Talk:Vitamin D

Production from sunlight

I What to add this two sections Production from sunlight and Absorption in the body from the sun. I have tried after best ability to follow WP:MEDRS.

To convey the difficulties, with getting vitamin D from the sun. And that getting vitamin D from sun/previtamin D is a different from supplement.

Production from sunlight

Finse: 60°N and 1220 m AMSL
Oslo, Bergen 60°N and 0 m AMSL,
Tromsø 69°N and 0 m AMSL,
Ny-Ålesund 78°N and 0 m AMSL.
Maximum UV index and how it varies throughout the year in Norway.

To produce Vitamin D, UVB light is required. To have sufficient light containing UVB, the UV index needs to be 3 or higher (≥45 solar zenith angle at sea level). Vitamin D production is maximal at one-third of the minimal erythemal dose. When UV exposure increases to a minimal erythemal dose, vitamin D synthesis stops. One must be south of latitude 50°N to produce vitamin D around the Winter solstice.

Number of minutes at different UV levels to achieve sufficient monthly needs

SKIN REACTION TO SUNLIGHT	UV INDEX
	0-2	3-5	6-7	8-10	11+
Skin type I: Always burn, never tan	56-∞	10-15	5-10	2-8	1-5
Skin type II: Burn easily, rarely tan	80-∞	15-20	10-15	5-10	2-8
Skin type III: Occasionally burn, slowly tan	90-∞	20-30	15-20	10-15	5-10
Skin type IV: Rarely burn, rapidly tan	140-∞	30-40	20-30	15-20	10-15
Skin type V & VI: Very rarely burn, always dark	180-∞	40-60	30-40	20-30	15-20

The table assumes that one is outdoors in sunlight for more than 3 times a week, wearing only swim trunks and a t-shirt or swimsuit, and has not applied sunscreen. Such exposure to the entire skin surface corresponds to receiving between 250–1250 μg of vitamin D (10k to 50k IU) per session, or a similar amount as obtained by consuming 125–500 ml of cod liver oil (200μg/100ml).

The "summer level" decreases to "winter level" within 6 to 8 weeks after insufficient sun exposure, without supplementation.

Barriers to UVB absorption:

• Sunscreen
• Clothing covering a larger area
• Overcast skies
• Staying in the shade
• Insufficient UV index.

Preparation for nominating for GA

Reviewing all references for compliance with WP:MEDRS, old versus new editions, old and potentially replacable by more recent, duplications, etc. David notMD (talk) 09:11, 21 November 2024 (UTC)

There quite a lot of times the articles fails to WP:MEDSAY. Bon courage (talk) 09:16, 21 November 2024 (UTC)

I agree, and will attempt to address that as part of my review process. David notMD (talk) 09:38, 21 November 2024 (UTC)

The closer I look, the worse it looks (including that there were two bone health sections, now consolidated). David notMD (talk) 03:41, 22 November 2024 (UTC)

Either copying or moving sections to my Sandbox to edit there, and then return to article. Example: History. David notMD (talk) 12:05, 23 November 2024 (UTC)

Moved COVID-19 to Health effects and removed WP:MEDSAY text. Need to check for new lit on government or non-gov organizations issuing statements on D and COVID. David notMD (talk) 14:26, 23 November 2024 (UTC)

Completely rewrote Excess section and moved to after Deficiency. David notMD (talk) 14:16, 27 November 2024 (UTC)

You're doing a great job reviewing this for the GA nomination. Thanks. However do you think the section of Excess should be longer than the one on Deficiency? The magnitudes of these problems is very different. I think the current version has lost the problem of incorrect measurement/contamination as a cause.Jrfw51 (talk) 18:07, 27 November 2024 (UTC)

Jrfw51 I addressed Excess first because I thought the quality was worse that Deficiency, but D definitely needs work!!! I expect Vitamin D deficiency will provide useful content and references. David notMD (talk) 23:38, 27 November 2024 (UTC)

Working on the Evolution section and last paragraph of Lead. The entire Lead will likely need work after all the other content is revised. David notMD (talk) 13:18, 4 December 2024 (UTC)

Added paragraph to History on cod liver oil as treatment for rickets predating identification of vitamin D as the active by 100 years. David notMD (talk) 09:28, 6 December 2024 (UTC)

Addod three images and removed a global map image. David notMD (talk) 03:56, 8 December 2024 (UTC)

Jrfw51 Almost ready to replace the Deficiency section, with some references removed and others added. David notMD (talk) 06:28, 17 December 2024 (UTC)

Replaced Deficiency and Fortification sections David notMD (talk) 19:58, 20 December 2024 (UTC)

Infobox

The vitamin D Infobox is short compared to other vitamins. Is there anyone comfortable with chemical compound infoboxes who can address this? David notMD (talk) 13:11, 24 November 2024 (UTC)

Other vitamin D related articles

As this article is revised toward the goal of nominating it for Good Article, there are vitamin D related articles that may be sources of content and references, and may also need revisions based on newer references identified during this GA effort: Vitamin D deficiency, Vitamin D toxicity, Vitamin D deficiency in Australia, Vitamin D receptor, Vitamin D response element, Vitamin D and neurology, Vitamin D and respiratory tract infections, Vitamin D5, Vitamin D analogues, Vitamin D and Omega-3 Trial, Calbindin, Cholecalciferol, Ergocalciferol, Calcitrol, 7-Dehydrocholesterol reductase and 22-Dihydroergocalciferol. Cod liver oil is also related. David notMD (talk) 13:17, 29 November 2024 (UTC)

While Wikipedia frowns on using individual clinical trials as references (see WP:MEDRS), it allows for articles ABOUT individual clinical trials. In addition to the Vitamin D and Omega-3 Trial (VITAL), see Selenium and Vitamin E Cancer Prevention Trial (SELECT) as another. David notMD (talk) 13:39, 29 November 2024 (UTC)