Link Between Vitamin D and Health Outcomes Unclear
A new systematic review by AHRQ confirms that vitamin D and calcium benefit both bone mineral density and bone mineral content but finds inconsistent evidence about the value of these nutrients for other health outcomes. These outcomes include cancers of the breast, colon and prostate; heart disease; pregnancy; immune function; falls and fractures; and all-cause mortality. The report, “Vitamin D and Calcium: A Systematic Review of Health Outcomes (Update),” echoes findings of a 2009 AHRQ systematic review that also showed inconsistent evidence regarding the effect of vitamin D alone or in combination with calcium on most health outcomes. The new report, written by researchers at the AHRQ-funded Southern California Evidence-based Practice Center, concludes that associations observed in various studies between these nutrients and health outcomes were either inconsistent or rarely supported by results of randomized controlled trials. Meanwhile, the review suggests that the levels of supplemental vitamin D and calcium used in the Women’s Health Initiative Calcium-Vitamin D Trial are not linked to an increased risk for heart disease or cancer among postmenopausal women who are not taking additional supplemental vitamin D and calcium.