Enhances bone mineralization, enables calcium absorption in the intestine, facilitates muscle strength.
Occurs in two forms D3(animal) and D2(vegetable); D3 may have greater activity.
Produced in the skin during direct sunlight exposure or absorbed from dietary intake.
Causasions need 15 minutes of direct bright sunlight exposure to hands and face per day. Longer for dark skinned individuals. Sunscreen limits Vit. D production.
Measured by 25-hydroxyvitamin D (25){OH}D. <20ng/ml is deficient. Orthopaedic patients should be >30ng/ml.
Only natural dietary sources are salmon, mackerel, sardines and other oily fish.
Daily Recommended intake: 400-800 IU in individuals who lack adequate sunlight exposure.
Consider assuming orthopaedic patients are deficient and supplement with 2,000units per day. (Lane JM, AAOS Now May 2015).
