Over the decade we have heard tall claims about the role of vitamin D in the prevention of various ills like brittle bones, cardiovascular problems, cancer, diabetes, dementia and blood pressure.

Now a new study suggests vitamin D supplements may not have blood pressure benefits.

High dose supplementation of vitamin D 3 (cholecalciferol) did not lower blood pressure or improve any other measures of cardiovascular health in hypertensive elders, the study found.

Dr Nicholas DuBois, a cardiologist at Mount Sinai Medical Center in New York City stated, “The findings are of interest because low levels of vitamin D have been associated with all of these conditions, and there was a hope that replacing vitamin D with supplements would help correct these conditions known to be causes of heart attack and stroke. Being able to modify that risk with a vitamin that has no side effects and is low in cost would be a fabulous advance for cardiovascular protection.”

Trial of 159 patients
In order to determine whether vitamin D supplements confer blood pressure benefits in older adults Miles Witham, of the University of Dundee in Scotland and his team conducted a study.

The trial involved 159 patients (mean age 77) with isolated systolic hypertension who were randomly allocated either 100,000 units of oral cholecalciferol or a placebo four times a year.

Study subjects were scrutinized for variations in office blood pressure, 24-hour blood pressure, arterial stiffness, endothelial function, cholesterol level, insulin resistance, and b-type natriuretic peptide level during the trial.

Outcome of the study
Vitamin D supplementation did not bestow any noteworthy treatment benefit for any of the secondary outcomes (24-hour BP, arterial stiffness, endothelial function, cholesterol level, glucose level and walking distance) as opposed to a placebo.

DuBois stated, “The key to me for this study is first that it is very small, and so has statistical ability to see only a large impact of the vitamin D supplement. In other words, there would have to be a very large drop in BP [blood pressure] for this study to detect any effect. A larger study with several thousand patients could detect a more subtle change.”

He added, “For me, the current study does not change much for current practice. If vitamin D levels are low, I will try to replete them, acknowledging that it’s not certain how much benefit this does… I certainly will not begin using vitamin D in the hopes of controlling high blood pressure.”

The study has been published in JAMA Internal Medicine.

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