2010 New Recommendation Vitamin D
文章来源: 医实注行 于 2010-12-28 10:39:18

Here are some key recommendations of the U.S. Insititued of  Medicine (IOM) report:

  • As the “Recommended Dietary Allowance,” or RDA, most healthy North American adults (in the U.S. and Canada) need no more than 600 IU of vitamin D per day to maintain health, and those aged 71 or older may need 800 IU/day. The IOM committee believes these amounts often can be acquired via dietary intake and are not necessarily dependent on sun exposure. [While these amounts are higher than a 1997 IOM report — recommending 200 IU/day in persons up to age 50, 400 IU/day in those 50-70 years old, and 600 IU/day in those older than age 70 — Dietary Guidelines for Americans in 2005 had specified 1,000 IU/day for children and adults.]

  • Furthermore, the committee newly established that all healthy individuals get sufficient vitamin D when their blood levels of the 25(OH)D metabolite are at or above 20 ng/mL (nanograms per milliliter). [Note that 30-50 ng/mL has been traditionally considered as the range of sufficiency in research trials, with anything lower being labeled as insufficient.]

  • The committee set the Upper Level Intake for vitamin D at 4,000 IU/day, representing the high end of safe daily intake and above which risks for harm increase. [This had previously been set at 2,000 IU/day.]

  • During a press conference webcast to launch the report, IOM committee members suggested that according to their findings most persons in North America are not vitamin D deficient, laboratory testing for blood levels of the vitamin is being overused, and current lab tests for 25(OH)D lack standardization and in many cases are inaccurate.

  • As for calcium, the amount needed (RDA) ranges from 700 to 1,300 milligrams per day (mg/day), depending on age, with the higher amounts generally needed in older adults. The Upper Intake Levels for calcium range from 2,000 to 3,000 mg/day, also depending on age.

  • Most North Americans are already getting sufficient calcium in their diets, the committee notes, with the possible exception of adolescent females and elderly persons. These individuals should increase their intake of foods rich in calcium before considering supplements. [However, it should be noted that, without sufficient vitamin D, calcium will not be properly absorbed and used in the body.]