I believe that vitamin D deficiency have something to do with the seasonal flu. I thought it was so strange that Mexico with all that sun should be hit so hard.
Then it hit me; could pollution in general (in the sky or/and in the skin/body)inhibit vit D production? Several people at this forum has told about having low vit. D , even if adequate time is spent outside.
"In Mexico City children rarely use the color blue when they paint the sky. The atmospheric pollution in the Mexican capital, one of the world's biggest cities, is one of the most severe air pollution cases in the world."
Just in case; I am upping my vit D with sunshine and D3 supplements.