Phosphorus intake in western countries is high due to abundant consumption of animal protein and also because of the expanding use of highly absorbable food additive phosphate (FAP) salts in food processing. P is essential for hydroxyapatite in bone, but short-term studies have shown that high P, especially FAP, intake has acute negative effects on bone metabolism. In this study, we investigated the associations between dietary P intake and bone turnover markers by using a cross-sectional design in 37- to 47-year-old premenopausal Caucasian females (n=370). Serum intact pro-collagen type I amino-terminal propeptide (iPINP), collagen type 1 cross-linked C-terminal telopeptide (CTX), total osteocalcin (totOC), carboxylated osteocalcin (cOC), and some other biomarkers related to bone metabolism were analyzed. Data were examined by ANOVAS and covariance in tertiles of both total P (TP) and FAP intake, and molar calcium:phosphorus (Ca:P) ratio, and subjects were stratified by contraceptive use. Among contraceptive users (n=123), high TP intake was associated with lower bone formation in terms of low cOC (P=0.034), and a tendency for an association with decreased turnover as lower totOC (P=0.094) was found. In subjects with a high Ca:P ratio, a tendency existed for an association with decreased bone resorption (i.e. lower CTX) (P=0.081). Among those who did not use contraceptives (n=247), high TP intake was associated with decreased bone formation (i.e. low iPINP, P=0.034), and a borderline association with decreased resorption (i.e. low CTX, P=0.056) was present. High FAP intake was associated with low cOC (P=0.008) and a tendency for low totOC (P=0.087). In summary, high P intake was weakly associated with lowered bone turnover, and the association was modulated by hormonal contraceptive use, but the exact role of high P intake in bone health remains to be elucidated.
17 May 2014 - 20 May 2014