September 2012
Vitamin D supplementation during the winter months reduces blood pressure, according to a new study published online in the Journal of Hypertension in April 2012. The Centers for Disease Control and Prevention report that approximately one in three American adults have hypertension, defined as a systolic blood pressure of 140 or greater and a diastolic blood pressure of 90 or greater.
In this randomized, placebo-controlled, double-blind study, 130 hypertensive Caucasian subjects residing in northern Denmark received either 75 mcg (3,000 IU) of vitamin D (cholecalciferol) or placebo for 20 weeks. The researchers performed the baseline exam during October and November, during which time cutaneous vitamin D synthesis is absent. The investigators assessed 24-hour blood pressure, central blood pressure and pulse wave velocity, which is a measurement of arterial stiffness. The researchers also measured plasma 25-hydroxyvitamin D, calcium and intact parathyroid hormone, as well as hormones regulating blood pressure including renin, angiotensin and aldosterone.
The researchers found that compared to placebo, vitamin D supplementation significantly increased plasma 25-hydroxyvitamin D and calcium and reduced levels of parathyroid hormone. No change was noted in the 24-hour ambulatory (non-resting) blood pressures overall. However, the subjects with plasma 25-hydroxyvitamin D levels less than 75 nmol/L showed a reduction in systolic blood pressure by 3.7 mmHg and diastolic blood pressure by 2.7 mmHg compared to placebo. Additionally, all subjects supplemented with vitamin D showed a reduction in central blood pressure compared to placebo, averaging a systolic reduction of 6.8 mmHg and diastolic reduction of 1.7 mmHg. No change was noted in the pulse wave velocity.
The study authors concluded, “In hypertensive Caucasians… 75 mcg of cholecalciferol daily during winter months caused a significant reduction in central systolic blood pressure. In a sub-analysis of patients with plasma 25-hydroxyvitamin D less than 75 nmol/L, a marginal reduction in both systolic and diastolic 24-hour ambulatory blood pressure was observed.”
Reference:
Larsen T, et al. J Hypertension. 2012;30:e103.
Soource: Vitamin D Impacts Blood Pressure
