When we think of running nutrition, our minds turn to what foods will help us run faster, better, easier. What foods give our bodies the pep they need to sustain our high-energy pursuits. But, there’s also that other consideration: how can not eating enough, especially during critical growth periods in our lives, affect our body structure and health when we take out more than we put in?
Researchers at San Diego State University in California and Rocky Mountain University of Health Professions in Utah looked at the eating and exercise habits of a group of adolescent female cross-country runners. Their report in this month’s American Journal of Clinical Nutrition discusses the possible relationships between disordered eating and menstrual irregularity and low bone mineral density in young female runners, ages 13-18 years old.
To start, the researchers wanted to begin to understand which components of disordered eating (shape, weight or eating concerns and dietary restraint) may be associated with menstrual irregularity and low bone mineral density. They used answers supplied by 93 young runners in an Eating Disorder Examination Questionnaire (EDE-Q) to divide them into groups for analysis on menstrual status and bone measures.
In the end, the researchers found that dietary restraint- “the intent to limit calorie intake, whether or not the effort was successful”- was the component of disordered eating most associated with low bone mineral density. High weight or shape concerns or reported pathological behaviors such as binge eating, vomiting and excessive exercise were not associated with low bone mineral density, unless they occurred alongside dietary restraint. Though they did not observe any significant differences in menstrual function among the groups, the results did reveal a trend toward more menstrual irregularities in runners with high dietary restraint than in runners with high weight or shape concern scores on the EDE-Q.
Though the results of this study are only a start to understanding the causes of menstrual dysfunction and low bone mineral density in adolescent female runners, according to study author Michelle Barrack, the hope is to “determine the eating and exercise behaviors that promote bone deposition in young runners so to provide practical recommendations that allow for optimal performance, injury prevention and accumulation of an adequate peak bone mass.” Future studies will further investigate how factors such as diet and exercise relate to the hormones that regulate menstruation and bone metabolism in young female runners. The results may offer clues on how to reduce the risk of developing osteoporosis and osteoporosis-related fractures.