I just turned 50,in good health and want to stay that way.I have heard I should change my daily multivitamin. How much, daily should I take of these: vitamin d, calcium,magnesium vitamin a, omega 3 dha, do I need to take any type of vitamin b or b12? And is there a multivitamin out there that has enough of everything, so I am not taking a handful of pills everyday. I do understand omega 3 is by itself. Thank You for the help. Shannon H.