Protein consumption and bone fractures in women. Protein intake: effects on bone mineral density and the rate of bone loss in elderly women. Calcium intake influences the association of protein intake with rates of bone loss in elderly men and women. The Effect of a Whey Protein Supplement on Bone Mass in Older Caucasian Adults. Effect of dietary protein supplements on calcium excretion in healthy older men and women. Association of protein intake with bone mineral density and bone mineral content among elderly women: The OSTPRE fracture prevention study Proteins, dietary acid load, and calcium and risk of postmenopausal fractures in the E3N French women prospective study. 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. Dietary protein intake and risk of osteoporotic hip fracture in elderly residents of Utah. Is dietary counselling effective in increasing dietary calcium, protein and energy intake in patients with osteoporotic fractures? A randomized controlled clinical trial. Protein intake and lumbar bone density: the Multi-Ethnic Study of Atherosclerosis (MESA). Effect of protein supplementation during a 6-month strength and conditioning program on areal and volumetric bone parameters. A high ratio of dietary animal to vegetable protein increases the rate of bone loss and the risk of fracture in postmenopausal women. Study of Osteoporotic Fractures Research Group. The Relation between Dietary Protein, Calcium and Bone Health in Women: Results from the EPIC-Potsdam Cohort Association of protein intake with the change of lean mass among elderly women: The Osteoporosis Risk Factor and Prevention – Fracture Prevention Study (OSTPRE-FPS) Protein intake, weight loss, and bone mineral density in postmenopausal women. Dietary protein intake is associated with better physical function and muscle strength among elderly women.
Dietary protein increases urinary calcium losses and has been associated with higher rates of hip fracture in cross-cultural studies . However , the relation between protein and risk of  osteoporotic bone fractures among individuals has not been examined in detail . In this prospect i ve study , usual dietary intake was measured in 1980 in a cohort of 85,900 women , aged 35 - 59 years , who were participants in the Nurses ' Health Study . A mailed food frequency question naire was used and incident hip ( n = 234 ) and distal forearm ( n = 1,628 ) fractures were identified by self-report during the following 12 years . Information on other factors related to osteoporosis , including obesity , use of postmenopausal estrogen , smoking , and physical activity , was collected on biennial question naires . Dietary measures were up date d in 1984 and 1986 . Protein was associated with an increased risk of forearm fracture ( relative risk ( RR ) = 1.22 , 95 % confidence interval ( Cl ) 1.04 - 1.43 , p for trend = 0.01 ) for women who consumed more than 95 g per day compared with those who consumed less than 68 g per day . A similar increase in risk was observed for animal protein , but no association was found for consumption of vegetable protein . Women who consumed five or more servings of red meat per week also had a significantly increased risk of forearm fracture ( RR = 1.23 , 95 % Cl 1.01 - 1.50 ) compared with women who ate red meat less than once per week . Recall of teenage diet did not reveal any increased risk of forearm fracture for women with higher consumption of animal protein or red meat during this earlier period of life . No association was observed between  adult protein intake  and the incidence of hip fractures , though power to assess this association was low BACKGROUND The role of dietary protein in bone metabolism is controversial . OBJECTIVE We investigated the associations of dietary protein intake with baseline bone mineral density ( BMD ) and the rate of bone loss over 3 y in postmenopausal elderly women . DESIGN Women aged 65 - 77 y ( n = 489 ) were enrolled in an osteoporosis intervention trial . We studied the associations of protein intake as a percentage of energy with baseline BMD and the rate of bone loss in 96 women in the placebo group ( n = 96 ) . We also examined the effect of the interaction of dietary  calcium  intake with protein intake on BMD . RESULTS In the cross-sectional study , a higher intake of protein was associated with higher BMD . BMD was significantly higher ( P < 0.05 ) in the spine ( 7 % ) , midradius ( 6 % ) , and total body ( 5 % ) in subjects in the highest quartile of protein intake than in those in the lower 2 quartiles . This positive association was seen in women with calcium intakes > 408 mg/d . There was no significant effect of protein intake on hip BMD . In the longitudinal study of the placebo group , there was no association between protein intake and the rate of bone loss . CONCLUSIONS The highest quartile of protein intake (: 72 g/d ) was associated with higher BMD  in elderly women at baseline only when the calcium intake exceeded 408 mg/d . In the longitudinal study , no association was seen between protein intake and the rate of bone loss , perhaps because the sample size was too small or the follow-up period of 3 y was not long enough to detect changes BACKGROUND There is currently no consensus on the effect of dietary protein intake on the skeleton , but there is some indication that low calcium intakes adversely influence the effect of dietary protein on fracture risk . OBJECTIVE The objective of the present study was to determine whether supplemental calcium citrate malate and vitamin D influence any associations between  protein intake and change in bone mineral density ( BMD ) . DESIGN Associations between protein intake and change in BMD were examined in 342 healthy men and women ( aged > or = 65 y ) who had completed a 3-y , r and omized , placebo-controlled trial of calcium and vitamin D supplementation . Protein intake was assessed at the midpoint of the study with the use of a food-frequency question naire and  BMD  was assessed every 6 mo by dual-energy X-ray absorptiometry . RESULTS The mean ( + /-SD ) protein intake of all subjects was 79.1 + /- 25.6 g/d and the mean total calcium intakes of the supplemented and placebo groups were 1346 + /- 358 and 871 + /- 413 mg/d , respectively . Higher protein intake was significantly associated with a favorable 3-y change in total-body BMD in the supplemented group ( in a model containing terms for age , sex , weight , total energy intake , and dietary calcium intake ) but not in the placebo group . The pattern of change in femoral neck BMD with increasing protein intake in the supplemented group was similar to that for the total body . CONCLUSION Increasing protein intake may have a favorable effect on change in BMD in elderly subjects supplemented with calcium citrate malate and vitamin CONTEXT It has been assumed that the increase in urine calcium ( Ca ) that accompanies an increase in dietary protein was due to increased bone resorption . However , studies using stable Ca isotopes have found that dietary protein increases Ca absorption without increasing bone resorption . OBJECTIVE The objective of the study was to investigate the impact of a moderately high protein diet on bone mineral density ( BMD ) . DESIGN This was a r and omized , double-blind , placebo-controlled trial of protein supplementation daily for 18 months . SETTING The study was conducted at two institutional research centers . PARTICIPANTS Two hundred eight older women and men with a body mass index between 19 and 32 kg/m(2 ) and a self-reported protein intake between 0.6 and 1.0 g/kg participated in the study . INTERVENTION Subjects were asked to incorporate either a 45-g whey protein or isocaloric maltodextrin supplement into their usual diet for 18 months . MAIN OUTCOME MEASURE BMD by dual-energy x-ray absorptiometry , body composition , and markers of skeletal and mineral metabolism were measured at baseline and at 9 and 18 months . RESULTS There were no significant differences between groups for changes in L-spine BMD ( primary outcome ) or the other skeletal sites of interest . Truncal lean mass was significantly higher in the protein group at 18 months ( P = .048 ) . C-terminal telopeptide ( P = .0414 ) , IGF-1 ( P = .0054 ) , and urinary urea ( P < .001 ) were also higher in the protein group at the end of the study period . There was no difference in estimated glomerular filtration rate at 18 months . CONCLUSION Our data suggest that protein supplementation above the recommended dietary allowance ( 0.8 g/kg ) may preserve fat-free mass without adversely affecting skeletal health or renal function in healthy older adults Currently there is no consensus on the impact of dietary protein on calcium and bone metabolism . This study was conducted to examine the effect of increasing protein intake on urinary calcium excretion and to compare circulating levels of IGF-I and biochemical markers of bone turnover in healthy older men and women who consumed either a high or a low protein food supplement for 9 wk . Thirty-two subjects with usual protein intakes of less than 0.85 g/kg.d were r and omly assigned to daily high ( 0.75 g/kg ) or low ( 0.04 g/kg ) protein supplement groups . Isocaloric diets were maintained by advising subjects to reduce their intake of carbohydrates . Selected biochemical measurements were made at baseline and on d 35 and either d 49 or 63 . Changes in urinary calcium excretion in the two groups did not differ significantly over the course of the study . The high protein group had significantly higher levels of serum IGF-I ( P = 0.008 ) and lower levels of urinary N-telopeptide ( P = 0.038 ) over the period of d 35 - 49 or 63 . We conclude that increasing protein intake from 0.78 to 1.55 g/kg.d with meat supplements in combination with reducing carbohydrate intake did not alter urine calcium excretion , but was associated with higher circulating levels of IGF-I , a bone growth factor , and lowered levels of urinary N-telopeptide , a marker of bone resorption . In contrast to the widely held belief that increased protein intake results in calcium wasting , meat supplements , when exchanged isocalorically for carbohydrates , may have a favorable impact on the skeleton in healthy older men and women Abstract It has been hypothesized that high protein intakes are associated with lower bone mineral content ( BMC ) . Previous studies yield conflicting results and thus far no studies have undertaken the interaction of body mass index ( BMI ) and physical activity with protein intakes in relation to BMC and bone mineral density ( BMD ) . Objective To evaluate the associations of dietary total protein ( TP ) , animal protein ( AP ) and plant protein ( PP ) intakes with BMC and BMD and their changes . We tested also the interactions of protein intake with , obesity ( BMI ≤30 vs. > 30 kg/m2 ) and physical activity level ( passive vs. active ) . Design / Setting Prospect i ve cohort study ( Osteoporosis Risk-Factor and Fracture-Prevention Study ) . Participants / measures At the baseline , 554 women aged 65 - 72 years filled out a 3-day food record and a question naire covering data on lifestyle , physical activity , diseases , and medications . Intervention group received calcium 1000 mg/d and cholecalciferol 800 IU for 3 years . Control group received neither supplementation nor placebo . Bone density was measured at baseline and year 3 , using dual energy x-ray absorptiometry . Multivariable regression analyses were conducted to examine the associations between protein intake and BMD and BMC . Results In cross-sectional analyses energy-adjusted TP ( P≤0·029 ) and AP ( P≤0·045 ) but not PP ( g/d ) were negatively associated with femoral neck ( FN ) BMD and BMC . Women with TP≥1·2 g/kg/body weight ( BW ) ( Ptrend≤0·009 ) had lower FN , lumbar spine ( LS ) and total BMD and BMC . In follow-up analysis , TP ( g/kg/BW ) was inversely associated with LS BMD and LS BMC . The detrimental associations were stronger in women with BMI < 30 kg/m2 . In active women , TP ( g/kg/BW ) was positively associated with LS BMD and FN BMC changes . Conclusions This study suggests detrimental associations between protein intake and bone health . However , these negative associations maybe counteracted by BMI > 30 kg/m2 and physical activity Excess dietary proteins and " acid ash " diets have been suspected to increase the risk of osteoporosis , but experimental and epidemiological evidence is mixed . We aim ed to determine whether the association between protein intake and the overall acid-base equilibrium of the diet ( as renal net acid excretion [ RNAE ] estimate ) and fracture risk vary according to calcium intake . During an average of 8.37 + /- 1.73 yr of follow-up , 2408 women reported a fracture ( excluding high-impact trauma ) among 36,217 postmenopausal women from the E3N prospect i ve study . We used Cox regression models to study the interaction between calcium and , respectively , proteins and RNAE , from the 1993 dietary question naire for fracture risk determination , adjusting for potential confounders . There was no overall association between fracture risk and total protein or RNAE . However , in the lowest quartile of calcium ( < 400 mg/1000 kcal ) , high protein intake was associated with a significant increased fracture risk ( RR = 1.51 for highest versus lowest quartile ; 95 % CI , 1.17 - 1.94 ) . An increasing fracture risk with increasing animal protein intake was also observed ( trend , p < 0.0001 ) . A similar pattern of interaction for fracture risk was observed between RNAE and calcium . In this Western population of postmenopausal women with normal to high protein intake and fairly high calcium intake , there was no overall association between total protein or RNAE and fracture risk . However , there was some evidence that high protein-high acid ash diets were associated with an increased risk of fracture when calcium intake was low ( < 400 mg/1000 kcal ) 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 UNLABELLED The role of protein intake in osteoporosis is unclear . In a case-control study in Utah ( n = 2501 ) , increasing level of protein intake was associated with a decreased risk of hip fracture in men and women 50 - 69 years of age but not in those 70 - 89 years of age . Protein intake may be important for optimal bone health . INTRODUCTION Protein is an important component of bone , but the role of dietary protein intake in osteoporosis and fracture risk remains controversial . MATERIAL AND METHODS The role of dietary protein intake in osteoporotic hip fracture was evaluated in a statewide case-control study in Utah . Patients , 50 - 89 years of age , with hip fracture ( cases ) were ascertained through surveillance of 18 Utah hospitals during 1997 - 2001 . Age- and gender-matched controls were r and omly selected . Participants were interviewed in their place of residence , and diet was assessed using a picture-sort food frequency question naire previously reported to give a useful measure of usual dietary intake in the elderly Utah population . The association between  protein intake  and risk of hip fracture was examined across quartiles of protein intake and stratified by age group for 1167 cases ( 831 women , 336 men ) and 1334 controls ( 885 women , 449 men ) . RESULTS In logistic regression analyses that controlled for gender , body mass index , smoking status , alcohol use , calcium , vitamin D , potassium , physical activity , and estrogen use in women , the odds ratios ( OR ) of hip fracture decreased across increasing quartiles of total protein intake for participants 50 - 69 years of age ( OR : 1.0 [ reference ] ; 0.51 [ 95 % CI : 0.30 - 0.87 ] ; 0.53 [ 0.31 - 0.89 ] ; 0.35 [ 0.21 - 0.59 ] ; p < 0.001 ) . No similar associations were observed among participants 70 - 89 years of age . Results from analyses stratified by low and high calcium and potassium intake did not differ appreciably from the results presented above . CONCLUSION Higher total protein intake was associated with a reduced risk of hip fracture in men and women 50 - 69 years of age but not in men and women 70 - 89 years of age . The association between  dietary protein intake  and risk of hip fracture may be modified by age . Our study supports the hypothesis that adequate dietary protein is important for optimal bone health in the elderly 50 - 69 years of age To determine the feasibility of increasing the calcium , protein and calorie intake of osteoporotic fracture patients by repeated dietary counselling delivered by a dietitian , a r and omized controlled trial was conducted . Among 189 patients presenting with osteoporotic fractures to an Orthopaedics and Traumatology Department of a large regional hospital , 98 patients were r and omized to the intervention group and 91 were r and omized to the control group ( with usual care ) . Intervention group received three sessions of dietary counselling with tailored made recommendations over a period of 4 months , while the control group only received dietary assessment and pamphlets on the prevention of osteoporosis . Almost all subjects in both intervention and control groups had calcium intake below the recommended level of 1000 mg at baseline . Half and 60 % of subjects in both groups had total energy and protein intake below recommended levels respectively . The mean weights of control and intervention groups at baseline were 51.5 and 50.9 kg respectively , while the body mass index ( BMI ) were 22.6 ( kg m(-2 ) ) and 22.6 ( kg m(-2 ) ) respectively . After dietary intervention , significant increase of intake was seen in calcium intake ( P = 0.0095 by t-test ) in the intervention group . No significant increase was seen in protein or calorie intake . No significant change was observed in the body weight or BMI although there was a positive trend in the intervention group for all these parameters . We concluded that there was general malnutrition in Chinese elderly who presented with osteoporotic fractures . Dietary calcium could be increased by repeated professional dietary counselling . Future studies with longer duration and more objective clinical outcomes will be helpful to further demonstrate the long-term effects of dietary intervention on osteoporosis and other chronic diseases Dietary protein has been shown to increase urinary Ca excretion in r and omised controlled trials , and diets high in protein may have detrimental effects on bone health ; however , studies examining the relationship between dietary protein and bone health have conflicting results . In the present study , we examined the relationship between dietary protein ( total , animal and vegetable protein ) and lumbar spine trabecular volumetric bone mineral density ( vBMD ) among participants enrolled in the Multi-Ethnic Study of Atherosclerosis ( n 1658 ) .  Protein intake was assessed using a FFQ obtained at baseline examination ( 2000 - 2 ) . Lumbar spine vBMD was measured using quantitative computed tomography ( 2002 - 5 ) , on average 3 years later . Multivariable linear and robust regression techniques were used to examine the associations between dietary protein and vBMD . Sex and race/ethnicity jointly modified the association of dietary protein with vBMD ( P for interaction = 0·03 ) . Among white women , higher vegetable protein intake was associated with higher vBMD ( P for trend = 0·03 ) , after adjustment for age , BMI , physical activity , alcohol consumption , current smoking , educational level , hormone therapy use , menopause and additional dietary factors . There were no consistently significant associations for total and animal protein intakes among white women or other sex and racial/ethnic groups . In conclusion , data from the present large , multi-ethnic , population -based study suggest that a higher level of protein intake , when substituted for fat , is not associated with poor bone health . Differences in the relationship between protein source and race/ethnicity of study population s may in part explain the inconsistent findings reported previously BACKGROUND Skeletal loading and proper nutrition are necessary for optimal bone health . The appropriate amount of dietary protein to maximize skeletal health , however , is under constant debate . OBJECTIVE To determine if 6 months of protein supplementation in conjunction with a strength and conditioning training program improves areal and volumetric bone mineral density ( BMD ) . DESIGN Fifty-two apparently healthy males and females ages 18 - 25 years were r and omized to protein supplement ( PRO , Myoplex , EAS , Inc. Golden CO ) containing 280 kcal , 42 g protein , 21 g carbohydrate , and 1.5 g fat ) or calorically equivalent carbohydrate control ( CS ) . All subjects participated in a 5 sessions/week strength and conditioning program .  Volumetric and areal BMD measurements were made by peripheral quantitative computed tomography ( pQCT ) of the tibia and whole body DXA . pSSI a measure of torsional bone strength , based on structural and material properties was obtained by pQCT . RESULTS Measurements at the 20 % tibia by pQCT revealed that overall there were significant increases in cortical vBMD ( 4.3 + /- 1.3 mg/cm(3 ) ) , cortical area ( 1.9 + /- 0.6 cm(2 ) ) , cortical thickness ( 0.05 + /- 0.02 mm ) and pSSI ( 67 + /- 24 mm(3 ) ) , and a decrease in endosteal circumference ( - 0.5 + /- 0.2 mm ) over the intervention period ( all , P < 0.05 ) . None of the changes in DXA measures were found to differ by group or sex , there was a trend for a greater increase in whole body BMC among the carbohydrate compared to protein supplemented group and a greater increase among males ( 16 + /- 8 g ) compared to females ( -9 + /- 9 g ) ( P = 0.06 ) . CONCLUSIONS The results of this study indicate that the consumption of additional protein does not improve measurements of vBMD or bone size during a 6-month strength and conditioning program . Longer duration studies may be necessary to determine the influence of increased dietary protein on bone in young adults . Males and females may have different bone responses to increased protein intake while participating in a strength and conditioning program BACKGROUND Different sources of dietary protein may have different effects on bone metabolism . Animal foods provide predominantly acid precursors , whereas protein in vegetable foods is accompanied by base precursors not found in animal foods . Imbalance between dietary acid and base precursors leads to a chronic net dietary acid load that may have adverse consequences on bone . OBJECTIVE We wanted to test the hypothesis that a high dietary ratio of animal to vegetable foods , quantified by protein content , increases bone loss and the risk of fracture . DESIGN This was a prospect i ve cohort study with a mean ( + /-SD ) of 7.0+/-1.5 y of follow-up of 1035 community-dwelling white women aged > 65 y.  Protein intake  was measured by using a food-frequency question naire and  bone mineral density was measured by dual-energy X-ray absorptiometry . RESULTS Bone mineral density was not significantly associated with the ratio of animal to vegetable protein intake . Women with a high ratio had a higher rate of bone loss at the femoral neck than did those with a low ratio ( P = 0.02 ) and a greater risk of hip fracture ( relative risk = 3.7 , P = 0.04 ) . These associations were unaffected by adjustment for age , weight , estrogen use , tobacco use , exercise , total calcium intake , and total protein intake . CONCLUSIONS Elderly women with a high dietary ratio of animal to vegetable protein intake  have more rapid femoral neck bone loss and a greater risk of hip fracture than do those with a low ratio . This suggests that an increase in vegetable protein intake and a decrease in animal protein intake may decrease bone loss and the risk of hip fracture . This possibility should be confirmed in other prospect i ve studies and tested in a r and omized trial Background / Aims : The role of dietary protein in bone health is controversial . The objective of the present study was to examine the association between protein intake , dietary calcium , and bone structure measured by broadb and ultrasound attenuation ( BUA ) . Methods : Our analysis includes 8,178 female study participants of the European Prospect i ve Investigation into Cancer and Nutrition ( EPIC ) Potsdam Study . Ultrasound bone measurements were performed on the right os calcis , and BUA was determined . Dietary intake was assessed by a st and ardized food frequency question naire . We applied linear regression models to estimate the association between dietary protein and BUA . Results : After multivariate adjustment , high intake of animal protein was associated with decreased BUA values ( β = –0.03 ; p = 0.010 ) whereas high vegetable protein intake was related to an increased BUA ( β = 0.11 ; p = 0.007 ) . The effect of dietary animal protein on BUA was modified by calcium intake . Conclusion : High consumption of protein from animal origin may be unfavourable , whereas a higher vegetable protein intake may be beneficial for bone health . Our results strengthen the hypothesis that high calcium intake combined with adequate protein intake based on a high ratio of vegetable to animal protein may be protective against osteoporosis Low protein intake can lead to declined lean mass ( LM ) in elderly . We examined the associations of total protein ( TP ) , animal protein ( AP ) and plant protein ( PP ) intakes with LM . The association of TP intake with LM change was further evaluated according to weight change status . This cross-sectional and prospect i ve cohort study included 554 women aged 68 ( sd 1·9 ) years from the Osteoporosis Risk Factor and Prevention – Fracture Prevention Study ( OSTPRE-FPS ) . The intervention group ( n 270 ) received daily cholecalciferol ( 800 IU ; 20 μg ) and Ca ( 1000 mg ) for 3 years while the control group received neither supplementation nor placebo ( n 282 ) . Participants filled out a question naire on lifestyle factors and a 3-d food record in 2002 and underwent dual-energy X-ray absorptiometry for body composition measurements at baseline and 3 years . Multiple linear regressions evaluated the association between protein intake and LM , adjusting for relevant covariates . At the baseline TP and AP intakes were positively associated with LM and trunk LM , TP was associated also with appendicular LM ( aLM ) . Follow-up results showed that in the total population and the intervention group  , higher TP and AP were associated with increased LM and aLM ( P ≤ 0·050 ) . No such associations were observed in the control  group . PP intake was also associated with aLM change in the total population . Overall , the associations were independent of fat mass . Further , among weight maintainers , TP intake was positively associated with LM , aLM and trunk LM changes ( P ≤ 0·020 ) . In conclusion , dietary  TP , especially AP , intake may be a modifiable risk factor for sarcopenia by preserving LM in the elderly BACKGROUND Higher protein diets are promoted for effective weight loss . Striated tissues in omnivorous diets contain high- quality protein , but limited data exist regarding their effects on bone . METHODS To examine the effects of energy restriction-induced weight loss with higher protein omnivorous diets versus lower protein vegetarian diets on  bone mineral density  in overweight postmenopausal women , two r and omized controlled feeding studies were conducted . In Study 1 , 28 women consumed 750 kcal/day energy deficit diets with 18 % energy from protein via lacto-ovo vegetarian sources ( normal protein , n = 15 ) or 30 % energy from protein with 40 % of protein from lean pork ( higher protein , n = 13 , omnivorous ) for 12 weeks . In Study 2 , 54 women consumed their habitual diet ( control , n = 11 ) or 1,250 kcal/day diets with 16 % energy from nonmeat protein sources ( n = 14 ) or 26 % energy from protein , including chicken ( n = 15 ) or beef ( n = 14 ) for 9 weeks . RESULTS Study 1 : With weight loss ( normal protein -11.2 % , higher protein -10.1 % ) , bone mineral density was not significantly changed in normal protein ( -0.003 ± 0.003 g/cm(2 ) , -0.3 % ) but decreased in higher protein ( -0.0167 ± 0.004 g/cm(2 ) , -1 . 4 % , group-by-time p < .05 ) . Study 2 : The control , nonmeat , chicken , and beef groups lost 1.5 % , 7.7 % , 10.4 % , and 8.1 % weight and 0.0 % , 0.4 % , 1.1 % , and 1.4 % bone mineral density , respectively . The change of bone mineral density was significant for chicken and beef compared with the control ( group-by-time , p < .05 ) . Markers of calcium metabolism and bone homeostasis in blood and urine were not changed over time or differentially affected by diet . CONCLUSION Consumption of higher protein omnivorous diets promoted decreased bone mineral density after weight loss in overweight postmenopausal women Dietary protein intake might be beneficial to physical function ( PF ) in the elderly . We examined the cross-sectional and prospect i ve associations of protein intake of g/kg body weight ( BW ) , fat mass ( FM ) and lean mass ( LM ) with PF in 554 women aged 65·3 - 71·6 years belonging to the Osteoporosis Risk Factor and Prevention Fracture Prevention Study . Participants filled a question naire on lifestyle factors and 3-d food record in 2002 . Body composition was measured by dual-energy X-ray absorptiometry , and PF measures were performed at baseline and at 3-year follow-up . Sarcopaenia was defined using European Working Group on Sarcopenia in Older People criteria . At the baseline , women with higher protein intake ( ≥ 1·2 g/kg BW ) had better performance in h and -grip strength/body mass ( GS/BM ) ( P=0·001 ) , knee extension/BM ( P=0·003 ) , one-leg stance ( P=0·047 ) , chair rise ( P=0·043 ) , squat ( P=0·019 ) , squat to the ground ( P=0·001 ) , faster walking speed for 10 m ( P=0·005 ) and higher short physical performance battery score ( P=0·004 ) compared with those with moderate and lower intakes ( 0·81 - 1·19 and ≤ 0·8 g/kg BW , respectively ) . In follow-up results , higher protein intake was associated with less decline in GS/BM , one-leg stance and t and em walk for 6 m over 3 years . Overall , results were no longer significant after controlling for FM . Associations were detected between protein intake and PF in non-sarcopaenic women but not in sarcopaenic women , except for change of GS ( P=0·037 ) . Further , FM but not LM was negatively associated with PF measures ( P<0·050 ) . This study suggests that higher protein intake and lower FM might be positively associated with PF in elderly women
There appears to be little benefit of increasing protein intake for bone health in healthy adults but there is also clearly no indication of any detrimental effect , at least within the protein intakes of the population s studied ( around 0.8–1.3 g/Kg/day ) .
We undertook a systematic review and meta- analysis of published papers assessing  dietary protein and bone health .
We found little benefit of increasing protein intake for  bone health in healthy adults but no indication of any detrimental effect , at least within the protein intakes of the population s studied .
This systematic review and meta- analysis analysed the relationship between dietary protein and bone health across the life-course .