Diet, weight, cytokines and bone health in postmenopausal women.

OBJECTIVES: To investigate diet and nutrition-related factors associated with bone loss in a group of postmenopausal (PM) women. Nutritional intake, inflammatory markers and body composition (weight, body mass index, fat/lean mass) were analysed for associations with bone mineral density (BMD).
DESIGN: A cross sectional study examining correlations between BMD (Duel-energy X ray absorptiometry; (DXA) and dietary intake (3-day diaries), body composition and plasma bone and inflammatory markers: C-terminal telopeptide of type I collagen (CTX) and procollagen type I N propeptide (P1NP), C- reactive protein (CRP), interleukin 6 and 10 (IL-6, IL-10), tumour necrosis factor (TNF) and osteoprotegerin (OPG).
SETTING: Community dwelling women from the Auckland, Hawke's Bay and Manawatu regions in New Zealand. PARTICIPANTS: 142 healthy, PM women aged 50-70 years.
RESULTS: OPG (per kilogram fat mass) was increased in women with osteoporosis (p<0.001) compared to groups classified with normal BMD and osteopenia. Protein, vitamin B12, zinc, potassium and dairy intake were all positively correlated with higher BMD while dairy and potassium intakes also inversely correlated with CTX. Body composition (weight, BMI and fat/lean mass) had strong positive associations with BMD. Multiple regression analysis showed body weight, potassium and dairy intake were predictors of increased BMD in PM women and explained 39% (r2=0.39, p< 0.003) of variance.
CONCLUSION: BMD was negatively correlated with OPG and positively with weight, dairy and potassium intake. This study highlights the importance of maintaining adequate body weight and emphasising dairy and potassium predominantly sourced from fruit/vegetables to reduce bone loss at midlife.