Calcium helps prevent low bone mass and osteoporosis, which affect an estimated 44 million Americans -- about three-quarters of whom are women.
You're a dedicated runner hoping to qualify for the Boston Marathon. Or a super-charged executive rushing from home to daycare to office. Or a mother of three hoping to shed a few pounds. Perhaps you're even all of the above. What should you eat to accomplish these feats?
"Women athletes are so concerned with what they get out of their bodies, as far as their performance, but they should be just as concerned with what they put into their bodies," says licensed dietitian Margo Sipiora, a spokesperson for the Illinois Dietetic Association.
That's a tricky task. Nutritional needs vary significantly between men and women. Even among women, a variety of factors influence nutritional needs.
While there is no "one-size-fits-all" nutritional formula, four key nutrients -- calcium, protein, iron and folic acid -- are of concern to women of all ages and activity levels, says Roxanne Moore of the American Dietetic Association.
"For women, whether they're sedentary or active, young or old, we still see an inadequate intake of these four nutrients all across the board," she says, "mostly because women are more inclined than men to go on diets and deliberately restrict calories."
"The old advice, 'Drink your milk,' is as good as gold," says Sherry Marts, scientific director of the Society for Women's Health Research. That's because the calcium in dairy products helps prevent low bone mass and osteoporosis, which affect an estimated 44 million Americans -- about three-quarters of whom are women, according to the National Osteoporosis Foundation.
The repetitive, weight-bearing motion of running actually helps to build bone mass. But women athletes nevertheless are at risk for developing osteoporosis because they tend to regard milk not as white gold but as liquid fat.
Nondairy sources include beans, almonds, green leafy vegetables and salmon with bones. Low-fat alternatives include calcium-fortified orange juice and chewy, chocolate-flavored supplements.
"As my grandmother says, you can't swing a cat in the grocery store without hitting something with a calcium supplement in it," Marts says.
Given the typical American diet, insufficient protein seldom is a concern, Marts says. But it can be a problem among a certain caliber of women athletes.
"I don't want to use the term 'elite athletes,' because that's too restrictive," she says. "But my judgment is that this would tend to be a problem only with girls and women who overdo it with the training and who simply don't eat enough to sustain that kind of activity."
Such extreme behaviors can lead to the Female Athlete Triad, a life-threatening condition characterized by anorexia, amenorrhea (cessation of menstruation) and, eventually, osteoporosis. The triad is most prevalent among athletes for whom low weight is an advantage, Marts says.
Moore is concerned that athletic women aren't typical in their protein intake. Red meat is often seen as a heart attack waiting to happen.