Vitamin D is a fat-soluble vitamin that is naturally present in very few foods, added to others, and available as a dietary supplement. It is also produced endogenously when ultraviolet rays from sunlight strike the skin and trigger vitamin D synthesis. Vitamin D obtained from sun exposure, food, and supplements is biologically inert and must undergo two hydroxylations in the body for activation. The first occurs in the liver and converts vitamin D to 25-hydroxyvitamin D [25(OH)D], also known as calcidiol. The second occurs primarily in the kidney and forms the physiologically active 1,25-dihydroxyvitamin D [1,25(OH)2D], also known as calcitriol.
Rickets and osteomalacia are the classical vitamin D deficiency diseases. In children, vitamin D deficiency causes rickets, a disease characterized by a failure of bone tissue to properly mineralize, resulting in soft bones and skeletal deformities.
Age Male Female
0-12m 400 IU 400 IU (10mcg)
1-70y 600 IU 600 IU (15mcg)
>70y 800 IU 800 IU (20mcg)
Sources of Vit D:
- Flesh of Fatty Fish (salmon, tuna, mackerel, canned sardines)
- Dole's Portobello Mushrooms
- Fortified cow's milks (some soy & rice milk contain the same amounts)
- Fortified orange juice (Two fortified brands, Florida Natural Orange Juice and Minute Maid Kids+ Orange Juice, contain 100 IUs per 8-ounce serving)
- Supplements (D2-ergocalciferol and D3-cholecalciferol)
Visit Dr. Stephanie Woo, DC-MBA at ChiroConcept of Bellevue or Baileys Wellness or to get the very best Vitamin D supplements.