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Winter 1995

Research Magazine > ARCHIVE > Winter 95 > Article

Women Athletes Build Body and Bone
by Helen Fosgate

Conventional wisdom holds that diet and exercise are crucial for a healthy body. That's a precarious balance, however, for a world-class gymnast -- especially one not yet in her teens.

"Young women athletes are trying to maintain very low body weight and low fat percentages," said UGA foods and nutrition researcher Richard Lewis. "My intention is to study long-term bone health as a consequence of diet and participation in athletics."

Female gymnasts and dancers, for example, may begin training as young as age three and by the time they enter their second decade are already under constant pressure to be fit and strong but to look lean and "feminine." For this reason, eating disorders are not uncommon among female athletes. Now researchers have begun to question whether girls and young women who train in gymnastics and other strenuous sports may be jeopardizing their future health.

Studies show female gymnasts consume fewer calories than non-athletes, especially calories from calcium-rich dairy products. More than half have a history of menstrual disruption because their bodies simply cannot carry out this biological function regularly. Studies also show that abnormal suppression of menstruation and some eating disorders promote bone loss. These facts led Lewis to take a closer look at the connection between strenuous athletic training and osteoporosis, a common disease of women.

"We began our research with the idea that these athletes may be at risk for osteoporosis because of the combination of restrictive eating, heavy-duty exercise and irregular menstruation," he said.

In fact, that preconception turned out to be completely wrong.

Osteoporosis -- literally, "porous bones" -- affects more than 25 million Americans. Twenty-five percent of women over the age of 45 and 90 percent of those older than 75 suffer from the condition, in which a loss of calcium gradually weakens the bones. The tiny spaces between bone tissue grow larger, making once-dense bones porous and fragile.

Using a special X-ray machine that measures bone density, Lewis compared the lumbar spine and hip bone densities of 30 female college gymnasts to a group of non-athletes of similar size, age and weight. He also studied 20 former college gymnasts who are now 35 to 40 years old and compared them to a similar group of women who had never competed in sports. He was especially interested in the bone health of former gymnasts since women begin to lose bone mass after about age 30.

Surprisingly, Lewis' studies showed that despite the gymnasts' restricted diets and prevalence toward menstrual irregularity, they had denser bone than their non-athlete counterparts. Even the former gymnasts, whose lifestyles now include a more normal diet and exercise regimen, posted higher bone densities than other women their age.

"It may be that participation in gymnastics actually offers some residual protection against osteoporosis," Lewis said.

Lewis' research, conducted in collaboration with Patrick O'Connor, a UGA assistant professor of exercise science, will be published in the journal Medicine, Science, Sports and Exercise this April. In the meantime he plans to study the interaction between calcium and other minerals with weight-bearing exercise in determining bone health.

Still, to confirm his findings about the effect of diet and athletic training on bone health, Lewis also intends to investigate the role genes play in determining bone density. By documenting the bone densities of very young gymnasts and then following them over time, Lewis plans to establish a baseline measure of bone density before a girl begins athletic training in earnest.

"It may be that young girls who stick with gymnastics to participate at the collegiate level have genetically denser bones," Lewis said, "and if so, we need to establish that."

For more information please check out http://www.fcs.uga.edu/people/fac.php3?bio_key=51 or e-mail rlewis@fcs.uga.edu


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