@Joannie the truth is majority of the population are actually low in Vit D, it's not just BC, interesting, I was told this by many Specialists. They put me on Vit D after Chemo as it further depletes it. It was always recommended to me to not take any supplements during Chemo and to me made sense....chemo was killing everything so nothing was going to help 6 months on it. Once finished thats why they put you onto Vit D to bring levels up. x