Vitamin D
Vitamin D[1]is ahormone.It is asteroidwhich is made in the body under the right conditions. To make it, the body needssunlight,which acts on the lower layers of theskin.
However, if the body does not make enough, it can be found from food sources in tiny amounts.[1][2]In fact, many countries add it automatically to certain foods likemilk.[3]Supplements[1]can be easily found in mostdeveloped countries.
Vitamin D is afat-solublenutrient. This means that any portion not used immediately is stored infat tissuefor future use.
What it does[change|change source]
As a hormone, Vitamin D does many things in the body.[1]It was first discovered as the substance which could prevent and curerickets.It controls the levels ofcalciumionsandphosphatesin the blood, as well as calcium and magnesiumabsorptionin theintestines.It helpsbonesgrow and form. It is also good for theimmune system.
Different kinds[change|change source]
In total, there are 5 different forms, D1to D5.The most common ones are D2and D3(see images).
D3(also called cholecalciferol) is the kind produced by the body. It is also found naturally inmarineoils and inlanolin(oil fromsheep's wool), the most common source forsupplements.
D2(also called ergocalciferol) is produced byfungi.It is similar to D3,but not exactly the same.
Getting enough[change|change source]
D3is made in theskinfromcholesterol,and changed into a more active form by theliver.However, the skin will not make it unless enoughultravioletlight shines on it. Assunlightcontains ultraviolet light, getting enough sun is one way of getting enough D3.
Many things can keep the skin from making enough D3.Wintersunlight may be too weak.Melanin,which protects skin from damage, also keeps it from making D3,which is why people with darker skin are more prone to deficiency. Older people are also prone, because aging skin makes less D3,even with enough sunlight. Clothing, glass,sunscreens and sunblocksalso shield the skin from getting enough ultraviolet light to make D3.
It is hard to know how much supplemental Vitamin D, if any, is needed. Less than 25micrograms(1000IU) per day, but up to 100 mcg (4000 IU) per day is considered safe.[4]A recent panel of Vitamin D researchers concluded thatat least20-25 mcg (800-1000 IU) per day would help most adults.[5]
Few foods naturally contain much D3.Fish do, especially oily ones, such assalmon,sardineandmackerel.Many kinds ofediblemushroomscontain some D2,likeshiitake.Mushrooms grown in full sunlight tend to have more.
References[change|change source]
- ↑1.01.11.21.3World, Fitness (2021-06-26)."7 Astonishing Effects of Taking Vitamin D Supplements, Says Science".Medium.Archived fromthe originalon 2021-06-26.Retrieved2021-06-27.
- ↑"Vitamins and minerals - Vitamin D".nhs.uk.2017-10-23.Retrieved2021-04-27.
- ↑Norman A.W. 2008. From vitamin D to hormone D: fundamentals of the vitamin D endocrine system essential for good health.The American Journal of Clinical Nutrition.88(2): 491S–499S.[1]
- ↑"DRIs for Calcium and Vitamin D - Institute of Medicine".Archived fromthe originalon 2010-12-24.Retrieved2013-08-16.
- ↑Dawson-Hughes, Bess; Heaney, Robert P.; Holick, Michael F.; Lips, Paul; Meunier, Pierre J.; Vieth, Reinhold (1 July 2005)."Estimates of optimal vitamin D status".Osteoporosis International.16(7): 713–716.doi:10.1007/s00198-005-1867-7.PMID15776217.S2CID5430507– via PubMed.
Other websites[change|change source]
- Benefits and sources of Vitamin DArchived2012-01-10 at theWayback Machine
- Benefits of Vitamin DArchived2019-04-07 at theWayback Machine
- Factsheet on Vitamin D
- FDA takes Vitamin D drugs and feeds them to prisonersArchived2007-03-28 at theWayback Machine