Talk:Vitamin D/Archive 9

Dismissive tone
Large portions of the article seem to bend over backwards to demonstrate that Vitamin D levels have little influence on anything. As a lay person I can't say that this is incorrect, but it seems unlikely. There's a strong whiff of WP:SOAPBOX about the article at present, and a bit more balance is needed. --Ef80 (talk) 12:21, 11 May 2014 (UTC)
 * Yes this is the difference between the advertising one is exposed to in the mainstream media and the best available evidence. It is also compounded by the fact that 5 years ago there was tentative evidence that has not panned out. It occurs in a number of topics. Doc James  (talk · contribs · email) (if I write on your page reply on mine) 00:28, 19 May 2014 (UTC)


 * But that section shouldn't be the first section after the introduction. It has the effect of presenting the negative results out of context. Instead the article should start, after the introduction with an expanded version of the current "biological activity" section. The article is about vitamin D and therefore one needs to explain first what it is and how it operates in the body. The effects section should come later, And having presented the techincal details on vitamin D, calcidiol, calcitriol etc. one can explain first what the theoretical motivations are to look for effects other than for bone health. Negative or positive effects can then be discussed in that sections in the right context. The way it is presented now makes the research into the health effects look like random shots in the dark ehile the opposite is true. E.g. this article explains why it's natural to think that vitamin D has an effect on heart disease:

"HOW VITAMIN D MAY REDUCE CARDIOVASCULAR RISK

Vitamin D may lower cardiovascular risk via several mechanisms:

Inhibiting inflammation. Vitamin D has a powerful immunomodulatory effect: laboratory studies show that it inhibits prostaglandin and cyclooxygenase 2 pathways, reduces matrix metalloproteinase 9 and several proinflammatory cytokines, and increases interleukin 10, all of which result in suppressed inflammation.1

Inhibiting vascular muscle proliferation and vascular calcification. Animal studies indicate that in moderate doses vitamin D decreases calcium cellular influx and increases matrix Gla protein, which inhibits vascular smooth muscle proliferation and vascular calcification. These protective effects contrast with the hypercalcemia associated with a high intake of vitamin D, especially in the context of renal failure or other risk factors, which may lead to increased vascular calcification.1

Regulates blood pressure. Vitamin D decreases renin gene expression and the synthesis of renin, which reduces activity of the renin-angiotensin-aldosterone system, leading to a reduction of blood pressure and a favorable effect on volume homeostasis.1

Regulates glucose metabolism. Limited evidence shows that vitamin D may increase insulin sensitivity and regulate glucose metabolism.1

Vitamin D and cardiac hypertrophy

The vitamin D receptor is present in virtually all tissues, including cardiac myocytes and endothelial cells. Animals with vitamin D deficiency have higher blood pressures, and animals genetically altered to have no vitamin D receptors (knock-out models) develop left ventricular hypertrophy and heart failure. Animals genetically altered to have no 1-alpha-hydroxylase (so that the most active form of vitamin D is not made) also develop left ventricular hypertrophy. They can be rescued by the administration of 1,25-dihydroxy vitamin D3.1

These findings are consistent with what is observed in patients with end-stage renal disease, who produce very little 1,25-dihydroxyvitamin D3: they often develop left ventricular hypertrophy, diastolic heart failure, atherosclerosis, and vascular calcification." Count Iblis (talk) 17:31, 20 May 2014 (UTC)


 * The science has moved on, so has Wikipedia. Alexbrn talk 18:01, 20 May 2014 (UTC)


 * No, it hasn't. The article is about the motivations of the VITAL study which is still underway, the results won't be known until a few years from now. Count Iblis (talk) 00:04, 21 May 2014 (UTC)
 * If it moves on again, we will follow again. But we have no WP:CRYSTALBALL. Alexbrn talk 06:00, 21 May 2014 (UTC)
 * Yes, but the problem is not about whether or not we have proof from clinical trials. The problem is that the reader now doesn't have the faintest idea why you have all these clinical trials in the first place. It's a bit like writing up an article about dark matter, without explaining why most physicists believe it exists and simply stating all the negative results from underground experiments. That would create the impression to readers that physicists are wasting billions of dollars in vain attempts to prove some ill motivated theory. Count Iblis (talk) 11:11, 21 May 2014 (UTC)
 * If something's worthy of note, it will be covered by secondary sources, like this one. I'm really not seeing there's any kind of problem here. Alexbrn talk 11:28, 21 May 2014 (UTC)
 * The problem is with presentation, the section should come after the ones about the biology, otherwise, one can't explain the motivations for the trials at all. Also note that when it comes to adverse effects, the opposite attitude is taken. What is mentioned has largely been debunked (like vitamin D supplementation for pregnant women etc.) The theoretical aspects of this topic is completely missing from the article (presumably because it would then debunk the idea that high dose vitamin D supplementation is unlikely to be harmful). If you want to get the very basics about this topic, you can't get it from Wikipedia at all, instead you need to read articles such as this one. Count Iblis (talk) 18:05, 21 May 2014 (UTC)


 * Count Iblis, what you are talking about is a hypothesis not theory. The Institute of Medicine of the National Academies found that there was no evidence of benefit from taking supplements, and there was indication of harm from supplements. Moreover, African Americans, not only don't benefit from raising their vitamin D levels by supplementation, but are are more easily harmed by doing so. Institute of Medicine of the National Academies found taking vitamin D supplements was not only unnecessary for African Americans but tended to harm their health. ("...preliminary reports from NHANES suggest that the risk for all-cause mortality among non-Hispanic blacks compared with whites occurs at a lower serum 25OHD level (60 vs. 75 nmol/L). [...] Additionally, a cross-sectional study conducted by Freedman et al. (2010) reported a positive association between serum 25OHD level and calcified atherosclerotic plaque in the aorta and carotid arteries of African Americans Here).


 * Wikipedia The Top Source Of Health Care Info For Doctors, Patients. The Wikipedia article gives the Institute of Medicine recommendations  too little weight, and puts a grab bag of recent findings Doc James collected on the same level. And what it says about taking 4000IU in pregnancy is seriously misguided. An individual's serum 25-OHD(3) concentration may appear to be "low" for reasons totally independent of sunlight exposure or vitamin D intake. Serum 25-OHD(3) concentration is only poorly responsive to increases in vitamin D intake, and the prolonged routine consumption of thousands of international units of vitamin D may interfere with the regulation of phosphate homeostasis by fibroblast growth factor-23 (FGF23) and the Klotho gene product, with consequences that are detrimental to human health. Extra Klotho gives an edge in cognitive function, see here.Overagainst (talk) 17:02, 30 July 2014 (UTC)


 * It's not for nothing that the human body produces thousands of IU's when exposed to UV light in an hour. That we don't know exactly what this is all used for and that we can survive with a lot less provided it's not too close to zero (you then get rickets), doesn't justify treating vitamin D as some drug for some disease X and then saying that just because tests show no benefit for X while other tests suggests (but do not prove) increased risks for Y, that we should stick to extremely low intakes for vitamin D. It is this stupid logic used by the medical community that I disagree with, which is why I keep on taking 8000 IU per day regardless of anything that comes out of the medical research short of rigorous proof that it is harmful.


 * We cannot know for sure if vitamin D at higher dosages will have any direct relations with any disease at all. For all we know, it may only impact muscle function allowing you to exercise harder and recuperate better. It may be that adequate levels of vitamin D will help you to keep a high level of physical fitness as you age and that any health benefits are then purely due to that fitness which you could, with more effort, also have obtained without vitamin D. It could even be the case that vitamin D is slightly harmful for your heart but that the net effect when you exercise with vitamin D is positive because the fitness overcompensates for this, and in practice you culd not have obtained that fitness level without vitamin D.


 * Under such a scenario, the usual tests will yield that vitamin D has no effect or that it is harmful. The official medical advice will be to not take dosages of the order of a few thousand IU per day, due to the harm. But of course, I will know better and I will keep on taking vitamin D while sticking to a rigorous exercise routine and eating healthy foods. Count Iblis (talk) 18:32, 30 July 2014 (UTC)


 * Skimmed through the article again as this discussion piqued my curiosity. The article appears quite fair; it identifies several highly promising lines of research with the caveat that the research is preliminary. It does miss a bit (for example, ties to inflammatory bowel disease) but that's OK. Incidentally, I recall that when the IOM released their study, they had a press conference (video likely online somewhere) where someone mentioned the NYTimes headline Extra Calcium and Vitamin D Aren't Necessary, Report Says. The panel chuckled and then scoffed at the headline as it was an absurd and misleading summary of their conclusions. II  | (t - c) 07:17, 31 July 2014 (UTC)

Pregnancy
Have restored the content as it is supported by high quality references. Doc James (talk · contribs · email) (if I write on your page reply on mine) 02:19, 31 July 2014 (UTC)


 * Indeed and the edit summary by Overagainst: " deleted, it was giving medical advice and advocating for dose at which harm begins according to IoM" is misleading. The IOM does not say that harm begins at 4000 IU/day, just that they cannot rule that out given all the known facts. They use a very high standard for proof of benefit while accepting any hints that it may not be safe, no matter how weak the evidence for that is. That leads to a very rigorous maximum tolrable upper limit which is completely theory independent and completely based on direct observations.


 * I think the IOM was basing the 4000 IU/day on a single study where old frail people were given a single dose of about 600,000 IU, their calcidiol levels rose to more than 100 nmol/l. But they tended to fall a bit more frequently than the placebo group. If yu take this unexplained obsrvaton as evidence for harm, then you have a potentially positive result for that at a calcidiol level which corresponds to 4000 IU/day. However, a more plausible interpretation is that vitamin D has a positive effect on muscle function (this is observed in many other tests), and the group who got the vitamin D would become a bit more active and the more you walk around the more likely it is that you will fall. Now, however plausible this interpretation is, this is not proven, so it's not 100% ruled out that there is some strange negative effect of vitamin D at 4000 IU/day. The IOPM's job is to be very rigorous so, they will say that one cannot rule out that at 4000 IU/day a negative side effect may start to occur.


 * Of course, we do have a pretty good idea where harm starts, see e.g. here: "...the wealth of animal studies and human anecdotal reports of vitamin D intoxication indicate that plasma 25(OH)D3 is a good biomarker for toxicity, and the threshold for toxic symptoms is ≈750 nmol/L. This threshold value implies that 25(OH)D concentrations up to the currently considered upper limit of the normal range, namely 250 nmol/L, are safe and still leave a broad margin for error because values significantly higher than this value have never been associated with toxicity." Count Iblis (talk) 03:12, 31 July 2014 (UTC)
 * This is probably a bit too much detail for this talkpage... it's interesting, but you don't have much of an audience here for it. As I imagine you're aware, animal studies are only weakly predictive of actual human results; I doubt that the toxic threshold for humans is as high as 750 nmol/L myself. II  | (t - c) 07:34, 31 July 2014 (UTC)
 * This is also based on experiments on humans. Most labs use 500 nmol/l as the lower level for potential toxicity, so this is all well founded. My point is simply that the IOM uses the 4000 IU/day and the 150 nmol/l or so in a particular context which is not approprate for a measure of where toxicity begins according to current medical opinion. It's not plausible that calcidiol at low levels would be harmful. Calcidiol doesn't interact strongly with the molecules that calcitriol interacts with, obviously not as that would undermine the mechanisms that are regulated by vitamin D.
 * So, calcidiol levels need to be extremely high before you are going to infuence these mechanisms. When this starts it is not immediately going to lead to adverse effects because these mechanism work by feedback loops. So, if a cell needs to have some amount of calcitriol to make a certain amount of molecules of X, but there are already some molecules of X being produced due to extremely high calcidiol levels, then less calcitriol will be made from calcidiol to make the remaining molecules of X. So, you actually don't get too many of the X molecules at first. Problems will only start when the calcidiol level becomes so extremely high that more of X is produced by only the calcidiol itself than is needed. Count Iblis (talk) 15:48, 31 July 2014 (UTC)


 * Good call. Thanks Doc. II  | (t - c) 07:34, 31 July 2014 (UTC)
 * No, it is out of line with the Institute of Medicine Dietary Reference Intakes for Calcium and Vitamin D ( 2011 ) "The IOM finds that the evidence supports a role for vitamin D and calcium in bone health but not in other health conditions. Further, emerging evidence indicates that too much of these nutrients may be harmful, challenging the concept that 'more is better.'" User:Jmh649 thinks we can go ahead and have the following section


 * Pregnancy Low levels of vitamin D in pregnancy are associated with gestational diabetes, pre-eclampsia, and small infants.[43] The benefit of supplements, however, is unclear.[43] Pregnant women who take an adequate amount of vitamin D during gestation may experience positive immune effects.[44] Pregnant women often do not take the recommended amount of vitamin D.[44] A trial of supplementation has found 4,000 IU of vitamin D3 superior to lesser amounts in pregnant women for achieving specific target blood levels.[44] "


 * That is improper weight; it doesn't exactly say that pregnant women would benefit from supplementing vitamin D but it implies it and then it tells you what dosage will raise your vitamin D levels. Even if it was clear that vitamin D had proven benefit and no risk, which isn't so, where does it say we can mention dosages, let alone ones  that are several times the recommended intake? And for PREGNANT WOMEN!-Overagainst (talk) 17:59, 31 July 2014 (UTC)
 * The IOM report is already 4 years old and since that time a lot of evidence has emerged in the literature linking the low levels of vitamin D advocated by you (50 nmol/l or lower) during pregnancy to diseases such as Parkinson's disease and type 1 diabetes. Indeed, the incidence of such diseases is much higher in Northern Europe than in Asia and Africa while the incidence is now increasing in these regions, consistent with people getting less Sun exposure there.
 * And you can also read from other articles by Holick et al. that mothers need to get at least 4000 IU/day otherwise their breastmilk will not contain a sufficient amount of vitamin D for the baby (about 400 IU/litre). So, this fits in well with the natural vitamin D requirement for babies. Count Iblis (talk) 18:20, 31 July 2014 (UTC)
 * Manual of Style/Medicine-related articles"Ensure that your writing does not appear to offer medical advice [...] Wikipedia is not a collection of case studies, and excessive examples should be avoided". "Wikipedia should concisely state facts about a subject. It should not discuss the underlying literature at any length."Overagainst (talk) 18:44, 31 July 2014 (UTC)
 * And it doesn't do that. The IOM report does give medical advice (as it should do). Your main point seems to be that just because what is in this article is not always consistent with the medical advice from the IOM report (actually your interpretation of it), that we are giving medical advice. But we are not doing that. Count Iblis (talk) 19:01, 31 July 2014 (UTC)
 * I am being told by Doc James something that I have taken off twice (diff here) "is supported by high quality references." The pregnancy subsection talks about various conditions and doesn't exactly say that pregnant women would benefit from supplementing vitamin D but it implies they well might  and then it tells you what dosage will raise your vitamin D levels, and that dosage is several times what the Institute of Medicine recommend. The massive Institute of Medicine Dietary Reference Intakes for Calcium and Vitamin D ( 2011 ) "The IOM finds that the evidence supports a role for vitamin D and calcium in bone health but not in other health conditions. Further, emerging evidence indicates that too much of these nutrients may be harmful, challenging the concept that 'more is better.'" Now they haven't withdrawn that conclusion based on their expert examination of  thousands of studies yet doc James seems to think  the article should not be bound to concisely state facts as to the current state of knowledge. Instead, we are apparently free to bring in various studies to synthesise a conclusion.


 * "Low levels of vitamin D in pregnancy are associated with gestational diabetes, pre-eclampsia, and small infants.[43] The benefit of supplements, however, is unclear.[43] Pregnant women who take an adequate amount of vitamin D during gestation may experience positive immune effects.[44] Pregnant women often do not take the recommended amount of vitamin D.[44] A trial of supplementation has found 4,000 IU of vitamin D3 superior to lesser amounts in pregnant women for achieving specific target blood levels.[44]"


 * The pregnancy section uses two separate refs to reach an implied conclusion that pregnant women should take, not the recommended amount but far more (ie 4000 iu). WP:SYNTHESIS ". If one reliable source says A, and another reliable source says B, do not join A and B together to imply a conclusion C that is not mentioned by either of the sources. This would be a synthesis of published material to imply a new conclusion, which is original research. "A and B, therefore C" is acceptable only if a reliable source has published the same argument in relation to the topic of the article. If a single source says "A" in one context, and "B" in another, without connecting them, and does not provide an argument of "therefore C", then "therefore C" cannot be used in any article".Overagainst (talk) 19:27, 31 July 2014 (UTC)

A reasonable compromise might be to delete the last sentence which mentions 4,000 IUs, as that seems like it is more the issue? I don't think that based upon a 2010 report we can completely discount other reviews of the literature, particularly more recent ones. II | (t - c) 05:54, 1 August 2014 (UTC)


 * The Vitamin D fact sheet sets it at 600 IU in normal pregnancies but 800IU is also a common recommendation. There is consensus that low Vitamin D status during pregnancy should be corrected by whatever (sane) means available. Personally I do not take the "IOM maximum RDA" seriously. Richiez (talk) 11:12, 1 August 2014 (UTC)
 * Imperfectly Informed, it's not just the dosage its the implied medical advice. The issue is it is not our place to use synth to imply that vague 'low' vitamin D levels are the cause of medical conditions when the Institute of medicine experts say there is no evidence for that, while ignoring that the IoM say there are definite indications that levels reached by high dose supplements can harm health. Up untill the IoM report, 30ng/ml was the level considered adequate while below that was considered low, but the IoM found 20ng/ml was more that sufficient and virtually everyone has that. The IoM found NO evidence to support the use of vitamin D in any of the medical conditions on the laundry list subsections Doc James has put under the Effects section What we have here is failure to use the best available source and the synthesising of medical advice by Doc James in his Effects section where it is clearly being implied that vitamin D might help various medical conditions. The pregnancy subsection is not the only one implying, against authoritative IoM conclusions, that vitamin D supplements might help with medical conditions. To take 1.3 (one of nine subsections):-
 * Cancer"There is insufficient evidence to recommend that vitamin D be prescribed for people with cancer, although there is some evidence that hypovitaminosis D may be associated with a worse outcome for some cancers,[30] and that higher 25-hydroxy vitamin D levels at the time of diagnosis are associated with better outcomes.[31]".


 * Here is the American Cancer Society "A 2010 analysis of data from 10 studies did not find any association of vitamin D levels and 6 less common types of cancer -- endometrial, esophageal, gastric, kidney, non-Hodgkin lymphoma, and ovarian. And, people with the highest vitamin D levels seemed to have a higher, rather than lower, chance of developing pancreatic cancer. In one study, smokers with higher blood levels of vitamin D were 3 times more likely to develop pancreatic cancer than those with low levels."._Overagainst (talk) 13:18, 1 August 2014 (UTC)


 * "...that vitamin D might help various medical conditions." The IOM report does not prove this thesis wrong either. It only says that at the moment of writing (2010) there was no conclusive, rigorously proof that there exists a disease not related to calcium metabolism or bone health for which vitamin D supplementation would help. They gave the medical advice in their report that vitamin D should not be prescribed to deal such other diseases. But this does not mean that there exist a wealth of literature that does strongly suggest that vitamin D is involved in many other diseases. It was the opinion of the IOM in 2010 that these results were not (yet) strong enough to merit giving the medical advice in favor of vitamin D supplementation for such conditions. Indeed the leading IOM report's authors JoAnn E. Manson and Clifford Johnson who have defended the conclusions of the IOM report against criticism that it was too conservative, are themselves involved in research of the role of vitamin D in heart disease and cancer (Manson) and diabetes (Johnson). So, the authors of the IOM report themselves would not agree with what Overagainst is saying, other effects are not ruled out, and the known facts are promising enough to conduct large scale clinical trials, in the judgment of the very same authors of the IOM report. Count Iblis (talk) 02:05, 2 August 2014 (UTC)
 * . There is not a single reliable source for what is implied about about vitamin D supplements in those two subsections under 'Effects', which I indented above in comments. I think I have shown them to be textbook-standard examples of synth.Overagainst (talk) 18:14, 3 August 2014 (UTC)
 * All statements are directly sourced, I don't see the synth. Count Iblis (talk) 18:18, 9 August 2014 (UTC)
 * A United States Institute of Medicine (IOM) report states: "Outcomes related to cancer, cardiovascular disease and hypertension, and diabetes and metabolic syndrome, falls and physical performance, immune functioning and autoimmune disorders, infections, neuropsychological functioning, and preeclampsia could not be linked reliably with calcium or vitamin D intake and were often conflicting". Conflicting means that sometimes the outcomes were WORSE. When sources contradict one another; the IoM is saying there are indications of harm. We can't ignore that, and add  wild speculation that  pregnant women in general are vitamin d deficient and may improve their health by taking  4000IU a day. That is not NPOV and even if it was standard medical advice we don't give medical advice. The most authoritative medical source says effects of vitamin D supplementation on health are contradictory and  explicitly cautions that there are indication of harm from vitamin D supplements, and further says that a dose of 4000 IU is where harm may begin to appear. You want the article to continue to imply that pregnant women ought to take that amount.Overagainst (talk) 20:54, 10 August 2014 (UTC)
 * Medical advice is a red herring, what we write isn't medical advice by definition. It's not that we can't say that some advocate a certain dose. Deleting information because you consider it dangerous medical advice is wrong. And by your own logic, you don;t ahve any problems giving the IOM's medical advice, so this proves your position on the medical advice issue to be inconsistent. Now, the IOM report appeared before that other review article, so you can't use the IOM report to block inclusion of the contrary findings.
 * And to the substance of the matter, note that 4000 IU/day is a normal dose most people would get if they spent some time in the Sun every day, so we're not taking about some extraordianry medical intervention here that a priori would require a lot of evidence. There is a disagreement about this in the medical community and it isn't the case that one side is advocating for an extreme fringe position, so both sides can be given some weight. The IOM report gets the most weight, but that should not come at the total exclusion of all other views. Count Iblis (talk) 19:34, 11 August 2014 (UTC)

This edit
Is disruptive. Without clear consensus further removal may result in a block. Doc James (talk · contribs · email) (if I write on your page reply on mine) 21:26, 11 August 2014 (UTC)

Addition
This edit adds a primary source. We should use secondary sources only. Also it inappropriately uses the main template as this section is not about rickets generally but about the effects of vitamin D on rickets. User:Lambiam Doc James  (talk · contribs · email) (if I write on your page reply on mine) 16:46, 12 August 2014 (UTC)


 * Now we have a Cognition and dementia subsection; yet more reported results of no importance or worth. Overagainst (talk) 21:09, 1 September 2014 (UTC).

Schizophrenia
Plenty of observational data showing association between deficiency and schizophrenia, but association might not prove causation so intervention studies now needed - secondary source 10.1210/jc.2014-1887 JFW &#124; T@lk  22:05, 4 October 2014 (UTC)

MeSH link broken
Good catch. It's fixed now. —Patrug (talk) 03:01, 21 January 2015 (UTC)

Vitamin D to be on FDA-mandated nutrition facts label
The FDA is preparing to require manufacturers to declare the amount of Vitamin D on the Nutrition Facts label, because they are new “nutrients of public health significance.”  It's also preparing to update the daily value for Vitamin D.  source It's to go from 15 mcg(400IU) to 20 mcg. Seems important, but I'm not sure where to work it in. http://www.jpands.org/vol14no2/kauffman.pdf -- &#123;&#123;U&#124;Elvey&#125;&#125; (t•c) 02:20, 1 October 2014 (UTC)


 * The article has been updated. —Patrug (talk) 03:01, 21 January 2015 (UTC)

Mechanism of Vitamin D protection against colon cancer and immune boosting - January 2015 groundbreaking study.
http://well.blogs.nytimes.com/2015/01/15/how-vitamin-d-may-fight-colon-cancer/?rref=health


 * “This study really shows that vitamin D has an effect on immunity,” said the senior author, Dr. Shuji Ogino, an associate professor of pathology at the Dana-Farber Cancer Institute in Boston, “and it’s the first study to show that in a human population. Vitamin D boosts immunity not just in cancer, but in fighting infections as well.”

Gut doi:10.1136/gutjnl-2014-308852

Plasma 25-hydroxyvitamin D and colorectal cancer risk according to tumour immunity status


 * Conclusions High plasma 25(OH)D level is associated with lower risk of colorectal cancer with intense immune reaction, supporting a role of vitamin D in cancer immunoprevention through tumour–host interaction.

Mingyang Song

Reiko Nishihara

Molin Wang

Andrew T Chan

Zhi Rong Qian

Kentaro Inamura

Xuehong Zhang

Kimmie Ng

Sun A Kim

Kosuke Mima

Yasutaka Sukawa

Katsuhiko Nosho

Charles S Fuchs

Edward L Giovannucci

Kana Wu1,

Shuji Ogino — Preceding unsigned comment added by Ocdcntx (talk • contribs) 23:45, 22 January 2015 (UTC)

Suspected copyright violation
Improperly cited material from Vander's Human Physiology, section 11F.2, was identified in the "Biosynthesis" section of this article. -- J.B.M.D. 02:21, 20 January 2015 (UTC)

@JB: If you have access to the book, perhaps you could just add a proper citation for the material in question, so that we don't lose the content? Even if it's the entire two paragraphs, I think the "over-quotation" template would allow us to put something like:

According to Vander's Human Physiology:

"Vitamin D3 (cholecalciferol) is produced through the action of ultraviolet irradiation (UV) on its precursor 7-dehydrocholesterol. This molecule occurs naturally in the skin of animals and in milk. Vitamin D3 can be made by exposure of the skin to UVB, or by exposing milk directly to UV (one commercial method).  Human skin makes vitamin D3 and supplies about 90% of vitamin D. D3 is also found in oily fish and cod liver oil.

Vitamin D2 is a derivative of ergosterol, a membrane sterol named for the ergot fungus, which is produced by some kinds of phytoplankton, invertebrates, yeasts, and higher fungi such as mushrooms. The vitamin ergocalciferol (D2) is produced in all of these organisms from ergosterol, in response to UV irradiation. Like all forms of vitamin D, it cannot be produced without UV irradiation. D2 is not produced by green land plants or vertebrates, because they lack the precursor ergosterol. The biological fate for producing 25(OH)D from vitamin D2 is expected to be the same as for 25(OH)D3, although some controversy exists over whether or not D2 can fully substitute for vitamin D3 in the human diet."

See what you think... Patrug (talk) 21:16, 20 January 2015 (UTC)


 * Hello, Patrug. As an uninvolved administrator responding to this from the copyright problems board, I'm afraid we can't do that. As per WP:NFC, extensive quotations are forbidden; additionally quotations must be used transformatively - we can't just wrap quotation marks around material because we want to use it. We need a good reason. I've removed the section for now to eliminate the copyright problem. Maybe somebody knowledgeable in the field can rewrite it? :/ --Moonriddengirl (talk) 14:23, 3 February 2015 (UTC)

Plasma Vitamin D vs Serum Vitamin D?
How can i convert Plasma Vitamin D blood test value to Serum Vitamin D? B-HKR to be used can be for example 45 % if that helps. ee1518 (talk) 20:29, 6 March 2015 (UTC)

Vit D recommendations
What do people think of this ? Removed until consensus for its inclusion. Doc James (talk · contribs · email) 00:45, 22 March 2015 (UTC)


 * This seems to be an important criticism of how the IOM recommendations were calculated -- where they appear to have made a fundamental statistical error. It should lead to revision of their recommendations.  But we cannot do their research for them!
 * I suggest a statement along the lines of "The statistical calculations which were used by the IOM to estimate the RDA giving adequate vitamin D levels for 95% of the population have been criticized as making a fundamental error. A much higher RDA was suggested to be appropriate."
 * (or if we do not like using the primary source!). Jrfw51 (talk) 09:39, 23 March 2015 (UTC)


 * This points to a bigger issue w.r.t. our sourcing policies. We assume that primary research is published in journal articles that will indeed report on that sort of research, then we have secondary review articles which consider many of such primary research results. They are better sources as all the different research results can be combined to forma better picture. And then we should have even more reliable tertiary articles where different secondary review articles are consered to get to consensus view. The IOM report is supposed to be such a tertiary review article, however, because of lack of consensus in the literature, they have been engaging in primary research, often disagreeing with the authours of the secondary review articles they were using for their report. Count Iblis (talk) 01:47, 28 March 2015 (UTC)

Low Risk of Problems from Too Much Vitamin D
See here:

""We found that even in those with high levels of vitamin D over 50 ng/mL, there was not an increased risk of hypercalcemia, or elevated serum calcium, with increasing levels of vitamin D," study co-author Dr. Thomas Thacher, a family medicine expert at the Mayo Clinic, said in a journal news release.

To gauge whether widespread supplementation might be boosting the risk for such toxicity, the study authors analyzed vitamin D level information that had been collected by the Rochester Epidemiology Project.

The data included more than 20,000 vitamin D blood level measurements taken between 2002 and 2011 from residents of a single community in Minnesota.

In the end, 8 percent of the measurements indicated levels exceeding 50 ng/mL, often involving women over age 65. Fewer than 1 percent had levels over 100.

Just one case of vitamin D toxicity was found over the decade-long study period, the researchers said. That person's vitamin D level was 364 ng/mL."

Count Iblis (talk) 17:15, 19 May 2015 (UTC)

Vitamin D and Cancer
Vitamin D metabolites have an anti-proliferative effect on cancer cells in vitro and vitamin D has been postulated to decrease the metastatic potential of cancer cells by favoring apoptosis and reducing angiogenesis. In humans, beginning with the first observational study in 1980, many peer-reviewed epidemiological studies have reported an association between sunlight exposure, dietary vitamin D intake, or higher serum levels of the principle circulating form of vitamin D (25-hydroxyvitamin D) and reduced incidence or mortality for cancer of several sites. The strongest evidence indicates a protective effect of vitamin D in colon cancer prevention. A meta-analysis of eight prospective cohort studies of serum levels of 25(OH)D that included more than 600,000 participants identified a total of 1,822 colon and 868 rectal cancer cases. Results showed that participants with higher circulating 25(OH)D levels had a 34% reduction in colorectal cancer risk compared with those with the lowest levels. Subgroup analyses confirmed a strong linear dose-response relationship with the lowest risk of colorectal cancer in participants with serum 25(OH)D levels above 40 ng/ml. A randomized controlled trial of 1179 women treated with 1,100 IU of vitamin D and 1450 mg of calcium each day for just 4 years observed a 60% reduction in risk of cancer for all sites combined.

I have moved this here. It was placed in front of this 2014 review which is more recent than the prior studies. The newer review article would also take into account the primary sources mentioned here. Others thoughts? Doc James (talk · contribs · email) 23:36, 11 June 2015 (UTC)
 * agree with DocJames, (and is consistent with MEDRS)--Ozzie10aaaa (talk) 00:02, 12 June 2015 (UTC)
 * yes, this is undue. Best simply to summarize the review. Alexbrn (talk) 02:44, 12 June 2015 (UTC)


 * The proposed sourcing is largely primary sources and/or out of date, so the content isn't an improvement. Agree we should stick to summarizing the available up to date secondary sources.   04:52, 12 June 2015 (UTC)


 * I have tried to nuance the Vitamin D and cancer section as it is difficult to ignore the debate in the secondary sources and subsequently around the large observational studies showing associations of pre-diagnostic vitamin D and subsequent cancer. Of course, these are only associations, and do not indicate causality and are not the desired RCT of vitamin D supplements. As an encyclopedia we do not recommend whether supplements should or should not be given wp:medrs but the debate and challenges to the consensus by many people needs a mention if only in a scientific or sociological context!  Jrfw51 (talk) 12:26, 10 July 2015 (UTC)
 * So let's see: you've now edit-warring in an old piece of primary work and a review older than the others we are using to "however" their more recent conclusions. That is not neutral and falls afoul of WP:MEDRS. Alexbrn (talk) 12:36, 10 July 2015 (UTC)
 * Did the 2011 IOM review include the 2010 EPIC study of half a million Europeans? In any case, please read what I wrote as I have not "howevered" this but used it to illustrate WHY there is debate. I have more fully quoted from the Ross paper to inform on their conclusions. I appreciate your views on this and am trying to help to improve the entry. Jrfw51 (talk) 12:47, 10 July 2015 (UTC)
 * We're all trying to improve the entry. The "debate" would require the assistance of a time machine since the review you added is from 2006. We should relay what more up-to-date secondary sources say without unduly dwelling on aspects which they don't. Alexbrn (talk) 12:54, 10 July 2015 (UTC)
 * OK delete the 2006 review. Shall we add (1 million subjects),  and   (high quality journal reviews), and/or  (U.S. Preventive Services Task Force), all since the IOM 2010 dietary intake review, and all suggesting some association with colorectal cancer. Jrfw51 (talk) 13:07, 10 July 2015 (UTC)
 * Those sources look more promising. Alexbrn (talk) 16:35, 10 July 2015 (UTC)

Have updated based on them. Everyone agrees there is an association. There however is little evidence that it is causal. Doc James (talk · contribs · email) 16:39, 10 July 2015 (UTC)
 * Thank you. Does anyone think really think vitamin D is a "causal" factor with all the genetic (and nutrient) associations so much stronger in a multifactorial, polymorphic condition -- I doubt it. But the modifying effects of these pre-diagnostic associations did deserve a mention which we now have nuanced. Can we address some of the other issues raised on your Talk page? Jrfw51 (talk) 17:32, 10 July 2015 (UTC)
 * I am not sure if some people think vit D is causal or not. What other issues you wish to address? Doc James  (talk · contribs · email) 18:54, 10 July 2015 (UTC)

This vitamin D and cancer section is currently a subsection of Health effects of supplementation. Is there support for a separate topic: Associations of vitamin D with human disease which looks at the cancer and other epidemiological associations without always getting back to whether or not supplements are recommended?

I would like to see the EPIC study reinstated, as it is large, high quality and not covered by the IOM article on intake in 2010 (and it is European rather than keeping a N American focus). The evidence is stronger for colon cancer (as per the other refs not now included). Jrfw51 (talk) 20:47, 10 July 2015 (UTC)
 * There are lots of recent review articles. No need to use a single primary source. Doc James  (talk · contribs · email) 21:23, 10 July 2015 (UTC)
 * We could include further details under "mechanism of action" Doc James  (talk · contribs · email) 21:24, 10 July 2015 (UTC)
 * Not sure why we're now emphasizing 2011 reviews when we have 2014 ones which reach different, more definitive conclusions. Alexbrn (talk) 10:39, 11 July 2015 (UTC)
 * I think they have looked at somewhat different sets of primary publications with different populations, doses of supplements, follow-up and effects. The 2010 Ross et al. summary of the IOM dietary intake review is widely cited and their conclusions are understandable, as are those in the Chung et al. 2011 review which has a better focus on cancer. The 2014 meta-analysis looks for a 15% effect size which was not found for unselected community-dwelling individuals and the detail in the Cochrane 2014 review was more than I expected to be acceptable in this section.  Please update these details but I think we do need to keep several large and prominent reviews in view of the debate about the different suggestions deriving from the association and supplementation studies. Jrfw51 (talk) 11:31, 11 July 2015 (UTC)
 * The USPSTF is another major position. I do not have an issue with including their review from 2011. But yes we need to be careful about giving older reviews too much weight. Doc James  (talk · contribs · email) 16:49, 11 July 2015 (UTC)

Check citations
I've now discovered two citations that had incorrect author attributions, which is leading me to question the quality of all of the citations. I've deleted one (because it was of dubious quality) and will correct the other one. Perhaps all the citations should be checked for accuracy. Rhombus (talk) 12:43, 27 October 2015 (UTC)

Broken ref
There is one ref that has been broken for years, due to 2 refs using the same name ("Ross_2011"). I had to go back in the history quite far to find the version in which this ref was not broken. In this version, one of the refs was named "RossetalAJCE2011". This one was not referenced anywhere else, whereas Ross_2011 was references many places.

The very next revision breaks the ref.

So I've corrected it by giving the duplicate (less prevalent) ref the old name of "RossetalAJCE2011". The current article also seems to have another reference that was to Ross_2011 that looks much like the other RossetalAJCE2011 reference so I've changed that also. --Ericjs (talk) 05:23, 5 November 2015 (UTC)

External links modified
Hello fellow Wikipedians,

I have just added archive links to 2 one external links on Vitamin D. Please take a moment to review my edit. If necessary, add after the link to keep me from modifying it. Alternatively, you can add to keep me off the page altogether. I made the following changes:
 * Added archive https://web.archive.org/20130221030710/http://www.nytimes.com:80/2005/05/17/science/17qna.html to http://www.nytimes.com/2005/05/17/science/17qna.html
 * Added archive https://web.archive.org/20130530132909/http://iuva.org/uv-faqs to http://iuva.org/uv-faqs

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1,25-Vitamin D3 Deficiency Induces Albuminuria
http://ajp.amjpathol.org/article/S0002-9440(16)00017-1/abstract

"Vitamin D plays an important role in renal (patho)physiology. Patients with glomerular diseases have an injured renal filtration barrier, leading to proteinuria and reduced renal function. An impaired renal function also leads to 1,25-vitamin D3 deficiency as a result of reduced renal 1α-hydroxylase activity. Vitamin D treatment to reduce proteinuria remains controversial, although there is an inverse correlation between vitamin D levels and proteinuria. Herein, we showed that 1,25-vitamin D3–deficient 25-hydroxy-vitamin-D3-1α-hydroxylase knockout mice and 1,25-vitamin D3–deficient rats develop podocyte injury and renal dysfunction. Glomerular injury was characterized by proteinuria and partial podocyte foot process effacement. Expression of nephrin, podocin, desmin, and transient receptor potential channel C6 in the podocyte was significantly altered in 1,25-vitamin D3–deficient animals. Supplementation with 1,25-vitamin D3 or 1,25-vitamin D2 prevented podocyte effacement or reversed glomerular and tubulointerstitial damage in 1,25-vitamin D3–deficient animals, thereby preserving and restoring renal function, respectively. The effect of 1,25-vitamin D3 deficiency and 1,25-vitamin D3 and 1,25-vitamin D2 repletion on proteinuria could not be explained by hypocalcemia, changes in parathyroid hormone, or fibroblast growth factor 23. This study demonstrates that 1,25-vitamin D3 deficiency directly leads to renal injury in rodents. Translated to human subjects, this would underline the need for early vitamin D supplementation in patients with glomerular disease and chronic renal insufficiency, which might inhibit or potentially reverse renal injury."

Count Iblis (talk) 20:48, 3 March 2016 (UTC)
 * primary rat study, of no use to us. Alexbrn (talk) 21:13, 3 March 2016 (UTC)

Serum 25-Hydroxyvitamin D Concentrations ≥40 ng/ml Are Associated with >65% Lower Cancer Risk
http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0152441

Age-adjusted cancer incidence across the combined cohort (N = 2,304) was 840 cases per 100,000 person-years (1,020 per 100,000 person-years in the Lappe cohort and 722 per 100,000 person-years in the GrassrootsHealth cohort). Incidence was lower at higher concentrations of 25(OH)D. Women with 25(OH)D concentrations ≥40 ng/ml had a 67% lower risk of cancer than women with concentrations <20 ng/ml (HR = 0.33, 95% CI = 0.12–0.90)." Count Iblis (talk) 23:06, 6 April 2016 (UTC)


 * unreliable. Alexbrn (talk) 06:22, 7 April 2016 (UTC)


 * A PubMed search on vitamin D and cancer, limited to meta-analyses, yielded scores of articles on specific types of cancer, cancer in general, cancer mortality, etc. Any addition to the Article on the topic of cancer will need to be carefully researched and written.David notMD (talk) 02:06, 2 May 2016 (UTC)


 * I attempted to add carefully weighted information on the associations of vitamin D and cancer last year. Including the reviews cited as refs 75 to 80 was the consensus along with the current wording.  There are similar excellent large prospective series to the one above and systematic reviews/meta-analyses on individual cancers, but I could not find any new reputable secondary sources to justify changing the current wording.  I am always in favor of a larger (scientific) section on Epidemiology of associated disorders, and making the recommendation for Health effects of supplementation separate, and subject to the best WP:MEDRS rules. Jrfw51 (talk) 20:18, 2 May 2016 (UTC)

Taste
Vitamin D has no discernible taste (at least for me and my vitamin D gel caps), should the article mention this? Aylissa-S (talk) 06:35, 23 September 2016 (UTC)

Drug box → Chem. box
TerpeneOtto (talk) 03:56, 16 December 2016 (UTC) The drug box on this page and others limits the data we can input as far as physical properties goes. I have the magnetic susceptibility of Vit. D. and I would like to publish it. I'm not sure why the drug box limits us from posting physical properties and I believe it should be changed. Vitamin D and Adenosine triphosphate are two molecule that could fit either a drug box or a chem box and when the drug box is published it prevents users from quick searching some of the necessary data they need. If the box is converted please input the following code to for the magnetic susceptibility in the physical properties section. | MagSus = -273.3·10−6 cm3/mol. Thanks

Diff re: vitamin D supplementation

 * Is there a way I can expand the text a little more? I think it's an interesting quote and point coming from the editor in chief of the journal. Would you be satisfied with, "While some researchers believe there needs to be more evidence to show the difference between vitamin D supplementation compared to a decent diet and 15 minutes in the sun each day, there are a number of randomized controlled trials in progress as of 2015 that will evaluate vitamin D supplementation."

My edit (revision 753873502):
 * In an editorial, Dr. John Hickner, editor-in-chief of The Journal of Family Practice, wrote, "...there is scant evidence that vitamin D supplementation in healthy Americans leads to any positive outcomes compared to a decent diet and 15 minutes in the sun each day. Luckily, there are several large randomized trials currently underway that will valuate vitamin D supplementation."

Your edit (revision 753917624):
 * There are a number of randomized controlled trials in progress as of 2015.

Diff link: [//en.wikipedia.org/w/index.php?title=Vitamin_D&diff=753917624&oldid=753873502]

Thanks, --Michael Powerhouse (talk) 21:50, 9 December 2016 (UTC)
 * Don't agree this edit should be used in the Research section for vitamin D. 1) Hickner has no vitamin D publications, so is not a proven expert; 2) J Fam Prac is not a vitamin D-relevant journal where the encyclopedia user would seek or trust information; 3) family medicine is not a discipline likely to run vitamin D clinical research; 4) the Hoel review is sufficient to support the statement that research is active and one can see the research activity is strong. I suggest removing the sentence and reference. --Zefr (talk) 22:30, 9 December 2016 (UTC)
 * Thank you for your comment; this issue seems really important to you. My view, however, is different. The passage I wrote is true (it's true that Hickner did write the text in an editorial) which is why I mentioned it. I think it's a valid passage per WP:5P2. --Michael Powerhouse (talk) 22:08, 19 December 2016 (UTC)

Review
This review

"One review stated that there is no clinical evidence that using sunscreen reduces the risk of melanoma, but rather insufficient sun exposure by lifestyle changes involving more time spent indoors over the past 50 years with increased incidence of vitamin D deficiency has paralleled the rise in melanoma seen in epidemiological studies.

A 2016 review stated that reports of favorable health outcomes deriving from moderate sun exposure and adequate vitamin D concentration or vitamin D supplementation were not adequately described in the medical literature. While medical authorities in the United States have recommended that men, women and children reduce their sun exposure based on concerns about skin cancer, the majority of Americans have vitamin D deficiency that may lead to increased risk of diseases possibly preventable by adequate sun exposure and the resulting higher vitamin D levels. "

Has no impact factor. Not sure I would call it a reliable source. Doc James (talk · contribs · email) 18:32, 19 December 2016 (UTC)


 * We have a lot of higher quality reviews that state the opposite. Doc James  (talk · contribs · email) 18:35, 19 December 2016 (UTC)
 * The Hoel paper is a systematic review from 4 different institutions and distinguished authors whose combined publication total is 993. Among many other topics well-discussed, it states a valid relationship in the literature that an indoor lifestyle combined with excessive sunscreen use has paralleled the increasing prevalence of vitamin D deficiency and melanoma over the past few decades. I wouldn't classify an article from Semin Cutan Med Surg as "higher quality"; and "no impact factor" doesn't mean zero impact factor. The Hoel review presents a valid argument per WP:5P2 and should be reinstated. --Zefr (talk) 18:58, 19 December 2016 (UTC)
 * Generally we avoid review articles with no impact factor. Expecially when they contain claims like "We can find no consistent evidence that use of chemical sunscreens reduces the risk of melanoma." The article fails WP:MEDRS
 * This 2014 review states "Ultraviolet radiation plays a major role in the development of nonmelanoma and melanoma skin cancers. Photoprotection by sunscreens has been shown to prevent the development of actinic keratosis, squamous cell carcinoma, melanoma, and photoaging." and has an IF of 2.47
 * It makes this state based partly on "In 2010, Green and colleagues 33 published the first randomized control study to evaluate the protective effects of sunscreen use on the development of melanoma. This study looked at melanoma as a secondary endpoint, 10 years after the conclusion of the Nambour Skin Cancer Prevention Trial. The investigators found a 50% reduction in new primary melanomas and a 73% reduction in invasive melanoma rates among participants previously assigned to the sunscreen group. This landmark study demonstrated that regular sunscreen use reduces the risk of developing melanoma. It is important to highlight that the investigators followed up the cohort for more than 15 years in this study." Doc James  (talk · contribs · email) 19:14, 19 December 2016 (UTC)
 * The review in the zero IF journal makes extraordinary claims that fly in the face of the consensus in medicine, expressed for example this CDC page that advises using sunscreen. We should not give this any weight as it is -- at least today -- not just a minority opinion but by flatly contradicting the consensus it is FRINGE.  And since sunscreen is a key preventative measure advised by public health authorities it is dangerous fringe. Jytdog (talk) 22:11, 19 December 2016 (UTC)


 * The problem is caused by people of Northern European descent whose skins start to fry at a UV index of 5 who live in places where the UV index can be as high as 14. Cloud cover can sometimes reduce the UV index by only a factor of 2, meaning that you can still get a severe sunburn even if the Sun isn't visible. This can also happen to skin under the cover of clothes. So, you need to use sunscreen every time before you leave your home, not just when sunbathing. This will then inevitably lead to vitamin D deficiency. Count Iblis (talk) 22:58, 19 December 2016 (UTC)
 * That is entirely off topic. Jytdog (talk) 00:19, 20 December 2016 (UTC)
 * Most of the research done on which the review papers are based have looked at US and Australian citizens. Count Iblis (talk) 06:09, 20 December 2016 (UTC)

Calcifediol regulates lipid metabolism by inducing degradation of SREBP cleavage-activating protein
http://www.cell.com/cell-chemical-biology/abstract/S2451-9456(16)30478-0

"Sterol regulatory element-binding proteins (SREBPs) are transcription factors that control lipid homeostasis. SREBP activation is regulated by a negative feedback loop in which sterols bind to SREBP cleavage-activating protein (SCAP), an escort protein essential for SREBP activation, or to insulin-induced genes (Insigs) (endoplasmic reticulum [ER] anchor proteins), sequestering the SREBP-SCAP-Insig complex in the ER. We screened a chemical library of endogenous molecules and identified 25-hydroxyvitamin D (25OHD) as an inhibitor of SREBP activation. Unlike sterols and other SREBP inhibitors, 25OHD impairs SREBP activation by inducing proteolytic processing and ubiquitin-mediated degradation of SCAP, thereby decreasing SREBP levels independently of the vitamin D receptor. Vitamin D supplementation has been proposed to reduce the risk of metabolic diseases, but the mechanisms are unknown. The present results suggest a previously unrecognized molecular mechanism of vitamin D-mediated lipid control that might be useful in the treatment of metabolic diseases."

Count Iblis (talk) 01:06, 13 February 2017 (UTC)

Photochemistry Graphic Needs Correction
The graphic showing the conversion of 7-dehydrocholesterol to Vitamin D3 needs to be corrected. The subscript numbers are placed incorrectly. For example, methyl groups are shown as "C3H", when they should be written "CH3". Every sidegroup carbon needs correction. The file name is "Vitamin D biosynthesis in fungi and animals.jpg". — Preceding unsigned comment added by Mja210 (talk • contribs) 15:49, 12 March 2017 (UTC)

Vitamin D, cytokine and others
Calling Alexbrn too. The wording in the lead has improved, but as Count Iblis also said (unless I misunderstood), there are too many conclusions and/or assumptions, particularly negative ones. If one study claims they found no effect of supplementation in a list of cases, but many studies claim that it does affect at least one of them (without mentioning said study), should the first study's claim still hold? It's worth noting that overviews and reviews are far less damning. Haimi and Kremer (2017) in the World Journal of Clinical Pediatrics state that "In adults, vitamin D deficiency has been implicated in numerous health conditions including osteoporosis, cancer, diabetes, and autoimmune diseases." The NIoH outline describes "Vitamin D has other roles in the body, including modulation of cell growth, neuromuscular and immune function, and reduction of inflammation." But the supplementation section immediately declares that according to one 2013 study and apparently the IoM (context?), it is not linked to several of these. There is no disputation, just authorative assertation of something that clearly has no consensus. Links between Vitamin D and Cytokine appear in ample recent articles as well. Bataaf van Oranje (Prinsgezinde) (talk) 13:15, 19 May 2017 (UTC)
 * It's fine. We say "Beyond its use to prevent osteomalacia or rickets ..." for the discussion of supplementation, which is largely just a scam for the "worried well" market. We're certainly not going to start implying big health benefits without very strong secondary sourcing. Alexbrn (talk) 13:18, 19 May 2017 (UTC)
 * "Just a scam for the 'worried well' market"! Maybe -- but that sounds very POVish.  I am concerned still that in the need to cover the inconsistent data on the use of supplements and not to promote mass treatment with minor benefits, we are ignoring specific benefits in defined groups, as well as a mass of epidemiological and biological associations.  In the lead, we are very detailed on effects (or lack of them) of supplements, with minimal reference to the other aspects of chemistry, molecular and cell biology. Jrfw51 (talk) 13:59, 19 May 2017 (UTC)
 * Well yeah, is the POV of our decent sources, which we are bound to adopt. If there's stuff on chemistry etc. to add, then fine. Alexbrn (talk) 14:04, 19 May 2017 (UTC)


 * I agree, the POV problem is caused by having that huge section on supplementation in the first place. There should be only a small section about supplementation and the controversies surrounding about about what the appropriate calcidiol levels should be, at the end of the article. The article can then be more focused on what is known and uncontroversial about vitamin D, and then one can mention all these other effects that vitamin D is known to have. E.g. when it comes to vitamin D and the immune system, this article should present information taken from articles like this one, and not focus on double blind studies that found no relations between taking vitamin D and the probability of getting the flu. One big problem for the medical articles we have is that we tend to focus on tertiary review articles, but these are written by experts with a focus on treatment of patients, e.g. the Institute of Medicine (IoM) writes such reports on various topics, in case of vitamin D they will have to come up with instructions for doctors about appropriate vitamin D levels given what is to be found in the literature. For Wikipedia such reports are not ideal, because the science in such reports will get compromised due to focus on treatment options. The IoM will have to invoke the precautionary principle which is then not consistent with an unbiased scientific assessment; that's not a problem for the IoM reports as they're looking into treatment options, it is a problem for us because we're supposed to focus on the science, we're not in the business of giving advice on supplementation. Count Iblis (talk) 20:05, 19 May 2017 (UTC)


 * "Worried well" is a good description of the enthusiasm for vitamin D among consumers and healthcare professionals. Blood levels are becoming a common part of normal blood testing, and people talk about their vitamin D status akin to how people talk about cholesterol. The RDAs and 100% Daily Value were increased in 2010. The supplement industry is happy. This too, may pass, in the way that enthusiasm for vitamin E (for heart disease), vitamin C (for colds), calcium (for bones) and fish oil (for brains) has declined. I disagree, however, with the position that having Wikipedia content on supplementation within articles about vitamins and essential minerals is distorting the purpose of Wikipedia. For many people, that is the primary reason for search. David notMD (talk) 10:08, 21 May 2017 (UTC)

Article is littered with weasel sections
This article has a consistent tone. Numerous large high-quality studies show benefits across a range of conditions and outcomes (and indeed for other conditions and outcomes there are no demonstrated benefits, or even harms). In each of these cases the article is written to suggest that these show no benefits, using modifier words like 'inconclusive', casting doubt on the mechanism of action, casting doubt on the effect size, etc. If these were poorly conducted studies then these modifiers would be reasonable, but they are not, and the collective impact is to create a highly negative tone. This may be the desired result of the authors in control of this page.

While there is a reasonable desire to keep junk science, supplements industry sponsored science, and unsupported claims off this page, it seems to have gone the other way in muddying the waters and downplaying the practical effect of the evidence presented.

Good luck to — Preceding unsigned comment added by 58.7.138.204 (talk) 22:09, 29 April 2017 (UTC)

agreed. this wiki is outright atrocious. It is one of the most useless pages I've seen on wikipedia, and that's saying a lot. The worst part is it's not hard to find solid information on vitamin D. The amount of groupism going on here is disgusting, and it's the reason why Wikipedia is losing its credibility. Trailmixers (talk) 22:27, 25 May 2017 (UTC)

Childhood pneumonia
This condition, sentence and source were added by Barbara (WVS). ''As an adjunct to antibiotic therapy, vitamin D has been studied to treat pneumonia in children. Though promising, little evidence exists for its efficacy'', with this citation. Issues: 1) have we established that WikiJournal of Medicine is a valid MEDRS source? Acceptance of this weak study would give evidence the answer is no; 2) the cited research uses two studies from India and one from Afghanistan (are credible clinical studies done in Afghanistan?), both providing inconclusive results. Why include such weak research if it allows no new understanding? 3) work like this, if deemed usable, should be in the Research section. --Zefr (talk) 00:07, 18 July 2017 (UTC)
 * We generally expect journal articles to be in pubmed indexed sources. When WJM is pubmed indexed I will support its careful use. P.S. I am associated with said journal. Doc James  (talk · contribs · email) 04:32, 18 July 2017 (UTC)

Vitamin D useless?
The apparent claim made in the lead seems bizarre.

"Beyond its use to prevent osteomalacia or rickets, the evidence for other health effects of vitamin D supplementation in the general population is inconsistent. The effect of vitamin D supplementation on mortality is not clear, with one meta-analysis finding a decrease in mortality in elderly people, and another concluding no clear justification exists for recommending vitamin D."

Is it seriously implied that Vitamin D is useless? Bataaf van Oranje (Prinsgezinde) (talk) 09:15, 11 May 2017 (UTC)
 * It's a super-strength source and is pretty clear yes. It ends thus:
 * Alexbrn (talk) 09:26, 11 May 2017 (UTC)
 * But that is not what the statement says at all. It's about recommending it to prevent diseases. Compare:
 * no clear justification exists for recommending vitamin D
 * vs
 * there is little justification for prescribing vitamin D supplements to prevent myocardial infarction or ischaemic heart disease, stroke or cerebrovascular disease, cancer, or fractures, or to reduce the risk of death in unselected community-dwelling individuals
 * I'd like a quote from any serious doctor that Vitamin D is useless. Might as well delete Vitamin D deficiency and all stay indoors then. Bataaf van Oranje (Prinsgezinde) (talk) 10:36, 11 May 2017 (UTC)
 * It didn't say useless as such, but I have expanded the wording to close down any misuderstanding. Alexbrn (talk) 12:24, 11 May 2017 (UTC)
 * A - The lead misrepresents the Lancet ref (currently #8). The conclusion of the abstract of the article is: "Our findings suggest that vitamin D supplementation with or without calcium does not reduce skeletal or non-skeletal outcomes in unselected community-dwelling individuals by more than 15%." The 15% part of this is included in the research section, but not in the lead. I also have concerns that the 15% was an arbitrary criteria on the part of the authors. I have not read the article, so perhaps the rationale is justified by the authors. Secondly, if I go to PubMed and type in vitamin D, limited to meta-analyses, the search yield is 620 articles. Surely, some of these reach valid conclusions in support of vitamin D, and perhaps deserve mention over one negative conclusion evaluation. David notMD (talk) 18:49, 17 May 2017 (UTC)
 * A - The lead misrepresents the Lancet ref (currently #8). The conclusion of the abstract of the article is: "Our findings suggest that vitamin D supplementation with or without calcium does not reduce skeletal or non-skeletal outcomes in unselected community-dwelling individuals by more than 15%." The 15% part of this is included in the research section, but not in the lead. I also have concerns that the 15% was an arbitrary criteria on the part of the authors. I have not read the article, so perhaps the rationale is justified by the authors. Secondly, if I go to PubMed and type in vitamin D, limited to meta-analyses, the search yield is 620 articles. Surely, some of these reach valid conclusions in support of vitamin D, and perhaps deserve mention over one negative conclusion evaluation. David notMD (talk) 18:49, 17 May 2017 (UTC)


 * Flawed straw man medical research: Assume that some compound X (say vitamin D, or broccoli for that matter) or some activity (say exercise) could be involved in disease Y. Then do some research to find out (using state of the art rigorous methods) if there is a causal relation between X (and only X, so you eliminate confounding factors as best as you can) and Y. Then the research results lead to the astonishing results that X is not causally related to Y. The media who had made a big deal about X being healthy because it could prevent Y, goes berserk; we don't need to bother about X as it is not related to deadly disease Y.


 * The right way to go about this is to start with a proper Bayesian methods where prior information is taken into account properly. So, if a drug company has synthesized a compound X that is not normally involved in human biology to cure heart disease then it's proper to test X by assuming he null hypothesis that X has no effect on heart disease and see if this null hypothesis can be ruled out. Even though you are then neglecting some of the prior information from any trials the drug company may already have done on heart disease, the focus on heart disease itself constitutes prior information that is properly being dealt with. But vitamin D, broccoli and exercise cannot be assessed in an analogous way, because these are natural things that are hard wired into the body. If we have lack of knowledge about this then the same sort of hypothesis testing that's useful to evaluate the efficacy of drugs won't work well, because a priori you don't know what to look for.


 * Example. Suppose that vitamin D at high dosages helps with recuperation from heavy exercise, allowing people to exercise harder and get to a very good cardio fitness that then greatly reduces the probability of getting heart disease. But suppose that a precise breakdown of how exactly this comes about would reveal that in theory you could reach the same fitness without vitamin D and then you would have even greater benefit because vitamin D has a slightly negative effect on the heart. But it's then also clear that in practice you would have great difficulties getting there without taking high vitamin D dosages. So, taking vitamin D and exercising hard will lead to a lower probability of heart disease, taking vitamin D and keeping your fitness at couch potato level will lead to a slightly higher probability of heart disease. Then any conventional double blind test with sufficient statistical power will reveal the "shocking truth" that vitamin D causes heart disease and the FDA would move quickly to ban vitamin D supplements. Count Iblis (talk) 20:07, 17 May 2017 (UTC)


 * Agree with the premise. Thing is, the extent of certain Vitamin D effects are vague while some of them are quite factual. Does anyone dispute that it is harmful to bone mineralization and may lead to such problems as rickets, osteomalacia and osteoporosis, meaning that a deficiency would be harmful? Calling its effects uncertain would blur these truths as well. But I'm happy with the changes. As long as it doesn't sound like only "it probably does nothing special". Bataaf van Oranje (Prinsgezinde) (talk) 11:26, 18 May 2017 (UTC)

The article still feels oddly unbalanced. The general tone of most of the article is that vitamin D doesn't do very much apart from building bones and that supplementation has no meaningful effect. However, the guidlines section towards the end of the article cites several national public health bodies as saying a large proportion of their populations are vitamin D deficient and recommending supplementation, particularly in the winter. Wikipedia medical articles are generally of a high standard and it's confusing to the general reader to find these mixed messages. I can't help suspecting that somebody has a axe to grind here. --Ef80 (talk) 15:18, 22 November 2017 (UTC)
 * Vitamin D has an effect which the article makes clear with sentences like "Vitamin D has a significant role in calcium homeostasis and metabolism" and the whole section on deficiency.
 * Supplementation however does not appear to have any greater benefit for most people. The guidelines recommend "Adequate calcium and vitamin D, as part of a well balanced diet" not supplementation.


 * Yes many find this confusing. Doc James  (talk · contribs · email) 07:20, 23 November 2017 (UTC)


 * We'll have to wait and see until the results of large scale RCTs that are currently being performed are concluded. E.g., next year the VITAL study that started in 2010 will report its result conducted with 25,874 people with women aged aged 55 or more and men 50 years or older with no history of heart attacks, strokes or cancer. Count Iblis (talk) 08:47, 23 November 2017 (UTC)
 * While I dislike the supplements industry as much as anybody, there is a dominant view that people living in Canada, northern Europe, northern Russia etc. receive suboptimal amounts of vitamin D from UVB exposure, particularly if they stay indoors a lot or wear a lot of clothing. It's all very well to tell people to eat lots of salmon and mackerel, but most won't for a number of reasons. Both RCTs and epidemiology studies are difficult to conduct in this area. I still feel that the article is pushing an agenda (supplements=BAD!) rather than taking a balanced view of the subject. --Ef80 (talk) 19:54, 23 November 2017 (UTC)
 * Please provide evidence from high quality sources per WP:MEDRS (NIH, CDC, WHO, review articles from major journals)
 * I can be convinced by good sources. Doc James  (talk · contribs · email) 23:27, 24 November 2017 (UTC)

Statistical mistake?
A series of articles/citations, generally traced back to, seem to claim that a) the US IOM recommendation used standard deviation wrong and b) the daily intake required to meet the 2SD level would have been much higher than what is currently recommended. I guess we will need to wait for some better sources on this. --Artoria2e5 contrib 07:07, 8 December 2017 (UTC)
 * Turns out I am bringing in Talk:Vitamin D/Archive 6 again. Really nothing new under the sun, which also helps you produce Vitamin D. Might be good to really add a dissenting opinions section though. --Artoria2e5 contrib 07:11, 8 December 2017 (UTC)

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Big dose (e.g. 3800 IU/day) of Vitamin D2 is very harmful for human health
https://medicalxpress.com/news/2014-01-vitamin-d2-poor-choice-athletes.html

"Taking vitamin D2 supplements decreased levels of vitamin D3 in the body and resulted in higher muscle damage after intense weight lifting.

During the double-blind study, one group of athletes consumed 3,800 international units (IU) a day of a plant-based vitamin D2. The other group of athletes took a placebo".

ee1518 (talk) 11:09, 21 January 2018 (UTC)
 * If/when this is covered in decent WP:MEDRS it can be included here, but the link above is to a new piece based on primary research in a not-terribly-good journal. Alexbrn (talk) 11:51, 21 January 2018 (UTC)

Vitamin D and HIV
This article says the following: "Deficiency has been linked to increased risk of viral infections, including HIV and influenza.[". It proceeds to quote three articles, two of which dealing directly or indirectly with HIV. In the article by Beard et al. the authors say clearly that the correlation between HIV and vitamin D is that vitamin D deficiency is frequently found among HIV-positive people. They also state that the nature of the correlation is unknown, and even quote studies suggesting that the vitamin D deficiency might be due to the anti-retroviral treatment with which affected people are engaged. This is to say that the study does not suggest the possibility that a lack of vitamin D may increase the risk of getting infected by the virus which, in my opinion, is what this sentence sounds like. The second study quoted in the article basically says the same things, namely that there is a correlation between being HIV-positive and having lower vitamin D levels, as well as saying that reduced vitamin D levels are associated with a faster progression from HIV to AIDS. Nevertheless, nothing is said about the likelihood of being infected with the virus according to one's vitamin levels.

All of this just to say that vitamin D deficiency does not seem to be linked to increased risk of HIV infection; it seems however that HIV-infected individuals are more prone to Vitamin D deficiency, and this may impact their quality of life. — Preceding unsigned comment added by Januoaxe (talk • contribs) 21:12, 13 February 2018 (UTC)

This article is out of date
There has been a flurry of research in this area recently. You might even call it "Vitamin D mania".

Another point of view: 5 years ago you went to Walmart and the standard dosage was 200IU(50% DV), and now I'm seeing 3000 IU(750% DV) on a standard bottle.

None of things is an endorsement of supplements though(especially since multivitamins in general are coming underattack - no exception for VIT D - especially for larger doses). However the excitement that vitamin D is causing right now is not presented in this article. — Preceding unsigned comment added by 2601:646:8782:32DF:E13F:1906:5A23:626F (talk) 17:07, 21 February 2018 (UTC)
 * Any WP:MEDRS sources? Alexbrn (talk) 17:09, 21 February 2018 (UTC)
 * The mobile IP user is reacting to a marketing trend in the vitamin D supplement industry, a case of WP:RECENTISM. The guidelines for recommended intake levels have been reviewed and updated within recent years by different countries and the EU, and are correctly presented according to accepted scientific fact in the Guidelines section. --Zefr (talk) 17:21, 21 February 2018 (UTC)

Lichen cholecalciferol in industrial production
Hello. Well, I don’t know what qualifies as “industrial production”, but here is a (primary, I know) source that shows cholecalciferol is extracted from lichen to produce commercial supplements (see section Ingredients). Grasyop ✉ 19:16, 2 April 2018 (UTC)
 * Not a good WP:SECONDARY source. We would need a review of industrial activity using lichen as a source significant in current manufacturing of vitamin D supplements. I'm unaware of such as source. --Zefr (talk) 19:32, 2 April 2018 (UTC)
 * Does this qualify? Grasyop ✉ 20:29, 2 April 2018 (UTC)

Using Vitamin C as model for section names and order
Vitamin C was recently upgraded to Good Article. Making changes here to match vitamin C for section names and order. For the moment, not adding or subtracting any content or citations. David notMD (talk) 12:07, 5 April 2018 (UTC)

Should we consider splitting into two articles: Vitamin D and Vitamin D supplements
Thank you for your work and rearrangement of this. The entry on Vitamin D is too bulky and needs more work. However this now gives relatively trivial data on RDA, dosages, supplements and food before encyclopedic facts such as synthesis and biochemical pathways. Is it time to split this into Vitamin D and Vitamin D supplements? Look at Iron supplements for a comparable article. Can you imagine putting this new order for iron? Have there been ever a consensus reached on such articles with biological and therapeutic aspects? I recall had views on this. What do others think?Jrfw51 (talk) 17:54, 5 April 2018 (UTC)
 * Also curious to hear from others. For the minerals that are also essential nutrients, some but not all, have a link to biology as a separate article (Magnesium, Magnesium in biology). Even if such a split exists, there is duplication of content. Someone editing one may not be aware of the other. Similarly, within the vitamins, there is Vitamin A and Retinol, Vitamin E and Tocopherol (and Tocotrienol); hypervitaminosis articles for A and D; vitamin deficiency articles for A, E, B12 and K. Using View history to get lengths for vitamins, I tally: A 63,400; C 128,400; D 121,600; E 78,100; K 69,200; Thiamine 36,900; Riboflavin 40,400; Niacin 59,500; Pantothenic 20,300; B6 32,100, Biotin 25,300; Folate 86,200; B12 82,200. (That's everything, not just readable prose.) The only ones that might exceed the Wikipedia almost-certainly-should-be-split length are vitamins C and D. And for now, the only one ranked Good Article is Vitamin C. My own preference is to aim for uniformity in section order and section naming. That way, non-scientists can view these vitamin articles and find the parts they want. David notMD (talk) 20:58, 5 April 2018 (UTC)
 * Non-scientists also include non-patients who may also be interested in the basic biology. Furthermore, many patients are interested in learning why a physician recommended a supplement, and hence would also be interested in basic biology. Because of conflicts between WP:MEDMOS/WP:PHARMMOS and WP:MCBMOS and disagreements on which should take priority, it often makes sense to split these types of articles. Boghog (talk) 11:51, 6 April 2018 (UTC)

Pathways for D2
Currently most pathways and mechanisms in this article are D3-centric. Should there be some words for ergocalciferol (D2) too? D2 appears to follow a pretty similar pathway for synthesis (sterol → previtamin → D2) and metabolism (25-OH thru CYP2R1, 1,25-OH thru CYP27B1, deactivaton by 24-hydroxylation), with minor differences currently noted in Ergocalciferol. Most of that can be just something along the lines of "Vitamin D2 follows a similar mechanism with X replaced by Y".

The pathway diagram might be a bit trickier to modify. I will open a talk there someday too.--Artoria2e5 contrib 23:50, 10 April 2018 (UTC)

Vitamin D and Influenza
There has been serious and significant scientific studies regarding vitamin D for the prevention and mitigation of influenza. The article does not reflect that.
 * The only review on this topic is [Sundaram ME, Coleman LA. Vitamin D and influenza. Adv Nutr. 2012 Jul 1;3(4):517-25. doi: 10.3945/an.112.002162. Review. ; .] Despite the provocative title, the article itself reports no evidence that vitamin D either prevents nor ameliorates symptoms of influenza. No newer reviews. No good clinical trials. David notMD (talk) 14:14, 5 April 2018 (UTC)
 * Have you seen this? 28202713 Not explicitly flu but all acute respiratory infections. High quality.Jrfw51 (talk) 17:54, 5 April 2018 (UTC)
 * It is an existing ref for the immune system section. David notMD (talk) 01:31, 11 April 2018 (UTC)

Agarwal and Stout references

 * Bicknell and Prescott, 1946
 * Carpenter and Zhao, 1999

These are cited in https://web.archive.org/web/20060129105712/http://www.direct-ms.org/pdf/VitDVieth/Vieth%20Anthropology%20vit%20D.pdf for the idea of oils from the skin held in feathers/fur converting into vitamin D and then being orally consumed. I would like to cite them directly. Is anyone able to find copies online?

A common idea explored in other areas too:
 * http://www.maureenwilliamsnd.com/articles/vitaminD.html
 * https://healthypets.mercola.com/sites/healthypets/archive/2014/05/09/dog-vitamin-d-levels.aspx

Guessing 1946 would be when they disocvered it. ScratchMarshall (talk) 19:04, 24 April 2018 (UTC)
 * Nothing wrong with citing Vieth 2003, especially as unlikely to get complete PDFs for the older citations. David notMD (talk) 20:49, 24 April 2018 (UTC)

Multiple sclerosis revised
The addition of the Thomas systematic review (2018) as a citation is valid, but it and the 2013 and 2014 citations - quotes in the refs taken from the abstracts of the articles - still do not conclusively support vitamin D as a therapy for MS. David notMD (talk) 14:29, 1 August 2018 (UTC)