If you're in a blue or turning-blue area--anywhere except the South and Southwest--in November, you're not going to get much
UVB sunlight to make vitamin D.
Most people either thought the SPF was an indication of levels of protection from both
UVB and UVA or simply did not know what the rating stood for.
Sunscreen prevents sunburn by blocking
UVB light, so theoreti cally, sunscreen use lowers vitamin D levels.
This is a particular problem during winter because the useful
UVB rays are filtered out and don't reach us.
Though it prevents
UVB from penetrating your skin, studies of sunscreen's effects in practice have shown that its adverse influence on vitamin D are minimal.
These secretions, distributed on the feathers through preening, are photoconverted under
UVB exposure to the active form of vitamin [D.
Sunscreen products offer protection against
UVB and UVA radiation.
The sun-blocking clothing industry has developed its own voluntary standards that show such clothing can effectively block more than 97 percent of both UVA and
UVB rays.
To understand the factors that contribute to low levels of vitamin D, first know that of the two ultraviolet (UV) forms of radiation that reach our skin--UVA and
UVB--it's
UVB that produces vitamin D.
TRY Jane Iredale's Powder- Me SPF 30 - An all-over face and body powder with protection from
UVB and UVA rays, pounds 34, stockists 020 8450 7111 or www.
The mice without caspase-14 had skin that was shiny and wrinkled from dehydration due to the loss of water via the skin and was also highly sensitive to damage from
UVB radiation.
Differential regulation of hyaluronan metabolism in the epidermal and dermal compartments of human skin by
UVB irradiation Averbeck M, Gebhardt CA, Voigt S, Beilharz S, Anderegg U, Termeer CC, Sleeman JP, Simon JC J Invest Dermatol, 2007, 127, 687-697
