回复：是不是40就应该开始补钙? 哪种钙比较合适?

actually, we should 补钙 as early as possible due the the change of our life style and food supply. However, 补钙 must use pharmaceutical grade with organic Ca, Mg, VD and other micro elements in certain ratio to avoid side effect on your heart/blood vessel. send your email to me by 悄悄话 if you need more info