Vitamin D and the prevention of hypertension and cardiovascular diseases: a review of the current evidence.

Vitamin D plays an essential role in bone mineralization and calcium homeostasis. More recently, there has been growing evidence for a role of vitamin D in extraskeletal health, including beneficial effects in the cardiovascular system. Daylight exposure and vitamin D intake in many western populations are insufficient for maintaining an adequate vitamin D status. It is at present unclear whether vitamin D supplementation could improve cardiovascular health. This paper summarizes the evidence from observational studies and randomized-controlled trials on the relation of vitamin D with blood pressure (BP) and risk of cardiovascular diseases (CVDs). Epidemiological data suggest that optimal vitamin D status is important for CVD prevention, but results from different studies are conflicting and confounding cannot be ruled out. Randomized-controlled trials of vitamin D supplementation and BP have yielded inconsistent results, and trials that addressed the effect of vitamin D on CVDs are lacking. It is therefore premature to recommend supplemental vitamin D intake specifically for the prevention of hypertension or CVDs. Data from large, well-controlled clinical trials in this field with vitamin D supplements of sufficiently high doses are awaited to settle this issue.