Bisphosphonates also slice your threat of colon cancer almost in half and reduce your breast cancer risk by about a third. Pretty nifty side effects.
How come? In the process of strengthening bones, bisphosphonates make a mess out of what's called a cancer "pathway," inhibiting cell growth in some tumors.
Bone breaks and hip fractures can be life-threatening, and bisphosphonates aren't perfect. For example, if you don't sit or stand for 30 minutes after taking them, they can cause intense heartburn and nausea. Also, long-term use can, ironically, increase certain unusual fractures (this is why doctors may advise an occasional "drug holiday"). Still, any bone-building drug that has cancer-fighting side effects --who's gonna knock that?!