A bare-bones lesson on calcium

The other morning I came downstairs to find Marge stirring her liquid calcium supplement into her calcium-fortified orange juice that would accompany her bowl of calcium-rich Total cereal, which was, of course, swimming in milk.

"Whoa, hold on there, my little buckaroo," I said. Well, not really — I just thought that sounded kind of cute.

No, what I actually said was something more boring and harsh, like: "I hope you don't think you've just taken care of your day's calcium needs." Yes, the sad truth is that when it comes to calcium, a little at a time goes a long way, but a lot all at once goes pretty much nowhere.

I'm not a dietitian or nutritionist, but I've read enough to know that our bodies absorb calcium best when it is taken in amounts of 500 milligrams or less. The National Osteoporosis Foundation recommends that adults under age 50 get 1,000 milligrams of calcium a day and those over 50, 1,200 milligrams daily, in conjunction with appropriate amounts of vitamin D.

So if you're hoping to get the recommended amount of calcium but trying to do it all at once, whether through food or supplements, you've just wasted 500 to 700 milligrams of calcium, not to mention a lot of money over the course of a year in the case of supplements. Your body will better absorb calcium if it is consumed in smaller amounts spread throughout the day.

If you'd like to know more about the role of calcium and your health, the National Institutes of Health has a comprehensive fact sheet here.

"Look, Ma — no bones!"

There was another one of those headlines last week that stopped me in my tracks: "Is Bicycling Bad for Your Bones?" Naturally, I wanted to know the answer, since I do a fair amount of mountain biking, so I read on.

The story by Gretchen Reynolds, reported in the New York Times online, discusses some surprising — or perhaps not — findings involving competitive cyclists and bone density. Those cyclists, evidence suggests, may be compromising their bone health.

In one study, the spinal bone density of 32 male competitive riders was found to be significantly less than that of the control-group subjects, who were active but not competitive athletes. Some of the riders even had osteopenia, a precursor to osteoporosis. The researcher behind the study, Aaron Smathers, was quoted as saying: "To find guys in their twenties with osteopenia was surprising and pretty disturbing."

The story goes on to explain that those findings and similar ones from other studies were maybe not all that surprising considering the unique demands placed on the body by competitive cycling. We're talking Lance Armstrong types here — athletes who ride tremendous distances at high intensities and burn far more calories than they consume in a day.

Furthermore, bicycling is not a weight-bearing exercise, so it doesn't help build and maintain bone density like running or walking does. Bones need a certain amount of stress to keep them strong, and cycling doesn't provide it.

The findings were interesting to me because I tend to think of osteoporosis primarily as a disease of elderly women. That young, elite male athletes were also at risk was intriguing.

But the findings aren't particularly relevant to most people's lives, and the story so much as said so: "Even more encouraging, most recreational cyclists probably don't need to worry too much about their bones."

I'd be curious to find out whether any bone-density studies have been conducted on mountain bikers. Mountain biking, with its impact forces, would seem to be more of a weight-bearing exercise than road biking.

Information about osteoporosis, and what you can do to help prevent it, is available from the National Osteoporosis Foundation.