The effects of different levels of calcium supplementation on the bone mineral status of postpartum lactating Chinese women: a 12-month randomised, double-blinded, controlled trial.

Increasing dietary Ca intake may prevent the excessive mobilisation of bone mineral in nursing mothers. We aimed to investigate whether higher Ca intake could positively modulate the bone mineral changes in Chinese postpartum lactating women. The study was a 12-month randomised, double-blinded, parallel group trial conducted over 12 months. A total of 150 postpartum women were randomly selected to receive either 40 g of milk powder containing 300 mg of Ca and 5 µg of vitamin D (Low-Ca group) or same milk powder additionally fortified with 300 mg of Ca (Mid-Ca group) or 600 mg of Ca (High-Ca group). Bone mineral density (BMD) for the whole body, the lumbar spine, the total left hip and its sub-regions was measured using dual-energy X-ray absorptiometry. A total of 102 subjects completed the whole trial. The duration of total lactating time was 7·9 (SD 2·8) months on average. The intention-to-treat analysis yielded the following mean percentage changes in BMD for the whole body, the lumbar spine and the total left hip, respectively: -0·93 (SD 1·97), 2·11 (SD 4·90) and -1·60 (SD 2·65)% for the Low-Ca group; -0·56 (SD 1·89), 2·21 (SD 3·77) and -1·43 (SD 2·30)% for the Mid-Ca group; and -0·44 (SD 1·67), 2·32 (SD 4·66) and -0·95 (SD 4·08)% for the High-Ca group. The differences between the groups were not statistically significant (P: 0·5-0·9). The results of the complete case analysis were similar. In sum, we found no significant differences in the bone mineral changes from baseline to 12 months in postpartum lactating women consuming milk powder fortified with different levels of Ca.

Fruit and vegetable intake and bone mass in Chinese adolescents, young and postmenopausal women.

OBJECTIVE: Previous studies showed an inconsistent association of fruit and vegetable consumption with bone health. We assessed the associations in Chinese adolescents, young and postmenopausal women. DESIGN: A cross-sectional study conducted in China during July 2009 to May 2010. SETTING: Bone mineral density (BMD) and content (BMC) at the whole body, lumbar spine and left hip were measured with dual-energy X-ray absorptiometry. Dietary intakes were assessed using an FFQ. All these values were separately standardized into Z-scores in each population subgroup. SUBJECTS: One hundred and ten boys and 112 girls (11-14 years), 371 young women (20-34 years, postpartum within 2 weeks) and 333 postmenopausal women (50-70 years). RESULTS: After adjustment for potential covariates, analysis of covariance showed a significantly positive association between fruit intake and BMD and BMC in all participants combined (P-trend: < 0.001 to 0.002). BMD Z-score increased by 0.25 (or 2.1 % of the mean), 0.22 (3.5 %), 0.23 (3.0 %) and 0.25 (3.5 %), and BMC Z-score increased by 0.33 (5.7 %), 0.25 (5.8 %), 0.34 (5.9 %) and 0.29 (4.7 %), at the total body, lumbar spine, total hip and femoral neck in participants belonging to the top tertile compared with the bottom tertile of fruit intake (all P < 0.05), respectively. There was no significant association between vegetable intake and bone mass at all bone sites studied except for total body BMD (P = 0.030). Relatively more pronounced effects were observed in boys and postmenopausal women. CONCLUSION: Our findings add to the existing evidence that fruits and vegetables may have a bone sparing effect.