Study leader Dr. Thomas Larsen and a group of researchers studied 112 patients visiting the Holstebro Hospital in Denmark -- at the 56th northern latitude, about the same latitude as Glasgow and Moscow. The study participants had initial levels of vitamin D measured, and then were given either vitamin D or a placebo for 20 weeks. At the beginning of the study, 92 of the 112 patients were found to have low levels of vitamin D.
The researchers found those patients taking the vitamin D supplement showed a significant reduction in central systolic blood pressure, when compared to the placebo group.
There was also a reduction in ambulatory blood pressure -- blood pressure measured at the upper arm, where several measurements are taken during the day -- in those patients who were originally vitamin D deficient, although this reduction was of borderline significance.
"Probably the majority of Europeans have vitamin D deficiency, and many of these will also have high blood pressure. What our results suggest is that hypertensive patients can benefit from vitamin D supplementation if they have vitamin D insufficiency," Larsen said in a statement. "Vitamin D would not be a cure for hypertension in these patients, but it may help, especially in the winter months. However, it is important to stress, that this was a small study, and that larger studies are needed to provide solid evidence."
The findings were presented at the European Society of Hypertension meeting in London.