Abstract
The 2011 Institute of Medicine recommendations for vitamin D-both the recommended daily amount (RDA) and the vitamin D status judged adequate for bone health-are too low. Calcium absorption, osteoporotic fracture risk reduction, and healing of histological osteomalacia all require values above 30 ng/ml, and probably even 40 ng/ml. Furthermore, the proposed RDA (600 international units per day up to the age of 70) is not compatible with the blood level of 25-hydroxyvitamin D (i.e., 20 ng/ml) recommended in the same report. Concerns regarding adverse consequences of higher intakes or status levels can be dismissed, in view of our extensive experience with outdoor summer workers (who regularly have values of 60 ng/ml or more) and the virtual certainty that human physiology evolved in-and is attuned to-an environment providing 10,000 IU/day or more.