Effect of calcium supplementation on serum cholesterol and blood pressure - A randomized, double-blind, placebo-controlled, clinical trial

Objective: To test the effect of daily supplemental calcium on serum total and high-density lipoprotein cholesterol (HDL-C) levels and blood pressure in adults. Design: Randomized, double-blind, placebo-controlled clinical trial; adjunc t study to a trial of calcium and colon cell proliferation in patients with sporadic adenoma. Setting: Outpatient clinic. Patients: A total of 193 men and women, aged 30 to 74 years. Intervention: Treatment with 1.0 and 2.0 g/d of elemental calcium vs placeb o over a 4-month period for cholesterol determinations and 6 months for blo od pressure. Main Outcome Measures: Serum total cholesterol and HDL-C levels, systolic a nd diastolic blood pressure. Results: Because there were no apparent differences in responses between th e 1.0-g and 2.0-g calcium groups, their data were combined and compared wit h those of the placebo group. Among all participants, the mean total choles terol level dropped 0.07 mmol/L (2.9 mg/dL) (1.3%) (P =.43) more, and the m ean HDL-C level dropped 0.01 mmol/L (0.4 mg/dL) (1.1%) (P =.71) less in the calcium group than in the placebo group. Among participants without a hist ory of hypercholesterolemia, the mean total cholesterol level dropped 0.18 mmol/L (6.8 mg/dL) (3.3%) (P =.10), and the HDL-C level dropped 0.02 mmol/L (0.6 mg/dL) (1.5%) (P =.61) more in the calcium group than in the placebo group. Among all participants, there was no apparent change in blood pressu re until 6 months, when the mean systolic blood pressure dropped 0.8 mm Hg (0.6%) (P =.85) and the mean diastolic blood pressure dropped 0.4 mm Hg (0. 5%) (P =.80) more in the calcium group than in the placebo group. Conclusions: There were no substantial or statistically significant effects of calcium supplementation on total cholesterol or HDL-C levels or on bloo d pressure. There was a suggestion (not statistically significant) of a 0.0 7 to 0.18 mmol/L (3-7 mg/dL) or 2% to 4% drop in the total cholesterol leve l, a finding similar to that reported in other studies, which indicates the need for further study.