Purpose of review: The clinical benefits of vitamin D therapy have received substantial attention over the past decade. Recently, several trials looked to clarify the optimal vitamin D dose or serum level needed to promote human health. The purpose of this review is to highlight selected studies published since January 2015. Recent findings: Several recent trials challenge whether serum vitamin D levels ?30 ng/mL promote human health. In postmenopausal women with 25(OH)D levels 21±3 ng/mL, high-dose vitamin D for one year increased calcium absorption by 1%, without changes in bone mineral density, physical function, or falls when compared to low-dose vitamin D and placebo. High-dose vitamin D increased risk of falling, in 200 adults 78±5 years old with baseline 25(OH)D levels of ~19±9 ng/mL. High-dose vitamin D in adults increased the number and duration of upper respiratory tract infections, compared to placebo. Asthma patients achieving 25(OH)D levels >30 ng/mL during a trial experienced more respiratory infections than those not achieving such levels. Summary: Recent studies are congruent with the Institute of Medicine?s conclusion that humans are vitamin D replete when their serum 25(OH)D levels are ?20 ng/mL. Higher levels seem to promote falls and respiratory infections.
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Curr+Opin+Endocrinol+Diabetes+Obes 2016 ; 23 (6): 440-4
