Nobody has to do what their doctor says but after surviving a massive stroke, I researched everything about the damage that was done to my kidneys, brain, limbs and general health. My neurologist and pcp agreed with the Renal Specialist to take the vitamin D as well as BP meds to avoid another aneurysm attack that this time would finish me off. The neurologist explained that when you are 50 and have a brain aneurysm rupture, they will put you in a drug induced coma with hopes you can recover but will not at my age now of 71. I understand this and try to take care of myself as well as I can to avoid more problems.