Grant: Operating Grant

Calcium and vitamin D are essential nutrients for optimal bone health throughout life. Research has shown that postmenopausal women who take appropriate amounts of these nutrients have better bone strength and fewer fractures than those who don't. However, researchers have recently questioned the safety of calcium and vitamin D obtained through supplements as they might increase the risk of cardiovascular events such as heart attacks and strokes. Because there are methodological concerns with these studies and because the exact cause behind these negative effects is not yet determined, many questions remain. Could calcium supplements be good for your bones but bad for your heart? Many individuals count on supplements to ensure an adequate intake of calcium and vitamin D to protect their bones against osteoporosis and fractures. It may be possible that calcium obtained from the diet have a better effect on vascular health than that obtained from supplements. Because this has never been studied prospectively, we propose to estimate the effect of dietary intake of calcium as compared to supplemental calcium on markers of vascular and bone health in postmenopausal women. We hope to enroll postmenopausal women who will be assigned to one of three interventions: to receive 1200 mg of calcium though milk and dairy foods or to receive a calcium supplement once daily or to be in a control group without specific intervention. At baseline and after 12 months, we will measure the health of the vascular system through assessment of the arteries with an ultrasound technique, monitoring of blood pressure and various blood tests. We think this study is well designed to provide information on whether calcium supplements have a different effect on vascular health than calcium obtained from the diet and shed light on the mechanisms that underlie these effects.