Are you getting enough Vitamin D ?

Tufts Health & Nutrition Letter (December 2007 - Vol 25, #10) has an article about what is enough Vitamin D. There are two take aways in terms of immediate action from this article:

• we are not getting enough Vitamin D. In late Winter the average American has 15 to 18 ng/mL in their blood of the principal and longest acting form of Vitamin D (25-hydroxyvitaminD). To get a cancer preventing impact a level of at least 55 ng/mL is needed.
  
• Vitamin D supplements do not contain sufficient Vitamin D. Supplements typically contain 400 to 600IU whereas an intake of 2,000IU is justified from the research.

Read the labels on your supplements, Vitamin D comes in several forms. It is the D3 version that is most potent.

This article summarizes the situation:

Suboptimal vitamin D status is a highly prevalent but treatable condition in both hospitalized patients and the general population

Authors: Moore, Nicole L.¹; Kiebzak, Gary M.

Source: Journal of the American Academy of Nurse Practitioners, Volume 19, Number 12, December 2007 , pp. 642-651(10)

The summary: Poor Vitamin D status (ranging from suboptimal to overt deficiency) is common in both hospitalized and ostensibly healthy individuals of all ages and geographic latitude. Suboptimal vitamin D status is associated with muscle weakness, functional deficits, and perhaps longer length of stay of hospitalized patients. Fortunately, treatment with 50,000IU of Vitamin D2 for several weeks is a very inexpensive and safe yet effective treatment to replete Vitamin D status.

This large dose of Vitamin D refers to the D2 variant. Vitamin D sufficiency can be sustained by sensible sun exposure or ingesting at least 800-1000IU of vitamin D₃ daily. Patients being treated for osteoporosis should be adequately supplemented with calcium and vitamin D to maximise the benefit of treatment.

This recommendation from:

Optimal Vitamin D Status for the Prevention and Treatment of Osteoporosis

Author: Holick, Michael F.¹

Source: Drugs & Aging, Volume 24, Number 12, 2007 , pp. 1017-1029(13)