I have been talking 5,000 IU a day for two years. Blood work showed that I was very Vit D deficient.
Come to think of it, I have not had a cold or the flu during this time.
my wifes dr. put her on 4000 iu per day about 1 1/2 yrs. ago,
because of bloodwork. after reading this article i now know why.
Lets keep our fingers crossed!