Problem: Choose the conclusions reached relating to vitamin D, calcium, or combined supplementation for the prevention of fractures in adults. More than one answer may be correct. Multiple select question. Calcium supplements from dolomite, bone meal, coral, or oyster shell are considered the safest for calcium supplementation. Current evidence is insufficient to assess the benefit or harm of vitamin D and calcium supplementation, alone or combined. Supplementation of less than 400 IU for vitamin D and less than 1000 mg for calcium may be recommended for people with a risk for osteoporosis. Current evidence is insufficient to recommend daily supplements greater than 400 IU for vitamin D or 1000 mg for calcium. Need Assignment Help?