vitamin d is produced in the body in vitamers.
where is vitamin d produced in the body?
vitamers
dark-skinned people living in low sunlight environments have been recorded to be very susceptible to vitamin d deficiency due to reduced vitamin d synthesis. a dark-skinned person requires about six times as much uvb than lightly pigmented persons. this is not a problem near the equator; however, it can be a problem at higher latitudes. for humans with dark skin in climates of low uvr, it can take about two hours to produce the same amount of vitamin d as humans with light skin produce in 15 minutes. dark-skinned people having a high body-mass index and not taking vitamin d supplements were associated with vitamin d deficiency. vitamin d plays an important role in regulating the human immune system and chronic deficiencies in vitamin d can make humans susceptible to specific types of cancers and many kinds of infectious diseases. vitamin d deficiency increases the risk of developing tuberculosis fivefold and also contributes to the development of breast, prostate, and colorectal cancer. the most prevalent disease to follow vitamin d deficiency is rickets, the softening of bones in children potentially leading to fractures and deformity. rickets is caused by reduced vitamin d synthesis that causes an absence of vitamin d, which then causes the dietary calcium to not be properly absorbed. this disease in the past was commonly found among dark-skinned americans of the southern part of the united states who migrated north into low sunlight environments. the popularity of sugary drinks and decreased time spent outside have contributed to significant rise of developing rickets. deformities of the female pelvis related to severe rickets impair normal childbirth, which leads to higher mortality of the infant, mother, or both. vitamin d deficiency is most common in regions with low sunlight, especially in the winter. chronic deficiencies in vitamin d may also be linked with breast, prostate, colon, ovarian, and possibly other types of cancers. the relationship between cardiovascular disease and vitamin d deficiency also suggest link between health of cardiac and smooth muscle. low vitamin d levels have also been linked to impaired immune system and brain functions. in addition, recent studies have linked vitamin d deficiency to autoimmune diseases, hypertension, multiple sclerosis, diabetes, and incidence of memory loss. outside the tropics uvr has to penetrate through a thicker layer of atmosphere, which results in most of the uvb reflected or destroyed en route; because of this there is less potential for vitamin d biosynthesis in regions far from the equator. higher amount of vitamin d intake for dark-skinned people living in regions with low levels of sunlight are advised by doctors to follow vitamin d rich diet or take vitamin d supplements, although there is recent evidence that dark-skinned individuals are able to process vitamin d more efficiently than lighter-skinned individuals so may have a lower threshold of sufficiency.
dark skin
a vitamin is an organic molecule (or related set of molecules) that is an essential micronutrient that an organism needs in small quantities for the proper functioning of its metabolism. essential nutrients cannot be synthesized in the organism, either at all or not in sufficient quantities, and therefore must be obtained through the diet. vitamin c can be synthesized by some species but not by others; it is not a vitamin in the first instance but is in the second. the term "vitamin" does not include the three other groups of essential nutrients: minerals, essential fatty acids, and essential amino acids. most vitamins are not single molecules, but groups of related molecules called vitamers. for example, vitamin e consists of four tocopherols and four tocotrienols. the thirteen vitamins required by human metabolism are: vitamin a (as all-"trans"-retinol, all-"trans"-retinyl-esters, as well as all-"trans"-beta-carotene and other provitamin a carotenoids), vitamin b (thiamine), vitamin b (riboflavin), vitamin b (niacin), vitamin b (pantothenic acid), vitamin b (pyridoxine), vitamin b (biotin), vitamin b (folic acid or folate), vitamin b (cobalamins), vitamin c (ascorbic acid), vitamin d (calciferols), vitamin e (tocopherols and tocotrienols), and vitamin k (quinones).
vitamin