Protein consumption is an important predictor of lower limb bone mass in elderly women.
BACKGROUND
The effect of protein intake on bone density is uncertain, and evidence exists for beneficial effects of both low and high protein intakes.


OBJECTIVE
The objective was to study the relation between protein consumption and bone mass in elderly women with allowance for other lifestyle factors affecting bone metabolism.


METHODS
We conducted a cross-sectional and longitudinal study of a population-based sample of 1077 women aged 75 +/- 3 y. At baseline, protein consumption was measured with a food-frequency questionnaire, and bone mass and structure were measured by using quantitative ultrasound of the heel. One year later, hip bone mineral density (BMD) was measured by using dual-energy X-ray absorptiometry.


RESULTS
Subjects consumed a mean (+/-SD) of 80.5 +/- 27.8 g protein/d (1.19 +/- 0.44 g protein/kg body wt). Regression analysis showed a positive correlation between protein intake and qualitative ultrasound of the heel and BMD after adjustment for age, body mass index, and other nutrients. The dose-response effect was best characterized by protein consumption expressed in tertiles, such that subjects in the lowest tertile (<66 g protein/d) had significantly lower qualitative ultrasound of the heel (1.3%) and hip BMD (2.6%) than did the subjects in the higher tertiles (>87 g protein/d).


CONCLUSIONS
These data suggest that protein intakes for elderly women above current recommendations may be necessary to optimize bone mass.
Devine
Amanda
A
School of Medicine and Pharmacology, University of Western Australia, Perth, Australia. adevine@cyllene.uwa.edu.au
Dick
Ian M
IM
Islam
Amirul F M
AF
Dhaliwal
Satvinder S
SS
Prince
Richard L
RL
D015502:Absorptiometry, Photon / Q000379:methods; D000368:Aged; D000375:Aging / Q000502:physiology; D000704:Analysis of Variance; D015992:Body Mass Index; D015519:Bone Density / Q000502:physiology*; D001842:Bone and Bones / Q000378:metabolism*; D002111:Calcaneus / Q000000981:diagnostic imaging; D015331:Cohort Studies; D003430:Cross-Sectional Studies; D004032:Diet; D004044:Dietary Proteins / Q000008:administration & dosage* / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D009751:Nutritional Requirements; D015663:Osteoporosis, Postmenopausal / Q000378:metabolism / Q000517:prevention & control*; D010384:Pelvic Bones / Q000000981:diagnostic imaging; D011237:Predictive Value of Tests; D011795:Surveys and Questionnaires; D014463:Ultrasonography
D004044:Dietary Proteins