Sialylated oligosaccharides in human milk and feces of preterm, full-term, and weaning infants

The amount of free and glycosidically bound sialic acid was quantitated in the oligosaccharide fraction of breast milk from nine women in the 2nd-3rd week of lactation. These amounts showed a certain individual variation but the amount of bound sialic acid was higher than the free sialic acid in each sample. A similar study on the feces from preterm and full-term breast-fed infants revealed that the amount of free sialic acid increased while the bound sialic acid decreased during maturation, which could possibly be a result of increasing activity of an intestinal sialidase in the newborn child. The fecal oligosaccharide patterns in one blood group A secretor breast-fed infant were studied every 2 months during weaning until the age of 1 year. It was seen that the fecal oligosaccharide pattern disappears, along with the blood group A-active compounds, with a corresponding decrease in the amount of breast milk in the diet.     

Antibacterial characteristics in the feces of breast-fed and formula-fed infants during the first year of life

BACKGROUND: Human milk is known to protect infants from a number of infectious diseases. Much less is known about the bioactivity of milk-derived factors in the intestine. In this study, potentially protective characteristics in the feces of breast-fed and formula-fed infants were compared. METHODS: The feces of 26 breast-fed and 18 formula-fed infants were collected during the first year of life. In each sample, the concentrations of total protein, immunoglobulin A, and sialic acid were measured. In addition, the effect of the fecal samples was measured on the adhesion of enteropathogenic Escherichia coli (EPEC) to Caco-2 cells and on transepithelial electrical resistance (TER) during an infection. RESULTS: In the first month, sialic acid and immunoglobulin A were found in the feces of breast-fed infants in substantially higher concentrations than in the feces of formula fed infants (sialic acid, 1197 +/- 370 microg/ mL versus 31 +/- 19 microg/ mL; immunoglobulin A, 0.11 +/- 7 mg/mL versus 0.3 +/- 1 mg/mL) and thereafter decreased to similar levels in half a year. Adhesion of EPEC to Caco-2 cells was inhibited between 65% and 85% by stools from both groups. The decrease of TER during EPEC infection was unaffected by fecal samples of any origin or age. CONCLUSION: Potentially protective factors are present in higher concentrations in the stools of breast-fed infants than in stools of formula-fed infants. Interestingly, feces from breast-fed and formula-fed infants inhibited bacterial adhesion to a similar level, but neither was able to preserve epithelial barrier function.     

Gas production by feces of infants.

BACKGROUND: Intestinal gas is thought to be the cause abdominal discomfort in infants. Little is known about the type and amount of gas produced by the infant's colonic microflora and whether diet influences gas formation. METHODS: Fresh stool specimens were collected from 10 breast-fed infants, 5 infants fed a soy-based formula, and 3 infants fed a milk-based formula at approximately 1, 2, and 3 months of age. Feces were incubated anaerobically for 4 hours at 37 degrees C followed by quantitation of hydrogen (H2), methane (CH4), carbon dioxide (CO2), hydrogen sulfide (H2S), methanethiol (CH3SH), and dimethyl sulfide (CH3SCH3) in the head-space. RESULTS: H2 was produced in greater amounts by breast-fed infants than by infants in either formula group, presumably the consequence of incomplete absorption of breast milk oligosaccharides. CH4 was produced in greater amounts by infants fed soy formula than by infants on other diets. CO2 was produced in similar amounts by infants in all feeding groups. Production of CH3SH was conspicuously low by feces of breast-fed infants and production of H2S was high by soy-formula-fed infants. CH3SCH3 was not detected. Only modest changes with age were observed and there was no relation between gas production and stool consistency, although stools were more likely to be malodorous when concentrations of H2S and/or CH3SH were high. CONCLUSIONS: Gas release by infant feces is strongly influenced by an infant's diet. Of particular interest are differences in production of the highly toxic sulfur gases, H2S and CH3SH, because of the role that these gases may play in certain intestinal disorders of infants.     

Persistence of human milk proteins in the breast-fed infant

Several proteins in human milk are postulated to have physiological functions in the breast-fed infant. Therefore, survival of human milk proteins after passage through the gastrointestinal tract of the breast-fed infant was investigated. Fecal samples were collected from exclusively breast-fed term infants and milk samples from their mothers. Soluble proteins in the feces were extracted and analyzed for total protein, nitrogen, lactoferrin, secretory IgA, serum albumin and lysozyme. Significant amounts of lactoferrin and secretory IgA were excreted by the infants and this excretion decreased throughout the study period in a trend similar to the decreasing milk concentrations of these proteins. Gel filtration demonstrated excreted lactoferrin and secretory IgA to be intact. No serum albumin or lysozyme was detected in the fecal extracts. Crossed immunoelectrophoresis showed three human milk proteins to be present in the feces--the third was identified as alpha 1-antitrypsin. Excretion of these proteins indicates the total protein content of human milk is an over-estimation of the protein nutritionally available to the infant.     

Effects of Mucin upon Growth of Low Birth-Weight Infants and Their Intestinal Microflora

Purified hog gastric mucin was administered to low birth-weight infants at a dose of 7 mg per kg body weight per day and the following results were obtained: 1) The rate of body-weight increase was higher in the mucin-administered group than in the nonadministered group. 2) In regard to the intestinal microflora of the mucin-administered group, L. bifidus became predominant and the pH value of the feces was lowered. Thus, a likeness in fecal properties to breast-fed infants was brought about in bottle-fed infants. 3) In addition to mucin, when lactulose was administered at a dose of 0.8 g per kg body weight per day, the enhanced growth of intestinal L. bifidus and the lowered pH value were more profound from the possible synnergistic action than in the group administered with mucin alone. From these results, the supplementation of powdered milk with mucin enhances the growth of bottle-fed infants and brings about a likeness in fecal properties to breast-fed infants. Further supplementation with lactulose results in much more likeness in fecal properties to breast-fed infants.     

Persistence of Human Milk Proteins in the Breast-Fed Infant

Several proteins in human milk are postulated to have physiological functions in the breastfed infant. Therefore, survival of human milk proteins after passage through the gastrointestinal tract of the breast-fed infant was investigated. Fecal samples were collected from exclusively breast-fed term infants and milk samples from their mothers. Soluble proteins in the feces were extracted and analyzed for total protein, nitrogen, lactoferrin, secretory IgA, serum albumin and lysozyme. Significant amounts of lactoferrin and secretory IgA were excreted by the infants and this excretion decreased throughout the study period in a trend similar to the decreasing milk concentrations of these proteins. Gel filtration demonstrated excreted lactoferrin and secretory IgA to be intact. No serum albumin or lysozyme was detected in the fecal extracts. Crossed Immunoelectrophoresis showed three human milk proteins to be present in the feces—the third was identified as α₁-antitrypsin. Excretion of these proteins indicates the total protein content of human milk is an over-estimation of the protein nutritionally available to the infant.     

Longitudinal zinc balances in breast-fed and formula-fed infants

Longitudinal zinc (Zn) balance studies were performed under domestic conditions in term breast-fed (n = 10), term formula-fed (n = 5; Zn concentration in the formula: 4 mg/l) and preterm formula-fed (n = 3) infants during the first 17 weeks of life. Samples of milk, urine and feces were analyzed by atomic absorption spectrometry. The median daily Zn intake in breast-fed infants decreased from 0.592 (0.457-0.829) mg Zn/kg body weight to 0.151 (0.095-0.304) mg Zn/kg body weight in the first 17 weeks of life; comparable values for bottle-fed term infants were 0.58 (0.511-0.701) and 0.674 (0.529-0.731) mg Zn/kg body weight. The median percent retention of Zn intake was 27 (-60 to 81.4)% in breast-fed infants and 21.5 (-42 to 64)% in formula-fed infants. In view of the urinary and fecal Zn losses measured, a daily intake of 0.3-0.5 mg Zn/kg body weight is considered to be sufficient to ensure a Zn retention equivalent to breast-fed infants. This requires a Zn concentration of 2-3 mg/l of Zn depending on milk volume intake.     

Preliminary study on DNA damage in non breast-fed infants

BACKGROUND: There are many advantages of human milk for infants, including protection against cancer development and the advantages have been emphasized in several studies. In this study, infants fed by human milk has been compared with those fed by cow's milk concerning DNA damage. METHODS: The level of genetic damage in the peripheral blood lymphocytes of infants who were fed mainly by cow's milk and breast milk has been studied by sister chromatid exchange (SCE) analysis, which is a sensitive measurement of chromosomal damage. Each group consisted of 30 infants, whose ages ranged from 9 to 12 months. RESULTS: A significant increase (P < 0.0001) was found in the frequencies of SCE of infants not breast-fed (n = 30, mean SCE/cell +/- SD: 8.66 +/- 1.15) compared to those who were breast-fed (n = 30, mean SCE/cell +/- SD: 4.93 +/- 0.82). CONCLUSION: To our knowledge, there has been no published study investigating SCE ratio regarding DNA damage in infants not breast-fed. Molecular mechanism of DNA damage caused by the absence of human milk protection is a subject of future investigations.     

Iron gain in low-birthweight infants: role of milk feeding

The availability of iron is critical in low-birthweight infants. We followed a group of small preterm infants without iron supplementation who were either exclusively breast-fed or weaned early to industrial infant milk formula or home-prepared cow's milk formula. The gain of iron was compared within the milk groups on the basis of hemoglobin and serum ferritin concentrations at the ages of 3 and 4 mth when only trace amounts of solid foods had been given. Contrary to the reports on term infants we found unsupplemented proprietary infant milk formula and breast milk similar as a source of iron. It is possible that there is no major inhibition of iron absorption from any milk during the time of simultaneously occurring accelerated erythropoiesis and exhaustion of iron stores in preterm infants. The apparent inferiority of cow's milk could be due to increased intestinal loss of blood.     

Alterations of serum bile acid profile in breast-fed infants with prolonged jaundice

Serum bile acid conjugates in breast-fed infants with prolonged jaundice were analyzed by a newly developed procedure using high-performance liquid chromatography with fluorescence labeling. Major bile acids were cholate and chenodeoxycholate conjugates. Some of the breast-fed jaundiced infants had high levels of serum bile acid conjugates (greater than 25 mumol/L), but the mean levels of individual bile acid conjugates found in jaundiced breastfed infants were not significantly different from those in breast-fed infants without jaundice. The glycine- to taurine-conjugated bile acid ratio in breast-fed jaundiced infants was significantly lower than in breast-fed nonjaundiced infants or bottle-fed nonjaundiced infants. In breast-fed infants, the portion of taurine-conjugated bile acids increased in proportion to serum bilirubin levels. These findings suggest that alteration in conjugated bile acid patterns of breast milk jaundice is related to an increased enterohepatic circulation of bile acids as well as bilirubin in infants fed on breast milk that contains high amounts of taurine.     

Bioavailability of iron in soy-based formula and its effect on iron nutriture in infancy

Soy products have been reported to inhibit absorption of nonheme food iron and fortification iron. Iron bioavailability from a soy formula (Prosobee-PP 710) (iron added as ferrous sulfate: 12 mg/L; ascorbic acid: 54 mg/L) was examined in 16 adult women using the extrinsic radioactive tag method. The geometric mean absorption from the soy formula was only 1.7%. The effect of this formula on iron nutrition in infants was studied in 47 healthy term infants weaned spontaneously before 2 months of age and who received the formula ad libitum until 9 months of age. For control, 45 infants received a cow's milk formula fortified with ferrous sulfate (iron: 15 mg/L; ascorbic acid: 100 mg/L), which has been shown to be effective in preventing iron deficiency, and 49 additional breast-fed infants were also followed. All babies received solid foods (vegetables and meat) starting at 4 months of age. Iron nutritional status was determined at 9 months. Infants fed soy formula and iron-fortified cow's milk had similar mean values of hemoglobin, mean corpuscular volume, transferrin saturation, free erythrocyte protoporphyrin, and serum ferritin; both formula groups differed significantly (P less than .05) from the breast-fed group in all measurements except free erythrocyte protoporphyrin. Anemia (hemoglobin less than 11 g/dL) was present in only 4.3% and 2.2% of infants receiving the soy and the fortified formulas, respectively, v 27.3% in the breast-fed group. These results indicate that soy formula, in spite of the lower iron bioavailability when measured in adults, is essentially as effective as iron-fortified cow's milk in preventing iron deficiency in infants.     

Characterization of breast milk received by infants with gross blood in stools

OBJECTIVE: The aim of this study was to ascertain factors that might be protective of the appearance of gross blood in the stools of breast-fed infants. METHODS: Logistic regression models were formed to search for variables possibly explaining the condition. In addition to the analyzed breast milk factors, mother's allergic disease was introduced into the models to control for its possible confounding effect. The breast milk samples, collected from mothers of infants with gross blood in stools (n = 23) and from mothers of healthy age-matched infants (n = 71), were analyzed for concentrations of transforming growth factor-beta2, tumor necrosis factor-alpha, interleukin (IL)-4, IL-10, prostaglandin (PG)E2, cysteinyl leukotrienes (Cys-LTs) and fatty acid composition. RESULTS AND CONCLUSIONS: Increase in the concentrations of PGE2 and Cys-LTs in the breast milk together with mother's allergic disease reduced the likelihood of gross blood in stools in the breast-fed infant. The results suggest that no single factor, but a combination of immunomodulatory factors may protect the child from gross blood in the stools of breast-fed infants. Allergic disease was not a risk factor as mother's allergic disease appeared to counterbalance the gross blood in stools. Due to the preliminary nature of the study, the results need to be verified in a larger setting. The challenge for the future lies in identifying of such active compounds for dietary modification to enforce particularly the properties of the breast milk which are immunoprotective for the infant and to reduce the likelihood of intestinal disorders in at risk infants.     

Human milk oligosaccharides are associated with protection against diarrhea in breast-fed infants

OBJECTIVE: To determine the association between maternal milk levels of 2-linked fucosylated oligosaccharide and prevention of diarrhea as a result of Campylobacter, caliciviruses, and diarrhea of all causes in breast-fed infants. STUDY DESIGN: Data and banked samples were analyzed from 93 breast-feeding mother-infant pairs who were prospectively studied during 1988-1991 from birth to 2 years with infant feeding and diarrhea data collected weekly; diarrhea was diagnosed by a study physician. Milk samples obtained 1 to 5 weeks postpartum were analyzed for oligosaccharide content. Data were analyzed by Poisson regression. RESULTS: Total 2-linked fucosyloligosaccharide in maternal milk ranged from 0.8 to 20.8 mmol/L (50%-92% of milk oligosaccharide). Moderate-to-severe diarrhea of all causes (n=77 cases) occurred less often (P=.001) in infants whose milk contained high levels of total 2-linked fucosyloligosaccharide as a percent of milk oligosaccharide. Campylobacter diarrhea (n=31 cases) occurred less often (P=.004) in infants whose mother's milk contained high levels of 2'-FL, a specific 2-linked fucosyloligosaccharide, and calicivirus diarrhea (n=16 cases) occurred less often (P=.012) in infants whose mother's milk contained high levels of lacto-N-difucohexaose (LDFH-I), another 2-linked fucosyloligosaccharide. CONCLUSION: This study provides novel evidence suggesting that human milk oligosaccharides are clinically relevant to protection against infant diarrhea.     

A longitudinal study of salivary sialic acid in preterm infants: Comparison of human milk-fed versus formula-fed infants

We found that the saliva of preterm infants fed human milk contains twice the level of sialic acid as that in infants fed commercial formulas. The higher sialic acid level suggests greater viscosity and enhanced protection of the mucosal surfaces in breast-fed infants. Human milk itself is a rich source of sialylated oligosaccharides.     

Delay in caffeine elimination in breast-fed infants

Because of a persistently elevated caffeine half-life observed in a breast-fed infant during caffeine maintenance therapy, we conducted this prospective longitudinal study in two groups of infants (five exclusively breast-fed and 12 formula-fed). After 46 weeks' postconceptional age, all five breast-fed infants had a marked delay in caffeine elimination, compared with one infant in the formula-fed group. Four breast-fed infants had measurements of significantly longer caffeine half-lives compared with 12 formula-fed infants (76 +/- 13 hours v 21 +/- 28 hours and 54 +/- 9 hours v 16 +/- 13 hours at 47 to 50 weeks and 51 to 54 weeks postconceptional age, respectively), as well as significantly higher trough blood levels (three- to five-fold) after 46 weeks' postconceptional age. The fifth breast-fed infant accumulated caffeine secondary to a steep increase in caffeine half-life from 102 hours at 44 weeks to 372 hours at 51 weeks. The elevated blood caffeine levels in breast-fed infants was not related to higher daily dosage of caffeine citrate (4.4 mg/kg compared with 8.3 mg/kg in the formula-fed group at 56 weeks' postconceptional age). Daily consumption of caffeine was low or nonexistent in four nursing mothers, and transfer of caffeine to the infant was considered to be trivial. The findings from this study suggest, as does breast milk jaundice due to inhibition of glycuronyl transferase, that some components of human milk (free fatty acid, lipase activity, or other factors) inhibit or repress the postnatal normal maturation process of caffeine metabolism by hepatic cytochrome P-450.     

A prospective study of cow's milk allergy in exclusively breast-fed infants. Incidence, pathogenetic role of early inadvertent exposure to cow's milk formula, and characterization of bovine milk protein in human milk

A cohort of 1,749 newborns in the municipality of Odense were followed prospectively for the development of cow's milk allergy (CMA) during their first year of life. Altogether 39 fulfilled the criteria for CMA (2.2%). Out of the 39 infants, 17 developed symptoms of CMA during breast-feeding, in all cases before the age of 3 months. Nine of these were solely breast-fed at the time of diagnosis, giving a one year incidence of CMA in exclusively breast-fed infants of 0.5% (9/1,749) in a study population with a frequency of exclusive breast-feeding of 52% at 3 months of age. None of the infants had signs of CMA in the neonatal period. Review of records from the newborn nursery revealed that all 9 infants had been exposed to cow's milk formula in amounts corresponding to approximately 0.4-3.0 g of beta-lactoglobulin (BLG) during the first three days of life. Human milk samples were analyzed by enzyme-linked immunosorbent assay (ELISA) for the content of bovine BLG. Detectable amounts (0.5-45 ng/ml) were found in 3/9 samples of human milk against which the infants reacted clinically. Analysis of the size distribution by high pressure liquid gel permeation chromatography in combination with ELISA indicated a molecular weight of BLG corresponding to that of monomeric BLG (18 kD). Possibly early inadvertent and occasional exposure to cow's milk proteins may initiate sensitization in predisposed neonates. Subsequent exposure to minute amounts of bovine milk proteins in human milk may act as booster doses eliciting allergic reactions.     

Calcium, phosphorus, and magnesium concentrations in plasma during first week of life and their relation to type of milk feed

Serial changes in plasma levels of calcium, phosphorus, magnesium, alkaline phosphatase, and total proteins have been investigated in 138 healthy, term Caucasian infants. Blood samples were obtained for each infant from cord blood and on day 1 and day 6. The infants were studied in three groups according to whether they were breast fed, received 'Ostermilk No. 1' or 'Cow and Gate V' formulas. Levels of calcium, phosphorus, magnesium, alkaline phosphatase, and total proteins did not differ between the groups at birth or on day 1. By day 6 calcium levels were higher and phosphorus levels lower in the breast-fed infants compared with either of the artificially-fed groups. Phosphorus levels were lower in the V Formula group compared with the Ostermilk group but the mean calcium levels of these two groups did not differ significantly. However, only 2-8% of the V Formula group developed hypocalcaemia compared with 18-2% of the Ostermilk group. The only infant developing clinical tetany belonged to the group fed Ostermilk. Evidence is also given which suggests that those infants with low calcium levels on day 1 who were fed the high-solute milk tended to show a fall in calcium by day 6. This did not apply to the two other groups. It is concluded that the use of adapted cows' milk preparations for infant feeding should lead to a reduction in the incidence of neonatal tetany.     

Dietary modifications versus dicyclomine hydrochloride in the treatment of severe infantile colics

This study examined 120 infants, aged 3–12 weeks, with severe colics and compared the results of a specific hypoallergenic diet (group A) with those of pharmacological treatment (group B). Non-breastfed group A infants received soy milk and if unresponsive, hydrolyzed milk formulas; mothers of breast-fed infants received a diet without cow's milk, eggs or fish. Breast-fed and non-breast-fed group B infants received dicyclomine hydrochloride 3 mg/kg/day. Results, based on quantitative measurements of crying. indicated that in breast-fed infants there was no significant improvement between group A (62.5%) and group B (66.6%) infants. Among formula-fed infants, comparison of positive results using soy milk (65.9%) with positive results using dicyclomine (53.3%) was not significant; positive results using soy milk and hydrolyzed milk formulas in non-responders to soy milk, provided an improvement in 95.4% of cases. Pharmacological treatment provided an improvement in 53.3%) of cases. The diffcrence was significant ( p <0.01).     

Transmission of cytomegalovirus from mothers to preterm infants by breast milk

OBJECTIVES: To assess the risk of transmission of cytomegalovirus (CMV) by breast milk from CMV-seropositive mothers to their breast-fed preterm infants and to evaluate their outcome. PATIENTS AND METHODS: The study population comprised breast-fed preterm infants with a birth weight of <1,500 g and gestational age of <35 weeks. Venous blood samples from the mothers and infants were tested for CMV IgG and IgM antibodies on the 5th and 30th day after birth. Breast milk was obtained for CMV DNA detection by polymerase chain reaction and viral culture on the 5th day and on the 3rd, 6th and 12th week. Urine samples of the babies were collected at the same time for CMV culture. Neurodevelopmental assessment was done at 6 months of age, corrected for preterm birth. RESULTS: Thirty-eight mothers and 42 infants (including 4 sets of twins) were enrolled in the study. A mother-infant pair was excluded because of inadequate breast milk collection. Thirty-six mothers (97.3%) were CMV-seropositive. CMV DNA of breast milk was detected in 35 seropositive mothers. Six infants of 5 mothers were infected (infected group) at a mean of 77 days after birth, and 34 infants of 31 mothers were not (noninfected group). In all the mothers of the infected group, CMV virus could be cultured from the milk whey. The average maternal CMV IgG on day 5 after delivery was higher in the infected than in the noninfected group. Sepsis-like symptoms and hyperbilirubinemia were more frequently noted in the infected infants than in the noninfected, but the difference was not statistically significant. Neurodevelopmental outcome did not significantly differ between the 2 groups. CONCLUSIONS: The risk of CMV infection in breast-fed premature infants was highest when the mothers shed viable virus in their breast milk. These mothers had high CMV IgG, which may help identify those mother-infant pairs at risk. Inactivation of the virus in milk by freezing may be a way of reducing the transmission of this virus via breast milk.     

Lack of pharmacological active saliva levels of caffeine in breast-fed infants

Caffeine, which is used for the treatment of apnoea in premature newborns, is known to be excreted into breast milk. However data on the amount of caffeine transferred to the breast-fed infant and on caffeine concentrations in the baby are lacking. In 18 healthy breast-feeding women caffeine concentrations in breast milk were measured 2 and 4 hours after the intake of coffee (145.8 mg caffeine, mean +/- sd, n = 18). For an estimation of kinetic parameters (eg, AUC), additional saliva samples were collected up to 6 hours after coffee intake. The daily caffeine intake of the infants was calculated from the average breast-milk concentration (AUCsaliva X milk/saliva ratio/24 hours) as average milk concentration X daily milk volume. From nine of the babies (aged 20 days to 19 weeks) at least one saliva sample could be obtained. The ratio milk/saliva was found to be 0.90 +/- 0.20 (mean +/- sd, n = 18) and the average breast-milk concentration was 0.82 +/- 0.29 mg/L (mean +/- sd, n = 18). The daily caffeine intake of the infants was calculated to range from 0.027 to 0.203 mg/kg/day. The caffeine concentrations measured in the babies ranged from less than 0.05 to 0.75 mg/L. Hence it can be concluded that the amount of caffeine ingested by the children is small compared to the therapeutic dose if usual amounts of coffee are taken by the mothers.