In older people with osteoporosis , higher protein intake ( ≥ 0.8-g/kg body weight/day , i.e. , above the current RDA ) is associated with higher BMD , a slower rate of bone loss , and reduced risk of hip fracture , provided that dietary calcium intakes are adequate .
Intervention with dietary protein supplements attenuate age-related BMD decrease and reduce bone turnover marker levels , together with an increase in IGF-I and a decrease in PTH .
There is no evidence that diet-derived acid load is deleterious for bone health .
Thus , insufficient dietary protein intakes may be a more severe problem than protein excess in the elderly .
A summary of systematic review s and meta-analyses addressing the benefits and risks of dietary protein intakes  for  bone health in adults suggests that dietary protein levels even above the current RDA may be beneficial in reducing bone loss and hip fracture risk , provided calcium intakes are adequate .
Several systematic review s and meta-analyses have addressed the benefits and risks of dietary protein intakes for bone health in adults .
Adequate supplies of dietary protein are required for optimal bone growth and maintenance of healthy bone .
Variation in protein intakes within the “ normal ” range accounts for 2–4 % of BMD variance in adults .
Biomarker-calibrated protein intake and bone health in the Women's Health Initiative clinical trials and observational study.
BACKGROUND The effects of dietary protein on bone health are controversial . OBJECTIVE We examined the relation between protein intake with fracture and  bone mineral density ( BMD )  within the Women 's Health Initiative ( WHI ) . DESIGN This prospect i ve analysis included 144,580 women aged 50 - 79 y at baseline in the WHI clinical trials ( CTs ) and observational study ( OS ) that recruited participants in 1993 - 1998 with follow-up through 2011 . Self-reported clinical fractures were collected semiannually through the original end of the trials ( WHI CTs ) and annually ( WHI OS ) by question naires . Hip fracture was adjudicated by a central review of radiology reports . BMDs for total body , hip , and spine were measured at baseline and 3 and 6 y in 9062 women at 3 WHI clinics by using dual-energy X-ray absorptiometry .  Protein intake was assessed via food-frequency question naire and calibrated by using biomarkers of energy and protein intakes . Associations between protein intake and fracture were estimated by using Cox proportional hazards regression , and the relation between protein intake and BMD was estimated by using linear regression . RESULTS Median biomarker-calibrated protein intake was 15 % of energy intake . Per 20 % increase in calibrated protein intake ( percentage of energy ) , there was no significant association with total fracture ( HR : 0.99 ; 95 % CI : 0.97 , 1.02 ) or hip fracture ( HR : 0.91 ; 95 % CI : 0.84 , 1.00 ) , but there was an inverse association with forearm fracture ( HR : 0.93 ; 95 % CI : 0.88 , 0.98 ) . Each 20 % increase in calibrated protein intake was associated with a significantly higher BMD for total body ( mean 3-y change : 0.003 g/cm² ; 95 % CI : 0.001 , 0.005 g/cm² ) and hip ( mean 3-y change : 0.002 g/cm² ; 95 % CI : 0.001 , 0.004 g/cm² ) . CONCLUSIONS Higher biomarker-calibrated protein intake within the range of usual intake was inversely associated with forearm fracture and was associated with better maintenance of total and hip BMDs . These data suggest higher protein intake is not detrimental to bone health in postmenopausal women
In older people with osteoporosis , higher protein intake ( ≥ 0.8-g/kg body weight/day , i.e. , above the current RDA ) is associated with higher BMD , a slower rate of bone loss , and reduced risk of hip fracture , provided that dietary calcium intakes are adequate .
Intervention with dietary protein supplements attenuate age-related BMD decrease and reduce bone turnover marker levels , together with an increase in IGF-I and a decrease in PTH .
There is no evidence that diet-derived acid load is deleterious for bone health .
Thus , insufficient dietary protein intakes may be a more severe problem than protein excess in the elderly .
A summary of systematic review s and meta-analyses addressing the benefits and risks of dietary protein intakes  for  bone health in adults suggests that dietary protein levels even above the current RDA may be beneficial in reducing bone loss and hip fracture risk , provided calcium intakes are adequate .
Several systematic review s and meta-analyses have addressed the benefits and risks of dietary protein intakes for bone health in adults .
Adequate supplies of dietary protein are required for optimal bone growth and maintenance of healthy bone .
Variation in protein intakes within the “ normal ” range accounts for 2–4 % of BMD variance in adults .