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 .
The effects of a two-year randomized, controlled trial of whey protein supplementation on bone structure, IGF-1, and urinary calcium excretion in older postmenopausal women.
The effects of dietary protein on bone structure and metabolism have been controversial , with evidence for and against beneficial effects . Because no long-term r and omized , controlled studies have been performed , a two-year study of protein supplementation in 219 healthy ambulant women aged 70 to 80 years was undertaken . Participants were r and omized to either a high-protein drink containing 30 g of whey protein ( n = 109 ) or a placebo drink identical in energy content , appearance , and taste containing 2.1 g of protein ( n = 110 ) . Both drinks provided 600 mg of calcium . Dual-energy X-ray absorptiometric ( DXA ) hip areal bone mineral density ( aBMD ) , 24-hour urinary calcium excretion , and serum insulin-like growth factor 1 ( IGF-1 ) were measured at baseline and at 1 and 2 years . Quantitative computed tomographic ( QCT ) hip volumetric bone mineral density ( vBMD ) and a femoral neck engineering strength analysis were undertaken at baseline and at 2 years . Baseline average protein intake was 1.1 g/kg of body weight per day . There was a significant decrease in hip DXA aBMD and QCT vBMD over 2 years with no between-group differences . Femoral neck strength was unchanged in either group over time . The 24-hour urinary calcium excretion increased significantly from baseline in both groups at 1 year but returned to baseline in the placebo group at 2 years , at which time the protein group had a marginally higher value . Compared with the placebo group , the protein group had significantly higher serum IGF-1 level at 1 and 2 years ( 7.3 % to 8.0 % , p < .05 ) . Our study showed that in protein-replete healthy ambulant women , 30 g of extra protein increased IGF-1 but did not have beneficial or deleterious effects on bone mass or strength . The effect of protein supplementation in population s with low dietary protein intake requires urgent attention
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 .