A report on the study, conducted at the University of North Carolina at Chapel Hill, appears in the current (October) issue of the Journal of the American College of Nutrition. Isoflavones are chemicals made by plants, possibly to protect them against oxidation and organisms that might attack them, and soy beans are an especially good source.
"We had seen earlier reports that isoflavones had beneficial effects on the bones of women undergoing menopause or who already were postmenopausal," said Dr. John J.B. Anderson, professor of nutrition at the UNC schools of public health and medicine. "We felt that if this were true for older women, it might also be true for healthy young women and could help protect their bones over their lifetimes."
The study involved 28 young women in their early 20s. One group of 15 volunteers took soy protein supplements enriched with isoflavones for a year. The second group consumed an isoflavone-deficient soy protein diet, along with other foods over the same period. No one knew until the study ended who was in which group.
Researchers assessed the bone mineral content and density of each subject using dual-energy X-ray absorptiometric measurements at the beginning of the project, after six months and after a year, Anderson said. In other words, they scanned the young women's whole bodies, spines and upper thighbones to determine how dense their bones were and if those measurements changed over time. The team also controlled for each woman's body mass index -- a measure of how heavy she was for her height along with her physical activity level and diet.
"We found no chan
Contact: David Williamson
University of North Carolina at Chapel Hill