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: To examine whether the duration of exclusive breastfeeding affects maternal nutrition or infant motor development , we examined data from two studies in Honduras : the first with 141 infants of low-income primiparous women and the second with 119 term , low birth weight infants . In both studies , infants were exclusively breastfed for 4 mo and then r and omly assigned to continue exclusive breastfeeding ( EBF ) until 6 mo or to receive high- quality , hygienic solid foods ( SF ) in addition to breast milk between 4 and 6 mo .  Maternal weight loss between 4 and 6 mo was significantly greater in the exclusive breastfeeding group ( EBF ) group than in the group(s ) given solid foods ( SF ) in study 1 ( -0.7 + /- 1.5 versus -0.1 + /- 1.7 kg , P < 0.05 ) but not in study 2 . The estimated average additional nutritional burden of continuing to exclusively breastfeed until 6 mo was small , representing only 0.1 - 6.0 % of the recommended dietary allowance for energy , vitamin A , calcium and iron . Women in the EBF group were more likely to be amenorrheic at 6 mo than women in the SF group , which conserves nutrients such as iron . In both studies , few women ( 10 - 11 % ) were thin ( body mass index < 19 kg/m(2 ) ) , so the additional weight loss in the EBF group in study 1 was unlikely to have been detrimental . Infants in the EBF group crawled sooner ( both studies ) and were more likely to be walking by 12 mo ( study 1 ) than infants in the SF group . Taken together with our previous findings , these results indicate that the advantages of exclusive breastfeeding during this interval appear to outweigh any potential disadvantages in this setting To evaluate the effect of introducing complementary foods before 6 mo of age , we r and omly assigned 164 infants who had been exclusively breast-fed for 4 mo to continue being exclusively breast-fed until 6 mo ( EBF group ) or to receive iron-fortified foods in addition to breast milk from 4 to 6 mo ( BF+SF group ) . At 6 mo , the BF+SF group had higher mean iron intake ( 4 mg/d compared with 0.2 mg/d in EBF infants ) and higher hemoglobin , hematocrit , and ferritin values than the EBF group ( P < 0.05 ) . The percentage with low hemoglobin ( < 103 g/L ) did not differ significantly between groups , but fewer infants in the BF+SF group had a low hematocrit ( < 0.33 ; 21.4 % compared with 32.0 % , respectively ; P < 0.05 ) . The percentage of infants with ferritin concentrations < 12 microg/L at 6 mo was lower than the percentage with low hemoglobin or hematocrit , raising questions about the validity of the cutoffs at this age . Infants at greatest risk for anemia and low ferritin were those with birth weights < 2500 g ; no infant with a birth weight > 3000 g had a low ferritin value at 6 mo . We conclude that the risk of iron deficiency is low among infants with birth weights > 3000 g who are exclusively breast-fed for 6 mo . Iron drops are recommended for low-birth-weight infants ; for breast-fed infants with birth weights between 2500 and 3000 g , further research is needed to determine whether iron drops are more effective than complementary foods for preventing iron deficiency before 6 mo BACKGROUND The optimal age at which to introduce complementary foods is a topic of considerable debate . OBJECTIVE This study was design ed to evaluate this issue in a nutritionally vulnerable population in Honduras . DESIGN Mothers of low-birth-weight ( 1500 - 2500 g ) term ( ie , small-for-gestational-age ) infants were recruited in the hospital and assisted with exclusive breast-feeding during the first 4 mo . At 4 mo , mothers were r and omly assigned to either continue exclusive breast-feeding to 6 mo ( EBF ; n = 59 ) or to feed complementary solid foods ( jarred rice cereal , chicken , and fruit and vegetables ) twice daily from 4 to 6 mo while continuing to breast-feed at their initial frequency ( SF ; n = 60 ) . At 4 and 6 mo , breast milk and total energy intake were measured for a nonr and om sub sample ( those who could stay overnight in a central unit : 32 EBF and 31 SF ) . RESULTS At 4 mo , breast milk intake in the sub sample was not significantly different between groups ( EBF : 729 + /- 135 g/d ; SF : 683 + /- 151 g/d : P > 0.2 ) ; from 4 to 6 mo it increased ( by 28 g/d ) in the EBF group but decreased ( by 39 g/d ) in the SF group ( P < 0.005 ) . Nonetheless , total energy intake ( including solid foods ) increased more from 4 to 6 mo in the SF than in the EBF group . However , there were no significant differences between groups in weight or length gain during the intervention or subsequently ( 6 - 12 mo ) . CONCLUSION There was no growth advantage of complementary feeding of small-for-gestational-age , breast-fed infants between 4 and 6 mo of age Lactational  amenorrhea  ( LA ) is associated with postpartum infertility and is known to be related to breast-feeding frequency and duration , but the exact role of complementary feeding of the infant has not been clearly defined . Data on LA were collected during and after a 2-mo intervention trial in which low-income Honduran women who had breast-fed fully for 4 mo were r and omly assigned to one of three groups : continued full breast-feeding until 6 mo ( FBF , n = 50 ) , introduction of complementary foods at 4 mo with ad libitum breast-feeding from 4 to 6 mo ( SF , n = 47 ) , or introduction of complementary foods at 4 mo with maintenance of baseline breast-feeding frequency from 4 to 6 mo ( SF-M , n = 44 ) . Women were followed up until the infant was 12 mo of age , or later if menses had not occurred by then . All but six of the women continued to breast-feed for > or = 12 mo . With the exclusion of those whose menses returned before 18 wk postpartum ( which could not have been due to the intervention ) , the proportion of women who were amenorrheic at 6 mo was 64.5 % in the SF group , 80.0 % in the FBF group , and 85.7 % in the SF-M group ( chi-square test = 4.13 , P = 0.02 ; one-tailed test with the latter two groups combined ) . The total duration of LA did not differ significantly among groups . The most significant determinant of LA was time spent breast-feeding ( min/d ) , which was in turn negatively associated ( P = 0.06 ) with the infant 's energy intake from complementary foods in regression analyses . These results indicate that there is a significant effect of introducing foods at 4 mo on the likelihood of amenorrhea at 6 mo postpartum , but not thereafter , and that this effect is not seen in mothers who maintain breast-feeding frequency CONTEXT A number of studies suggest a positive association between breastfeeding and cognitive development in early and middle childhood . However , the only previous study that investigated the relationship between breastfeeding and intelligence in adults had several method ological shortcomings . OBJECTIVE To determine the association between duration of infant breastfeeding and intelligence in young adulthood . DESIGN , SETTING , AND PARTICIPANTS Prospect i ve longitudinal birth cohort study conducted in a sample of 973 men and women and a sample of 2280 men , all of whom were born in Copenhagen , Denmark , between October 1959 and December 1961 . The sample s were divided into 5 categories based on duration of breastfeeding , as assessed by physician interview with mothers at a 1-year examination . MAIN OUTCOME MEASURES Intelligence , assessed using the Wechsler Adult Intelligence Scale ( WAIS ) at a mean age of 27.2 years in the mixed-sex sample and the Børge Priens Prøve ( BPP ) test at a mean age of 18.7 years in the all-male sample . Thirteen potential confounders were included as covariates : parental social status and education ; single mother status ; mother 's height , age , and weight gain during pregnancy and cigarette consumption during the third trimester ; number of pregnancies ; estimated gestational age ; birth weight ; birth length ; and indexes of pregnancy and delivery complications . RESULTS Duration of breastfeeding was associated with significantly higher scores on the Verbal , Performance , and Full Scale WAIS IQs . With regression adjustment for potential confounding factors , the mean Full Scale WAIS IQs were 99.4 , 101.7 , 102.3 , 106.0 , and 104.0 for breastfeeding duration s of less than 1 month , 2 to 3 months , 4 to 6 months , 7 to 9 months , and more than 9 months , respectively ( P = .003 for overall F test ) . The corresponding mean scores on the BPP were 38.0 , 39.2 , 39.9 , 40.1 , and 40.1 ( P = .01 for overall F test ) . CONCLUSION Independent of a wide range of possible confounding factors , a significant positive association between duration of breastfeeding  and intelligence was observed in 2 independent sample s of young adults , assessed with 2 different intelligence tests 54 babies who had been solely breast-fed for more than 6 months , 77 babies who had been breast-fed for 2 - -6 months , and 105 babies who had been weaned to cow's-milk-based formulas at less than 2 months were followed for the first 3 years of life . All the babies had the same pattern of solid food intake until 1 year of age . Compared with formula feeding , prolonged breast-feeding result ed in a lower incidence of severe or obvious atopic disease particularly in babies with family history of atopy In developing countries , the age at which breastfed infants are first given complementary foods is of public health importance because of the risk of diarrhoeal disease from contaminated weaning foods , and the potential risk of growth faltering if foods are inappropriately delayed . To evaluate whether there are any advantage of complementary feeding prior to 6 months , low-income primiparous mothers who had exclusively breastfed for 4 months were r and omly assigned to one of 3 groups : continued exclusive breastfeeding to 6 months ( EBF ) ( n = 50 ) ; introduction of complementary foods at 4 months with ad libitum nursing from 4 - 6 months ( SF ) ( n = 47 ) ; and introduction of complementary foods at 4 months , with maintenance of baseline nursing frequency from 4 - 6 months ( SF-M ) ( n = 44 ) . Baby foods in jars were provided to the SF and SF-M groups from 4 to 6 months . Subjects were visited weekly and provided with lactation guidance ; at 4 , 5 , and 6 months measurements were made of infant intake and breast milk composition . At 4 months , breast milk intake averaged 797 ( 139 ) g per day ( no difference among groups ) . Between 4 and 6 months , breast milk intake was unchanged in EBF infants ( + 6 ) but decreased in the SF ( -103 ) , and SF-M ( -62 ) groups ( p < 0.001 ) . Change in total energy intake ( including solid foods ) and infant weight and length gain did not differ significantly between groups . Weight and length gain from 4 - 6 months were comparable to those of breastfed infants in an affluent USA population . The results indicate that breastfed infants self-regulate their total energy intake when other foods are introduced . As a result , there is no advantage in introducing complementary foods before 6 months in this population , whereas there may be disadvantages if there is increased exposure to contaminated weaning foods BACKGROUND Results on growth and nutrient intake in infants in the second half of infancy fed human milk or formulas with varying protein concentrations in combination with supplementary foods  have not previously been reported . METHODS Seventy-one healthy infants were studied from 3 to 12 months of age . They were exclusively breast-fed until 3 months and were then r and omly assigned to one of three feeding groups , F13 , F15 , or F18 , indicating formulas with 13 , 15 or 18 g/l of protein , respectively . Formula was gradually introduced when breast-feeding was terminated . Infants fed  breast milk only were included in the breast-fed group , and those with breast milk and formula were included in the mixed-fed group . The same supplementary foods were provided to all infants . RESULTS There were no differences in growth between the feeding groups . Total protein intake exceeded minimum recommendations in all groups at all ages and was higher at 6 months in F18 than in F13 ( 2.3 vs. 1.9 g/kg per day ; p < 0.01 ) , whereas formula protein intake was higher at all ages in F18 compared with F13 . Intake of protein from supplementary foods increased , but that from formula decreased between 6 and 12 months in all groups . CONCLUSIONS Intake of breast milk or infant formula with 13 g/l of protein along with high-protein supplementary foods provided enough protein with no adverse effect on growth . Infants fed formulas with higher protein concentrations had similar growth , despite higher intakes of formula protein The hypothesis that breast-feeding can provide protection against the development of  insulindependent diabetes mellitus ( IDDM 
    Output:
    
agent
***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: To examine whether the duration of exclusive breastfeeding affects maternal nutrition or infant motor development , we examined data from two studies in Honduras : the first with 141 infants of low-income primiparous women and the second with 119 term , low birth weight infants . In both studies , infants were exclusively breastfed for 4 mo and then r and omly assigned to continue exclusive breastfeeding ( EBF ) until 6 mo or to receive high- quality , hygienic solid foods ( SF ) in addition to breast milk between 4 and 6 mo .  Maternal weight loss between 4 and 6 mo was significantly greater in the exclusive breastfeeding group ( EBF ) group than in the group(s ) given solid foods ( SF ) in study 1 ( -0.7 + /- 1.5 versus -0.1 + /- 1.7 kg , P < 0.05 ) but not in study 2 . The estimated average additional nutritional burden of continuing to exclusively breastfeed until 6 mo was small , representing only 0.1 - 6.0 % of the recommended dietary allowance for energy , vitamin A , calcium and iron . Women in the EBF group were more likely to be amenorrheic at 6 mo than women in the SF group , which conserves nutrients such as iron . In both studies , few women ( 10 - 11 % ) were thin ( body mass index < 19 kg/m(2 ) ) , so the additional weight loss in the EBF group in study 1 was unlikely to have been detrimental . Infants in the EBF group crawled sooner ( both studies ) and were more likely to be walking by 12 mo ( study 1 ) than infants in the SF group . Taken together with our previous findings , these results indicate that the advantages of exclusive breastfeeding during this interval appear to outweigh any potential disadvantages in this setting To evaluate the effect of introducing complementary foods before 6 mo of age , we r and omly assigned 164 infants who had been exclusively breast-fed for 4 mo to continue being exclusively breast-fed until 6 mo ( EBF group ) or to receive iron-fortified foods in addition to breast milk from 4 to 6 mo ( BF+SF group ) . At 6 mo , the BF+SF group had higher mean iron intake ( 4 mg/d compared with 0.2 mg/d in EBF infants ) and higher hemoglobin , hematocrit , and ferritin values than the EBF group ( P < 0.05 ) . The percentage with low hemoglobin ( < 103 g/L ) did not differ significantly between groups , but fewer infants in the BF+SF group had a low hematocrit ( < 0.33 ; 21.4 % compared with 32.0 % , respectively ; P < 0.05 ) . The percentage of infants with ferritin concentrations < 12 microg/L at 6 mo was lower than the percentage with low hemoglobin or hematocrit , raising questions about the validity of the cutoffs at this age . Infants at greatest risk for anemia and low ferritin were those with birth weights < 2500 g ; no infant with a birth weight > 3000 g had a low ferritin value at 6 mo . We conclude that the risk of iron deficiency is low among infants with birth weights > 3000 g who are exclusively breast-fed for 6 mo . Iron drops are recommended for low-birth-weight infants ; for breast-fed infants with birth weights between 2500 and 3000 g , further research is needed to determine whether iron drops are more effective than complementary foods for preventing iron deficiency before 6 mo BACKGROUND The optimal age at which to introduce complementary foods is a topic of considerable debate . OBJECTIVE This study was design ed to evaluate this issue in a nutritionally vulnerable population in Honduras . DESIGN Mothers of low-birth-weight ( 1500 - 2500 g ) term ( ie , small-for-gestational-age ) infants were recruited in the hospital and assisted with exclusive breast-feeding during the first 4 mo . At 4 mo , mothers were r and omly assigned to either continue exclusive breast-feeding to 6 mo ( EBF ; n = 59 ) or to feed complementary solid foods ( jarred rice cereal , chicken , and fruit and vegetables ) twice daily from 4 to 6 mo while continuing to breast-feed at their initial frequency ( SF ; n = 60 ) . At 4 and 6 mo , breast milk and total energy intake were measured for a nonr and om sub sample ( those who could stay overnight in a central unit : 32 EBF and 31 SF ) . RESULTS At 4 mo , breast milk intake in the sub sample was not significantly different between groups ( EBF : 729 + /- 135 g/d ; SF : 683 + /- 151 g/d : P > 0.2 ) ; from 4 to 6 mo it increased ( by 28 g/d ) in the EBF group but decreased ( by 39 g/d ) in the SF group ( P < 0.005 ) . Nonetheless , total energy intake ( including solid foods ) increased more from 4 to 6 mo in the SF than in the EBF group . However , there were no significant differences between groups in weight or length gain during the intervention or subsequently ( 6 - 12 mo ) . CONCLUSION There was no growth advantage of complementary feeding of small-for-gestational-age , breast-fed infants between 4 and 6 mo of age Lactational  amenorrhea  ( LA ) is associated with postpartum infertility and is known to be related to breast-feeding frequency and duration , but the exact role of complementary feeding of the infant has not been clearly defined . Data on LA were collected during and after a 2-mo intervention trial in which low-income Honduran women who had breast-fed fully for 4 mo were r and omly assigned to one of three groups : continued full breast-feeding until 6 mo ( FBF , n = 50 ) , introduction of complementary foods at 4 mo with ad libitum breast-feeding from 4 to 6 mo ( SF , n = 47 ) , or introduction of complementary foods at 4 mo with maintenance of baseline breast-feeding frequency from 4 to 6 mo ( SF-M , n = 44 ) . Women were followed up until the infant was 12 mo of age , or later if menses had not occurred by then . All but six of the women continued to breast-feed for > or = 12 mo . With the exclusion of those whose menses returned before 18 wk postpartum ( which could not have been due to the intervention ) , the proportion of women who were amenorrheic at 6 mo was 64.5 % in the SF group , 80.0 % in the FBF group , and 85.7 % in the SF-M group ( chi-square test = 4.13 , P = 0.02 ; one-tailed test with the latter two groups combined ) . The total duration of LA did not differ significantly among groups . The most significant determinant of LA was time spent breast-feeding ( min/d ) , which was in turn negatively associated ( P = 0.06 ) with the infant 's energy intake from complementary foods in regression analyses . These results indicate that there is a significant effect of introducing foods at 4 mo on the likelihood of amenorrhea at 6 mo postpartum , but not thereafter , and that this effect is not seen in mothers who maintain breast-feeding frequency CONTEXT A number of studies suggest a positive association between breastfeeding and cognitive development in early and middle childhood . However , the only previous study that investigated the relationship between breastfeeding and intelligence in adults had several method ological shortcomings . OBJECTIVE To determine the association between duration of infant breastfeeding and intelligence in young adulthood . DESIGN , SETTING , AND PARTICIPANTS Prospect i ve longitudinal birth cohort study conducted in a sample of 973 men and women and a sample of 2280 men , all of whom were born in Copenhagen , Denmark , between October 1959 and December 1961 . The sample s were divided into 5 categories based on duration of breastfeeding , as assessed by physician interview with mothers at a 1-year examination . MAIN OUTCOME MEASURES Intelligence , assessed using the Wechsler Adult Intelligence Scale ( WAIS ) at a mean age of 27.2 years in the mixed-sex sample and the Børge Priens Prøve ( BPP ) test at a mean age of 18.7 years in the all-male sample . Thirteen potential confounders were included as covariates : parental social status and education ; single mother status ; mother 's height , age , and weight gain during pregnancy and cigarette consumption during the third trimester ; number of pregnancies ; estimated gestational age ; birth weight ; birth length ; and indexes of pregnancy and delivery complications . RESULTS Duration of breastfeeding was associated with significantly higher scores on the Verbal , Performance , and Full Scale WAIS IQs . With regression adjustment for potential confounding factors , the mean Full Scale WAIS IQs were 99.4 , 101.7 , 102.3 , 106.0 , and 104.0 for breastfeeding duration s of less than 1 month , 2 to 3 months , 4 to 6 months , 7 to 9 months , and more than 9 months , respectively ( P = .003 for overall F test ) . The corresponding mean scores on the BPP were 38.0 , 39.2 , 39.9 , 40.1 , and 40.1 ( P = .01 for overall F test ) . CONCLUSION Independent of a wide range of possible confounding factors , a significant positive association between duration of breastfeeding  and intelligence was observed in 2 independent sample s of young adults , assessed with 2 different intelligence tests 54 babies who had been solely breast-fed for more than 6 months , 77 babies who had been breast-fed for 2 - -6 months , and 105 babies who had been weaned to cow's-milk-based formulas at less than 2 months were followed for the first 3 years of life . All the babies had the same pattern of solid food intake until 1 year of age . Compared with formula feeding , prolonged breast-feeding result ed in a lower incidence of severe or obvious atopic disease particularly in babies with family history of atopy In developing countries , the age at which breastfed infants are first given complementary foods is of public health importance because of the risk of diarrhoeal disease from contaminated weaning foods , and the potential risk of growth faltering if foods are inappropriately delayed . To evaluate whether there are any advantage of complementary feeding prior to 6 months , low-income primiparous mothers who had exclusively breastfed for 4 months were r and omly assigned to one of 3 groups : continued exclusive breastfeeding to 6 months ( EBF ) ( n = 50 ) ; introduction of complementary foods at 4 months with ad libitum nursing from 4 - 6 months ( SF ) ( n = 47 ) ; and introduction of complementary foods at 4 months , with maintenance of baseline nursing frequency from 4 - 6 months ( SF-M ) ( n = 44 ) . Baby foods in jars were provided to the SF and SF-M groups from 4 to 6 months . Subjects were visited weekly and provided with lactation guidance ; at 4 , 5 , and 6 months measurements were made of infant intake and breast milk composition . At 4 months , breast milk intake averaged 797 ( 139 ) g per day ( no difference among groups ) . Between 4 and 6 months , breast milk intake was unchanged in EBF infants ( + 6 ) but decreased in the SF ( -103 ) , and SF-M ( -62 ) groups ( p < 0.001 ) . Change in total energy intake ( including solid foods ) and infant weight and length gain did not differ significantly between groups . Weight and length gain from 4 - 6 months were comparable to those of breastfed infants in an affluent USA population . The results indicate that breastfed infants self-regulate their total energy intake when other foods are introduced . As a result , there is no advantage in introducing complementary foods before 6 months in this population , whereas there may be disadvantages if there is increased exposure to contaminated weaning foods BACKGROUND Results on growth and nutrient intake in infants in the second half of infancy fed human milk or formulas with varying protein concentrations in combination with supplementary foods  have not previously been reported . METHODS Seventy-one healthy infants were studied from 3 to 12 months of age . They were exclusively breast-fed until 3 months and were then r and omly assigned to one of three feeding groups , F13 , F15 , or F18 , indicating formulas with 13 , 15 or 18 g/l of protein , respectively . Formula was gradually introduced when breast-feeding was terminated . Infants fed  breast milk only were included in the breast-fed group , and those with breast milk and formula were included in the mixed-fed group . The same supplementary foods were provided to all infants . RESULTS There were no differences in growth between the feeding groups . Total protein intake exceeded minimum recommendations in all groups at all ages and was higher at 6 months in F18 than in F13 ( 2.3 vs. 1.9 g/kg per day ; p < 0.01 ) , whereas formula protein intake was higher at all ages in F18 compared with F13 . Intake of protein from supplementary foods increased , but that from formula decreased between 6 and 12 months in all groups . CONCLUSIONS Intake of breast milk or infant formula with 13 g/l of protein along with high-protein supplementary foods provided enough protein with no adverse effect on growth . Infants fed formulas with higher protein concentrations had similar growth , despite higher intakes of formula protein The hypothesis that breast-feeding can provide protection against the development of  insulindependent diabetes mellitus ( IDDM 
    Output:
    