8 ms·

So Vitamin D deficiency is linked to cancer, heart disease, respiratory infection, stroke, diabetes, and death. But taking it as a supplement helps with none of

• wukerplank 6y ago
  I read (maybe here on HN comments) that Vitamin D could only be the indicator. People who live a certain lifestyle have low risk of the mentioned diseases AND have good Vitamin D levels. But you have to live that lifestyle, not just take supplements.
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• chownie 6y ago
  It might just be that the production of vitamin D via sunlight has other effects on the body, perhaps vitamin D has been a proxy for those effects but for obvious reasons taking it as a supplement doesn't trigger the same outcome. It's unfortunate that exposure to UV is so harmful, I'm left wondering if trials using UV lightboxes to stimulate vitamin D production would change the kinds of outcomes (cancer, heart disease, depression...) we're expecting it to .
  • glofish 6y ago
    Exposure to UV light is not "so harmful". What is harmful is being indoors all the time, and getting out so rarely that you get sunburned in short amount of time. Far more damage is done by being indoors too much than being outdoors too much. The white skin has evolved because the body needs sun and UV light to function, one would die otherwise.
  • scott_s 6y ago
    It's possible, but we have no positive evidence for it. Absent that evidence, I don't think we should assume that possibility is reality.
  • ComputerGuru 6y ago
    > It's unfortunate that exposure to UV is so harmful, This is an extremely popular simplification. The scientific jury is still out on this one, as it seems that paradoxically people with constant exposure to sunlight are less likely to get skin cancer as compared to those that get sporadic exposure.
    • eloff 6y ago
      There was an interesting study (sorry I don't like to lookup citations on my mobile) showing that the prognosis for skin cancer patients is better in the summer than the winter, presumably because they get more sunlight. Not causative, but interesting nonetheless. Also MS is extremely prevalent at high latitudes compared to the tropics. Why? We know vitamin D has a role in protecting the insulation of the nerves, so maybe that's the mechanism. Anecdotal, but the one person I know with MS is white as the snow and avoids the sun like it's the devil.
• gameswithgo 6y ago
  Nobody knows yet, but sunlight exposure causes the body to produce other things than Vitamin D, like nitric oxide (or similar correct me if I'm wrong here). It also affects circadian rhythms, so maybe people who get out more sleep better, maybe they are in better health from being more active, etc etc.
• beagle3 6y ago
  There are thousands of reasonable hypothesis, and it is extremely costly (and in some cases, nearly impossible) to test. e.g. our bodies need sunlight and cholesterol in order to synthesize vitamin D; This process also apparently has some other outputs like NO which are much harder to measure since they get used quickly. It is possible that vitamin D is merely (mostly) a measure of the prevalence of this process, and it is the other (harder to measure) outputs are much more important; Or that it's the consumption of cholesterol that's more important than the production of vitamin D; Or that sunlight has other functions we don't measure that are the important ones. Or that it's all just a correlation to some other process we're not even aware of. That said, my own experience and anecdotally other people I know (and gwern has some blind n=1 experiments on his site to back this up) is that taking vitamin D early in the morning improves sleep at night, and taking vitamin D in the afternoon/evening reduces sleep quality. For that reason alone, I take vitamin D in the morning, and anecdotally, I burn less when I'm in the sun without sunscreen as well.
  • merpnderp 6y ago
    The NO production might explain most of this through it's anti-inflammatory properties. The instant reduction in blood pressure is likely just the tip of the iceberg for UV's effects on the body.
    • maaaaattttt 6y ago
      Is "NO" Nitric Oxyde in this context?
      • pmiller2 6y ago
        Yes.
• scott_s 6y ago
  I would frame it in the opposite direction: having a serious illness is correlated with low levels of Vitamin D. People with a serious illness may stay inside more, and go outside less. It's possible that "low levels" of Vitamin D are still within the healthy range, and they merely are an indication of how much time the person has spent outside during the day. In other words, it's possible that Vitamin D is pure symptom. It's not even necessarily the case that going outside is healthy, but that healthy people tend to go outside more.
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  • black_puppydog 6y ago
    > It's not even necessarily the case that going outside is healthy, but that healthy people tend to go outside more. This is a departure from the discussion of supplementing vitamin D though, isn't it? I guess the treatment "go out and do sports" is a very different one compared to "X amount of vitamin D per day as a supplement" and the former may indeed be healthy, while the latter may not be, even though they both result in higher levels of vitamin D.
    • fuckyah 6y ago
      The point is, you can’t just supplement everything and just eat starch and sit before the computer all day. It’s a healthy balanced lifestyle that matters.
    • scott_s 6y ago
      > This is a departure from the discussion of supplementing vitamin D though, isn't it? I don't think so, no. If my hypothesis is correct, the problem is not that they didn't go outside and play sports. The problem is that they are sick, and sick people don't go outside as much. Forget Vitamin D for a moment. Imagine that every time you were outside for an hour, the Outside Fairy granted you one Outside Token. Over the course of a month, it's reasonable to assume that healthy people would have more Outside Tokens than sick people. But these Outside Tokens obviously would have no causal effect on whether or not people are sick. Giving sick people Outside Tokens would obviously not help them - their problem is that they are sick. They have less Outside Tokens because being sick makes it more difficult to be outside for an hour. In other words, the arrow of causation is being sick -> less Outside Tokens, and not being sick -> more Outside Tokens. If that's the case, then Outside Tokens are irrelevant to treating the sick people. If, say, they have cancer, you should ignore the Outside Tokens and treat the cancer with all of the standard means we have of treating cancer. They hypothesis is that "low levels of Vitamin D" are just those Outside Tokens. (Yes, when Vitamin D levels are low enough, that can cause other kinds of health problems. But this hypothesis is that what we're measuring as "low" is still within the healthy range. How do we know when it's not in the healthy range? When it tends to cause the kinds of problems we are more confident are directly linked to low levels of Vitamin D.)
• glofish 6y ago
  There is a fundamental difference between vitamin D generated in your skin versus vitamin D placed in your gut. The mechanisms by which it acts and the effects it has on you are probably radically different. We are more than just a pile of various materials.
  • copperx 6y ago
    What is that fundamental difference?
    • glofish 6y ago
      for starters one is in the gut the other in the skin, sounds like a fundamental difference to me
• hannob 6y ago
  That's a reasonable hypothesis. Another one is that it's a reverse causality: Several diseases may inhibit Vitamin D uptake. And don't forget: It can be multiple causes combined. (I.e. it may be a mix of a confounder like being outside and reverse causality.)
• devaboone 6y ago
  That is a reasonable hypothesis. Also, people who are very ill are less likely to get outside and get enough sun, so they will develop low Vitamin D. Vitamin D is likely a marker of poor health. (Once the Vitamin D gets low enough, we do see direct harmful effects from it (think rickets in children), and this may contribute to poor health at that point.)
  • bakul 6y ago
    Have there been any studies that test if the absorption of Vitamin D (from supplements) is influenced by disease compared to healthy people?
  • tarsinge 6y ago
    I’m healthy, fit and relatively active (3-4 hours exercise / week, 30-1h walk everyday), and I just tested relatively low in Vitamin D (before winter even started). What should I do?
    • citruscomputing 6y ago
      Talk to your doctor.
      • tarsinge 6y ago
        I’m not sure my doctor has access to better studies than what is in the TFA. My question is weirdly formulated, what I ask is is supplementation useless given what we know? Or is it safer to stay in the (arbitrary?) recommended range? What I get from the parent post is that given low vitamin D is a symptom of poor health, supplementation is useless if someone is in good health.
        • pmiller2 6y ago
          The thing with vitamin D supplementation is that, as TFA mentions, low to moderate doses (under 4000 IU per day) are generally very safe. And, being deficient in such a crucial nutrient certainly isn't a good thing. So, if you are deficient, supplementing in that range is probably something you could feel comfortable doing on your own. If it were me, I'd go out and buy a bottle of D3 and get my levels tested at my next checkup.
• gwd 6y ago
  From TFA: > How can we reconcile promising early observational studies linking Vitamin D to most major causes of death with our current results? One thing that seems increasingly clear is that in most cases low Vitamin D (truly low Vitamin D) is a marker of poor health rather than a cause. Vitamin D is made in the skin after exposure to sunlight. A chronically ill, frail individual may leave the house less often, leading to lower Vitamin D levels. Fixing the Vitamin D will not fix the chronic illness.
  • geoka9 6y ago
    TFA == "The Fucking Article"
    • DoreenMichele 6y ago
      Although that's what I originally learned it to mean -- from a horribly toxic online space -- some people use TFA to mean "The Featured Article" aka "the article under discussion."
    • gwd 6y ago
      And nice means "mean or small-minded", and silly means "saintly", and terrible means "inspiring terror". Or at least they used to -- but usage evolves over time past etymological roots. "TFA" is indeed a back-formation from "RTFA", which is the online-forum equivalent of the aggressive and obnoxious acronym "RTFM". But it contains no verb; and in online discussions there's a sort of a hole in our language for an efficient way to say for "the article currently under discussion". So it quickly lost the aggressive and obnoxious connotations that RFTA has. As such, I think "The Fine Article" is an expansion more fitting with its evolved usage.
• dcolkitt 6y ago
  > What is a reasonable hypothesis then? The logical conclusion is that vitamin D, as we measure it, is proxying for another factor that we haven't yet detected. This X-factor is heavily influenced by sun exposure, but at most weakly influenced by vitamin D supplementation in its current form. Analogously imagine that we had no concept of the health benefits of exercise. We detected that people with gym memberships were much healthier than those without. So, we try giving a bunch of people a free gym membership. Yet few of the recipients end up using it to do any exercise. In this case the supplement group would show nowhere near the health gains of the baseline gym members. The key issue is that gym membership is only proxying for the underlying X-factor of physical activity. Michael Pollan makes a great critique of a type of thinking called "nutrionism". Basically that the determinants of health can be broken down into their isolated sub-components. "You need X amount of protein, Y amount of this vitamin, and Z amount of this mineral." The problem is that unless our understanding of biology is perfect, there's almost certainly going to be flaws in the decomposition. When we try to replicate a healthy diet with a synthetic mixture of vitamins and macronutrients, we still fall well short of natural food. A very famous example of this is when people on total parenteral nutrition kept dying, because the original formulations lacked chromium. Humans only need a microscopic amount, yet die without it. Nobody realized this because almost all natural foods have trace amounts that satisfy the requirement. As for vitamin D specifically, I think there's three pretty good candidates for what the missing X-factor is. In order from least to most controversial: 1) Our current understanding of the sub-types of Vitamin D is not complete. It wasn't too long ago that we began to learn that Vitamin D3 is much more essential than Vitamin D2. It's possible that there are sub-types of Vitamin D3 that are made in the correct proportion in the skin, but aren't represented in supplements. 2) There are other micronutrients, not yet discovered, that are synthesized in the skin. This goes back to the chromium example. Sun-exposed people may have high levels of Vitamin D + Vitamin X. Yet we can only measure the former, so we over-attribute the importance of Vitamin D. 3) Sun exposure induces the same physiological adaptations as physical exercise. Consider what we know about the mechanism of how exercise induces its health benefits. Micro-traumas to the muscle fibers and metabolic stress leads to an acute stress response. That peak leads to a down regulation of the HPA axis with accompanying metabolic benefits. The muscles recover, with an adaptation against the stress. Is it not possible that something similar happens when we sunbathe? Without a doubt UV exposure induces micro-traumas in the skin cells, that looks very similar to what's found in the muscle cells. There's also emerging evidence that sun exposure triggers the HPA stress response[1], in the same way that exercise does. If this is the case, then trying to replicate the benefits of sun exposure with supplements is a fool's errand. It's the sun exposure itself, specifically the sun damage, that is directly responsible for the health benefits. [1]https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4398592/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4398592/
• andi999 6y ago
  Its probably same reasonwhy there are some correlations with alcohol intake and health, real reason probably: sick people dont drink wine.
• tboyd47 6y ago
  Perhaps it's just more complicated than the prevailing paradigm of "have problem -> take drug -> problem go away." It could be that Vitamin D deficiency is itself a symptom of an array of underlying problems, or that it is one factor among many leading to a pathology, or that various levels of Vitamin D have various effects among different patients, or all of the above.
  • nicoffeine 6y ago
    I think it's also that health has become a product, which is skewing all the solutions into things that are easy to market, package, and distribute. You probably need sunlight in addition to foods with other nutrients to optimize systems that regulate Vitamin D levels, whether it's just a marker or not. Just like they discovered using cannabinoids to treat seizures required the "full spectrum" of the plant to be the most effective, we are finding out the hard way that trying to isolate compounds to treat anything in a biological system is often the wrong approach. It's been 20 years since "the only thing more effective is regular exercise" was a punchline on the Simpsons. It's disappointing that we are still prioritizing R&D for magic pills rather than getting fresh food and physical activity reintegrated into our lives.
• weezer 6y ago
  Sun exposure (and even tanning beds) produces vitamin D, but it also causes other changes in the human body. It appears sun exposure OR tanning bed use (!!!) reduces all cause mortality. "Avoidance of sun exposure is a risk factor for all-cause mortality: results from the Melanoma in Southern Sweden cohort" https://pubmed.ncbi.nlm.nih.gov/24697969/ https://pubmed.ncbi.nlm.nih.gov/24697969/ I think there's some confounding factors in 'outdoorsy' people having other healthy lifestyle habits, but it also seems likely that there is some other mechanism, beneficial to human health, triggered by uv exposure.
  • rland 6y ago
    I've always refused the idea that any sun == bad. Being in the sun (not excessively) feels incredible, at a very deep level. The same way eating a really healthy diet and exercising every day feels. I frequently wonder: if I'm correct, what other things are like this? Fats are good for you, not carbs as they've said. That's one example that comes trivially to mind. But I'm convinced there is a ton of stuff we do because it's "good" when in really, the positives far outweigh the negatives.
• kebman 6y ago
  It's a classic case of correlation does not imply causation. As implied in the article, people who are sick, stay indoors. So naturally, when they don't get enough sun from staying indoors, they also get lower levels of Vitamin D. And so that is the correlation. It doesn't mean that a lack of Vitamin D causes illness, or that taking Vitamin D supplements will magically cure those illnesses.
• hhas01 6y ago
  Correlation confused for causation? Say it isn’t so! /s #APillForEveryIll -- “For every complex problem there is an answer that is clear, simple, and wrong.” H. L. Mencken