Latest Findings: Taking Vitamin D Associated with Lowering Blood Pressure

Highlights

• Higher doses of vitamin D were significantly linked to lowered systolic (when the heart ejects blood) and diastolic (when the heart fills with blood) blood pressure.
• Similar trends were seen with lower doses of vitamin D; however, the degree of lowered blood pressure did not reach statistical significance.

Vitamin D deficiency is common, affecting about 1 billion people globally, and research has associated low levels of vitamin D with cardiovascular disease and cancer. Moreover, some research has linked low circulating vitamin D with high blood pressure (hypertension). All the same, evidence for vitamin D supplementation’s ability to lower blood pressure has remained inconclusive.

Now, published in the Journal of the Endocrine Society, Fuleihan and colleagues from the American University of Beirut Medical Center in Lebanon show an association between higher doses of vitamin D supplementation and lowered systolic and diastolic blood pressure in overweight elderly adults. Furthermore, similar trends of lowered blood pressure were seen at lower doses of vitamin D; however, the most consistent blood pressure-lowering outcomes came from higher doses. These findings suggest the potential of vitamin D to help lower blood pressure in people who are older and overweight, two characteristics which research suggests predispose to hypertension.

“Our trial and critical synthesis of data from other relevant [randomized controlled trials] suggest a putative beneficial effect of vitamin D in older populations…” say Fuleihan and colleagues.

Vitamin D Significantly Lowered Blood Pressure When Taken at Higher Doses

The study included about 250 participants over the age of 65 who were overweight but still capable of walking. Subjects in the experiment were divided into two groups: a low-dose group that received 600 IU per day of vitamin D with calcium citrate (known to increase calcium levels in the body) and a high-dose group that took 3,750 IU per day of vitamin D with calcium citrate.

At six months and at a year of taking vitamin D, the high-dose group had a significantly decreased systolic and diastolic blood pressure compared to when they were not taking vitamin D. The low-dose group showed a trend toward lowered systolic and diastolic blood pressure that did not quite reach statistical significance. These results suggest that vitamin D supplementation lowers blood pressure in overweight elderly individuals and that the vitamin’s effects are most consistent at higher doses.

Taking Calcium Citrate with Vitamin D May Work Additively to Lower Blood Pressure

The addition of calcium citrate to vitamin D supplementation serves as a potential variable that may have obscured whether vitamin D supplementation on its own, in fact, is associated with lowered blood pressure. In that regard, Fuleihan and colleagues point to research suggesting that boosting calcium levels on its own does not lower blood pressure to the degree that vitamin D with calcium citrate was associated with in this study. The researchers add that evidence gathered from other studies examining vitamin D’s positive influence on blood pressure speak against this possibility as well.

Thus, while vitamin D supplementation seems to be a primary underlying contributor associated with lowered blood pressure in overweight elderly individuals in this study, effects from calcium citrate cannot be ruled out. In that sense, research has associated supplementally increasing calcium levels in the body with the prevention of hypertension. Therefore, it may be the case that adding calcium citrate to vitamin D supplements could additively lower blood pressure. More human trials using vitamin D supplementation on its own and with calcium citrate will be necessary to find whether this is the case.

Finally, the evidence provided in this study suggests that supplementing with vitamin D at higher doses may help to lower blood pressure in overweight elderly adults. In that sense, more trials are required to parse out the optimal dosages of daily vitamin D to lower blood pressure in overweight aged people. The possibility also exists that overweight elderly people who also have substantial vitamin D deficiencies will require higher doses yet to optimize effects on blood pressure.