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D-vitamiini


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#51 Blueteam

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Lähetetty 04 toukokuu 2012 - 13:54

Life Extensionin suositushan on 125 nmol/l. Lisäksi toteavat, että yli 200 nmol/l ei kannata mennä.
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#52 Panu

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Lähetetty 04 toukokuu 2012 - 18:32

Life Extensionin suositushan on 125 nmol/l. Lisäksi toteavat, että yli 200 nmol/l ei kannata mennä.


Bill sanoo tuossa näin:

"Based on a large volume of published data, we recommended that the optimal range of 25-hydroxy-vitamin D to protect against disease is between 50–80 ng/mL"

ja näin:

"We nonetheless continue to recommend that members keep 25-hydroxyvitamin D levels below 100 ng/mL."

eli suosituksen alaraja 125 nmol/l ja yli 250 nmol/l ei kannattaisi mennä. Ehkä jossain muualla LEF kertoo muuta.

#53 Panu

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Lähetetty 05 kesäkuu 2012 - 10:39

Yhä alhaisempaa suositusta pukkaa tutkimuksista:

The lowest mortality risk was at 50–60 nmol/liter.


140 nmol/liter liittyi 42% suurempaan kuolleisuuteen.

http://jcem.endojour...2-1176.abstract

Ensimmäiseksi tulee mieleen, että tuo assosiaatio voi johtua liiasta/vääränlaisesta auringonottamisesta, jolloin nuo kuolemat johtuisivat melanoomasta.

#54 Blueteam

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Lähetetty 05 kesäkuu 2012 - 10:42

^Tuossa voi kuitenkin olla se sama juttu, että Tanskassa korkean arvon omaavilla arvot heittelee rajusti eri vuodenaikoina.

Lisäksi sanottiin:

The study did not allow inference of causality, and further studies are needed to elucidate a possible causal relationship between 25(OH)D levels, especially higher levels, and mortality.


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#55 Panu

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Lähetetty 05 kesäkuu 2012 - 22:35

Tässä näkyy liian auringon vaikutus ihoon, tosin ikkunan läpi eli vain UVA:n:

http://www.iltasanom...8474654948.html

Ehkäpä UVB taas tekee ihosta sileän :)

#56 Neonomide

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Lähetetty 13 kesäkuu 2012 - 00:28

Noiden elinennustekohorttien sekoittava tekijä on myös etnisyys - sairausriskien ja kuolinennusteen nadirit vaihtelee jonkin verran sadan nmol/L molemmin puolin.

Kontrolloiduissa D-tutkimuksissa taas ongelmana voi olla, että mukana on mm. laitostunutta lonkkamurtumaporukkaa - suora näyttö terveiden elinvuosien lisäämisestä on vähän kortilla.

#57 Neonomide

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Lähetetty 13 kesäkuu 2012 - 00:30

^Tuossa voi kuitenkin olla se sama juttu, että Tanskassa korkean arvon omaavilla arvot heittelee rajusti eri vuodenaikoina.

Juuri näin, kausaalisuutta tutkivia projekteja on tekeillä jenkeissä ja meillä, mutta tuloksia joudutaan odottelemaan lähemmäs vuosikymmenen verran. Aiempiakin on, mutta täysin läppätason annoksilla. Tulokset sen mukaisia.

Niitä odotellessa ajattelin nappailla sen 50-100 nmol/L ja take my chances.

#58 Neonomide

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Lähetetty 13 kesäkuu 2012 - 00:35

Yhä alhaisempaa suositusta pukkaa tutkimuksista: 140 nmol/liter liittyi 42% suurempaan kuolleisuuteen.

http://jcem.endojour...2-1176.abstract

Ensimmäiseksi tulee mieleen, että tuo assosiaatio voi johtua liiasta/vääränlaisesta auringonottamisesta, jolloin nuo kuolemat johtuisivat melanoomasta.

Melanooma ei riitä, koska se on niin harvinainen sairaus (ja tappaa vain noin 20% sairastuneista 5 vuodessa). Sen sijaan tulosta voi selittää koko joukko tekijöitä, kuten auringonottoon tai jopa 25(OH)D-geeneihin assosioituvat riskialttiit elämäntavat jne.

D-vitamiinihan nostaa testosteronitasoja...

http://www.ncbi.nlm....pubmed/21154195

Ja korkea testo voi lisätä mm. itsevarmuutta, hyvänolontunteita ja riskinottoa. Lisäksi on toki muutkin auringon efektit, myös mielialaan.

#59 Panu

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Lähetetty 06 marraskuu 2012 - 10:34

Siirrellään taas Tiede-foorumilta:

These findings support an association between low vitamin D levels and familial longevity.


http://www.scienceda...21105130355.htm
  • Blueteam tykkää tästä

#60 Blueteam

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Lähetetty 09 marraskuu 2012 - 07:58

http://areena.yle.fi/tv/1726561

Suvi Virtanen ja Christel Lamberg-Allardt kovasti puolustivat tuossa näitä IOM:n kantoja:

http://www.iom.edu/~...eport Brief.pdf

IOM:kin toisaalta sanoo jo 100 mikrogramman annostakin turvalliseksi, vaikka suositukset ovat todella alhaisia. Ei vakuuttanut minua Virtasen ja Lamberg-Allardtin perustelut.

D-vitamiiniasiantuntijat tohtorit Heaney ja Holick myös tyrmäävät täysin IOM:n suositukset:

http://onlinelibrary...2/jbmr.328/full
"In the past two years, vitamin D supplement sales to consumers have increased by more than 100% per year.1 Now, following publication of the report2 on Dietary Reference Intakes (DRIs) for calcium and vitamin D by the Institute of Medicine (IOM), many physicians report that they are decreasing their vitamin D recommendations to patients. This change was explicitly proposed by members of the IOM panel in their various media statements. While a small fraction of consumers may well have all the vitamin D they need, on balance, we consider a general downward trend to be harmful to the health of the public.

Both the authors of this Perspective served as members of the panel that drafted the 1997 report of the IOM on the DRIs for calcium and vitamin D. That report was the first issued by the IOM under the then-new evidence-based guidelines for evaluating studies and making recommendations. We are thus familiar with the process and, most important, with vitamin D itself. On the basis of this experience, we respectfully dissent from many of the findings and recommendations in the current report, and we set forth here a small fraction of the reasons for that dissent.

The IOM report (and its presentation to the media) stressed that its recommendations for vitamin D were based primarily on the intake (and serum 25-hydroxyvitamin D concentration) needed to ensure skeletal health and that, in the panel's judgment, there was insufficient evidence to make any recommendations with respect to nonskeletal benefits, if any. Second, the report concluded that a serum level for 25-hydroxyvitamin D [25(OH)D] of 20 ng/mL was sufficient to ensure bone health. And third, the panel concluded that since the bulk of the American public had 25(OH)D values that were above 20 ng/mL, most individuals were getting all the vitamin D they needed and had no reason for further supplementation. These conclusions fail on three grounds: logic, science, and guidance.

First, logic. Since the panel, in its judgment, concluded that it did not know whether there might be nonskeletal benefits (or at what blood level they could be ensured), then it is patently incorrect to say that they know that people are getting enough. The most the panel could have said logically was, “Here's what you need for bone; most people get that much; we do not know whether more would confer possible nonskeletal benefits.” That, at least, would have been an honest communication of the state of the issue as the panel apparently understands it. However, to state publicly that the general public does not need more goes well beyond what the panel admits it knows.

Second, science. The statement that skeletal health can be ensured at serum 25(OH)D levels of 20 ng/mL is simply incorrect. Without going into an exhaustive recital of all the evidence pointing to a skeletal need for higher levels, we cite here three illustrative observations that, in our collective judgment, indicate that instead of 20 ng/mL, a serum level of 30 ng/mL is closer to the bottom end of the acceptable range for skeletal health. First, there is the large randomized, controlled trial in the United Kingdom that raised serum 25(OH)D level from 21 to 29 ng/mL and produced a 33% reduction in all major osteoporotic fractures combined.3 The fact that other trials, with less good compliance, failed to reproduce that effect does not negate the evidence of a well-conducted trial. Second, there are the many meta-analyses of Bischoff-Ferrari and colleagues4, 5 demonstrating that, taken overall, fracture reduction with vitamin D does not occur reproducibly below serum 25(OH)D levels of 30 ng/mL and for some fractures even 40 ng/mL. Finally, there is the demonstration, in a large German autopsy series (strangely misinterpreted by the panel), that osteoid seam width—the histologic hallmark of vitamin D deficiency—does not reach fully normal values until serum 25(OH)D levels are above 30 ng/mL.6 [N.B.: Of 33 patients with 25(OH)D values between 20 and 30 ng/mL, more than half (18) had elevated osteoid volume. A Recommended Daily Allowance (RDA), by definition, meets the need of 97.5% of the population.] In a closely related finding, investigators from South Australia7 showed seasonal variation in osteoid seam width and mineral appositional rate, reflecting variations in serum 25(OH)D precisely within the 20 to 30 ng/mL range, that is, above the IOM panel's “adequate” level.

Additionally, there is an apparent inconsistency between the recommended intake (600 IU/day for all individuals up through age 70) and the bottom end of the acceptable 25(OH)D serum concentration range (let alone higher values). As virtually universal experience with vitamin D supplementation demonstrates, 600 IU/day, if the body's sole input of vitamin D, would not be enough to produce a value of even 10 ng/mL, let alone 20 ng/mL or above. There is a generally recognized “rule of thumb” to the effect that each additional 100 IU of vitamin D per day raises serum 25(OH)D concentration by approximately 1 ng/mL. That is, in fact, a “rounding up” for convenience of calculation. Several studies indicate that the response increment is closer to 0.7 ng/mL/100 IU.8, 9 Either way, 600 IU/day will not suffice without appreciable solar and dietary input. Furthermore, as is also widely recognized, 600 IU/day produces barely perceptible changes in individuals who are overweight or obese (now better than 50% of the US adult population). Hence the increase from the 1997 DRIs, while welcome, and certainly in the right direction, is simply inconsistent with current professional experience. It not only is inadequate, by itself, to meet even the panel's recommended serum levels, but this internal inconsistency detracts from the credibility of the whole report inasmuch as it flies in the face of the everyday experience of clinicians who recommend supplements to their patients and measure the resulting responses.

Finally, guidance. At already noted, the panel indicated that it was uncertain about extraskeletal benefits—benefits that might accrue at intakes above the new intake recommendations. At the same time, the panel raised the upper-level intake “TUIL” to 4000 IU/day. (The report acknowledges that intakes up to 10,000 IU/day are probably safe for everyone and applied an uncertainty factor10 to that 10,000-IU figure to generate the 4000-IU TUIL. It is important to stress that the TUIL is not a limit but instead constitutes an assurance of safety for such an intake.) One should have thought that even a very simplistic game-theory approach would have led to a guidance statement such as the following: “We do not know whether taking more vitamin D than we are currently recommending will help you, but it could, and we can assure you that supplemental intakes up to at least 4000 IU/day are safe.” Such a statement, couched, perhaps, in less straightforward language, nevertheless would provide guidance that both the public and governmental agencies could find useful. Instead, we now have only a confused public.

Beyond these errors and inconsistencies, though, serious as they are, lies a much deeper flaw in the approach taken by the panel, exemplified by a quote from one of the panel members to the New York Times at the time of release of the report.11 The statement was simply that the “onus” (ie, burden of proof) fell on anyone who claimed benefits for intakes higher than the panel's current recommendations. This is an approach that is correct for drugs, which are foreign chemicals and which do carry an appropriately heavy requirement for proof. For drugs, the position of privilege is given to the placebo. And in the current IOM report, the privilege is given to a serum 25(OH)D level that is effectively the status quo. We judge that this is exactly backward for nutrients. The privilege instead must be given to the intake that prevailed during the evolution of human physiology, the intake to which, presumably, that physiology is fine-tuned. So far as can be judged from numerous studies documenting the magnitude of the effect of sun exposure,12, 13 the primitive intake would have been at least 4000 IU/day and probably two to three times that level, with corresponding serum 25(OH)D levels ranging from 40 to 80 ng/mL. The fact that primitive levels would have been higher than current IOM recommendations does not, of course, prove their necessity today. But such intakes should be given the presumption of correctness, and the burden of proof must be placed on those who propose that lower intakes (and lower serum levels) are without risk of preventable dysfunction or disease. The IOM, in its report, has utterly failed to recognize or meet that standard.

Finally, we commend the IOM panel for their concern about safety, certainly an appropriate posture for a body crafting public policy. However, the standards adopted by the panel for taking into evidence papers indicating possible risk were, we note, far lower than those the panel required to indicate benefit. Additionally, many of the purported risks were, on their face, implausible and inconsistent with the experience of population subgroups that routinely have serum levels in the range mentioned by the panel as possibly risky (eg, approximately 50 ng/mL). We note that one of the widely accepted Hill14 criteria for acceptance of observational data is precisely biologic plausibility. Furthermore, we consider it highly implausible that serum levels such as prevailed during hominid evolution could carry more risk than benefit for the populations concerned. Had that been the case, one should have expected that natural selection would have eliminated those prone to such risks.

In this Perspective, we have deliberately avoided a mind-numbing laundry list of the vast number of factual inaccuracies and misinterpretations in the report. We are informed that there is a request, through the Freedom of Information Act, to obtain the external review comments submitted to the IOM in response to a prepublication draft. When those materials become available, those interested can review the many problems with the IOM report in detail. For now, our recommendation to the American public is that the IOM report should be taken with a grain of salt (another nutrient the IOM finds risky)."
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#61 Blueteam

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Lähetetty 09 marraskuu 2012 - 08:04

Noi Suomen suositukset on vielä IOM:n suosituksiakin alhaisempia. :logik:
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#62 Panu

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Lähetetty 10 marraskuu 2012 - 15:26

Nyt vasta tajusin (Tiede-foorumia luettuni), että IOM siis tuossa pudotti suosituksensa >30ng/mL:sta >20ng/mL:aan. Ilmaskos D-vitamiinitohtorit ovat raivoissaan.

#63 Blueteam

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Lähetetty 24 tammikuu 2013 - 17:05

Diacorissa kävin testauksessa ilman lähetettä. Hinta oli 48 euroa. Laittakaa hintoja, jos olette käyneet jossain muualla. :)


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#64 Blueteam

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Lähetetty 30 tammikuu 2013 - 14:41

Tässähän oli optimiksi määritelty 90-100 nmol/l:

http://ajcn.nutritio...nt/84/1/18.long

 

Tässä taas syövän estoon arvioidaan optimiksi 90-120 nmol/l:

http://www.ncbi.nlm....pubmed/18348447

 

Tuo 100 nmol/l vaikuttaisi ihan hyvältä lukemalta. Mahdollisesti voisi olla vähän ylikin eli tuo 50 ng/ml(125 nmol/l). Itse pitäisin miniminä tuota 90 nmol/l. :)


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#65 Blueteam

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Lähetetty 29 kesäkuu 2013 - 06:55

Mielenkiintoinen D-vitamiinista riippumaton vaikutus UV-säteilyllä verenpaineeseen. Vaikutus kuitenkin aika pieni ja lyhytkestoinen. Verenpaineen saa myös alemmaksi muillakin keinoilla. Ei ainakaan minua tämä houkuttele ihon käryttämiseen. :)

 

http://www.nature.co...id2013104a.html

UVA lowers blood pressure and vasodilates the systemic arterial vasculature by mobilisation of cutaneous nitric oxide stores

D Liu,1 BO Fernandez,3 NN Lang,2 JM Gallagher,4 DE Newby,2 M Feelisch3 and RB Weller1,5 1Dermatology, University of Edinburgh, Edinburgh, United Kingdom, 2Cardiology, University of Edinburgh, Edinburgh, United Kingdom, 3Medicine, University of Southampton, Southampton, United Kingdom, 4Leithmount Surgery, Edinburgh, United Kingdom and 5Centre for Inflammation Research, University of Edinburgh, Edinburgh, United Kingdom

The incidence of hypertension and cardiovascular disease (CVD) correlates with latitude and rises in winter. Population vitamin D levels inversely correlate with CVD, but oral supplementation does not alter CVD rates. Skin contains large stores of nitrite(NO2) and nitrate(NO3). Nitrate is biologically inert, but can be photo-reduced to active NO2 and nitric oxide (NO). The dermal vasculature enables rapid systemic dispersal of NO2 and NO.We hypothesised that ultraviolet A (UVA) mobilises NO bioactivity from skin to circulation to exert beneficial cardiovascular effects. Vit’ D is a marker for sunlight exposure. 24 healthy volunteers were sham (temp’ control) irradiated then actively irradiated with 20 J/cm2 UVA. Mean arterial pressure (MAP) fell and heart rate rose during active but not sham irrad’n (3.50±0.73 mmHg vs 2.80±0.98). The MAP fall was sustained for 50 mins in the active group only. Temperature rise was the same in both groups. Circulatory nitrite rose (0.50±0.04 μM to 0.72±0.04 μM p<0.001) and nitrate fell (11.79± 0.64 μM to 8.99±0.40 μM (p<0.001)) during active, but not sham irradiation. There was no change in circulating vitamin D levels. 12 volunteers had forearm blood flow (FBF) measured by venous plethysmography while 8 μmol/min of the NOS antagonist L-NMMA was infused to the brachial artery. FBF rose during active but not sham irradiation (23.7±6.5 % over baseline vs no change p<.0002). Physiological levels of UVA irradiation cause systemic vasodilation and lower BP in a vitamin D and NOS independent manner. Deaths from CVD and stroke are 60 to 100 times higher than from skin cancers in northern Europe. This study provides a mechanistic explanation for the inverse correlation between sunlight exposure and CVD mortality. Sunlight has beneficial effects independently of vitamin D synthesis.


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#66 Panu

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Lähetetty 19 elokuu 2013 - 21:08

Tutkijalle oli yllätys, että D-vitamiini ei oikein imeytynyt kaikilla:

 

 

Tutkittavat söivät lumepillerin tai D-vitamiinia joko 40 tai 80 mikrogrammaa päivässä. Sen vaikutusta seurattiin verinäytteistä sekä rasvakudoksen geenien ilmentymisestä. Tulokset ilmestyivät Plos One -julkaisussa.

"Vaikutukset näkyivät puolella tutkittavista, mutta puolella ei", kertoo tutkimusta johtanut Itä-Suomen yliopiston professori Carsten Carlberg.

 

Onhan se toki yllättävää jos 25-OH-D ei nouse 80 mcg:llä päivässä. Heitän kuitenkin oman näkemykseni: tutkimuspillerit eivät tyypillisesti ole mitään öljykapseleita vaan kuivia jauhepillereitä. Osa otti pillerin rasvaisen aterian kanssa ja osa ei. Eli kuten LEF uusimmassa julkaisussaan sanoo:

 

Remember to take your vitamin D with the meal of the day that contains the most fat, as this greatly enhances vitamin D absorption.



#67 Panu

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Lähetetty 01 helmikuu 2014 - 13:35

Naistentautien ja synnytysten erikoislääkäri Hannu Vierola kommentoi Fogelholmille ja Schwabille:

 

Suomalaista suositusta 10 mikrog/pv raskaana oleville ei hyväksyttäisi edes kontrolliryhmän D annokseksi Yhdysvalloissa, koska se on liian alhaisena sikiölle ja äidille vaarallinen (Wagner, 2010, Bejerot, 2011)


#68 cgs

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Lähetetty 04 helmikuu 2014 - 01:20

Miten se voi olla vaarallinen USA:ssa, kun Suomessakin on synnytetty terveitä lapsia ilman mitään D-vitamiinilisiä?

Britanniassa näkyy olevan samat suositukset kuin Suomessakin: http://www.nhs.uk/Co.../Vitamin-D.aspx

#69 Panu

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Lähetetty 04 helmikuu 2014 - 17:50

Miten se voi olla vaarallinen USA:ssa, kun Suomessakin on synnytetty terveitä lapsia ilman mitään D-vitamiinilisiä?

Britanniassa näkyy olevan samat suositukset kuin Suomessakin: http://www.nhs.uk/Co.../Vitamin-D.aspx

 

Vaarallinen on varmaan väärä sana mutta ilmeisesti riskit pienenee isommilla annoksilla, ainakin joidenkin tutkimusten mukaan. Vierola tuntuu kyllä olevan D-vitamiinifanaatikko, on ottanut vahvasti kantaa muuallakin.



#70 cgs

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Lähetetty 11 tammikuu 2016 - 23:39

joku juttu D-vitamiinista: http://www.scienceal...-nothing-at-all

 

D-vitamiinilisistakin on siis enempi haittaa kuin hyotya?






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