Vitamin D has received worldwide attention not only for its importance for bone health in children and adults but also for reducing risk for many chronic diseases including autoimmune diseases, type 2 diabetes, heart disease, many cancers and infectious diseases. Vitamin D deficiency is pandemic due to the fact that most humans have depended on sun for their vitamin D requirement which they now either avoid or wear sun protection for fear of skin cancer. There are few foods that naturally contain vitamin D. Some countries permit vitamin D fortification especially dairy products, some cereals and juice products. The Institute of Medicine made its recommendations based on a population-based model; the Endocrine Society's Practice Guidelines on Vitamin D was for the prevention and treatment of vitamin D deficiency, which helps explain the differences in the recommendations. The Guidelines defined vitamin D deficiency as a 25-hydroxyvitamin D < 20 ng/mL, insufficiency as 21-29 ng/mL and sufficiency as 30-100 ng/mL. To prevent vitamin D deficiency The Guidelines recommended vitamin D intake should be: children < 1 y 400-1,000 IU/d, children 1-18 y 600-1,000 IU/d and adults 1,500-2,000 IU/d.
Keywords: 25-hydroxyvitamin D; Endocrine Society Practice Guidelines; Institute of Medicine; sunlight; vitamin D.