According to the Higuchi Biosciences Center and the Drug Information Center at Kansas University, one kind of cell in our bodies is constantly making new bone, while a second kind tears it down. That's how bone stays youthful.
But eventually the bone-destroying cells may get an edge, and by the time we're old, many of us have osteoporosis.
In fact, in the United States, 8 million women and 2 million men have the porous, fragile bones that go with the disease.
The old way to treat osteoporosis -- using high doses of calcium and vitamin D -- was only marginally effective. But beginning in 1995, the bisphosphonates -- drugs like Fosamax, Actonel and Skelid -- came to market.
The drugs stick to bone a long time, blocking bone-eating cells so that the bone-building cells can play catch-up.
Bisphosphonates can irritate the esophagus. So you can't lie down for half an hour after taking the drug, which has to be swallowed with lots of water on an empty stomach.
When you consider the cost of osteoporosis -- the fractures, the pain -- that's a small price to pay.