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
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
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
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