I pay attention to how much calcium I get each day. But I recently heard that  without enough vitamin D, my body can't make use of the calcium. Please explain.
D000328:Adult; D000367:Age Factors; D000368:Aged; D002118:Calcium / Q000008:administration & dosage*; D004032:Diet; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D014807:Vitamin D / Q000008:administration & dosage*
D014807:Vitamin D; D002118:Calcium