Vitamin D: When it helps, when it harms
Evidence supports its use for protecting bone health and preventing falls in the elderly, but little else. For postmenopausal women, daily supplementation at doses ≤400 IU can actually be harmful.
The IOM expresses concern about testing for vitamin D levels because there is no validated cutoff, and some labs report cutoffs above what the IOM considers a deficient level, leading to inflated numbers of those labeled as deficient.2 The USPSTF is about to weigh in on this issue. It has posted a draft research plan that will guide its evidence report and recommendation considerations.9
Take-home message
Information on the health benefits of vitamin D is difficult to sort out. Evidence for anything other than bone health and fall prevention is problematic. Consider vitamin D supplements along with calcium for the frail elderly at risk for falls10and for those who have osteoporosis. Screening for vitamin D deficiency is of questionable value and the USPSTF will be producing an evidence-based report on this topic, which should be available in about a year. The IOM RDA tables are available to guide dietary advice.
