Compromised Bone Health in Non-Obese, Older Women with Low Caloric Intake

Low calorie diets are often employed to reverse obesity and lower the risk of other diseases. Further, to maintain a certain physique and/or minimize the incidence of obesity, normal weight, older women may consume a diet low in calories. However, a low caloric intake can potentially compromise bone formation elevating the risk of osteoporosis. Thus, the purpose of this study was to compare the bone mineral density (BMD) from non-obese, peri- and postmenopausal women who were placed into one of three groups based upon their daily caloric intake to determine if bone health was compromised when caloric intake was low. Women (age range 44-80 years old) with a body mass index < 25 were separated into one of three groups based upon a dietary analysis to assess nutritional intake: those who consumed 100% of the recommended minimum daily requirement (RMDR, n = 21), 80% RMDR (n = 16), or 55% RMDR (n = 15). BMD was determined via dual energy X-ray absorptiometer from the lumbar spine and femur (left & right). The 55% RMDR group demonstrated significantly lower femoral BMD (similar to 10% lower, P < 0.05) and a trend toward lower BMD of the spine compared to both the 80% RMDR (P = 0.13) and 100% RMDR groups (P = 0.15). There were no significant differences in BMD between the 80% RMDR and 100% RMDR groups. The results suggest that bone health was maintained with moderately low caloric intake (i.e. 80%RMDR) whereas extremely low caloric intake (i.e. 55% RMDR) can compromise bone health in non-obese, older women.