D Redux

clipped from www.msnbc.msn.com "When a T cell is exposed to a foreign pathogen, it extends a signaling device or 'antenna' known as a vitamin D receptor, with which it searches for vitamin D," said Carsten Geisler of Copenhagen University's department of international health, immunology and microbiology, who led the study. "This means the T cell must have vitamin D or activation of the cell will cease. If the T cells cannot find enough vitamin D in the blood, they won't even begin to mobilize." "What we didn't realize is how crucial vitamin D is for actually activating the immune system — which we know now," Geisler wrote in the study in the journal Nature Immunology. Most Vitamin D is made by the body as a natural by-product of the skin's exposure to sunlight. It can also be found in fish liver oil, eggs and fatty fish such as salmon, herring and mackerel, or taken as a supplement. Almost half of the world's population has lower than optimal levels of vitamin D and scientists say the problem is getting worse