We're learning more about what Vitamin D does to our bodies

(technologyreview.com)

96 points | by Brajeshwar 4 hours ago ago

65 comments

  • tsoukase 2 minutes ago

    Linking a molecule, that takes part in a complex cellular mechanism, with a general health outcome will never go well and is nonsense.

    Fellow tech people forget hacking your body with innocent pills or having any meaningful effect without sacrifice. Kill your stress, maintain normal weight and have nice relations.

  • cheald 44 minutes ago

    "Putting the entire population on vitamin D supplements would be too expensive for the country’s national health service, he told me."

    This seems absolutely bonkers. Vitamin D is dirt cheap, and if you can think at all beyond first-order effects, the improvement in immune health alone would likely pay for itself in terms of cost to the healthcare system.

    • Tubelord 40 minutes ago

      I guess the logistics of prescribing an entire population of anything is expensive, and overkill when people can supplement it in pills or diet, or just go outside more.

      • danaris 37 minutes ago

        "Go outside more" is absolutely a nonstarter in the places that most need this: northern latitudes in the winter.

        Not only is "outside" often so cold that you need to cover enough of your skin that the sunlight would barely help, the weaker sun we get in winter just doesn't produce enough vitamin D in our bodies. That's the problem.

  • coldtea 27 minutes ago

    >In fairness to researchers, it can be difficult to run a randomized clinical trial for vitamin D supplements. That’s because most of us get the bulk of our vitamin D from sunlight

    And how hard is it to make such controlled studies on prison populations (where both sun and food intake is also a known value)? Make it voluntary and give some incentives for those wanting to participate. Can study supplement effects for one or even five years, it's not like they're going anywhere.

    That's also a question I have when I hear about diet studies. What's easier than doing such in prison populations? Make it as voluntary as it's for people outside, and there's no ethical issue. We're talking like checking the effect of this or that food or diet style, which they can let different people chose their own. They already eat what they're given anyway, that would be an improvement.

  • dn3500 an hour ago

    I live in the tropics and there is plenty of sunshine here. So my skin doctor told me to avoid the sun at all costs, always wear suncreen and a hat, don't go out in the daytime. A few years of that and now I have a vitamin D deficiency.

    • coldtea 22 minutes ago

      Unless you're non-native and have redhead-style very white skin or some history, the doctor sounds overly cautious to paranoid.

      Hundreds of millions live in such climates (including people with fairer skin) and have no problems, even though they don't do anything extreme like "avoid the sun at all costs, always wear suncreen and a hat, don't go out in the daytime".

      I'm white and I lived near the tropics for a few years, big white and asian population, everybody was out in the sun all the time, hardly covered too. Skin cancer stats as good as Europe or US.

    • victor_xuan an hour ago

      Wearing sunscreen might be a good idea if you are white ethnicity (that is your ancestors lived in northern Europe for thousands of years).

      For others. It depends.

      Native South Americans, Africans and Indians seem to get skin cancer at much lower rates.

    • cachius an hour ago

      Can supplement D easily, together with K2.

      • mentos 33 minutes ago

        Careful with this I took vitamin d every day no problem for a year. Randomly started getting heart palpitations one week and was trying to figure out why. Got an Apple Watch to monitor for a fib. Was asking myself what changed in my life that it happened all of a sudden and realized I had started taking K2. ChatGPTs theory is that it really made the absorption of vit d effective and led to hypercalcemia.

        Stopped taking vit d and k2 it resolved after a week no problems almost a year later.

        • candiddevmike a minute ago

          It should be the opposite, not taking K2 leads to calcification as K2 helps your body absorb calcium instead of lingering in your circulatory system.

        • gbear605 7 minutes ago

          You’re warning people to be cautious of taking Vitamin D… because you had problems with potassium supplements? Those are entirely different things with entirely different risk profiles.

    • hammock an hour ago

      Reminder that the FDA recommended daily allowance of vitamin D is 10x lower than it was supposed to be, because of a math error, and they have never corrected it.

      https://pubmed.ncbi.nlm.nih.gov/28768407/

      • OneMorePerson 32 minutes ago

        Between the vitamin D error (this affected US and Europe and probably more places) and the sodium/blood pressure study that was misleading if not outright false, it's amazing how a few data points can become widespread advice without much verification and follow-up.

        I'm sure there's tons more cases that we don't even know about, not in the conspiracy sense, but more in the sense that there's some issues with how carefully these claims are validated before they get put out there as a rule to be followed.

        • jeltz 24 minutes ago

          One of the big issues is the momentum. Even long after these misstakes have been found doctors still give advice based on the error.

    • delfinom an hour ago

      Yea sun damage and cancer vs. vitamin d deficiency is a little bit of a balancing act. It also doesn't help skin color is very critical part in all of this but people view that topic as taboo to discuss. The entire reason for skin color variations is a genetic optimization for UV absorption at specific latitudes vs sunburn risks.

      That and the other half of the problem is we are all sedentary as hell in all latitudes these days. Be it people hiding under AC at the tropics or hiding in heated homes in the north. We don't go outside to get enough sunlight and our fat reserves that store vitamin d don't grow large enough because we still don't go outside when the weather is tolerable.

      • inciampati 42 minutes ago

        > The entire reason for skin color variations is a genetic optimization for UV absorption at specific latitudes vs sunburn risks.

        This seems obvious but was not confirmed by genetic evidence. The rate of adaptation turns out to be much higher than can be explained by skin cancer.

        The real cause appears to be fertility. UV radiation breaks down folate (vitamin B9) in the bloodstream, and folate is critical for DNA synthesis and repair. Folate deficiency causes serious problems in pregnancy, neural tube defects like spina bifida, and may impair sperm production. So darker skin in high-UV equatorial regions likely evolved partly to protect reproductive capacity.

        In the other direction, lower melanin production helps with vitamin D synthesis in lower sunlight environments. Vitamin D requires UV-B radiation to be synthesized in the skin, and melanin inhibits this. Vitamin D is also linked to fertility. It's involved in sex hormone production and has been associated with successful implantation and pregnancy outcomes.

        If you're curious, check out Nina Jablonski and George Chaplin's work. Their hypothesis is that skin color evolution as fundamentally about reproductive fitness: dark enough to protect folate, light enough to synthesize vitamin D. Both nutrients affect fertility, fetal development, and offspring survival. They have an immediate primary impact on fertility and success, while skin cancer even in the most extreme environment/phenotype mismatch, has an onset after reproductive age.

      • immibis an hour ago

        I don't think anyone is making it taboo to say someone's melanin content affects how they absorb UV light. It's taboo when you tie it to all sorts of other things, say, how well they should do at school.

  • Scene_Cast2 3 hours ago

    I found that taking a specific brand of Vitamin D (the Genestra D-mulsion in particular) right before bed was guaranteed to give me vivid dreams. I've had half a dozen friends try it, with every single one reporting similar results.

    • dsp_person 2 hours ago

      I've heard not to take vitamin D right before bed because it will kinda keep you up. Maybe the vitamin D as a stimulant is what's gives you the extra dream awareness.

    • Janicc 2 hours ago

      Supplementing any "large" amount of either Vitamin D or Bs really messes with my sleep. It makes it harder to fall asleep and I get crazy dreams (and sometimes hallucinations in bed too)

    • rapsey 2 hours ago

      I checked the ingredients. That is because it contains glycerin. Which is a great and safe supplement to take for anyone with sleeping issues. But will cause very vivid dreams at the start. D3 will not by itself have a huge effect on dreams.

      • ltbarcly3 2 hours ago

        This is such a weird fact that I googled it and sure enough it is widely noted!

    • kylecazar 2 hours ago

      That's interesting. I know vitamin D can improve sleep quality in people who are deficient, and sleep quality helps with dream recall -- I wonder if that's the mechanism or it's something else.

      A cursory search shows lots of redditors taking Vitamin D (some of them way, way too much btw) and having wild dreams too.

      I take 800IU a day and haven't noticed anything on that little.

      • steve1977 2 hours ago

        What is way too much? I take around 4000IU per day. Which just about brings my blood levels into the “green” area in blood testing.

        • kylecazar 2 hours ago

          The reddit post was taking 50,000IU a day, which is usually the amount prescribed for someone to take once a week.

          Your 4000IU isn't too much. Lots of the brands you see in stores are 5k for daily supplementation.

        • rsyring 2 hours ago

          FWIW: my functional provider recently noted low levels in my labs and I was already taking 2K IU daily. She bumped me up to 6K UI daily.

        • thegeekpirate an hour ago

          4,000 is perfect.

      • jimmySixDOF an hour ago

        Given 10min of sunlight the body can naturally produce 15,000UI equivalent so I think gp is likely astroturfing for that brand

      • rapsey 2 hours ago

        That is actually a low dose.

        • kylecazar 2 hours ago

          Yeah, I showed a really mild deficiency in my work so they just suggested adding a low daily dose for me. I wouldn't expect to have had any side effects.

          • ltbarcly3 2 hours ago

            I was very deficient and they gave me 50k UI per day prescription vitamin D3 for 60 days. Sure enough I was high-normal on my next test. 800ui is likely not enough to have any effect unless you consistently take it for years.

            • kylecazar an hour ago

              That's wild. I've never heard of such a high dose being prescribed daily.

              Yes, I wouldn't expect to notice anything on my dose.

              • seba_dos1 27 minutes ago

                It was for 60 days. If they continued to take this much indefinitely it would surely cause troubles, but 60 days when starting from deep deficiency is reasonable.

    • exe34 2 hours ago

      Spicy food and dehydration do wonders for me!

  • strontian 37 minutes ago

    No one will probably believe this, but I think dust mite exposure is a major cause of vitamin D deficiency and a lot of the negative outcomes associated with low vitamin D are actually second+ order effects of dust mite exposure. Just posting in case it reaches one person out of the 100s of millions who are sick from dust mites.

    • orochimaaru 33 minutes ago

      citation? There's many open to believing it and the reach maybe more if there are studies that confirm causation with a high probability.

      fwiw - vit-d supplementation is one of the easiest supplements available. The recommended dosage 400IU is way lower than what can actually bring your levels up. You need about 4000IU of supplementation and regular testing if you're not exposed to sunlight and/or your dairy intake is poor.

  • padjo 2 hours ago

    Isn’t vague mixed evidence of a small, limited effect pretty much what you’d find if it it did basically nothing in aggregate?

    • epgui 2 hours ago

      This article aside, there are a number of very well established benefits of vitamin D. I think “mixed evidence of small limited effect” is not a phrase that is reflective of current knowledge.

  • vondur 3 hours ago

    It’s interesting that his doctor wouldn’t prescribe a vitamin D supplement because it would supposedly be too expensive for the health care system. Fortunately, vitamin D supplements are generally inexpensive to buy. I doubt I’d ever get a prescription for one, they’d probably just tell me to pick some up at the pharmacy downstairs.

    • celticninja 2 hours ago

      That will be why the doc tells you it's too expensive, because over the counter is cheap. It's not that they can't afford it, but in the UK there is a standard prescription price. It's under £10 per prescription for any drug that prescribed, but it's a flat fee. So if they prescribe something that costs less than the prescription charge it makes no sense for the patient.

      • b33f 2 hours ago

        There's a standard perscription price in England, not the UK. in Scotland and Wales there's 0 charges to the patient

  • pfannkuchen 2 hours ago

    I’ve wondered whether vitamin D is a real time signal within the circadian rhythm regulation system. Perhaps it is released in response to sunlight in order to let other parts of the system know it is daytime.

    If it were like this, bulk dosing would be expected to be better than nothing (“maximum daytime!!!! Followed immediately by a very long slow sunset at whatever curve it is cleaned up in the body), but it would be better to dose continuously in real time at a level and body location(s) that would simulate the range of sunlight throughout the day.

    Can anyone professionally familiar with the research in this area comment?

  • Johnny555 2 hours ago

    >For me, that means topping up with a supplement. The UK government advises everyone in the country to take a 10-microgram vitamin D supplement over autumn and winter

    My last blood test showed I was slightly deficient in vitamin D - my doctor recommended a 50 microgram (2000 IU) supplement. My next test to see how well it' working isn't for a few more months.

    • Noaidi an hour ago

      Get a metabolic test as well to check your calcium levels since D can increase serum calcium if you have genetics like mine.

      • cheald 41 minutes ago

        It's frequently suggested that you take vitamin K2 with vitamin D, which helps direct calcium to the bones.

        • Noaidi 35 minutes ago

          Yes, Salmon is also high in K2, but for me the calcitonin was more important. My D levels and calcium levels are great now.

  • tagami 2 hours ago

    Mushrooms exposed to UV convert egosterol to vitamin D - an almost identical mechanism found in our skin

    • epgui 2 hours ago

      Cool fact, but so what?

      • ggm an hour ago

        So you can boost D by eating mushrooms, and keep them in sunlight if you can.

      • doublerabbit an hour ago

        Well, mushrooms when exposed to UV convert egosterol to vitamin D - an almost identical mechanism found in our skin.

  • almosthere 3 hours ago

    During the Pan I took a lot of VitD. It started giving me the feeling that my heart was beating out of my chest, so I stopped.

    • epgui 2 hours ago

      Vitamins A, D, E and K can be overdosed… But for vitamin D to be toxic you would have to veer quite far from the posology.

    • Insanity 2 hours ago

      How much Vitamin D? Vitamins are good but as with many things, the poison is in the dosage. You can definitely take too much of it.

  • Noaidi an hour ago

    I have polymorphisms in a gene called CYP2R1 (Vitamin D 25-hydroxylase, involved in activation of vitamin D precursors). My polymorphism lead to lower levels of D3.

    My doc put me on 1000mcg of D3 a day for a month after I tested low. I came back in for blood testing and my Calcium levels were extremely high (Not good!). So the doctor ordered me to stop the vitamin D to see what was going on.

    As it turns out I have even more lower frequency polymophisms in a gene called CALCA (Calcitonin is a peptide hormone that causes a rapid but short-lived drop in the level of calcium and phosphate in blood by promoting the incorporation of those ions in the bones.). So basically since I do not realease a lot of Calcitonin naturally I need to get it from food.

    Guess what food is extremely high in Vitamin D3[1] and Calcitonin[2]?

    Salmon! I have a genetic history of people that ate a lot of salmon so this makes sense.

    Genetics matter people. I will assume that most people who have irish/britsh should be getting their D3 from fatty fish since sunlight is so rare there.

    [1] https://pmc.ncbi.nlm.nih.gov/articles/PMC6566758/ [2] https://en.wikipedia.org/wiki/Salmon_calcitonin).

  • DustinEchoes an hour ago

    Is it necessary to take k2 along with d3?

  • mondainx 3 hours ago

    Good article, but it does not cover toxicity; you can take too much vitamin D and this has very negative affects. Usually a multivitamin is enough for supplementing; taking extra is where you can run into issues; consult your Doctor.

    • nervysnail an hour ago

      IIRC, toxicity is very rare even in very high doses (like 20 k IU a day) for weeks/ two or so months.

    • alexnewman 2 hours ago

      Evidence that multivitamin d is useful?

  • sxp 3 hours ago

    > At a checkup a few years ago, a doctor told me I was deficient in vitamin D. But he wouldn’t write me a prescription for supplements, simply because, as he put it, everyone in the UK is deficient. Putting the entire population on vitamin D supplements would be too expensive for the country’s national health service, he told me.

    Ugh. It's amazing how incompetent medical systems are. I was also deficient in vitamin D and my doctor wrote a prescription. When I did the math, the cost was something like >$.10 per 1000IU. But if I bought the vitamins from a normal store, I would pay <$.01 per 1000IU. Since a person lacking sunlight only needs 1000IU, the price for giving everyone in the UK Vitamin D would be <$700k/day. And probably much less since most people won't need this high of a dose and bulk quantities would be cheaper.

    For healthy people, taking extra vitamins is pointless, but giving them to people who are deficient in vitamins is one of the cheapest health interventions for the benefits.

    PSA: if you're feeling off, make sure your doctor checks your various vitamin levels and see if cheap OTC vitamins help.

    • masterphai 2 hours ago

      From a strictly biomedical point of view, mild vitamin D deficiency is trivial to correct and supplementation is indeed one of the lowest-cost interventions we have. But large health services often optimize around procurement, prescribing ceilings, and clinical workload rather than marginal benefits. In that logic, pushing people toward OTC supplements is simply cheaper to administer, even if it looks absurd from the outside.

      There’s also a less-discussed layer: population screening for micronutrients tends to be episodic rather than continuous, and the thresholds for “deficiency” versus “insufficiency” have shifted over the years. Some clinicians quietly adopt a pragmatic stance - if the risk is low and the intervention is cheap, they’d rather patients self-supplement without pulling the system into it.

      The general point still stands, though. If someone has persistent fatigue, mood changes, sleep disruption, or immune irregularities, checking basic micronutrient status is a reasonable first step. A small, targeted correction often produces disproportionate improvements, even if it sits outside the more glamorous parts of medicine.

    • peppersghost93 3 hours ago

      Too add to this, if anyone is considering looking for otc vitamin supplementation, please check to see if the brand you're interested in has been lab tested. Heavy metals have been found in cheap stuff before in the US and the government isn't really screening for this stuff proactively.

    • gessha 3 hours ago

      If you consider the deficiency a national health issue, you can even subsidize a nation scale production reducing the cost even more. From a state perspective, that should be chump change considering the nation-wide effects.