Vitamin D

  •  fat-soluble steriod derived from cholesterol.
  • 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).