Time once again for the Moment of Science Word of the Day. Today's word is: osteoporosis!
Yep, osteoporosis. Now, you've heard this word before, and you know it has something to do with bones. But can you actually explain what it is?
The answer is straight-forward. It comes down to the fact that we human beings need calcium in our blood--it allows us to do all sorts of neat things, from contracting muscles to conducting nerve impulses. Where to get some calcium? Food is a good idea. But what if there isn't always calcium-rich food to be had, as was probably the case for most of our long evolutionary history?
Best to store some for a rainy day. Store it where? The skeleton works! Then, when the blood runs low on calcium, a signaling device called the parathyroid gland can activate a process by which calcium is taken from the skeleton and put back into the blood.
Which is just what happens. This is a great short-term fix, but what about the poor skeleton? Eventually it will suffer from the loss of its own calcium--bones will become brittle.
What can we do? Two things. Help your body get more calcium by eating fatty fish and vitamin-D rich dairy products. Why vitamin D? Because that causes the small intestine to increase its calcium uptake, bypassing the need to grab extra from the bones. Under a doctor's supervision, calcium tablets might also be helpful, along with the old standard--more exercise. Weight-bearing exercise helps keep bones strong and less likely to fall prey to the body's own mechanisms in later age.