Weak bones and osteoposrosis are supposedly caused by a lack of calcium, the solution: add calicum!  Bone health is about more than strength; elasticity, balance and reaction are just as important.  Bones aren't made from just calcium, nor is calcium directly absorbed into bones.  Supplementing with just calcium, creates a surplus that turns into build up in the vessels, joints, tendons, heart and brain that can lead to events like a heart attack.  The picture you see is a mammogram of a woman who took high dose calcium for 10 years to prevent osteoporosis.  The white parts are lime concentration in the vessels; vascular calcification.