin 6y ago
  There is another important pair, too: Vitamin D and Magnesium. But consult your doctor before taking extra amounts of anything. There is a lot of misinformation on the web around Vitamin D, such as that even high amounts (>= 5000IU) are tolerable and safe. After a blood test showed me Vitamin D deficient, taking 5000IU (that size is readily available over the counter at my grocery store) daily gave me disturbing heart palpitations, which I didn't realize were related to Vitamin D until after thousands of dollars in tests showed my heart to be perfectly healthy. It wasn't until I had slacked off in taking the vitamins and then started taking them again that I discovered the connection. Apparently magnesium has something to do with it, but IANAD. (I was not taking magnesium supplements at the time.) I can tolerate 1000IU occasionally, but people need to be aware that not everyone tolerates supplements (especially high doses) the same. I was happy to see the article you linked to above only claims Vitamin D is considered safe up to 4000IU. Although IMHO, after my experience, anything over 1000IU should require a prescription. Of course nothing would stop people from taking five 1000IU OTC doses to get 5000IU, but I think most people know better than to take five of the same type of vitamin daily without talking to their doctor first.
rafaelturk 6y ago
For me this is a perfect example of wishful thinking. It's really hard for average person to accept reality: This virus, like all others, will last for a long time. We won't have, in a foreseeable future, a treatment neither a cure. Cancer, HIV or even seasonal flue are good examples examples of diseases that were discovered decades ago for which science still don't have a cure, there are a few treatments or easing medication, but none of them can be actually cured. I expect that people will move from crazy solution to another on a regular basis until a final cure is found.. my expectation is this will last for years.
- learc83 6y ago
  We have multiple vaccine candidates that based on early human trials, and animal trials are very likely to work. Sure it's possible all of them could fail, but I wouldn't set my bet on that.
  - ericb 6y ago
    Right. There are around 100 vaccines in development. We have vaccines that have created binding antibodies in primates already. We have some that have been given to humans and produced antibodies as well. Even pessimistically assuming 90% fail, you end up with 10 vaccines. https://www.centerwatch.com/articles/12702-new-mit-study-puts-clinical-research-success-rate-at-14-percent https://www.centerwatch.com/articles/12702-new-mit-study-put...
    - soperj 6y ago
      that's not pessimistic. Regularly only 6% of vaccines make it past trials.
      - ericb 6y ago
        Do you have a source, because I provided one, and if you look, it says: "Approval rates ranged from a high of 33.4 percent in vaccines for infectious diseases to 3.4 percent for investigational cancer treatments" So by that source, I was wildly pessimistic.
antishatter 6y ago
I feel like Vitamin D deficiency correlates with every disease. A large % of everyone has a vitamin D deficiency so there is always a high correlation.
- spuz 6y ago
  The percentage of the population that is vitamin D deficient can't affect its correlation with disease. It's perfectly possible that after this, vitamin D is added to tap water such that very few people are deficient but the correlation with deficiency and disease would be unchanged.
  - nickles 6y ago
    > It's perfectly possible that after this, vitamin D is added to tap water Vitamin D is fat soluble, not water soluble.
raverbashing 6y ago
Very good writeup That being said, VitD has much fewer potential side effects than CQ (in the recommended dosage) On this epidemic we should be looking at potential preventative quick gains, especially as the most disrupting solutions are, well, disrupting.
goda90 6y ago
"Adipose tissue (“belly fat”) appears to absorb but not release vitamin D. If we want to do some armchair hypothesizing, perhaps people historically used to lose weight in winter, which definitely would release the stored vitamin D just when it was needed." This is an interesting idea. It's believed our bodies get fat to ensure we have energy when food is scarce. It makes sense that we'd also want to have vitamins available too.
- Izkata 6y ago
  An addition to that: Over a decade ago (so unfortunately I have no reference, this just stuck with me for how against common sense it was) I remember reading that being overweight but not obese correlated with good health better than being "normal" weight did. Their theory was that if being sick made it so you were less hungry, you could still get an energy boost by using up fat reserves and be able to fight off illness faster. This sounds like a much more specific and more testable version of that theory.
  - anonuser123456 6y ago
    >I remember reading that being overweight but not obese correlated with good health better than being "normal" weight did. This is mostly selection bias. Society is so fat that being normal / underweight is correlated with sickness/disease.
  - balnaphone 6y ago
    There is a problem with the BMI [1] calculation, which is the standard measure used to determine "normal" weight, in that it is dimensionally incorrect. The BMI calculation gives results that are appropriate for those around 5'6" (168cm) in height. The units are in kg/m^2. The Ponderal Index [2] (AKA the "Corpulence Index") gives values that work for any height, with units in kg/m^3. If you are a young child or over 6 feet tall, you might find the PI/CI works better for you. [1] https://www.cdc.gov/healthyweight/assessing/bmi/adult_bmi/english_bmi_calculator/bmi_calculator.html https://www.cdc.gov/healthyweight/assessing/bmi/adult_bmi/en... [2] https://www.omnicalculator.com/health/ponderal-index https://www.omnicalculator.com/health/ponderal-index
watertom 6y ago
Since I was a child I’ve been a walking respiratory illness machine. Bronchitis, sinusitis, flu, pneumonia, common cold, etc. During “flu” season I was usually sick for the entire season with a rotating assortment of viral respiratory issues, this lasted until about 7 years ago. 8 years ago in September I started taking 10,000 IU of vitamin D3 and 180mg of K2 daily. I haven’t had a deputies illness since. My children were getting sick at their normal clip, my wife the same, but not me. I went from being sick all the time to not getting sick ever. I made one change in my life, adding the D3 and K2. After 2 years of not getting sick my wife and children started supplementing with D3 and K2, everyone stopped getting sick. My son went off to college and stopped taking the D3 and K2 and during the winter semester he got sick twice, he had me sent him the D3 and K2, he hasn’t been sick since. It’s a small sample size, but even at 10,000 IU daily D3 is not dangerous or expensive, the only caveat seems to be that you need to supplement with K2 or you can cause gardening if the arteries due to calcification. My doctor thinks it’s a lot of nonsense, but then again he wants every patient on blood pressure and cholesterol medication “just in case”.
- kmonsen 6y ago
  Which supplements do you get?
- bencollier49 6y ago
  Ironically there are papers suggesting that blood pressure and cholesterol medication is bad for people if they get Covid.
  - dehrmann 6y ago
    How is that ironic? The doctor's recommendation sounded like it was pre-covid, or just their standard recommendation.
- camccar 6y ago
  I switched to a high cholesterol diet. Almost only meat , raw milk(grass fed) and raw egg yolks (monthly liver) combined with 20 minutes of running shirtless. Besides getting very lean I’ve also not been sick once during this. I usually get sick all the time. It’s antidotal but my diet would now be really high in k2 vitamin A and natural Vitamin D
tomhoward 6y ago
All these articles about different individual nutrients start to feel like heath whack-a-mole. How about this: to be in the best possible position to beat any serious infection, you need to be in generally good health. That means having adequate levels of all essential nutrients - i.e., all the vitamins, minerals, amino acids, enzymes etc that you get from maintaining a good diet and healthy lifestyle over the long term. To focus on just one nutrient as a pandemic looms just isn't the answer; it's not how health works. That said, I've personally researched what nutrients (note the plural) are most important for beating an infection like this, and have adjusted my nutrient intake somewhat, and recommended to close relatives they do the same. But this is after I and they have spent many years researching and maintaining good health practices. Update: if I was in not-so-good health (and not in medical treatment for a diagnosed condition, in which case, consult your doctor), my approach would be: - boost my amino acids, fatty acids and minerals with a few spoonfuls of hemp seeds every day - take extra supplements of vitamins A, B complex, C and D (and perhaps K?) - do plenty of walking in the fresh air and sun, - keep a generally healthy diet of good quality protein and veg. Update 2: Others are mentioning Vitamin K, which seems like a good idea to supplement if you're generally nutrient deficient, but may not be necessary if you have a good diet. [1] Disclaimer: not a health professional, but have had personal reasons to get very knowledgable about health and diet over many years. [1] https://www.healthline.com/nutrition/foods-high-in-vitamin-k https://www.healthline.com/nutrition/foods-high-in-vitamin-k
- deweller 6y ago
  "Just" focusing on one nutrient isn't the answer. But sufficient Vitamin D is important. It is something we should pay attention to. Health is complex. No one is advocating ignoring all the other aspects of immune system function by paying attention to vitamin D. [Update] I see you have toned down your comment since I started composing this response. We are in agreement.
  - billman 6y ago
    I think it's important to note that Vitamin D is a hormone. And the body produces it as well.
ashtonkem 6y ago
Sufficient levels of Vitamin D are good for your health in general, separate from this pandemic. Getting sufficient levels of it is something we all should’ve been doing before anyways, which is not true of Chloroquine.
psychometry 6y ago
There are so many medical questions that can only be answered definitively with large-scale, years-long randomized experiments. Anything relating to supplements, where effect sizes are probably small, especially. These are expensive and difficult to perform and there's (to my knowledge) no institution dedicated to that goal.
forgot_user1234 6y ago
How can you do science for long term effects? where RCTs are not possible.
- manifoldgeo 6y ago
  When I took an epidemiology course in college, our professors taught us about both control studies and cohort studies. Cohort studies might be an example of what you're looking for. This article [0] hosted on the NIH's site discusses cohort studies and their effectiveness / pitfalls. References: [0] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2998589/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2998589/
- wenc 6y ago
  RCTs are not the only way to obtain evidence of causality. In causal inference, limited causal claims can be made through observational studies (where no control is done), such as retrospective natural experiments [1]. These methods are of course limited by assumptions and by how closely they match reality. Note: while a controlled experiment is the gold standard, it is not always feasible or necessary. We don't need to do RCTs on parachutes to prove their efficacy for instance. [2] -- [1] https://en.wikipedia.org/wiki/Natural_experiment https://en.wikipedia.org/wiki/Natural_experiment [2] https://www.scientificamerican.com/article/volunteers-jumped-with-or-without-a-parachute-to-gauge-its-effectiveness/ https://www.scientificamerican.com/article/volunteers-jumped...
guptaneil 6y ago
This requires a huge correlation != causation flag. The article briefly mentions this, noting that it’s possible vitamin D is just a sign of a healthy person, so of course they’ll do better with COVID. Another correlation that doesn’t get discussed whenever vitamin D comes up is that people with darker skin generally have less vitamin D, because our skin doesn’t absorb sunlight as much. We also know that COVID is disproportionately hitting colored neighborhoods in the US. Is that just because of vitamin D differences? Who knows! By the way, if you are a person of color, you probably need vitamin D supplements. The recommended doses are for white people, so adjust accordingly.
- kedean 6y ago
  I felt like the article spent sufficient time on the idea that the explanation could be that healthier people simply have higher vitamin D levels, and that the vitamin D itself is not the cause. At no point did they choose a side on that part, the bias was only that they believe vitamin D is a promising avenue. I really loved that the whole piece was informational, and not trying to convince the reader that Vitamin D is or isn't a cure or remedy for anything. It simply presented the available facts, the research, and the positives and negatives of that research. It even explained multiple aspects and positions of the debate on whether vitamin D supplementation is good or bad.
trevorkoob 6y ago
Did my masters on Vitamin D - It is very difficult to extract CLINICALLY RELEVANT information from retrospective epidemiological studies. However, there a a few things that are clear: 1. Calcium absorption from the intestine increases with vitamin D supplementation dose up to around 8-10,000 IU D3 daily. 2. 15 minutes of full body exposure in noon sun is equivalent to a dose of ~20,000 IU D3 3. There are few cases of vitamin D overdose in the literature - doses in the 1,000,000 IU+ range within days is generally where symptoms are noted - this excludes people with kidney disorders. Personally, I take 10k IU D3 a day. The D3 is important because D2 has 1/2 to 1/3 the effect per dose in raising calcium absorption levels. I would recommend this level of supplementation to anyone who doesn’t have a kidney disorder.
- anibalin 6y ago
  Hi trevor, super intereseting what you mention. Wondering where you did the master since its not common (at least in my country). Thanks man.
- didgeoridoo 6y ago
  Interesting, I've always heard of the calcium absorption effect as a negative aspect of D over-supplementation — I guess the theory is that it raises your blood calcium level too high, leading to arterial calcification? Is that effect overblown in your opinion?
  - trevorkoob 6y ago
    In acute hypervitaminosis D, there can be organ calcification that has to be treated. These cases are rarely reported - one case occurred when the patient ingested crystalline vitamin D - dosing themselves in the range of 1-2 million IU D3 per day for weeks, and although there was not an extensive follow-up to determine the long-term effect on the patient, the acute calcification was reversed with treatment. Vitamin D is involved with calcium in the body in many different ways, specifically I was talking about a measure of the absorption of calcium into the body from food as promoted by vitamin D. Organ calcification is extremely serious and a very understandable reason why doctors have been hesitant to recommend higher doses of vitamin D, however most medical thinking about vitamin D until recently has focused on the prevention of Rickets, which requires only a small amount of constant supplementation (500 IU D3) to avoid serious effects. In context, 10,000 IU seems like an enormous dose. However if you look at the blood serum levels of people who receive consistent UV exposure, they have much higher levels than someone who is being supplemented with 500 IU D3 and no UV. So much of this debate is around trying to find out what the "optimal" vitamin D level is rather than what level is "sufficient" to prevent Rickets.
ed25519FUUU 6y ago
These studies need to keep up until we can fully account for the difference in fatality not only worldwide, but state to state. Why has Japan, with an older population (median age 47), a tiny island, crowded indoor subways —- has only experienced 900 deaths and never locked down! while some zip codes in New York experiences 2x that amount. Even state to state the difference is alarming.
- cgh 6y ago
  Diabetes is likely a factor: https://www.medscape.com/viewarticle/931132 https://www.medscape.com/viewarticle/931132 And obesity is strongly correlated with diabetes: https://www.diabetes.co.uk/diabetes-and-obesity.html https://www.diabetes.co.uk/diabetes-and-obesity.html There is a distinction to be drawn between obesity rates in the US and Japan and that might be part of the answer to your question.
  - nradov 6y ago
    New York state has about 6× the obesity rate of Japan.
- deleted 6y ago
  [deleted]
chl 6y ago
dminder is a great app to estimate Vitamin D "intake"/production through sun exposure (and also food, albeit this won't matter much for most people): http://dminder.ontometrics.com/ http://dminder.ontometrics.com/ I only wish the algorithm used to derive the estimates was public/documented somewhere ... http://dminder.ontometrics.com/Estimation.html http://dminder.ontometrics.com/Estimation.html
elric 6y ago
With all this talk about Vitamin D and K deficiencies, which inevitable meanders onto Magnesium and fish oil supplements and whatnot; maybe it's time for a "vitamin subscription service"? Enter a bunch of information (location, lifestyle, diet, health issues) and get tailor made supplements sent to your home every month? The levels of some vitamins could vary depending on time of year (more D in winter) or circumstances (more Mg when more active in summer). Ideally all packaged into one tablet or something. I take an unholy cocktail of supplements to help curb my migraines, that's 5 tablets/caps a day. Not much fun.
- Erwin 6y ago
  These guys create a supplement based off your DNA: https://www.nutrahacker.com/ https://www.nutrahacker.com/ https://ginihealth.com/ https://ginihealth.com/ These let you create the vitamin/supplement mix you want: https://getvitaminlab.com/ https://getvitaminlab.com/ last time I tried, it ended up quite more expensive than my D vitamins.
haltingproblem 6y ago
The article "Is Sunscreen the new margarine" argues that "what made the people with high vitamin D levels so healthy was not the vitamin itself. That was just a marker. Their vitamin D levels were high because they were getting plenty of exposure to the thing that was really responsible for their good health—that big orange ball shining down from above." [1]. If this is true, we have mistaken coincidence due to a common latent cause for causation. The article "Limits of Vitamin D supplements" is a summary of the Lancet meta-analysis: "Vitamin D status and ill health: a systematic review", which is paywalled [2]. The review shows that Vitamin D supplementation has no clinically beneficial outcome on heart disease, stroke, or cancer. FWIW, I have been supplementing with Vitamin D for over a decade. I would rather like Vitamin D to work because I have chronically low levels and it would be good to have such a good silver bullet of a nutrient. I have not stopped my supplementation but I do take more frequent walks in the Sun. [1] https://www.outsideonline.com/2380751/sunscreen-sun-exposure-skin-cancer-science https://www.outsideonline.com/2380751/sunscreen-sun-exposure... [2] (https://well.blogs.nytimes.com/2013/12/11/limits-of-vitamin-d-supplements/ https://well.blogs.nytimes.com/2013/12/11/limits-of-vitamin-...)
szastupov 6y ago
Covid or not, you should test for vitamin deficiency and supplement if necessary. I do it every 3 month via Thriva (UK) and can see the progress.
Havoc 6y ago
I definitely dug out my vit D pills as a result of the coverage. Worst case scenario it creates expensive pee. Maybe it'll have some upside though
- makeset 6y ago
  > Worst case scenario it creates expensive pee. Well, that's one thing you don't need to worry about. Vitamin D is fat-soluble, so any excess isn't excreted in urine (hence the arguments over effective vs. excessive dosage).
  - Havoc 6y ago
    >Well, that's one thing you don't need to worry about. Vitamin D is fat-soluble Good point. Thanks for pointing that out. I knew about the whole concept of water vs fat but didn't occur to me in this context
m0zg 6y ago
FYI also, researchers are suggesting that the Lancet HCQ study everyone (and the WHO) references nowadays is fake: https://www.theguardian.com/world/2020/may/29/covid-19-surgisphere-hydroxychloroquine-study-lancet-coronavirus-who-questioned-by-researchers-medical-professionals https://www.theguardian.com/world/2020/may/29/covid-19-surgi.... The authors could not have had the data they claimed they had. This is just one bit of news you will never find on CNN.
- jakeogh 6y ago
  Yep. More: https://news.ycombinator.com/item?id=23305606 https://news.ycombinator.com/item?id=23305606
mixmastamyk 6y ago
My anecdote. I learned about the importance of D3 on Steve Gibson's podcast about a decade ago. At the time had a kid in preschool and spent almost the whole year sick, so was quite intrigued. Started with 1,000 IU a day and getting sick stopped abruptly. For the last decade or so, haven't been sick more than one day, two at max, with one exception. Yes, believe I had CV in March and "walked it off" in about 6 days or so with mild symptoms. Last few years I've taken 5,000 IU several times a week (from Trader Joes, which has an excellent price of $4.99). As compared to Albertsons which disgustingly tries to get $15-20 for the same thing. Unfortunately this news has made both C and D unavailable at Trader Joe's for months. We'll run out soon and need to buy the gouging price somewhere else.
kpfleger 6y ago
Having read this whole piece, I think my review is much more comprehensive in covering all relevant evidence: http://agingbiotech.info/vitamindcovid19/ http://agingbiotech.info/vitamindcovid19/ Note that the title changed and many improvements made since it was first posted to HN 3 weeks ago here: https://news.ycombinator.com/item?id=23119949 https://news.ycombinator.com/item?id=23119949 In the title of this piece, analogizing to chloroquine is irresponsible. A high % of readers will take the message to stay away from D and never read the rest. I'm glad he has a similar top-level rec as me: Take all measures to avoid deficiency, probably by D3 of 2000-4000 IU/day (I'd prefer 4000). The piece unfortunately fails to make the other most important top-level comment: that all COVID-19 patients should have their D levels tested and more data on D & COVID-19 severity should be published urgently (possibly based on records that already exist). And all clinical trials for COVID-19 should be testing D levels as well. Overall, this piece is not emphatic enough that vitamin D may significantly help during this COVID-19 crisis. Several important responses to some of the top material in this piece: The NYT article dismissing Holick is terrible and not worthy of being linked at the top of this piece. I won't go into the point-by-point criticisms of this article, but it's not worthy of a piece that is supposed to be weighing evidence. The bullet point claiming the COVID-19 association could still be a fluke does not adequately acknowledge the causal aspects of the evidence: Many RCTs on D supplementation helping viral/respiratory infections (Martineau et al BMJ 2017), D causally affecting rate of aging in roundworms, causal inference model overwhelming supporting D's role as causal, studies on the correlation correcting for age, sex, comorbidities, and reverse causality, and causal mechanistic biological arguments. Some portion of the strength of the correlation seen in the 1000+ patient cases published in preprint studies so far may be due to other causal factors, but the causal evidence so far makes it very unlikely for the full extent of the large effect size seen to all be a fluke. The piece wrote: "A healthy full body exposure to sunlight can generate 25000 IU of vitamin D in one sitting, without getting burned. 2000-4000 IU daily of D3 supplements will also work." No. People wrongly believing that some sun gives them enough is probably one of the causes of widespread deficiency. From my review, in the "Practical considerations for avoiding D levels that are too low" section: There are several studies showing that even a lot of sun exposure leaves many people with insufficient D levels. For one list of studies see Tsiaras & Weinstock, “Factors influencing vitamin D status” Acta dermato-venereologica, 2011: “Studies in Hawaii (97), South Florida (98), Southern Arizona (99), Brazil (100), rural India (101) and Queensland, Australia (102) found that significant proportions of the study populations had low vitamin D levels despite abundant sun exposure.” For example, in the Hawaiian study, 51% of the 93 young, non-obese adults had D<30ng/ml despite 29hr/week (>4hr/day) in the sun at latitude 21 degrees. The variability in both seasonal sun intensity and daily hours of exposure for any given individual provide yet another reason that testing blood levels would be helpful. These studies show that even those who seem to get a lot of sun exposure should probably supplement if not testing to ensure adequacy. Also, the bullet point summary in this piece fails to point out the history of the RDA being set too low by statistical mistake. (Which I've updated my review to include. The story is crazy---the original data used to set the RDA would have resulting in 8000 IU/day if it had been analyzed correctly.)

181 points by chl 6y ago

Welp. I don't think it's gonna make the difference if I get COVID-19, but I did order some Vitamin D supplements. I live in a low-sunlight area, work indoors, and don't drink a lot of milk. 75% of people in my region are Vitamin D deficient. I can put two and two together.

api 6y ago
There's enough evidence for vitamin D being beneficial that it's certainly not likely to hurt anything and is probably a good idea.
chl 6y ago
My guess: It might not make _the_ difference whether you _get_ it, but it's not at all unlikely (given all the evidence that has accumulated so far & extrapolation from experience w/ other viral respiratory infections) that it will influence disease severity significantly.

api 6y ago

One difficulty in determining if vitamin D actually helps with COVID is determining if vitamin D levels are directly affecting outcomes or whether they are a proxy for something else. For example: are low levels a proxy for people who don't go outside much and therefore don't exercise? That's a huge problem in medical studies generally.

chl 6y ago
There are now 24 trials (of some kind) listed on ClinicalTrials.gov: https://clinicaltrials.gov/ct2/results?term=vitamin+d&cond=COVID-19 https://clinicaltrials.gov/ct2/results?term=vitamin+d&cond=C... At some point, high-quality RCT results will be in.
OJFord 6y ago
In other words: establishing causation (or lack of it) is more useful than merely correlation. Yes. But hardly breaking news, or even specific to medicine.
- antishatter 6y ago
  I mean yes, but OP's comment is especially notable with Vit D because it's deficiency is very common and often a marker for other common age related diseases. It is highly likely that Vitamin D isn't saving these people's lives, it's that the folks without vitamin D are older and/or have disease.
pjkundert 6y ago
There is strong evidence of this, summarized: https://www.outsideonline.com/2380751/sunscreen-sun-exposure-skin-cancer-science https://www.outsideonline.com/2380751/sunscreen-sun-exposure... Huge inverse correlation between Vitamin D and all-cause mortality -- but almost complete failure of vitamin D supplementation vs. cancer, heart disease and stroke. What? Turns out that sunlight produces vitamin D -- and a host of other difficult to detect artifacts, which seem to be at the root of the reduction in all-cause mortality. Seems interesting. Or, carry on -- I'm sure there's nothing to see here, and your pasty-white overweight doctor's advice to avoid sun exposure is right...
- Dylan16807 6y ago
  Doctors advising people to avoid sun exposure? Is that strawman based on anything? I hope you don't mean the advice to use sunscreen when you're going to be outside so long you'd get sunburn without it.
  - jerf 6y ago
    How old are you? I can assure you, whether it was the intent or not, that the message got out in the 1980s and 1990s that all sunlight exposure is uniformly bad and its only effect is to increase your likelihood of skin cancer, so everyone should avoid it and unconditionally use strong sunscreen for any exposure.
  - radford-neal 6y ago
    See https://www.canada.ca/en/health-canada/services/sun-safety/sun-safety-basics.html https://www.canada.ca/en/health-canada/services/sun-safety/s... for one example of an official health authority advising people to zealously avoid sun exposure, with no mention whatever of vitamin D deficiency or other downsides of not getting any sun.
- pdonis 6y ago
  The studies referenced in the Outside Online article failed to collect a crucial piece of data: what were the actual blood levels of Vitamin D in the participants? Without that piece of data you have no idea what, if any, difference the supplements were actually making vs. placebo.

mcfly1985 6y ago

What does the author mean "the new chloroquine"? No one knows if chloroquine + zinc is effective when taken early. Anyone telling you they know is lying.

andreygrehov 6y ago

I'm surprised the article barely mentions Vitamin K, which is needed along with Vitamin D - D to mobilize the calcium and K2 to put it into the right place. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5613455/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5613455/

raverbashing 6y ago
There are some interesting discussions about Vit K and Covid, basically Vit K promotes coagulation but it seems that its deficiency is associated with the coagulation issues seen in Covid patients. And it might as well be that the correlation is inverted (that is, the development of coagulation troubles might cause low Vit K)
- perl4ever 6y ago
  What is Vitamin K & K2? My associations are (respectively) potassium and the mountain near Everest.
paulirwin 6y ago
There is another important pair, too: Vitamin D and Magnesium. But consult your doctor before taking extra amounts of anything. There is a lot of misinformation on the web around Vitamin D, such as that even high amounts (>= 5000IU) are tolerable and safe. After a blood test showed me Vitamin D deficient, taking 5000IU (that size is readily available over the counter at my grocery store) daily gave me disturbing heart palpitations, which I didn't realize were related to Vitamin D until after thousands of dollars in tests showed my heart to be perfectly healthy. It wasn't until I had slacked off in taking the vitamins and then started taking them again that I discovered the connection. Apparently magnesium has something to do with it, but IANAD. (I was not taking magnesium supplements at the time.) I can tolerate 1000IU occasionally, but people need to be aware that not everyone tolerates supplements (especially high doses) the same. I was happy to see the article you linked to above only claims Vitamin D is considered safe up to 4000IU. Although IMHO, after my experience, anything over 1000IU should require a prescription. Of course nothing would stop people from taking five 1000IU OTC doses to get 5000IU, but I think most people know better than to take five of the same type of vitamin daily without talking to their doctor first.

rafaelturk 6y ago

For me this is a perfect example of wishful thinking. It's really hard for average person to accept reality: This virus, like all others, will last for a long time. We won't have, in a foreseeable future, a treatment neither a cure. Cancer, HIV or even seasonal flue are good examples examples of diseases that were discovered decades ago for which science still don't have a cure, there are a few treatments or easing medication, but none of them can be actually cured. I expect that people will move from crazy solution to another on a regular basis until a final cure is found.. my expectation is this will last for years.

learc83 6y ago
We have multiple vaccine candidates that based on early human trials, and animal trials are very likely to work. Sure it's possible all of them could fail, but I wouldn't set my bet on that.
- ericb 6y ago
  Right. There are around 100 vaccines in development. We have vaccines that have created binding antibodies in primates already. We have some that have been given to humans and produced antibodies as well. Even pessimistically assuming 90% fail, you end up with 10 vaccines. https://www.centerwatch.com/articles/12702-new-mit-study-puts-clinical-research-success-rate-at-14-percent https://www.centerwatch.com/articles/12702-new-mit-study-put...
  - soperj 6y ago
    that's not pessimistic. Regularly only 6% of vaccines make it past trials.
    - ericb 6y ago
      Do you have a source, because I provided one, and if you look, it says: "Approval rates ranged from a high of 33.4 percent in vaccines for infectious diseases to 3.4 percent for investigational cancer treatments" So by that source, I was wildly pessimistic.

antishatter 6y ago

I feel like Vitamin D deficiency correlates with every disease. A large % of everyone has a vitamin D deficiency so there is always a high correlation.

spuz 6y ago
The percentage of the population that is vitamin D deficient can't affect its correlation with disease. It's perfectly possible that after this, vitamin D is added to tap water such that very few people are deficient but the correlation with deficiency and disease would be unchanged.
- nickles 6y ago
  > It's perfectly possible that after this, vitamin D is added to tap water Vitamin D is fat soluble, not water soluble.

raverbashing 6y ago

Very good writeup That being said, VitD has much fewer potential side effects than CQ (in the recommended dosage) On this epidemic we should be looking at potential preventative quick gains, especially as the most disrupting solutions are, well, disrupting.

goda90 6y ago

"Adipose tissue (“belly fat”) appears to absorb but not release vitamin D. If we want to do some armchair hypothesizing, perhaps people historically used to lose weight in winter, which definitely would release the stored vitamin D just when it was needed." This is an interesting idea. It's believed our bodies get fat to ensure we have energy when food is scarce. It makes sense that we'd also want to have vitamins available too.

Izkata 6y ago
An addition to that: Over a decade ago (so unfortunately I have no reference, this just stuck with me for how against common sense it was) I remember reading that being overweight but not obese correlated with good health better than being "normal" weight did. Their theory was that if being sick made it so you were less hungry, you could still get an energy boost by using up fat reserves and be able to fight off illness faster. This sounds like a much more specific and more testable version of that theory.
- anonuser123456 6y ago
  >I remember reading that being overweight but not obese correlated with good health better than being "normal" weight did. This is mostly selection bias. Society is so fat that being normal / underweight is correlated with sickness/disease.
- balnaphone 6y ago
  There is a problem with the BMI [1] calculation, which is the standard measure used to determine "normal" weight, in that it is dimensionally incorrect. The BMI calculation gives results that are appropriate for those around 5'6" (168cm) in height. The units are in kg/m^2. The Ponderal Index [2] (AKA the "Corpulence Index") gives values that work for any height, with units in kg/m^3. If you are a young child or over 6 feet tall, you might find the PI/CI works better for you. [1] https://www.cdc.gov/healthyweight/assessing/bmi/adult_bmi/english_bmi_calculator/bmi_calculator.html https://www.cdc.gov/healthyweight/assessing/bmi/adult_bmi/en... [2] https://www.omnicalculator.com/health/ponderal-index https://www.omnicalculator.com/health/ponderal-index

watertom 6y ago

Since I was a child I’ve been a walking respiratory illness machine. Bronchitis, sinusitis, flu, pneumonia, common cold, etc. During “flu” season I was usually sick for the entire season with a rotating assortment of viral respiratory issues, this lasted until about 7 years ago. 8 years ago in September I started taking 10,000 IU of vitamin D3 and 180mg of K2 daily. I haven’t had a deputies illness since. My children were getting sick at their normal clip, my wife the same, but not me. I went from being sick all the time to not getting sick ever. I made one change in my life, adding the D3 and K2. After 2 years of not getting sick my wife and children started supplementing with D3 and K2, everyone stopped getting sick. My son went off to college and stopped taking the D3 and K2 and during the winter semester he got sick twice, he had me sent him the D3 and K2, he hasn’t been sick since. It’s a small sample size, but even at 10,000 IU daily D3 is not dangerous or expensive, the only caveat seems to be that you need to supplement with K2 or you can cause gardening if the arteries due to calcification. My doctor thinks it’s a lot of nonsense, but then again he wants every patient on blood pressure and cholesterol medication “just in case”.

kmonsen 6y ago
Which supplements do you get?
bencollier49 6y ago
Ironically there are papers suggesting that blood pressure and cholesterol medication is bad for people if they get Covid.
- dehrmann 6y ago
  How is that ironic? The doctor's recommendation sounded like it was pre-covid, or just their standard recommendation.
camccar 6y ago
I switched to a high cholesterol diet. Almost only meat , raw milk(grass fed) and raw egg yolks (monthly liver) combined with 20 minutes of running shirtless. Besides getting very lean I’ve also not been sick once during this. I usually get sick all the time. It’s antidotal but my diet would now be really high in k2 vitamin A and natural Vitamin D

tomhoward 6y ago

All these articles about different individual nutrients start to feel like heath whack-a-mole. How about this: to be in the best possible position to beat any serious infection, you need to be in generally good health. That means having adequate levels of all essential nutrients - i.e., all the vitamins, minerals, amino acids, enzymes etc that you get from maintaining a good diet and healthy lifestyle over the long term. To focus on just one nutrient as a pandemic looms just isn't the answer; it's not how health works. That said, I've personally researched what nutrients (note the plural) are most important for beating an infection like this, and have adjusted my nutrient intake somewhat, and recommended to close relatives they do the same. But this is after I and they have spent many years researching and maintaining good health practices. Update: if I was in not-so-good health (and not in medical treatment for a diagnosed condition, in which case, consult your doctor), my approach would be: - boost my amino acids, fatty acids and minerals with a few spoonfuls of hemp seeds every day - take extra supplements of vitamins A, B complex, C and D (and perhaps K?) - do plenty of walking in the fresh air and sun, - keep a generally healthy diet of good quality protein and veg. Update 2: Others are mentioning Vitamin K, which seems like a good idea to supplement if you're generally nutrient deficient, but may not be necessary if you have a good diet. [1] Disclaimer: not a health professional, but have had personal reasons to get very knowledgable about health and diet over many years. [1] https://www.healthline.com/nutrition/foods-high-in-vitamin-k https://www.healthline.com/nutrition/foods-high-in-vitamin-k

deweller 6y ago
"Just" focusing on one nutrient isn't the answer. But sufficient Vitamin D is important. It is something we should pay attention to. Health is complex. No one is advocating ignoring all the other aspects of immune system function by paying attention to vitamin D. [Update] I see you have toned down your comment since I started composing this response. We are in agreement.
- billman 6y ago
  I think it's important to note that Vitamin D is a hormone. And the body produces it as well.

ashtonkem 6y ago

Sufficient levels of Vitamin D are good for your health in general, separate from this pandemic. Getting sufficient levels of it is something we all should’ve been doing before anyways, which is not true of Chloroquine.

psychometry 6y ago

There are so many medical questions that can only be answered definitively with large-scale, years-long randomized experiments. Anything relating to supplements, where effect sizes are probably small, especially. These are expensive and difficult to perform and there's (to my knowledge) no institution dedicated to that goal.

forgot_user1234 6y ago

How can you do science for long term effects? where RCTs are not possible.

manifoldgeo 6y ago
When I took an epidemiology course in college, our professors taught us about both control studies and cohort studies. Cohort studies might be an example of what you're looking for. This article [0] hosted on the NIH's site discusses cohort studies and their effectiveness / pitfalls. References: [0] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2998589/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2998589/
wenc 6y ago
RCTs are not the only way to obtain evidence of causality. In causal inference, limited causal claims can be made through observational studies (where no control is done), such as retrospective natural experiments [1]. These methods are of course limited by assumptions and by how closely they match reality. Note: while a controlled experiment is the gold standard, it is not always feasible or necessary. We don't need to do RCTs on parachutes to prove their efficacy for instance. [2] -- [1] https://en.wikipedia.org/wiki/Natural_experiment https://en.wikipedia.org/wiki/Natural_experiment [2] https://www.scientificamerican.com/article/volunteers-jumped-with-or-without-a-parachute-to-gauge-its-effectiveness/ https://www.scientificamerican.com/article/volunteers-jumped...

guptaneil 6y ago

This requires a huge correlation != causation flag. The article briefly mentions this, noting that it’s possible vitamin D is just a sign of a healthy person, so of course they’ll do better with COVID. Another correlation that doesn’t get discussed whenever vitamin D comes up is that people with darker skin generally have less vitamin D, because our skin doesn’t absorb sunlight as much. We also know that COVID is disproportionately hitting colored neighborhoods in the US. Is that just because of vitamin D differences? Who knows! By the way, if you are a person of color, you probably need vitamin D supplements. The recommended doses are for white people, so adjust accordingly.

kedean 6y ago
I felt like the article spent sufficient time on the idea that the explanation could be that healthier people simply have higher vitamin D levels, and that the vitamin D itself is not the cause. At no point did they choose a side on that part, the bias was only that they believe vitamin D is a promising avenue. I really loved that the whole piece was informational, and not trying to convince the reader that Vitamin D is or isn't a cure or remedy for anything. It simply presented the available facts, the research, and the positives and negatives of that research. It even explained multiple aspects and positions of the debate on whether vitamin D supplementation is good or bad.

trevorkoob 6y ago

Did my masters on Vitamin D - It is very difficult to extract CLINICALLY RELEVANT information from retrospective epidemiological studies. However, there a a few things that are clear: 1. Calcium absorption from the intestine increases with vitamin D supplementation dose up to around 8-10,000 IU D3 daily. 2. 15 minutes of full body exposure in noon sun is equivalent to a dose of ~20,000 IU D3 3. There are few cases of vitamin D overdose in the literature - doses in the 1,000,000 IU+ range within days is generally where symptoms are noted - this excludes people with kidney disorders. Personally, I take 10k IU D3 a day. The D3 is important because D2 has 1/2 to 1/3 the effect per dose in raising calcium absorption levels. I would recommend this level of supplementation to anyone who doesn’t have a kidney disorder.

anibalin 6y ago
Hi trevor, super intereseting what you mention. Wondering where you did the master since its not common (at least in my country). Thanks man.
didgeoridoo 6y ago
Interesting, I've always heard of the calcium absorption effect as a negative aspect of D over-supplementation — I guess the theory is that it raises your blood calcium level too high, leading to arterial calcification? Is that effect overblown in your opinion?
- trevorkoob 6y ago
  In acute hypervitaminosis D, there can be organ calcification that has to be treated. These cases are rarely reported - one case occurred when the patient ingested crystalline vitamin D - dosing themselves in the range of 1-2 million IU D3 per day for weeks, and although there was not an extensive follow-up to determine the long-term effect on the patient, the acute calcification was reversed with treatment. Vitamin D is involved with calcium in the body in many different ways, specifically I was talking about a measure of the absorption of calcium into the body from food as promoted by vitamin D. Organ calcification is extremely serious and a very understandable reason why doctors have been hesitant to recommend higher doses of vitamin D, however most medical thinking about vitamin D until recently has focused on the prevention of Rickets, which requires only a small amount of constant supplementation (500 IU D3) to avoid serious effects. In context, 10,000 IU seems like an enormous dose. However if you look at the blood serum levels of people who receive consistent UV exposure, they have much higher levels than someone who is being supplemented with 500 IU D3 and no UV. So much of this debate is around trying to find out what the "optimal" vitamin D level is rather than what level is "sufficient" to prevent Rickets.

ed25519FUUU 6y ago

These studies need to keep up until we can fully account for the difference in fatality not only worldwide, but state to state. Why has Japan, with an older population (median age 47), a tiny island, crowded indoor subways —- has only experienced 900 deaths and never locked down! while some zip codes in New York experiences 2x that amount. Even state to state the difference is alarming.

cgh 6y ago
Diabetes is likely a factor: https://www.medscape.com/viewarticle/931132 https://www.medscape.com/viewarticle/931132 And obesity is strongly correlated with diabetes: https://www.diabetes.co.uk/diabetes-and-obesity.html https://www.diabetes.co.uk/diabetes-and-obesity.html There is a distinction to be drawn between obesity rates in the US and Japan and that might be part of the answer to your question.
- nradov 6y ago
  New York state has about 6× the obesity rate of Japan.
deleted 6y ago
[deleted]

chl 6y ago

dminder is a great app to estimate Vitamin D "intake"/production through sun exposure (and also food, albeit this won't matter much for most people): http://dminder.ontometrics.com/ http://dminder.ontometrics.com/ I only wish the algorithm used to derive the estimates was public/documented somewhere ... http://dminder.ontometrics.com/Estimation.html http://dminder.ontometrics.com/Estimation.html

elric 6y ago

With all this talk about Vitamin D and K deficiencies, which inevitable meanders onto Magnesium and fish oil supplements and whatnot; maybe it's time for a "vitamin subscription service"? Enter a bunch of information (location, lifestyle, diet, health issues) and get tailor made supplements sent to your home every month? The levels of some vitamins could vary depending on time of year (more D in winter) or circumstances (more Mg when more active in summer). Ideally all packaged into one tablet or something. I take an unholy cocktail of supplements to help curb my migraines, that's 5 tablets/caps a day. Not much fun.

Erwin 6y ago
These guys create a supplement based off your DNA: https://www.nutrahacker.com/ https://www.nutrahacker.com/ https://ginihealth.com/ https://ginihealth.com/ These let you create the vitamin/supplement mix you want: https://getvitaminlab.com/ https://getvitaminlab.com/ last time I tried, it ended up quite more expensive than my D vitamins.

haltingproblem 6y ago

The article "Is Sunscreen the new margarine" argues that "what made the people with high vitamin D levels so healthy was not the vitamin itself. That was just a marker. Their vitamin D levels were high because they were getting plenty of exposure to the thing that was really responsible for their good health—that big orange ball shining down from above." [1]. If this is true, we have mistaken coincidence due to a common latent cause for causation. The article "Limits of Vitamin D supplements" is a summary of the Lancet meta-analysis: "Vitamin D status and ill health: a systematic review", which is paywalled [2]. The review shows that Vitamin D supplementation has no clinically beneficial outcome on heart disease, stroke, or cancer. FWIW, I have been supplementing with Vitamin D for over a decade. I would rather like Vitamin D to work because I have chronically low levels and it would be good to have such a good silver bullet of a nutrient. I have not stopped my supplementation but I do take more frequent walks in the Sun. [1] https://www.outsideonline.com/2380751/sunscreen-sun-exposure-skin-cancer-science https://www.outsideonline.com/2380751/sunscreen-sun-exposure... [2] (https://well.blogs.nytimes.com/2013/12/11/limits-of-vitamin-d-supplements/ https://well.blogs.nytimes.com/2013/12/11/limits-of-vitamin-...)

szastupov 6y ago

Covid or not, you should test for vitamin deficiency and supplement if necessary. I do it every 3 month via Thriva (UK) and can see the progress.

Havoc 6y ago

I definitely dug out my vit D pills as a result of the coverage. Worst case scenario it creates expensive pee. Maybe it'll have some upside though

makeset 6y ago
> Worst case scenario it creates expensive pee. Well, that's one thing you don't need to worry about. Vitamin D is fat-soluble, so any excess isn't excreted in urine (hence the arguments over effective vs. excessive dosage).
- Havoc 6y ago
  >Well, that's one thing you don't need to worry about. Vitamin D is fat-soluble Good point. Thanks for pointing that out. I knew about the whole concept of water vs fat but didn't occur to me in this context

m0zg 6y ago

FYI also, researchers are suggesting that the Lancet HCQ study everyone (and the WHO) references nowadays is fake: https://www.theguardian.com/world/2020/may/29/covid-19-surgisphere-hydroxychloroquine-study-lancet-coronavirus-who-questioned-by-researchers-medical-professionals https://www.theguardian.com/world/2020/may/29/covid-19-surgi.... The authors could not have had the data they claimed they had. This is just one bit of news you will never find on CNN.

jakeogh 6y ago
Yep. More: https://news.ycombinator.com/item?id=23305606 https://news.ycombinator.com/item?id=23305606

mixmastamyk 6y ago

My anecdote. I learned about the importance of D3 on Steve Gibson's podcast about a decade ago. At the time had a kid in preschool and spent almost the whole year sick, so was quite intrigued. Started with 1,000 IU a day and getting sick stopped abruptly. For the last decade or so, haven't been sick more than one day, two at max, with one exception. Yes, believe I had CV in March and "walked it off" in about 6 days or so with mild symptoms. Last few years I've taken 5,000 IU several times a week (from Trader Joes, which has an excellent price of $4.99). As compared to Albertsons which disgustingly tries to get $15-20 for the same thing. Unfortunately this news has made both C and D unavailable at Trader Joe's for months. We'll run out soon and need to buy the gouging price somewhere else.

kpfleger 6y ago

Having read this whole piece, I think my review is much more comprehensive in covering all relevant evidence: http://agingbiotech.info/vitamindcovid19/ http://agingbiotech.info/vitamindcovid19/ Note that the title changed and many improvements made since it was first posted to HN 3 weeks ago here: https://news.ycombinator.com/item?id=23119949 https://news.ycombinator.com/item?id=23119949 In the title of this piece, analogizing to chloroquine is irresponsible. A high % of readers will take the message to stay away from D and never read the rest. I'm glad he has a similar top-level rec as me: Take all measures to avoid deficiency, probably by D3 of 2000-4000 IU/day (I'd prefer 4000). The piece unfortunately fails to make the other most important top-level comment: that all COVID-19 patients should have their D levels tested and more data on D & COVID-19 severity should be published urgently (possibly based on records that already exist). And all clinical trials for COVID-19 should be testing D levels as well. Overall, this piece is not emphatic enough that vitamin D may significantly help during this COVID-19 crisis. Several important responses to some of the top material in this piece: The NYT article dismissing Holick is terrible and not worthy of being linked at the top of this piece. I won't go into the point-by-point criticisms of this article, but it's not worthy of a piece that is supposed to be weighing evidence. The bullet point claiming the COVID-19 association could still be a fluke does not adequately acknowledge the causal aspects of the evidence: Many RCTs on D supplementation helping viral/respiratory infections (Martineau et al BMJ 2017), D causally affecting rate of aging in roundworms, causal inference model overwhelming supporting D's role as causal, studies on the correlation correcting for age, sex, comorbidities, and reverse causality, and causal mechanistic biological arguments. Some portion of the strength of the correlation seen in the 1000+ patient cases published in preprint studies so far may be due to other causal factors, but the causal evidence so far makes it very unlikely for the full extent of the large effect size seen to all be a fluke. The piece wrote: "A healthy full body exposure to sunlight can generate 25000 IU of vitamin D in one sitting, without getting burned. 2000-4000 IU daily of D3 supplements will also work." No. People wrongly believing that some sun gives them enough is probably one of the causes of widespread deficiency. From my review, in the "Practical considerations for avoiding D levels that are too low" section: There are several studies showing that even a lot of sun exposure leaves many people with insufficient D levels. For one list of studies see Tsiaras & Weinstock, “Factors influencing vitamin D status” Acta dermato-venereologica, 2011: “Studies in Hawaii (97), South Florida (98), Southern Arizona (99), Brazil (100), rural India (101) and Queensland, Australia (102) found that significant proportions of the study populations had low vitamin D levels despite abundant sun exposure.” For example, in the Hawaiian study, 51% of the 93 young, non-obese adults had D<30ng/ml despite 29hr/week (>4hr/day) in the sun at latitude 21 degrees. The variability in both seasonal sun intensity and daily hours of exposure for any given individual provide yet another reason that testing blood levels would be helpful. These studies show that even those who seem to get a lot of sun exposure should probably supplement if not testing to ensure adequacy. Also, the bullet point summary in this piece fails to point out the history of the RDA being set too low by statistical mistake. (Which I've updated my review to include. The story is crazy---the original data used to set the RDA would have resulting in 8000 IU/day if it had been analyzed correctly.)