so we've all read about the fact that without vitamin D we don't absorb calcium like we should; but how about low serum Vit D levels = losing muscle mass,
not performing as well, not having as good a sense of balance? how about it might protect you from the flu?

http://www.vitamindcouncil.org/newsl...2007-mar.shtml

"So the level of vitamin D (50 ng/mL) associated with peak athletic performance is the very same level that recent studies show also helps to prevent cancer, diabetes, hypertension, influenza, multiple sclerosis, major depression, cognitive decline, etc. But who cares about all that disease stuff old people get! We're talking about important stuff here: speed, balance, reaction time, muscle mass and strength, squats, reps. As for my young basketball player, guess who's now taking 5,000 IU vitamin D a day? That's right! And his 25-hydroxyvitamin D level is now 54 ng/mL. Has this improved his game? Well...he said to me he feels his timing is better, can jump a little higher, run faster and...oh yeah! and that the ball feels "sweeter"—whatever that means."