At dinner, Mom, your kid asks you how come you get to drink a soda while she has to drink milk.
"I'm done growing," you tell her. "Your bones are still growing; you need milk."
But you're wrong. Your kid is right, and you should be drinking milk, too -- and taking a calcium supplement and lifting weights. And if that kid takes a soda in her lunch, she is contributing to what promises to be a major national health crisis in years to come -- an epidemic of osteoporosis.
Health experts are alarmed by the fact that women -- and the young girls who will be women -- are getting less calcium than ever, even as the recommended daily allowances have increased to reflect the new understanding of bone growth, even as report after report has made osteoporosis a household word in recent years.
Researchers now know that bones don't stop growing once they attain their full length. Growth now is defined as the adding of bone mass, and that continues into a person's 30s. In fact, women's peak bone mass occurs at 30, says Vicki Lucas, vice president of Women's Services for Helix/Medlantic Health System in Baltimore.
Before then, you need to do all you can to increase your bone mass, because you are going to lose it with aging.
"If you haven't done weight-bearing exercise and taken appropriate vitamin D and calcium and all that jazz, then you haven't maximized your bone mass," Lucas says.
Women can expect to lose 10 percent of bone mass during menopause, or
about 1 percent a year, says Yvonne Bronner, a registered dietitian and assistant professor of family health sciences at the Johns Hopkins Medical Institutions.
About 28 million Americans have osteoporosis; 80 percent are women. There are 1.5 million fractures each year; 300,000 are hip fractures, and 30 percent of the hip-fracture victims will die.
The old diet guidelines called for women between 19 and 50 to consume 800 milligrams of calcium a day; that has been raised to 1,000. Children should get 1,300 milligrams -- up from 1,200 -- and people older than 50 should consume 1,200 milligrams a day. (People should not consume more than 2,500 milligrams -- that becomes toxic.)
Most women get only 600 to 700 milligrams a day, while teen-agers get only 500 to 600. That data is from 1996, and Bronner fears that the new data, expected to be released in 2000, will show even less calcium consumption.
Once, children easily drank a quart of milk a day, but now they're more likely to be drinking sodas -- a trend that's not dropping despite the omnipresent drink-milk campaign. Ironically, parents worried about too much fat contribute to the problem by packing juices instead of milk into their children's lunches. And older kids regard foods like milk, cheese and cereal -- foods rich in calcium -- as something little kids eat, and therefore not cool.
There are many sources of calcium -- collard greens, broccoli, fortified orange juices and cereals, salmon and tuna, and, of course, dairy products. An 8-ounce glass of 2 percent milk has 313 milligrams; skim milk has 302. A cup of collard greens has 148 milligrams. A Tums -- used by women as a quick source of calcium -- has 200 milligrams of calcium carbonate.
The body needs vitamin D to absorb calcium, and again the requirements have jumped; women 50 and older should get 10 micrograms a day, up from 5, while women older than 70 should get 15 micrograms.
Fifteen minutes of sunshine a day is one of the best sources for vitamin D, but a lifestyle centered around the office keeps women indoors more and more. Other good sources are dairy products -- milk, cheese, yogurt and ice cream.
Smoking and alcohol are risk factors for osteoporosis, too -- they de-mineralize bones -- and adolescent females, ever eager to be cool, are the fastest-growing group of smokers.
But a dowager's hump and a later life in a wheelchair aren't cool, either, and that's what today's teens are setting themselves up for.
Osteoporosis typically shows up in post-menopausal women. A bone scan of a woman with osteoporosis will reveal an image that looks like a spider web -- and is just as fragile. "They could plop down in a chair and fracture their hip," says Lucas.
One of the easiest ways to monitor for osteoporosis is simply to measure a women's height, something not routinely done at checkups. "Women don't notice they've lost so much bone density until their favorite skirt is now below their knees," says Lucas. They're losing height because the vertebrae in their spine are being crushed.
Lucas recommends that women between 30 and 40 get a baseline bone-density scan, a noninvasive procedure costing around $200 that takes about 15 minutes and does not require undressing.
Perhaps one of the most tragic things about osteoporosis is that it begins to strike women in their 50s, at an age when they still should have a decade or more of productive work life ahead of them.
The good news is that it is not too late for women of any age to make lifestyle changes.