VITAMIN D
What is Vitamin D?
What Conditions has it been used to treat?
What is Vitamin D?
Vitamin D is fat-soluble like vitamins A, E and K are. You will often find it in an oil form if you take it as a supplement and it is sometimes derived from cod-liver oil.
Other names : Vitamin D3 (Cholecalciferol), Vitamin D2 (ergocalciferol).
Where is it found?
Vitamin D3 is referred to as the 'sunshine vitamin' because it can be synthesized in the skin from sunlight, in which case, it need not be obtained from food sources. No other vitamin acts in this way. It is also, in its active form, a hormone by the name of cacitrol.
Vitamin D2 is derived from fungal and plant sources, and is not produced by the human body. Vitamin D3 is derived from animal sources and is made in the skin when 7-dehydrocholesterol reacts with UVB ultraviolet light at wavelengths between 270–300 nm, with peak synthesis occurring between 295-297 nm.These wavelengths are present in sunlight when the UV Index is greater than 3. At this solar elevation, which occurs daily within the tropics, daily during the spring and summer seasons in temperate regions and almost never within the artic circles adequate amounts of vitamin D3 can be made in the skin after only ten to fifteen minutes of sun exposure at least two times per week to the face, arms, hands, or back without sunscreen. With longer exposure to UVB rays, an equilibrium is achieved in the skin, and the vitamin simply degrades as fast as it is generated.
In humans, D3 is as effective as D2 at increasing the levels of vitamin D hormone in circulation,[1]although others state that D3 is more effective than D2.[2] Vitamin D2 has less than 1/6th of the potency of Vitamin D3 for human nutrition, if that. However, in some species, such as rats, vitamin D2 is more effective than D3.[3] Both vitamin D2 and D3 are used for human nutritional supplementation, and pharmaceutical forms include calcitriol(1alpha, 25-dihydroxycholecalciferol), doxercalciferol and calcipotriene.
Vitamin D needs to go through two processes in order to end up as cacitrol - it firstly needs to go to the liver and then through to the kidneys.
Why is it needed?
Its main role is to regulate phosphorous and calcium which are two minerals. These minerals are responsible for hardening of bones and aid in normal growth and development.
Vitamin D works by stimulating the gut into absorbing calcium and also stimulates the kidneys into reabsorbing some calcium, that way, excess calcium need not be excreted through the urine and can be used when needed.
What happens if you are deficient?
If you become Vitamin D deficient then the body's regulation of phosphorous and calcium is affected, the body begins to produce an increased amount of a hormone which removes calcium from the bones.
The disease "rickets" which is normally seen in children rather than adults is the result of calcium deficiency due to vitamin D deficiency. Rickets in adults is called "osteomalacia" where the bones become so soft they can no longer support weight and start to bow and buckle.
Click here to read what conditions Vitamin D can treat.
Click here to read recent research on Vitmain D and the possible prevention of Multiple Sclerosis (MS)
References:
1. Holick MF, Biancuzzo RM, Chen TC, et al (March 2008). "Vitamin D2 is as effective as vitamin D3 in maintaining circulating concentrations of 25-hydroxyvitamin D". J. Clin. Endocrinol. Metab. 93 (3): 677–81. doi;10.1210/jc.2007-2308 PMID 18089691
2. Institute of Medicine. (2006) Dietary Reference Intakes Research Synthesis: Workshop Summary, p. 27. National Academies Press.
3. Coates, M. E. (1968). "Requirements of different species for vitamins. Proceedings of the Nutrition Society 27 (2): 143–148. doi:10.1079/PNS19680039. PMID 5755261. http://docstore.ingenta.com/cgi-bin/ds_deliver/1/u/d/ISIS/33840020.1/cabi/pns/1968/00000027/00000002/art00019/89A25EAB89BAB011116525855554705D47CC65A51B.pdf?link=http://www.ingentaconnect.com/error/delivery&format=pdf