Brittle bone disease

If you're like so many women, you don't give much thought to your bones--that's something to worry about later, right? After all, you're young, and osteoporosis is a disease of old age.

The truth is, early adulthood is a key time to make sure your bones are in their best possible shape, says Miriam Nelson, Ph.D., author of Strong Women, Strong Bones (Perigee, 2001) and director of the John Hancock Center for Physical Activity and Nutrition at Tufts University in Boston. "It's a critical time period, but it's one in which women are quite complacent about bone health," she says.

Waiting too long to ensure your bones stay strong, however, could be a costly mistake that leads to debilitating fractures down the road. An estimated 8 million American women have the brittle-bone disease osteoporosis, and millions more have osteopenia, a precursor condition marked by significant bone loss. But you don't have to be one of them. Bone up on six common misconceptions about osteoporosis--and take action so you remain healthy for years to come.

Myth I'm too young to be concerned about my bone health.

The stage for brittle bones is set early in life. "By the time you're 25, you've reached your peak bone mass," says Felicia Cosman, M.D., clinical director of the National Osteoporosis Foundation (NOF) in Washington, D.C. After this point, you can't add more bone mass but you can keep the stores you have from becoming depleted. "Think of it as a 'bone bank,'" Cosman says. "As you're building your peak bone mass, you want to get it as high as you possibly can--and that's like putting money in the bank," she explains. "Later, even though you can't add more to the bank, you can prevent withdrawal."

Bone constantly renews itself in the body, but as women age, the withdrawals begin to exceed the deposits--particularly after menopause, when we lose bone-protecting estrogen. So invest in your bone bank now, by taking preventive steps such as getting enough calcium (1,000 milligrams daily) and exercise, and you'll reap the benefits in years to come.

Myth I take a calcium supplement, so I don't need to worry.

Supplements can help you get your daily calcium requirements, but the mineral is most easily absorbed from foods. Dairy products such as skim milk, lowfat yogurt (1 cup provides 300 and 415 milligrams, respectively) and Swiss cheese are the richest sources, but broccoli, kale and oranges also contain the mineral. (See our Lowfat & Easy column on page 216 for delicious, calcium-rich recipes.) A healthful diet boosts bone in other ways, too, such as by providing vitamin D, as well as magnesium and vitamins C and K, all of which benefit the skeleton.

If you're not getting enough calcium through your diet, a supplement can help. There are a variety to choose from, each with pros and cons. If you're taking a calcium-carbonate supplement, do so with food, which enhances absorption; calcium-citrate supplements, on the other hand, can be taken at any time. But avoid supplements made with unrefined oyster shell, warns the NOF.

Experiment with supplements from reputable manufacturers (a USP symbol on a label is a good guide) to find one that suits you. And keep in mind that you don't need to spend a lot of money or put up with unpleasant side effects (like gas or constipation) to keep your bones strong, says Robert P. Heaney, M.D., a professor of medicine at Creighton University's Osteoporosis Research Center in Omaha, Neb.

Myth Becoming hunched with age is normal.

"A small amount of height loss is a normal accompaniment of aging," Cosman says. Women who live into old age may lose about half an inch due to the degeneration of discs in the spine, she says. They may also shrink a little due to poor posture and weakened back muscles. But loss of an inch or more in height, particularly when accompanied by the "dowager's hump," might signal osteoporosis and the presence of fractured vertebrae--and that's not normal. If women with these symptoms haven't already suffered a hip or wrist fracture, it's likely that they will, though drug treatments may help offset the risk. Half of all women over 50 are expected to experience an osteoporosis-related fracture at some point in their lives, but it doesn't have to be that way. "Fractures are not a normal consequence of aging," Cosman says.

Myth Osteoporosis only affects women my grandmother's age.

Though not at all common, osteoporosis can strike young women--even teens. Most at risk are those who stop menstruating due to extreme dieting or eating disorders. Inadequate nutrition can cause the body to shut down nonessential functions like menstruation, says Angela Smith, M.D., an orthopedic surgeon at Children's Hospital of Philadelphia and a past president of the American College of Sports Medicine. Estrogen levels plummet, and bones weaken as a result.

Some female athletes develop what is known as the "female athlete triad": disordered eating patterns, loss of menstruation, and osteoporosis. While it was once thought that too much exercise was the culprit, researchers now believe that even the most active women can maintain normal cycles as long as they're properly nourished.

Also, young women can develop weakened bones if they simply do not get enough calcium. Long-term dieters and people who undergo gastric bypass surgery are particularly prone to this problem.

In addition to eating disorders, conditions that can deplete bone include kidney problems, liver disease, thyroid disorders, rheumatoid arthritis, and intestinal disorders that interfere with nutrient absorption. Women who've had their ovaries removed are at high risk for osteoporosis too.

Certain prescription medications also pose a threat, such as GnRH agonists for endometriosis, anti-seizure medicines, Depo-Provera and steroids. Inhaled steroids taken by asthmatics may not be as bad for bones as those taken orally, though the issue remains unsettled. If you use any medications on a regular basis, ask your doctor whether they might affect your bones.

Myth Osteoporosis runs in my family, so there's not much I can do to prevent it.

Having a mother or grandmother with osteoporosis raises your risk, but it doesn't mean you're doomed. It does, however, mean you have to be extra-vigilant about prevention. (On the flip side, a woman isn't off the hook just because she doesn't have a family history. There are other risk factors, such as being thin, small-framed and/or white or Asian.)

One of the most important steps all women should take is getting the recommended 1,000 milligrams of calcium a day until age 50 and 1,200 milligrams after that--something many of us fail to do. "About three-quarters of women don't meet the calcium requirement," says Jackie Berning, Ph.D., R.D., an associate professor of nutrition at the University of Colorado at Colorado Springs. On average, women get a paltry 600 milligrams daily.

That's not nearly enough to keep your bone bank balance where it needs to be. If dietary intake of the mineral is low, your body steals it from your bones and delivers it to where it's required, Berning explains. Over time, these withdrawals can add up to a serious bone deficit. Not getting enough calcium during pregnancy--expectant mothers need 1,000 milligrams a day too--can take an especially heavy toll, as the body will use the calcium from your bones to fuel the baby's growth.

There are other good reasons to get your calcium: It may reduce your risk of colon cancer and kidney stones and help keep blood pressure in check. What's more, research suggests that getting plenty of calcium from lowfat dairy products may actually help people lose weight. (See "Calcium & Weight Loss" on page 218.)

Another critical nutrient for preventing osteoporosis is vitamin D, which helps your body absorb calcium. The Institute of Medicine recommends 200 international units (IU) a day until age 50 and 400 IU for ages 51-70. Food sources include fortified milk and cereals, egg yolks and salmon, or get it by exposing your face, arms and hands to the sun for 10-15 minutes a few times a week. Exercising regularly, avoiding smoking and limiting alcohol intake to about a drink a day helps too--although a recent study showed that premenopausal women who consumed beer in moderation had significantly higher bone mineral densities than non-beer drinkers. "Beer is a major source of silicon, a mineral strongly associated with bone health," explains Katherine Tucker, Ph.D., a senior scientist at the Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University in Boston. But instead of pounding down four beers a day to reach the recommended 30 milligrams of silicon, try eating green beans, whole grains and bananas, all of which contain good amounts of the mineral.

Myth Any kind of exercise is good for the bones.

Getting your heart pumping on a regular basis can help prevent a range of diseases. But not all types of aerobic activity are equally good for warding off osteoporosis. The best are weight-bearing exercises, specifically those with the greatest impact on bone, says Timothy Lohman, Ph.D., a professor of physiology at the University of Arizona in Tucson, who has studied the effects of exercise on bone mass. "Biking, swimming and walking are less effective for bone density than hiking, jogging and stair climbing," he says. Other good choices: racquetball, tennis, volleyball, basketball and jump-rope. Aim for 30-40 minutes, three days a week to get bone benefits.

Also key is strength training all the major muscle groups. But make sure you're lifting enough weight to challenge yourself, Lohman says. He advises performing two sets of six to eight repetitions of an exercise at a weight that's 70-80 percent of the maximum weight you can lift, press or pull at one time. As you become stronger, you'll need to increase the weight. Lohman's recommended activities: leg presses, squats, lat pulldowns, lateral rows, back extensions and dumbbell presses.

To really target the wrist, a common fracture site, Dianne Daniels, an exercise physiologist in New York City and author of Exercises for Osteoporosis (Hatherleigh Press, 2000) recommends doing push-ups, squeezing a rubber ball in your hand or wringing out a towel (one wrist flexes while the other extends).

RELATED ARTICLE: do you need a bone-density test?

The short answer: probably not. Generally speaking, doctors recommend bone-mineral-density testing starting around age 50. But tests may be performed on younger women in certain circumstances where bone loss is suspected, such as when they're taking prescription steroids or have missed periods. Talk to your doctor if you fall into either category, or have a family history or other risk factors.

The most accurate test is known as a dual-energy X-ray absorptiometry, or DEXA, and measures bone density at the hip and spine. The cost is around $150-$250 and usually is covered by insurance if a doctor recommends it. Cheaper, less accurate tests--often available at malls and health fairs--measure bone density at the wrist, heel and finger. These will give you some idea of your risk, and if you have a low reading your doctor may recommend a follow-up DEXA for a more definitive assessment of your overall bone health.

Jacqueline Stenson is a freelance health and nutrition writer based in Pasadena, Calif.

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