STEVE INSKEEP, HOST:
On a Monday, it's MORNING EDITION, from NPR News. I'm Steve Inskeep.
RENEE MONTAGNE, HOST:
And I'm Renee Montagne.
Today in Your Health, we have a case of two much medical information. Excessive medical screening by for-profit companies may lead to needless treatment.
INSKEEP: First, building healthy bones in young children. Doctors worry that kids are not getting enough exercise, Vitamin D or calcium. Those are all building blocks for strong bones.
NPR's Patti Neighmond reports.
PATTI NEIGHMOND, BYLINE: Its really only a sliver of time when humans build the bulk of their skeleton. From age nine to the end of puberty, around 14 or 15, is when our major growth spurt happens.
DR. LAURA TOSI: It's the magic window of time when bone is built.
NEIGHMOND: Orthopedic surgeon Laura Tosi directs the pediatric Bone Health Program at Children's National Health System in Washington, D.C. Because that magic window is so short, she says it's crucial to build as much bone as possible during that time.
TOSI: For me personally, the most important things are exercise, vitamin D and calcium.
NEIGHMOND: Think of calcium as the cement in bone. It builds density. And because it's not made by the body it has to be absorbed through food.
Dr. Neville Golden, with the American Academy of Pediatrics, says federal recommendations say kids between nine and 18 should get 1300 milligrams of calcium every day.
DR. NEVILLE GOLDEN: That translates into somewhere between four to five glasses of milk or equivalent per day. And most teens are not doing that.
NEIGHMOND: In fact, a recent study found only about 15 percent of high school students drank three or more glasses of milk a day. Only about 9 percent of girls did. In part, milk drinking is often viewed as sort of uncool, says Golden. But also its often viewed as fattening.
GOLDEN: And that's not in fact true. For example, one glass of skim milk contains no fat and approximately 80 calories. That's about the same caloric content as an apple.
NEIGHMOND: Now, of course, there are other sources of calcium: yogurt, cheese and vegetables. But Golden says you'd have to eat an awful lot of vegetables to reach the required 1300 milligrams.
GOLDEN: One cup of broccoli contains about 42 milligrams. So if you think about that; how many cups of broccoli do you need to consume in order to get enough calcium in a day. But there are other sources - orange juice that's fortified as a good source, breakfast cereals that are fortified, tofu that is fortified. These are all good sources of calcium.
NEIGHMOND: Golden says that today, 30 percent of boys and up to 70 percent of girls do not get the calcium they need. And there's some evidence that teenagers are suffering an increasing number of bone fractures. Part of the problem, Golden adds, many kids are also deficient in vitamin D.
GOLDEN: In fact, you can drink as much calcium as you like. But if you don't have enough vitamin D, you're not going to absorb the calcium.
NEIGHMOND: Sunshine helps the body make Vitamin D. It's also in certain foods, like salmon and sardines. But if you can't sit out in the sun or eat fish, Golden says supplements will do the trick.
Orthopedic surgeon Laura Tosi says exercise can also make a huge difference. She points to research from Canada that had kids jump up and down for just a few minutes when they were changing classes.
TOSI: They found that just doing that - was about 15 minutes of jumping a day - made a highly statistically significant difference in how they increased their bone mass over a couple of years.
NEIGHMOND: It's the bounce, says Tosi, that stimulates bone growth.
TOSI: The bounce sends probably an electrical or other signal right up the skeleton saying, OK, time to build more.
NEIGHMOND: So, jumping, jogging, basketball - all help build bone. Federal health officials say kids should get at least one hour of exercise every day. And they should get their calcium from food, not supplements.
Patti Neighmond, NPR News.