Recent research is challenging the conventional recommendations of 1000 – 1500 mg of supplemented calcium for women. Once recent study from Germany found an 86% increase in incidence of heart attacks among those taking calcium supplements versus those who are not. Those who had adequate dietary calcium (about 800 mg), moreover, had a significantly reduced risk of heart attacks versus those who had much lower levels. This study builds on previous research showing an increase in heart attacks among those taking more than 500 mg of calcium in supplement form. Read more on these studies here and in a summary in the LA Times.