Again, duh. But, for those with malabsorption (because of celiac disease, gastric bypass, whatever), taking a supplement makes sense as the low vitamin levels are due to the inability to absorb properly so higher intake should be performed to compensate. Moreover, low vitamin D maternally has some impacts on fetal development that last into preschool age one should not rule out that vitamins might be a good thing for mothers and mothers to be.
