The effects of a 30-month dietary intervention on bone mineral density: the Postmenopausal Health Study

Abstract

Low dietary Ca intake and vitamin D insufficiency have been implicated as part of the aetiology leading to osteoporosis. The aim of the present study was to examine the effects of a 30-month dietary intervention that combined supplementation of dairy products fortified with Ca and vitamin D3 and lifestyle and nutrition counselling sessions on bone mineral density (BMD) of postmenopausal women. Sixty-six postmenopausal women (aged 55-65 years) were randomised into a dietary group (DG; n 35), receiving daily and for the first 12 months 1200 mg Ca and 7.5 microg vitamin D3, while for the next 18 months of intervention 1200 mg Ca and 22.5 microg vitamin D3 through fortified dairy products, and a control group (CG; n 31) receiving neither counselling nor dairy products. The DG was found to have more favourable changes in arms (P < 0.001), total spine (P = 0.001) and total body BMD (P < 0.001) compared with the CG. Furthermore, a significant increase was observed for the DG in lumbar spine BMD (0.056; 95 % CI 0.009, 0.103), which was not found to differentiate significantly compared with the change observed in the CG (P = 0.075). In conclusion, the present study showed that intakes of vitamin D of about 22.5 microg/d and of Ca close to the recommended level of 1200 mg from fortified dairy foods for 30 months, with compliance ensured by lifestyle and nutrition counselling sessions, can induce favourable changes in arms, total spine and total body BMD of postmenopausal women.