CHANGES IN BONE-MINERAL DENSITY ASSOCIATED WITH DIETARY-INDUCED LOSS OF BODY-MASS IN YOUNG-WOMEN

1. Moderately overweight, premenopausal women were assessed for bone m ineral density of the total body, lumbar spine and proximal femur befo re and after 6 months of modest dietary restriction (minimum 4800 kJ/d ay). The aim was to evaluate the effect of loss of body mass on bone m ineral density. 2. Dietary assessment included two analyses of 3 day w eighed food intakes, one before and the other after 4 months of dietar y restriction. Energy and calcium intakes were significantly reduced b y 27% and 5%, respectively. The change in calcium intake was negativel y and significantly related to initial levels of calcium intake. 3. A significant mean loss of 3.4 +/- 3.1 kg in body mass was achieved main ly in the first 3 months of the study; it was accompanied by significa nt losses at 6 months in bone mineral density in the total body of 0.7 % and in the lumbar spine of 0.5%. There were no changes in the femur. 4. The change in bone mineral density in the total body was significa ntly related to the reduced absolute calcium intake, initial bone mine ral density and loss of body mass. The change in bone mineral density in the spine was significantly related to the change in calcium intake . 5. These modest losses could be a threat in women with lower bone mi neral density, and indicate the importance of maintaining a high intak e of calcium during dietary restriction.