Higher Vitamin D Linked to Lower Risk of Hypertension

Individuals with higher concentrations of vitamin D showed reduced blood pressure and lower risk of hypertension, in a new study that appears online in The Lancet Diabetes & Endocrinology.

“The key message from our paper is simply that for individuals with hypertension, as well as for the population in general, it is important to avoid vitamin D deficiency,” says study leader Elina Hyppönen, PhD, MSc, MPH, a professor of nutritional and genetic epidemiology at the University of South Australia in Adelaide.
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Hyppönen and an international team of researchers performed a meta-analysis using 35 studies from D-CarDia, a large-scale collaboration of epidemiological studies. They conducted a Mendelian randomization study of the genetic data from more than 146,500 individuals from across Europe and North America.

To measure whether there was a causal association between vitamin D status with blood pressure and hypertension risk, the researchers used two common genetic variants that affect 25-hydroxyvitamin D concentrations.

They found that each 10% increase in the concentration of 25-hydroxyvitamin D was associated with lower diastolic and systolic blood pressure and an 8.1% decrease in the risk of developing hypertension.

“Increasing vitamin D intakes cannot be used to replace hypertension medication, and indeed, it would be very dangerous to suggest that,” Hyppönen cautions. “Instead, perhaps by ensuring adequate, and not excessive, vitamin D status and optimizing health in this way, we can help the body to regulate blood pressure better.”

While this was not a study on mechanisms, Hyppönen says there are several biologically plausible explanations for why this association may exist.

“Hormonal vitamin D, calcitriol, suppresses the expression of the renin gene by a vitamin D receptor-dependent mechanism, thereby lowering blood pressure,” she explains. “Vitamin D metabolites could also exert antihypertensive effects through other mechanisms, including influences on the regulation of calcium absorption, renoprotective, or anti-inflammatory effects.”

While the researchers see their findings as a positive step, they say additional high-powered independent studies will be needed to confirm their results. In the mean time, they plan to further examine this causal link and its effects.

“We are planning to continue the work to establish the causal effects of vitamin D on the cardiovascular diseases, the mechanisms through which those may operate, and whether there may be a need for caution with excessive intakes,” Hyppönen says.

—Colleen Mullarkey

Reference

Vimaleswaran KS, Cavadino A, Berry DJ, Jorde RJ, Dieffenbach AK, Lu C, et al. Association of vitamin D status with arterial blood pressure and hypertension risk: a mendelian randomization study. Lancet Diabetes Endocrinol. 2014 Jun 26. [Epub ahead of print].