STATE COLLEGE, Pa. – A recent study indicates that exercise is more important than calcium in developing strong bones in girls and young women.
Researchers at Penn State University and Johns Hopkins University found that even when girls took in far less calcium than the recommended daily allowance, bone strength was not significantly affected, said Tom Lloyd of Penn State’s College of Medicine at the Milton S. Hershey Medical Center.
However, when the girls were asked about their exercise habits, a strong correlation was found between exercise and bone strength.
No one is encouraging teens to stop drinking milk, though. The researchers noted that the young women studied were still getting more calcium than many female American teens.
Lloyd said that in tests over a decade, 17 percent of bone strength could be attributed to exercise habits. What’s more, girls with better muscle development also had stronger bones.
“When we looked at their lean mass, what we saw was that a 1 kilogram increase in lean mass was associated with a 21/2 percent increase in their bone strength,” said Moira Petit, another Penn State researcher. Lean body mass is the mass of the body minus the fat.
The Penn State Young Women’s Health Study began in 1990 with 112 12-year-old girls from central Pennsylvania. The ongoing study has tracked the cardiovascular, reproductive and bone health of the subjects, now in their mid-20s. The study was published in the June issue of the Pennsylvania-based Journal of Pediatrics, a lesser known publication than the official journal of the Academy of Pediatrics in Chicago, which is simply called Pediatrics.
Studies have shown that women build most of their bone mass in their early and mid-teens. That bone mass then slowly erodes as women age. Building good bone mass in adolescence, then, is thought to be the best way to prevent osteoporosis in old age.
Dr. Thomas Olenginski, who works with osteoporosis patients at Geisinger Medical Center in Danville, Pa., praised the study for its detailed look at bone strength, but warned that no one should ignore calcium entirely.
“There is a concern that kids might think, ‘I can still drink nothing but sodas as long as I’m working out,’” Olenginski said. “It’s the whole package that’s still important.”
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