The introduction below is from an excellent article from Harvard Public Health that can be found at this link.
Those advertisements pushing milk as the answer to strong bones are almost inescapable. But does “got milk?” really translate into “got strong bones?”
The pro-milk faction believes that increased calcium intake—particularly in the form of the currently recommended three glasses of milk per day—will help prevent osteoporosis, the weakening of bones. Each year, osteoporosis leads to more than 1.5 million fractures, including 300,000 broken hips.
On the other side are those who believe that consuming a lot of milk and other dairy products will have little effect on the rate of fractures but may contribute to problems such as heart disease or prostate cancer.
Which view is right? The final answers aren’t in. But here is a summary of what’s currently known about calcium and its effects on the body.