Talk:Calcifediol

Untitled
Calcidiol does not promote bone and teeth mineralization directly. Calcidiol is converted to calcitriol which actually promotes bone DE-mineralization as well as increased uptake of calcium into the bloodstream. Because of this, people with calcidiol converted rapidly into calcitriol are assumed to be 'deficient' when they may simply have an infection which upregulates TLR-4 leading to upregulation of CYB27B1 which converts calcidiol -> calcitriol.

In this model, high calcidiol is an indicator of health, not a cause of it.

High levels of 1,25D3 (calcitriol, which is produced from calcidiol) are associated with increased risk of heart disease as high blood calcium leads to calcification of soft tissues. Vitamin K2 (Menaquinone) is capable of blocking the effect of bone demineralization caused by calcitriol, as the Rotterdam study indicates.

--Ryan Wise (talk) 23:02, 1 November 2008 (UTC)

25(OH)D
The reference given, http://www.chem.qmul.ac.uk/iupac/misc/D.html (or its PDF equivalent, http://www.iupac.org/publications/pac/1982/pdf/5408x1511.pdf) doesn't mention 25(OH)D anywhere... CielProfond (talk) 20:56, 20 June 2012 (UTC)

Article about identification process says nothing about who uses it.
This article is not a survey about whether "physicians worldwide" (trust this test), and that is not a valid indicator of reliability in the test, anyway, so I want to say something else. Also, the pubmed version has no abstract, so maybe we should be linking to jama. 70.74.198.226 (talk) 00:34, 3 March 2015 (UTC)

Availability at pharmacies at different countries?
And availability at hospitals?

Regular vitamin D is of course available everywhere, but can one buy Calcifediol tablets or softgels with or without a prescription in some countries?

--91.159.184.159 (talk) 13:13, 4 October 2020 (UTC)

Medical use and cost
Since it looks like there is a possibility that this might be the cure for active COVID-19, it would be good if there was discussion about the use of this chemical as a medicine, and a statement of its cost both injectable and oral both domestically and internationally. Aragorn 01:11, 8 October 2020 (UTC) — Preceding unsigned comment added by Jkshrews (talk • contribs)

Treatment for covid
There have been several new studies on VD3 treatment for Covid. On presentation to hospital those who received it 2% went to ICU those that did not 50% ended in ICU None died compared to 7% of the placebo group! The other 3 studies of VD3 have all shown amazing results.--Cynthia BrownSmyth (talk) 10:57, 18 November 2020 (UTC)
 * The calcifediol study by Castillo is already described here. Hopefully others will add to our knowledge of how this could help. Jrfw51 (talk) 19:05, 18 November 2020 (UTC)

The more rapid actions of calcifediol
Zefr deleted content based on two sources, both reviews, PMID 29713796, PMID 32535032, by established scientists in good journals indicating that calcifediol (25-OH vitamin D) has a faster action than cholecalciferol.(vitamin D3) and is undergoing trials in COVID-19. All WP:MEDRS compliant. Please edit rather than removiing if you think I have misrepresented these sources. Jrfw51 (talk) 09:27, 20 February 2021 (UTC)

Conversion time of D3 to Calcifediol
Under the section of Biology: the following phrase occurs: "At a typical daily oral intake of vitamin D3, full conversion to calcifediol takes approximately 7 days." refers to the article: "25-Hydroxylation of vitamin D3: relation to circulating vitamin D3 under various input conditions" by Robert P Heaney et al. This study is a meta analysis of several including the following primary study: "Pharmacokinetics of a single, large dose of cholecalciferol" by Marium Ilahi  1, Laura A G Armas, Robert P Heaney. Please note: P Heaney is a co-author of both papers. This primary study was rejected by wikipedia article editor even though the referenced meta study referred directly by the wikipedia article is taken directly from the primary source. The only difference is the graph's baseline is moved to zero in the meta study paper. The meta study papers only adds additional interpretations old data.

I believe the above mentioned phrase misrepresents the meta-analysis and the primary study result and conclusions.

If you read the the meta-analysis paper it doesn't mention about anything to do with a "normal" daily dose of vitamin D3 being "fully converted" to calcifediol in 7 days. The meta analysis paper refers to is the primary study "Pharmacokinetics of a single, large dose of cholecalciferol" by Marium Ilahi et al. If you look at figure 1 of the meta analysis it indicates that level of calcifediol peaks at 7 days after the administration of large dose of vitamin D3. The level of vitamin D3 continues above baseline until day 14. It could be concluded that vitamin D3 continues being converted up to at least day 14. The implication is that although the calcifediol starts to decline after 7 days the initial large dose of vitamin D3 is still being converted to caclifediol after day 7. This conclusion can only be made for large doses of vitamin D3 not normal daily doses.

The important conclusion of the meta analysis paper is that 2000 IU per day from all sources of vitamin D3 is the optimum input for conversion to a stable calcifediol serum level.

The important conclusion of the the primary study actually concludes a very large dose (100,000 IU) of vitamin D3 is a safe and effective way to increase the serum level of calcifediol. The study could be used as guide to physicians for treating low serum calcifediol levels of vitamin D deficient patients for a duration of up to 2 months.

To summarize the two referred to papers don't support the phrase: "At a typical daily oral intake of vitamin D3, full conversion to calcifediol takes approximately 7 days." For the following reasons: (a) the primary study was talking about very large dosing of vitamin D3 of 100,000 IU at 50-100 times normal daily dosage, not normal daily dosage of 600-800 IU. (b) the serum level of calcifediol peaks at 7 days after initial administration of a very large dosage of vitamin D3. It doesn't discuss complete conversion of vitamin D3. Nor does it discuss complete conversion of a daily dose. (c) you cannot conflate very large dosages with normal daily dosages. Acute dosages may result in other mechanisms that result in the decreasing levels of serum vitamin D3. For instance vitamin D3 is fat soluble and a high level may result in significant storage in the fat cells of normal people. See the obesity section of Vitamin D deficiency Wikipedia entry. (d) at the normal daily dosages of vitamin D3 may convert to calcifediol quickly. It is possible that the liver has a specific capacity to convert small amounts (i.e. normal daily dose of 800 IU) of vitamin D3 to calcifediol much faster than very large amounts (i.e. 100,000 IU). An analogy is a bank teller can help one customer in 5 minutes but may take 8 hours to help 100 customers. (e) the meta-analysis paper suggests an average conversion rate of 1000 IU per day. Since the 1000 IU is near the recommended daily dietary intake, the daily dietary intake can be converted within 1 day not 7 days.

Given the above information, I suggest the phrase should be removed since it isn't supported by the referenced papers. Discussing the time conversion of large doses of vitamin D3 to calcifediol should only be done in the context of treating vitamin D deficiency. — Preceding unsigned comment added by 216.197.221.147 (talk) 06:49, 30 March 2021 (UTC)


 * Well spotted. Correction made to text.Jrfw51 (talk) 19:18, 2 April 2021 (UTC)