Calcium and vitamin D fortified milk reduces bone turnover and improves bone density in postmenopausal women over 1 year

Abstract

Purpose: In Malaysia, hip fracture incidence is higher in Chinese women than other ethnic groups. This study compared the effects of a high-calcium vitamin D fortified milk with added FOS-inulin versus regular milk over 1 year on aspects of bone health in Chinese postmenopausal women in Malaysia.

Methods: One-hundred and twenty-one women (mean age 59 (± 4) years) were randomized into two groups: control (n = 60; regular milk, 428 mg calcium per day) or intervention (n = 61; fortified milk at 1200 mg calcium, 96 mg magnesium, 2.4 mg zinc, 15 μg vitamin D and 4 g FOS-inulin per day). At baseline, weeks 12, 24, 36 and 52, parathyroid hormone (PTH), C-Telopeptide of Type I Collagen (CTx-1), Procollagen I Intact N-Terminal propeptide (PINP) and vitamin D levels were assessed. Bone density (BMD) was measured at baseline and week 52 using a GE Lunar iDXA.

Results: Body mass index, lumbar spine and femoral neck BMD did not differ between groups at baseline. Over 52 weeks, mean plasma 25 (OH) D₃ levels increased to 74.8 nmol/L (intervention group) or remained at 63.1 nmol/L (control group) (p < 0.001 between groups). PTH levels increased in the control group (p = 0.001). The intervention resulted in a significant suppression of CTx-1 and PINP at p = 0.018 and p = 0.004. Femoral neck BMD remained stable in the intervention group but decreased significantly in the controls, with a borderline treatment effect (p = 0.07).

Conclusion: Compared with regular milk, the fortified milk suppressed bone turnover markers and tended to increase femoral neck BMD.

Keywords: Bone density; Bone markers; Fortified milk; Postmenopausal women.