Expected blood pressure lowering with calcium:
A. meta-analysis of 40 trials (2,492 subjects with high blood pressure) showed significant reductions in systolic blood pressure of about -1.8 mmHg and reduction of diastolic blood pressure of -0.99 mmHg with an average calcium supplement dose of 1,200 mg daily. Among patients with a lower calcium intake on average of about 800 mg daily, an average 1200 mg calcium supplement reduced systolic blood pressure by -2.63 mmHg, and reduced diastolic blood pressure by -1.30 mmHg. (42)
Calcium plus vitamin D compared to calcium alone in hypertension:
A double-blind randomized controlled trial of 148 women with a mean age of 74 years was conducted to study the effects of calcium supplements on blood pressure. The study participants received 1200 mg calcium plus 800 IU vitamin D or only 1200 mg calcium daily for 8 weeks. At the end of the study, researchers found that supplementation with vitamin D and calcium resulted in a significant increase in vitamin-D levels by 72% and decreased parathyroid hormone (PTH) levels, which controls calcium, phosphorus, and vitamin D levels in the blood and bone, by 17% along with significant decreases in systolic blood pressure of 9.3% (p=0.02) and heart rate of 5.4% (p=0.02) compared with calcium supplementation alone. 81% of subjects in the vitamin D3 and calcium group compared with 47% in the calcium group showed a decrease in SBP of 5 mm Hg or more. The researchers concluded that short-term vitamin D and calcium supplements are more effective in reducing systolic blood pressure than calcium alone in elderly women. (43)