human
***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: BACKGROUND The effect of meat protein on calcium retention at different calcium intakes is unresolved . OBJECTIVE The objective was to test the effect of dietary protein on calcium retention at low and high intakes of calcium . DESIGN In a r and omized controlled feeding study with a 2 x 2 factorial crossover design , healthy postmenopausal women ( n = 27 ) consumed either approximately 675 or approximately 1510 mg Ca/d , with both low and high protein ( providing 10 % and 20 % energy ) for 7 wk each , separated by a 3-wk washout period . After 3 wk , the entire diet was extrinsically labeled with (47)Ca , and isotope retention was monitored by whole-body scintillation counting . Clinical markers of calcium and bone metabolism were measured . RESULTS High compared with low dietary protein significantly increased calcium retention from the low-calcium ( 29.5 % compared with 26.0 % absorbed ) but not the high-calcium diet ( 18 % absorbed ) . For the low-calcium diet , this effect nearly balanced a protein-related 0.5-mmol/d greater urinary calcium excretion . Protein-related calciuretic effects were independent of dietary calcium . Testing at 1 , 2 , 3 , 5 , and 7 wk showed no long-term adaptation in urinary acidity or urinary calcium excretion . High compared with low dietary protein decreased urinary deoxypyridinoline and increased serum insulin-like growth factor I without affecting parathyroid hormone , osteocalcin , bone-specific alkaline phosphatase , or tartrate-resistant acid phosphatase . CONCLUSIONS In healthy postmenopausal women , a moderate increase in dietary protein , from 10 % to 20 % of energy , slightly improved calcium absorption from a low-calcium diet , nearly compensating for a slight increase in urinary calcium excretion . Under practical dietary conditions , increased dietary protein from animal sources was not detrimental to calcium balance or short-term indicators of bone health Many postmenopausal women have a calcium intake far below the recommended amount and , in addition to attempting to improve their diet , need a calcium supplement . The aim of the study was to assess the effects of the consumption of a high calcium mineral water ( HCaMW ) on biochemical indices of bone remodeling in postmenopausal women with low Ca intake . A 6-month r and omized double-blind placebo-controlled trial was design ed to assess the effects of a daily consumption of 1 liter of a HCaMW ( 596 mg Ca/l ) on serum parathyroid hormone ( PTH ) and biochemical markers of bone remodeling in postmenopausal women with a dietary Ca intake lower than 700 mg/day . The placebo group drank 1 liter of a mineral water with a low calcium content ( 10 mg/l ) . One hundred eighty healthy women were recruited ( mean age : 70.1±4.0 years ) ; 152 completed the 6-month trial . The changes from baseline of biochemical indices after 6 months consisted of a significant 14.1 % decrease of serum PTH , osteocalcin ( –8.6 % ) , bone alkaline phosphatase ( –11.5 % ) , serum ( –16.3 % ) and urine ( –13.0 % ) type-1 collagen C-telopeptide in the HCaMW group compared to the placebo group , where all biochemical indices increased after 6 months . The additive effect of a small vitamin D supplement ( 400 iu/day ) was also evaluated . In women receiving vitamin D in addition to HCaMW , the decrease in bone indices was not found to be greater than in women drinking only the HCaMW . A daily supplement of 596 mg of Ca through the consumption of 1 l of HCaMW was able to lower serum PTH and the indices of bone turnover in postmenopausal women with a low Ca intake . This could contribute to the repair of calcium deficiency and to the reduction of age-related bone loss in this population This paper describes and quantifies acute responses of the kidneys in correcting plasma volume , acid-base , and ion disturbances result ing from  NaHCO(3 ) and KHCO(3 )  ingestion . Renal excretion of ions and water was studied in five men after ingestion of 3.57 mmol/kg body mass of sodium bicarbonate ( NaHCO(3 ) ) and , in a separate trial , potassium bicarbonate ( KHCO(3 ) ) .  Subjects had a Foley catheter inserted into the bladder and indwelling catheters placed into an antecubital vein and a brachial artery . Blood and urine were sample d in the 30-min period before , the 60-min period during , and the 210-min period after ingestion of the solutions . NaHCO(3 ) ingestion result ed in a rapid , transient diuresis and natriuresis . Cumulative urine output was 44 + /- 11 % of ingested volume , result ing in a 555 + /- 119 ml increase in total body water at the end of the experiment . The cumulative increase ( above basal levels ) in renal Na(+ ) excretion accounted for 24 + /- 2 % of ingested Na(+ ) . In the KHCO(3 ) trial , arterial plasma K(+ ) concentration rapidly increased from 4.25 + /- 0.10 to a peak of 7.17 + /- 0.13 meq/l 140 min after the beginning of ingestion . This increase result ed in a pronounced , transient diuresis , with cumulative urine output at 270 min similar to the volume ingested , natriuresis , and a pronounced kaliuresis that was maintained until the end of the experiment . Cumulative ( above basal ) renal K(+ ) excretion at 270 min accounted for 26 + /- 5 % of ingested K(+ ) . The kidneys were important in mediating rapid corrections of substantial portions of the fluid and electrolyte disturbances result ing from ingestion of KHCO(3 ) and NaHCO(3 ) solutions 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 Objective : Assessment of the physiological effects of a diet rich in phosphorus in young women . Design : Control period I — commercial basic diet containing 1700 mg P and 1500 mg Ca/day for 4 weeks . Supplementation period — a 6 week high-phosphorus period of 3008 mg P and 1995 mg Ca/day . Control period II—4 weeks washout with basic diet as in period I. Setting : Institute of Nutritional Science , Friedrich Schiller University , Jena . Subjects : Ten healthy women , aged 20–30 y. Interventions : Orange juice and tablets , containing supplements of Ca5(PO4)3OH and NaH2PO4 , totalling 1436 mg elemental phosphorus per day . Results : There was an increase of 10.7±13.7 pg/ml in serum PTH , a decrease of 0.6±0.6 ng/ml in serum osteocalcin , an increase of 73.6±136.6 nmol/mmol creatinine in urinary pyridinoline and of 19.3±36.0 nmol/mmol creatinine in urinary deoxypyridinoline , and a decrease of 2.6±9.3 mg/l in urinary microalbumin . All changes were insignificant . There were no changes in serum levels of Ca , PO4 or Zn , in serum concentration of 1,25-(OH)2D3 , and in urinary β-2-microglobulin excretion  . Phosphorus supplementation  caused intestinal distress , soft stools or mild diarrhoea . Conclusions : In spite of a high phosphorus supplementation no significant changes in bone-related hormones , pyridinium crosslinks as markers of bone resorption and parameters of renal function in young women were found . European Journal of Clinical Nutrition ( 2001 ) 55 , BACKGROUND Intake of carbonated beverages has been associated with increased fracture risk in observational studies . The usual explanation given is that one or more of the beverage constituents increase urinary calcium . OBJECTIVE We assessed the short-term effects on urinary calcium excretion of carbonated beverages of various compositions . DESIGN An incomplete r and om block design was used to study 20 - 40-y-old women who customarily consumed > or = 680 mL carbonated beverages daily . Four carbonated beverages were tested : 2 with caffeine and 2 without . Two contained phosphoric acid as the acidulant and 2 contained citric acid . The study included one neutral control ( water ) and one positive control ( skim or chocolate milk ) . Serving size was 567 mL for the carbonated beverages and water and 340 mL for the milks . Beverages were consumed with a light breakfast after an overnight fast ; no other foods were ingested until urine collection was complete . pH , titratable and total acidity , sodium , creatinine , and calcium were measured in 2-h ( morning ) fasting and 5-h postbeverage urine specimens . RESULTS Relative to water , urinary calcium rose significantly only with the milks and the 2 caffeine-containing beverages . The excess calciuria was approximately 0.25 mmol , about the same as previously reported for caffeine alone . Phosphoric acid without caffeine produced no excess calciuria ; nor did it augment the calciuria of caffeine . CONCLUSIONS The excess calciuria associated with consumption of carbonated beverages is confined to caffeinated beverages . Acidulant type has no acute effect . Because the caffeine effect is known to be compensated for by reduced calciuria later in the day , we conclude that the net effect of carbonated beverage constituents on calcium economy is negligible . The skeletal effects of carbonated beverage consumption are likely due primarily to milk displacement This study was conducted to determine whether the markers of bone resorption , pyridinium cross-links of collagen , are sensitive to changes in dietary protein and calcium intake . Fifteen young healthy subjects ( 7 males and 8 females ) participated in three 5-d diet periods . Dietary intake during each dietary period consisted of : 1 ) low nitrogen and low calcium [ 0.49 + /- 0.11 g protein/ ( kg.d ) , 429 + /- 190 mg calcium/d ] ; 2 ) low nitrogen and high calcium [ 0.44 + /- 0.08 g protein/(kg.d ) , 1643 + /- 171 mg calcium/d ] ; and 3 ) a high nitrogen and high calcium [ 2.71 + /- 0.75 g protein/(kg.d ) , 1589 + /- 633 mg calcium/d ] diet , and this was compared with subjects ' baseline dietary intake [ 0.99 + /- 0.51 g protein/(kg.d ) , 589 + /- 152 mg calcium/d ] . The order of these diets was r and omly assigned . Twenty-four-hour and 3-h urine sample s were collected before and during each dietary period and were analyzed for pyridinium cross-links ( pyridinoline , deoxypyridinoline ) , nitrogen and creatinine . The rate of pyrdinium cross-link excretion did not vary with protein intake but was approximately 33 % lower ( P < 0.01 ) during periods of high compared with low calcium intake . These data indicate that a short-term increase 
    Output:
    
agent
Urine calcium excretion rates were consistent with osteoporosis development ; however calcium balance studies did not demonstrate loss of whole body calcium with higher net acid excretion .
No study revealed a biologic mechanism functioning at physiological pH. Finally , r and omized studies did not provide evidence for an adverse role of phosphate , milk , and grain foods in osteoporosis .
Conclusions A causal association between dietary acid load and osteoporotic bone disease is not supported by evidence and there is no evidence that an alkaline diet is protective of bone health
***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: BACKGROUND The effect of meat protein on calcium retention at different calcium intakes is unresolved . OBJECTIVE The objective was to test the effect of dietary protein on calcium retention at low and high intakes of calcium . DESIGN In a r and omized controlled feeding study with a 2 x 2 factorial crossover design , healthy postmenopausal women ( n = 27 ) consumed either approximately 675 or approximately 1510 mg Ca/d , with both low and high protein ( providing 10 % and 20 % energy ) for 7 wk each , separated by a 3-wk washout period . After 3 wk , the entire diet was extrinsically labeled with (47)Ca , and isotope retention was monitored by whole-body scintillation counting . Clinical markers of calcium and bone metabolism were measured . RESULTS High compared with low dietary protein significantly increased calcium retention from the low-calcium ( 29.5 % compared with 26.0 % absorbed ) but not the high-calcium diet ( 18 % absorbed ) . For the low-calcium diet , this effect nearly balanced a protein-related 0.5-mmol/d greater urinary calcium excretion . Protein-related calciuretic effects were independent of dietary calcium . Testing at 1 , 2 , 3 , 5 , and 7 wk showed no long-term adaptation in urinary acidity or urinary calcium excretion . High compared with low dietary protein decreased urinary deoxypyridinoline and increased serum insulin-like growth factor I without affecting parathyroid hormone , osteocalcin , bone-specific alkaline phosphatase , or tartrate-resistant acid phosphatase . CONCLUSIONS In healthy postmenopausal women , a moderate increase in dietary protein , from 10 % to 20 % of energy , slightly improved calcium absorption from a low-calcium diet , nearly compensating for a slight increase in urinary calcium excretion . Under practical dietary conditions , increased dietary protein from animal sources was not detrimental to calcium balance or short-term indicators of bone health Many postmenopausal women have a calcium intake far below the recommended amount and , in addition to attempting to improve their diet , need a calcium supplement . The aim of the study was to assess the effects of the consumption of a high calcium mineral water ( HCaMW ) on biochemical indices of bone remodeling in postmenopausal women with low Ca intake . A 6-month r and omized double-blind placebo-controlled trial was design ed to assess the effects of a daily consumption of 1 liter of a HCaMW ( 596 mg Ca/l ) on serum parathyroid hormone ( PTH ) and biochemical markers of bone remodeling in postmenopausal women with a dietary Ca intake lower than 700 mg/day . The placebo group drank 1 liter of a mineral water with a low calcium content ( 10 mg/l ) . One hundred eighty healthy women were recruited ( mean age : 70.1±4.0 years ) ; 152 completed the 6-month trial . The changes from baseline of biochemical indices after 6 months consisted of a significant 14.1 % decrease of serum PTH , osteocalcin ( –8.6 % ) , bone alkaline phosphatase ( –11.5 % ) , serum ( –16.3 % ) and urine ( –13.0 % ) type-1 collagen C-telopeptide in the HCaMW group compared to the placebo group , where all biochemical indices increased after 6 months . The additive effect of a small vitamin D supplement ( 400 iu/day ) was also evaluated . In women receiving vitamin D in addition to HCaMW , the decrease in bone indices was not found to be greater than in women drinking only the HCaMW . A daily supplement of 596 mg of Ca through the consumption of 1 l of HCaMW was able to lower serum PTH and the indices of bone turnover in postmenopausal women with a low Ca intake . This could contribute to the repair of calcium deficiency and to the reduction of age-related bone loss in this population This paper describes and quantifies acute responses of the kidneys in correcting plasma volume , acid-base , and ion disturbances result ing from  NaHCO(3 ) and KHCO(3 )  ingestion . Renal excretion of ions and water was studied in five men after ingestion of 3.57 mmol/kg body mass of sodium bicarbonate ( NaHCO(3 ) ) and , in a separate trial , potassium bicarbonate ( KHCO(3 ) ) .  Subjects had a Foley catheter inserted into the bladder and indwelling catheters placed into an antecubital vein and a brachial artery . Blood and urine were sample d in the 30-min period before , the 60-min period during , and the 210-min period after ingestion of the solutions . NaHCO(3 ) ingestion result ed in a rapid , transient diuresis and natriuresis . Cumulative urine output was 44 + /- 11 % of ingested volume , result ing in a 555 + /- 119 ml increase in total body water at the end of the experiment . The cumulative increase ( above basal levels ) in renal Na(+ ) excretion accounted for 24 + /- 2 % of ingested Na(+ ) . In the KHCO(3 ) trial , arterial plasma K(+ ) concentration rapidly increased from 4.25 + /- 0.10 to a peak of 7.17 + /- 0.13 meq/l 140 min after the beginning of ingestion . This increase result ed in a pronounced , transient diuresis , with cumulative urine output at 270 min similar to the volume ingested , natriuresis , and a pronounced kaliuresis that was maintained until the end of the experiment . Cumulative ( above basal ) renal K(+ ) excretion at 270 min accounted for 26 + /- 5 % of ingested K(+ ) . The kidneys were important in mediating rapid corrections of substantial portions of the fluid and electrolyte disturbances result ing from ingestion of KHCO(3 ) and NaHCO(3 ) solutions 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 Objective : Assessment of the physiological effects of a diet rich in phosphorus in young women . Design : Control period I — commercial basic diet containing 1700 mg P and 1500 mg Ca/day for 4 weeks . Supplementation period — a 6 week high-phosphorus period of 3008 mg P and 1995 mg Ca/day . Control period II—4 weeks washout with basic diet as in period I. Setting : Institute of Nutritional Science , Friedrich Schiller University , Jena . Subjects : Ten healthy women , aged 20–30 y. Interventions : Orange juice and tablets , containing supplements of Ca5(PO4)3OH and NaH2PO4 , totalling 1436 mg elemental phosphorus per day . Results : There was an increase of 10.7±13.7 pg/ml in serum PTH , a decrease of 0.6±0.6 ng/ml in serum osteocalcin , an increase of 73.6±136.6 nmol/mmol creatinine in urinary pyridinoline and of 19.3±36.0 nmol/mmol creatinine in urinary deoxypyridinoline , and a decrease of 2.6±9.3 mg/l in urinary microalbumin . All changes were insignificant . There were no changes in serum levels of Ca , PO4 or Zn , in serum concentration of 1,25-(OH)2D3 , and in urinary β-2-microglobulin excretion  . Phosphorus supplementation  caused intestinal distress , soft stools or mild diarrhoea . Conclusions : In spite of a high phosphorus supplementation no significant changes in bone-related hormones , pyridinium crosslinks as markers of bone resorption and parameters of renal function in young women were found . European Journal of Clinical Nutrition ( 2001 ) 55 , BACKGROUND Intake of carbonated beverages has been associated with increased fracture risk in observational studies . The usual explanation given is that one or more of the beverage constituents increase urinary calcium . OBJECTIVE We assessed the short-term effects on urinary calcium excretion of carbonated beverages of various compositions . DESIGN An incomplete r and om block design was used to study 20 - 40-y-old women who customarily consumed > or = 680 mL carbonated beverages daily . Four carbonated beverages were tested : 2 with caffeine and 2 without . Two contained phosphoric acid as the acidulant and 2 contained citric acid . The study included one neutral control ( water ) and one positive control ( skim or chocolate milk ) . Serving size was 567 mL for the carbonated beverages and water and 340 mL for the milks . Beverages were consumed with a light breakfast after an overnight fast ; no other foods were ingested until urine collection was complete . pH , titratable and total acidity , sodium , creatinine , and calcium were measured in 2-h ( morning ) fasting and 5-h postbeverage urine specimens . RESULTS Relative to water , urinary calcium rose significantly only with the milks and the 2 caffeine-containing beverages . The excess calciuria was approximately 0.25 mmol , about the same as previously reported for caffeine alone . Phosphoric acid without caffeine produced no excess calciuria ; nor did it augment the calciuria of caffeine . CONCLUSIONS The excess calciuria associated with consumption of carbonated beverages is confined to caffeinated beverages . Acidulant type has no acute effect . Because the caffeine effect is known to be compensated for by reduced calciuria later in the day , we conclude that the net effect of carbonated beverage constituents on calcium economy is negligible . The skeletal effects of carbonated beverage consumption are likely due primarily to milk displacement This study was conducted to determine whether the markers of bone resorption , pyridinium cross-links of collagen , are sensitive to changes in dietary protein and calcium intake . Fifteen young healthy subjects ( 7 males and 8 females ) participated in three 5-d diet periods . Dietary intake during each dietary period consisted of : 1 ) low nitrogen and low calcium [ 0.49 + /- 0.11 g protein/ ( kg.d ) , 429 + /- 190 mg calcium/d ] ; 2 ) low nitrogen and high calcium [ 0.44 + /- 0.08 g protein/(kg.d ) , 1643 + /- 171 mg calcium/d ] ; and 3 ) a high nitrogen and high calcium [ 2.71 + /- 0.75 g protein/(kg.d ) , 1589 + /- 633 mg calcium/d ] diet , and this was compared with subjects ' baseline dietary intake [ 0.99 + /- 0.51 g protein/(kg.d ) , 589 + /- 152 mg calcium/d ] . The order of these diets was r and omly assigned . Twenty-four-hour and 3-h urine sample s were collected before and during each dietary period and were analyzed for pyridinium cross-links ( pyridinoline , deoxypyridinoline ) , nitrogen and creatinine . The rate of pyrdinium cross-link excretion did not vary with protein intake but was approximately 33 % lower ( P < 0.01 ) during periods of high compared with low calcium intake . These data indicate that a short-term increase 
    Output:
    