good read on Vit D. I know a few posters swear by sunlight or supplements. here is a mechanism for a possible explanation. It puts some science behind the anecdotal stories.
“Right now we believe that 1 alpha, 25-dihydroxy vitamin D3 downregulates pro-inflammatory cytokines including interleukin 12, interleukin 2, and interferon gamma, and that it enhances cytokines that inhibit inflammation, including interleukin 4 and interleukin 10,” explained Christakos.
it also appears to act as an anti-inflammatory agent by downregulating the activity of cyclo-oxygenase II (COX-II), the critical enzyme for synthesis of inflammatory prostaglandins,
Source a December 2007 article so new research. Vit D andf inflammation