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 .
Influence of a fermented protein-fortified dairy product on serum insulin-like growth factor-I in women with anorexia nervosa: A randomized controlled trial.
BACKGROUND & AIMS Patients with anorexia nervosa ( AN ) have low serum IGF-I levels that may contribute to a lower bone mineral mass . We investigated the effects of a fermented , protein-fortified , dairy product on serum IGF-I levels in patients with AN during an in-hospital refeeding program . METHODS In this multicenter , r and omized , double-blind , placebo-controlled , clinical trial conducted at 3 university hospitals and 3 private clinics in France and Switzerl and , 62 women recently admitted with confirmed AN and with a baseline low serum IGF-I level were r and omized to 2 daily isocaloric fresh cheese pots containing either 15 g/150 g or 3 g/150 g ( controls ) of protein for 4 weeks . The primary outcome was the change in IGF-I levels . RESULTS In the primary intention-to-treat analysis , mean serum IGF-I levels increased during the intervention phase from 22.9 ± 1.5 to 28.6 ± 1.3 nmol/L ( means ± SEM ) ( + 20.2 % ) in the intervention group and from 20.2 ± 1.2 to 25.7 ± 1.5 nmol/L ( + 16.8 % ) in controls . In a preplanned analysis of covariance with repeated measures , the between-group difference was close to statistical significance ( P = 0.071 ) . In a post-hoc mixed-regression model analysis , the difference was statistically significant ( 4.9 nmol/l increase ; P = 0.003 ) , as was the change of the ratio IGF-I/IGF-BP3 ( P=0.004 ) . There was no between-group difference in biochemical markers of bone turnover ( osteocalcin , P1NP , CTX ) or in serum parathyroid hormone level . Serum calcium levels slightly increased during the intervention phase in the higher protein group ( P = 0.02 ) . IGF-BP2 decreased significantly more in the intervention group during the follow up period at week 4 after supplements cessation ( P = 0.019 ) . CONCLUSIONS Intake of a fermented , protein-fortified , isocaloric dairy product during 4 weeks may slightly increase serum IGF-I levels in women with AN , without significant changes in bone turnover markers . CLINICAL TRIAL REGISTRATION NUMBER NCT01823822 ( www . clinical trials.gov )
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 .