There is evidence that supplemental calcium may hasten vascular calcification and can raise the risk of heart attacks in otherwise healthy older women. An analysis of 15 double-blind, randomized trials with more than 8000 participants taking at least 500 mg of calcium supplements each day or a placebo, has shown significantly higher rates of heart attack in those taking calcium supplements. The data suggests that treating 1000 people with calcium supplements for 5 years would only prevent 26 fractures but would cause 14 additional heart attacks.
PositiveTip: Taking calcium supplements? You should talk to your physician about the small bone benefits against the cardiovascular risks.