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 .
Effects of a multi-component exercise program and calcium–vitamin-D3-fortified milk on bone mineral density in older men: a randomised controlled trial
Summary We examined the independent and combined effects of a multi-component exercise program and calcium – vitamin-D3-fortified milk on bone mineral density ( BMD ) in older men .  Exercise result ed in a 1.8 % net gain in femoral neck BMD , but additional calcium – vitamin D3 did not enhance the response in this group of older well-nourished men . Introduction This 12-month r and omised controlled trial assessed whether calcium – vitamin-D3-fortified milk could enhance the effects of a multi-component exercise program on BMD in older men . Methods Men ( n = 180 ) aged 50–79 years were r and omised into : ( 1 )  exercise + fortified milk ; ( 2 ) exercise ; ( 3 ) fortified milk ; or ( 4 ) controls . Exercise consisted of high intensity progressive resistance training with weight-bearing impact exercise . Men assigned to fortified milk consumed 400 mL/day of low fat milk providing an additional 1,000 mg/day calcium and 800 IU/day vitamin D3 . Femoral neck ( FN ) , total hip , lumbar spine and trochanter BMD and body composition ( DXA ) , muscle strength 25-hydroxyvitamin D and parathyroid hormone ( PTH ) were assessed . Results There were no exercise-by-fortified milk interactions at any skeletal site . Exercise result ed in a 1.8 % net gain in FN BMD relative to no-exercise ( p < 0.001 ) ; lean mass ( 0.6 kg , p < 0.05 ) and muscle strength ( 20–52 % , p < 0.001 ) also increased in response to exercise . For lumbar spine BMD , there was a net 1.4–1.5 % increase in all treatment groups relative to controls ( all p < 0.01 ) . There were no main effects of fortified milk at any skeletal site . Conclusion A multi-component community-based exercise program was effective for increasing FN BMD in older men , but additional calcium – vitamin D3 did not enhance the osteogenic response
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 .