It can also be produced in the skin following exposure to ultraviolet (UV) radiation from the sun. Foods such as fish, beef liver, eggs, and cheese naturally contain vitamin D3. Moderate sun exposure is sufficient to produce enough vitamin D 3, assuming otherwise good health and nutrition. Vitamin D3 ( cholecalciferol) has a few health benefits, including helping the body absorb calcium. Vitamin D binding protein ensures that synthesis proceeds as efficiently as possible.Īt temperatures at or near body temperature, the reaction can proceed for around three days, continuing even after sun exposure ends. If D 3, the product of the isomerization, becomes overconcentrated, the reaction may be forced into equilibrium, stopping vitamin D 3 synthesis. To keep the reaction going, a protein -the descriptively named vitamin D binding protein -binds to the newly created vitamin D 3 and transports it into the blood, via capillaries located where the epidermis meets the lower skin layer, the dermis. The final stage, isomerization, or converting preD 3 into vitamin D 3 is dependent on the temperature within the skin.
Ultraviolet B radiation (wavelength 280-315 nanometers) penetrates through the skin, converting 7-DHC into an isomer -same chemical formula, but different spatial configuration of atoms -of vitamin D 3 called preD 3. Vitamin D synthesis begins with 7-dehydrocholesterol (7-DHC), a molecule present throughout the skin but most highly concentrated in the lowest layers of the epidermis, the stratum basale and especially the stratum spinosum. Holick and colleagues that used rat skin as a model for human skin. The process was first detailed in a 1980 study by M. While vitamin D 3 can be obtained through diet, the human body synthesizes it through exposure to sunlight. Its absence leads to a variety of ailments, most notably the bent limbs and weak bones characteristic of rickets. Rosen of the Maine Medical Center Research Institute in Scarborough told Vox that "This is the largest and most definitive trial with long enough follow-up and substantial representation from minorities to be an excellent cross-section of Americans.Vitamin D 3 is essential to human health. The results of this study were published in the November 2018 issue of the New England Journal of Medicine. She is also a study director of VITAL, the single largest ongoing research study of its kind on the effects of vitamin D and omega-3 supplements across over 25,000 participants. is the chief of the division of preventive medicine at Brigham and Women's Hospital and professor of medicine and the Michael and Lee Bell professor of women's health at Harvard Medical School. We know that vitamin D is an important hormone that helps our digestive systems absorb calcium and phosphorus - and that it's a necessary nutrient for human health.īut it isn't nicknamed "the sunshine vitamin" for nothing - the sun is the best source of vitamin D.ĭr.
Account icon An icon in the shape of a person's head and shoulders.
0 kommentar(er)
