Can vitamin D supplements help to lower blood pressure?

This study looked at blood pressure (BP) in patients taking high or low doses of vitamin D supplements. They found that vitamin D reduces BP in both doses and a high dose of vitamin D was more effective in reducing variations in BP.

High BP (hypertension) is associated with many health problems including heart disease and strokes. Research shows that people with low vitamin D levels are more likely to have high BP. However, it is not clear if supplementing vitamin D helps to reduce BP, or what dose of vitamin D is best.

250 participants were involved in this study. They were part of another study on arthritis of the knee. Therefore, all participants were over 60 years old and had had a recent knee replacement. They were divided into two groups. Group 1 was given high dose vitamin D (2000 units daily) and group 2 was given a standard-dose vitamin D (800 units daily). BP was monitored at the start of the study and then at 6 weeks, 1 year, and 2 years. Their vitamin D levels were also checked at the start of the study and at 2 years.

At the start of the study, 56.8% of participants had low vitamin D levels. 46.9% of participants had high BP. After 2 years of vitamin D supplements, BP was reduced by a small but significant amount in both groups. There was no significant difference in the reduction between the two groups. Reductions in BP were similar in patients with normal or high BP at the beginning of the study.

Patients with moderate blood levels of vitamin D (28.7 ng/ml) after 2 years showed the greatest reduction in BP. Fluctuations in BP were significantly reduced in patients from group 1 compared to group 2.

This study suggests that vitamin D supplements may improve blood pressure in some patients. It also suggests that there may be an ideal level of vitamin D that should be reached in order to reduce blood pressure and that higher levels of vitamin D may help in keeping the BP stable.

Due to the design of this study, all patients involved were taking vitamin D supplements (there was no placebo group). It is therefore not possible to say for sure that the reduction in BP seen is due to vitamin D. More studies are needed to clarify this.