Blood pressure effects of supplemental calcium in older adults

The purpose of this study was to determine (1) if calcium carbonate supplementation could reduce blood pressure (BP) in older adults with mildly increased pressure, and (2) if BP reduction could be maintained over the course of 1 year with continued supplementation. Patients ages 50 to 80 years with untreated systolic BP that was consistently greater than 140 mm Hg or diastolic BP more than 90 mm Hg during a 4-week baseline period were enrolled. Each person received placebo tablets for 4 weeks followed by calcium carbonate (1 g) for 12 weeks (n = 103). If either systolic or diastolic BP was reduced by more than 5 mm Hg with calcium compared with placebo, supplementation was continued for 36 weeks (n = 42). Twelve of these 42 subjects completed a further 12-week placebo run-out phase. Blood pressure did not change significantly with 12 weeks of calcium carbonate compared with placebo. In 42 of 103 patients who were given calcium supplementation for 1 year, BP did not change significantly through 36 weeks. In subjects who completed the placebo run-out period, systolic BP increased significantly (P < .05) and did not differ from baseline (P = NS). These findings do not support general use of calcium supplementation to reduce BP in an older population. Whereas conclusions are limited by the study design, persons whose BP can be reduced with calcium supplementation may maintain this response for at least 1 year.