The Nutritional Role of Breast-Milk IgA and Lactoferrin

ABSTRACT. The nutritional enigma concerning the extent to which breast-milk immune proteins are digested has been investigated by measuring the intakes and faecal outputs of IgA and lactoferrin over 7 days in 10 exclusively breast-fed (BF) and 9 formula-fed (FF) fullterm infants at 6 and 12 weeks post-partum. BF outputs (mg/day) greatly exceeded FF values ( p <0.001): at 6 weeks secretory-IgA BF=160±28, FF=14±2, lactoferrin BF=M±2, FF=0.9±0.1; at 12 weeks secretory-IgA BF=94±17, FF=25±5, lactoferrin BF=7±1, FF=1±0.3. Secretory-IgA represented 42% and 27% of BF faecal protein at 6 and 12 weeks compared with 6% for FF infants at both ages. BF secretory-IgA outputs were highly correlated with intakes ( r =0.83, p <0.001). IgA and lactoferrin outputs and the presence of faecal secretory-IgA fragments in BF and FF infants were influenced by defaecation rate, suggesting that partial degradation occurred in the large intestine. By 6 weeks post-partum only 1% lactoferrin and 17% secretory-IgA intakes appeared in the faeces and 95% breast-milk protein could be regarded as nutritionally available. The elevated BF outputs of IgA and lactoferrin relative to endogenous excretion suggest, however, that breast-milk may still make a considerable contribution to intestinal defence mechanisms after the neonatal period despite the small proportion of daily intake which escapes digestion. The protective action of IgA and lactoferrin may also depend on their site of degradation and the nature of fragments.     

Breast-milk IgA and lactoferrin survival in the gastrointestinal tract--a study in rural Gambian children

The survival of breast-milk secretory-IgA and lactoferrin has been investigated in 23 Gambian children aged 1.5, 3 and 17 months. Endogenous excretion of these immune proteins was measured in 7 weaned 34-month-old children. Defaecation rate was the prime determinant of faecal secretory-IgA and lactoferrin outputs, indicating that partial degradation occurs in the large intestine. Calculations showed that at least 30% of IgA and 2% of lactoferrin ingested from breast-milk must survive in the small intestine. Variations in faecal immune protein outputs were related to differences in intake and defaecation rate and were not affected by age or solid food consumption. The raised faecal outputs of 5 children with diarrhoea were a consequence of their high stool frequencies. IgA disappearance in the large intestine proceeded twice as fast in Gambian breast-fed children as in comparable Cambridge infants, suggesting that differences in gut flora may influence IgA survival. Thus breast-feeding, irrespective of age or additional food, can deliver significant quantities of these antimicrobial proteins to the small intestine but differences in defaecation rate and gut flora may affect their protective potential in the large intestine.     

Breast-Milk IgA and Lactoferrin Survival in the Gastrointestinal Tract–a Study in Rural Gambian Children

ABSTRACT. The survival of breast-milk secretory-IgA and lactoferrin has been investigated in 23 Gambian children aged 1.5, 3 and 17 months. Endogenous excretion of these immune proteins was measured in 7 weaned 34-month-old children. Defaecation rate was the prime determinant of faecal secretory-IgA and lactoferrin outputs, indicating that partial degradation occurs in the large intestine. Calculations showed that at least 30 % of IgA and 2 % of lactoferrin ingested from breast-milk must survive in the small intestine. Variations in faecal immune protein outputs were related to differences in intake and defaecation rate and were not affected by age or solid food consumption. The raised faecal outputs of 5 children with diarrhoea were a consequence of their high stool frequencies. IgA disappearance in the large intestine proceeded twice as fast in Gambian breast-fed children as in comparable Cambridge infants, suggesting that differences in gut flora may influence IgA survival. Thus breast-feeding, irrespective of age or additional food, can deliver significant quantities of these antimicrobial proteins to the small intestine but differences in defaecation rate and gut flora may affect their protective potential in the large intestine.     

Evaluation of full-term infants fed an evaporated milk formula

The objective of this prospective, cohort study was to compare the nutritional status of full-term infants who were fed human milk (BF, n = 29). formula (FF, n = 30) or evaporated milk formulae (EM, n = 30) for at least 3 months. Infants were seen at enrollment, 3 and 6 months, at which times a blood sample, diet record and anthropometric data were collected. Infants in the EM group received solids earlier (12 ± 5 weeks) than did FF infants (15 ± 4 weeks), and both were earlier than BF infants (19 ± 4 weeks). Only 26% of the EM fed group received iron supplements as ferrous sulphate drops. Seven BF, 12 FF and 20 EM had abnormal ferritin values (<10ngml^-1) at 6 months. Copper intake was lower in the EM infants at 3 and 6 months. However, plasma copper and erythrocyte copper zinc superoxide dismutase (ZnCuSOD) levels did not differ between groups. Selenium intake was lower in the EM group (5 ± 1 and 10 ± 5 μg d^-1; 3 and 6 months) than in the FF infants (13 ± 4 and 19 ± 7 μgd^-1; 3 and 6 months). Erythrocyte SeGHSPx levels in EM infants were lower at 6 months (EM, 33.2 ± 3.4; FF, 35.2 ± 3.9; BF, 36.1 ± S.SmUmgHb^-1). Thiamin intake (0.99 ± 0.08 and 1.24 ± 0.32; 3 and 6 months, mg 1000 kcal^-1) was higher in the FF group than in EM infants (0.38 ± 0.39 and 0.66 ± 0.38; 3 and 6 months). There were more (13%) abnormal thiamin assays in the EM group at 6 months than in the BF and FF infants (0%). In conclusion, infants fed evaporated milk formula receive adequate copper but may not receive enough thiamin or selenium. Unless supplemented from birth with medicinal iron, intakes of iron will be inadequate.     

Breast-milk antimicrobial factors of rural Gambian mothers. II. Influence of season and prevalence of infection

The effects of season and variations in the prevalence of infectious disease on the concentrations and daily production of breast-milk immunoproteins were studied in 152 rural Gambian mothers and their children up to 26 months post-partum. IgA, IgG, IgM, C3, C4, lactoferrin, lysozyme and secretory component concentrations and breast-milk volumes were measured longitudinally over a six month period which encompassed dry and rainy seasons. No increase in the production of any immunoprotein was observed at the time of maximum prevalence of serious infectious diseases, especially diarrhoea, in the children. Enhanced secretion of certain immunoproteins was noted in mothers of children aged 9-18 months at the beginning of the rainy season. There was some evidence that this may have been associated with skin sepsis, particularly impetigo, in the children. The production of most immunoproteins fell during the rainy season. This was not the result of declining maternal food intakes as similar decreases were seen for women receiving a dietary supplement.     

Breast feeding increases concentrations of IgA in infants' urine.

To investigate the influence of breast feeding on mucosal immunity the concentrations and daily outputs of IgA and lactoferrin in urine were measured in 10 breast fed and 12 infants fed on formula milk at 6 and 12 weeks of age. The concentrations and outputs of secretory IgA in urine were significantly higher in the breast fed group by a factor of three. The secretion of IgA in urine by the breast fed infants was characteristic of the baby and was not related to the intake of IgA from breast milk. Lactoferrin concentrations were similar in the two groups at both ages. In addition to secretory IgA, two thirds of all samples contained proteins with alpha chain but no secretory component antigenic determinants. Breast feeding seems to increase the local production of secretory IgA into the urinary tract during early childhood, thus providing enhanced protection from infection.     

In vitro fermentation of carbohydrate by breast fed and formula fed infants

Unabsorbed carbohydrates are fermented by colonic bacteria to short chain fatty acids (SCFA) which are rapidly absorbed, salvaging energy and reducing stool output. There are marked differences between the faecal flora and SCFA of breast fed (BF) and formula fed (FF) infants which may be related to the higher incidence of diarrhoea in FF infants. Part of this effect may be caused by a difference in the ability of the microflora to ferment carbohydrate. To test the hypothesis that BF and FF have different fermentation capacities for simple and complex carbohydrates, in vitro cultures of faeces from healthy infants (2-10 weeks; 11 BF, 11 FF) containing glucose, lactose, raftilose (a fructo-oligosaccharide), or soybean polysaccharide were incubated anaerobically. Results were compared with those of adult faecal cultures using the same carbohydrates. Cultures of faeces from BF and FF infants produced comparable amounts of total SCFA in all cultures. These cultures produced less SCFA than those from adult faeces and produced very little SCFA from complex carbohydrate. BF cultures produced more acetic acid than FF in all cultures, whereas FF cultures produced more propionate with sugars and more butyrate with raftilose. Both groups of infants produced less butyrate than adults in all cultures. Thus it is unlikely that a lower ability to ferment carbohydrate is a major cause of increased risk of diarrhoea in FF fed infants but individual SCFA production may be important.     

In vitro fermentation of carbohydrate by breast fed and formula fed infants

Accepted 4 November 1996
Unabsorbed carbohydrates are fermented by colonic bacteria to short chain fatty acids (SCFA) which are rapidly absorbed, salvaging energy and reducing stool output. There are marked differences between the faecal flora and SCFA of breast fed (BF) and formula fed (FF) infants which may be related to the higher incidence of diarrhoea in FF infants. Part of this effect may be caused by a difference in the ability of the microflora to ferment carbohydrate. To test the hypothesis that BF and FF have different fermentation capacities for simple and complex carbohydrates, in vitro cultures of faeces from healthy infants (2-10 weeks; 11 BF, 11 FF) containing glucose, lactose, raftilose (a fructo-oligosaccharide), or soybean polysaccharide were incubated anaerobically. Results were compared with those of adult faecal cultures using the same carbohydrates. Cultures of faeces from BF and FF infants produced comparable amounts of total SCFA in all cultures. These cultures produced less SCFA than those from adult faeces and produced very little SCFA from complex carbohydrate. BF cultures produced more acetic acid than FF in all cultures, whereas FF cultures produced more propionate with sugars and more butyrate with raftilose. Both groups of infants produced less butyrate than adults in all cultures. Thus it is unlikely that a lower ability to ferment carbohydrate is a major cause of increased risk of diarrhoea in FF fed infants but individual SCFA production may be important.

     

Breast-milk Antimicrobial Factors of Rural Gambian Mothers: Influence of Season and Prevalence of Infection

ABSTRACT. The effects of season and variations in the prevalence of infectious disease on the concentrations and daily production of breast-milk immunoproteins were studied in 152 rural Gambian mothers and their children up to 26 months post-partum . IgA, IgG, IgM, C3, C4, lactoferrin, lysozyme and secretory component concentrations and breast-milk volumes were measured longitudinally over a six month period which encompassed dry and rainy seasons. No increase in the production of any immunoprotein was observed at the time of maximum prevalence of serious infectious diseases, especially diarrhoea, in the children. Enhanced secretion of certain immunoproteins was noted in mothers of children aged 9–18 months at the beginning of the rainy season. There was some evidence that this may have been associated with skin sepsis, particularly impetigo, in the children. The production of most immunoproteins fell during the rainy season. This was not the result of declining maternal food intakes as similar decreases were seen for women receiving a dietary supplement.     

Do ambient temperature and humidity influence the breast-milk intake of babies?

This study explored the possible effect of ambient temperature and humidity on the breast-milk intakes of Australian infants (n = 35) aged 6-12 weeks. Over a 24 h period, each baby was fed only on milk from the breast; milk intakes, temperature and humidity were monitored. Milk intakes--determined by test-weighing the baby, with a correction for evaporative losses during feeds--showed a mean of 830 g/24 h, with median 818 and s.d. 152. The mean correction for evaporative losses was 46 g/24 h; omission of this correction would have led to an average underestimate of 5.5% in 24 h intakes. Ambient conditions varied substantially between subjects: 24 h mean temperatures ranged from 14 to 28 degrees C, and humidities from 48 to 97%. Over these ranges, breast-milk intakes did not appear to be significantly influenced by ambient temperature or ambient humidity; however, the rate of evaporative losses increased by 0.008 g/min for each 1 degree C rise in ambient temperature.     

Breast-fed infants have higher leptin values than formula-fed infants in the first four months of life

BACKGROUND: Leptin is a hormone present in breast milk, which regulates food intake and energy metabolism. AIM: To investigate whether leptin levels are different in breast-fed (BF) or formula-fed (FF) infants in the first months of life. METHODS: We evaluated serum leptin by radio-immunoassay and anthropometric parameters in 51 infants at the average age of 62.8+/-30 days, 25 exclusively BF and 26 exclusively FF. RESULTS: Leptin serum values were higher in BF (7.1+/-10.4 ng/ml) than in FF (3.7+/-3.87 ng/ml) infants (p <0.05). Leptin values were higher in females (6.9+/-9.87 ng/ml) than in males (3.5+/-3.88 ng/ml) (p <0.05). No differences were found in anthropometric measurements and body mass index. CONCLUSION: The kind of feeding might be a factor affecting serum leptin concentration in term infants. The long-term consequences of this difference between BF and FF infants and leptin's role in promoting obesity later in life are unknown.     

Enhanced fecal excretion of selected immune factors in very low birth weight infants fed fortified human milk

The amounts of lactoferrin, lysozyme, total IgA, secretory IgA (SIgA), and specific SIgA antibodies to a pool of Escherichia coli O antigens were measured in 96-h collections of feces obtained from 28 very low birth weight infants, 28-30 wk of gestation, studied at 2.5 and 6 wk of age. Eighteen of these infants were fed their mothers' milk fortified with fractions of skim and cream derived from pasteurized, lyophilized, mature human milk (FM) and 10 infants were fed commercial cow's milk-based formula. The concentrations of these selected immune factors in the FM and formula also were measured. Specific SIgA antibodies to E. coli O antigens were detected in the feces of 90% of the FM-fed infants, but in none of the feces of the formula-fed infants. The feces obtained from FM-fed infants had markedly greater quantities of lactoferrin (p less than 0.001), lysozyme (p = 0.006), and IgA (p less than 0.001) than those of cow's milk formula-fed infants. The concentrations of total and secretory IgA were correlated significantly (r = 0.88, p less than 0.001) and 95% of total IgA was SIgA. The fecal concentration of specific SIgA antibodies to E. coli O antigens in FM-fed infants correlated with the concentration of these antibodies in their milk (p less than 0.001). However, there were no direct relationships between the milk concentrations or the infant's intakes of the other selected immune factors and the excretion of these factors in the feces.(ABSTRACT TRUNCATED AT 250 WORDS)     

Partition of nitrogen intake and excretion in low-birth-weight infants

Although nitrogen balance studies have been carried out in low-birth-weight infants, few have partitioned the nitrogen into its components. In this study, 72-hour balance studies were conducted in 24 low-birth-weight infants (gestational age, 30.7 +/- 1.6 weeks; birth weight 1.36 +/- 0.25 kg) fed their mothers' milk (preterm milk) or 50% preterm milk and 50% formula. Total nitrogen, nonprotein nitrogen, and whey protein intake and excretion were measured. Total nitrogen intake (preterm milk group, 452 +/- 138 mg/kg per day; preterm + formula group, 406 +/- 93 mg/kg per day), absorption (85%), and retention (71%) were not significantly different between groups. Intact and fragments of secretory IgA and lactoferrin were detected in soluble fecal extracts, and represented 25% and 9% of intake, respectively. Feeding preterm milk allows for nitrogen accretion similar to intrauterine growth rates for 5 weeks postnatally, and provides potentially functional proteins for the low-birth-weight infant.     

Plasma vitamin E concentrations of older infants fed cow's milk or infant formula.

Nutrition of older infants, though important for optimal brain development, is inadequately studied. The beverage choice markedly influences nutrient intake, but little is known regarding nutrition status of older infants, particularly for vitamin E. This study assessed vitamin E intakes and plasma tocopherol concentrations in two groups of healthy infants, 8 to 13 months of age, who had consumed either cow's milk (n = 45) or milk-based formula (n = 55) for a minimum of the 3 preceding months. Mean (+/- SEM) vitamin E intake was significantly lower (p < or = 0.001) by the infants who had consumed cow's milk (CMF) than by infants who had consumed formula (FF); 4.1 +/- 0.25 mg/day and 10.9 +/- 0.57 mg/day, respectively. Mean (+/- SEM) intake of linoleic plus linolenic acids was significantly lower (p < or = 0.005) by CMF infants (3.4 +/- 0.2 g) than by FF infants (9.9 +/- 1.0 g), although mean (+/- SEM) dietary vitamin E to polyunsaturated fat ratio (E/PUFA ratio) was the same in both FF and CMF infants (1.3 +/- 0.1). Plasma alpha-tocopherol concentration (mean +/- SD) was significantly lower (p < or = 0.005) in CMF than in FF infants (0.86 +/- 0.28 mg/dl vs. 1.14 +/- 0.42 mg/dl, respectively). Dietary vitamin E intakes were positively correlated (p < or = 0.05) with plasma alpha-tocopherol concentrations. No correlations were found between plasma alpha-tocopherol concentrations and total fat intake, dietary E/PUFA ratios, erythrocyte polyunsaturated fatty acids > or = C18:2, or number of hours postprandial that blood was drawn.(ABSTRACT TRUNCATED AT 250 WORDS)     

Selenium and human lactation in Australia: milk and blood selenium levels in lactating women, and selenium intakes of their breast-fed infants

A series of 20 mother-infant pairs were studied in Brisbane, Australia, at 6-12 weeks postpartum. The mean selenium concentration in maternal blood was 101 (SD +/- 19) ng/g and in maternal serum 81(+/- 15) ng/g; serum values appeared low in comparison with those reported for lactating women from Japan and the USA, but similar to those from Finland and from a previous Australian study. Breast milk selenium concentrations (11.9 +/- 3.5 ng/g) were also low by international standards, but not as low as in New Zealand or Scandinavia. There was no correlation between selenium concentrations in milk and blood (or serum). The infants' 24-h breast-milk intakes were 856 +/- 172 g, and their 24-h selenium intakes 10.7 +/- 4.1 micrograms (compared to the Australian RDI of 10 micrograms).     

Intracellular and plasma cytokine profile in neonates born to non-atopic parents: the impact of breast feeding

The aim of this study was to profile the changes in intracellular and plasma cytokines during the neonatal period and evaluate the impact of breast feeding on these parameters. For this purpose, we measured the interleukin (IL)-2 and IL-4 producing CD3+/CD69+ T-cells using flow cytometry and plasma concentrations of interferon (IFN)-gamma and IL-4 using ELISA, in 122 healthy term neonates, aged 6–12 h, born to non-atopic parents, and 25 healthy children aged 1–12 years. A total of 42/122 neonates exclusively breast-fed (BF) and 39/122 formula fed (FF) were studied again on the 30th day of life for the above parameters. Finally, a clinical evaluation for the presence of atopic disease was conducted at 2 years of age. We found that at birth, the percentage of CD3+/CD69+/IL-4+ T-cells (median = 15.8%, range = 4.4%–49%) and plasma concentrations of IL-4 (median = 0.22 pg/ml, range = 0.18–0.25 pg/ml) were significantly higher (P<0.0001) compared to those of children (median = 1.6%, range = 0.16%–2.7% for CD3+/CD69+/IL-4+ and median = 0.17 pg/ml, range = 0.13–0.26 pg/ml for IL-4), whereas plasma concentrations of IFN-gamma were significantly lower in neonates (median = 0.42 pg/ml, range = 0.3–1.5 pg/ml) than in children (median = 1.2 pg/ml, range = 0.3–2.6 pg/ml, P<0.0001). During the neonatal period, only the CD3+/CD69+/IL-4+ T-cells increased significantly in both BF and FF groups. Comparison between BF and FF groups revealed no significant difference in any of the parameters measured. Moreover, no difference in the development of atopy during the first 2 years of life was found between BF and FF infants. Conclusion: our findings demonstrate that during the entire neonatal period type 2 immunity dominates, regardless of the mode of feeding, whereas type 1 immunity dominates during childhood. Moreover, in the absence of family history of atopy, the mode of feeding per se does not play a crucial role in the development of atopy within the first 2 years of life.Abbreviations BF breast-fed - BFA brefeldin A - FITC fluorescein isothiocyanate - FF Formula-fed - IFN interferon - IL interleukin - MoAbs monoclonal antibodies - PBS-BSA phosphate buffered saline bovine serum albumin - PE-Cy 5 phycoerythrin-cyanin 5 - PMA phorbol 12-myristate 13-acetate - Tc T-cytotoxic - Th T-helper     

Development of serum IgA and IgM levels in breast-fed and formula-fed infants during the first week of life

Background

IgA and IgM antibodies play important roles to protect infants in early life

Aim

To study the effects of breast milk feeding versus formula feeding in early infancy on the development of serum IgA and IgM.

Methods

A group of 220 healthy infants born after uncomplicated pregnancies and deliveries were enrolled. The infants were divided into three groups according to feeding type: breast-fed (BF), formula-fed (FF), and mixed-fed (MF). Capillary blood was collected for serum IgA and IgM detection at the first week of life.

Results

The average concentrations of serum IgA and IgM in all infants were 1.171 ± 1.079 and 256.2 ± 165.8 μg/ml, respectively. There were significantly higher concentrations of serum IgA in the FF group than MF group at 3, 4 and 6 days of age and BF group at 5 and 6 days old. Paired serum IgA concentrations revealed that IgA significantly decreased in the BF group, but not in the FF and MF groups. Meanwhile, paired serum IgM concentrations revealed that IgM increased significantly during early infancy in all groups. However, the IgM levels had no difference among the 3 groups within 7 days of age.

Conclusions

Our study demonstrated the development of serum IgA and IgM in early life. Formula feeding induced higher serum IgA concentrations than breast‐feeding within 7 days of age. However, serum IgM concentration was significantly increased in early life in all groups but had no differences between the different feeding types. Breast‐feeding may protect antigen loading in early life.     

Mineral homeostasis in very premature infants: serial evaluation of serum 25-hydroxyvitamin D, serum minerals, and bone mineralization

This study was designed to evaluate the role of vitamin D sufficiency, as reflected in serum 25-hydroxyvitamin D (25-OHD) concentrations, on serum minerals and bone mineralization in very premature infants. Seventy-two infants (mean +/- SD gestation 30.1 +/- 2.5 weeks, mean +/- SD birth weight 1178 +/- 278 gm) were observed serially for the first 3 months of life. Mean serum calcium and phosphorus values, but not magnesium, remained low prior to 12 weeks. The percentage of infants with moderate to severe hypomineralization was 75% at 3 weeks, 55% at 6 weeks, 54% at 9 weeks, and 15% at twelve weeks. Low serum calcium and phosphorus values, high alkaline phosphatase activity, and moderate-severe hypomineralization were more frequent in infants weighing less than 1000 gm and in those with lower mineral intake. With a 400 IU vitamin D supplement, 45% of infants could maintain an initially normal serum 25-OHD concentration or increase low concentrations, whereas 55% had falling or persistently low (less than or equal to 15 ng/ml) 25-OHD concentrations. Birth weight and mineral intakes were comparable in these two groups, yet the group with the lower serum 25-OHD concentration had lower serum calcium and higher alkaline phosphatase values, and a higher percentage of moderate to severe hypomineralization. Regardless of birth weight, mineral intake, or 25-OHD concentration, increases in serum calcium and phosphorus values and in mineralization were seen at postconception term (12 weeks in most infants, nine weeks in those weighing 1250 to 1600 gm). At 12 weeks of age, but not before, serum 25-OHD concentration was directly correlated with serum calcium (r = 0.47, P less than 0.01) and serum phosphorus (r = 0.47, P less than 0.01) and inversely correlated with alkaline phosphatase values (r = -0.71, P less than 0.01). Mineral availability and 25-OHD sufficiency both appear to be important and to act synergistically, with neither totally compensating for the other.     

Protein intake in early infancy: effects on plasma amino acid concentrations, insulin metabolism, and growth

The effects of different protein intakes on wt gain, insulin secretion, and plasma concentrations of amino acids have been evaluated in a prospective study involving 30 normal term infants. The infants were studied from 4.0 to 6.0 mo of age. Ten infants were breast-fed (BF), the others were randomly divided into two groups of 10 infants. One group was fed a formula containing 1.3 g protein/100 mL (F 1.3), the other a formula with 1.8 g protein/100 mL (F 1.8). The formulas were isocaloric (72 kcal/100 mL), and the fat concentrations were 3.5 g/100 mL (F 1.3) and 3.2 g/100 mL (F 1.8). All infants received the same supplementary foods. The urinary C-peptide excretion in the infants fed the F 1.8-formula was 4.4 +/- 2.1 nmol/mmol creatinine or 19.4 +/- 12.9 nmol/m2, significantly higher than that in the infants fed the F 1.3-formula (2.6 +/- 1.5 and 7.9 +/- 5.1) or the BF infants (1.7 +/- 1.4 and 6.3 +/- 6.0). Gain in wt was 18.0 +/- 4.3, 19.9 +/- 3.9, 22.8 +/- 1.6 g/kg/wk and corresponded to protein intakes of 1.3 +/- 0.2, 1.9 +/- 0.3, and 2.6 +/- 0.2 g/kg/d, in the BF, F 1.3, and F 1.8 groups, respectively. Gain in length was 6.7 +/- 1.8 (BF-group), 6.2 +/- 2.5 (F 1.3-group), and 7.6 +/- 2.2 (F 1.8-group) mm/m/wk. Wt gain correlated with urinary C-peptide excretion at 6.0 mo (r = 0.51, p less than 0.01) and with protein intake (r = 0.43, p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)     

Serum ghrelin concentration, fasting time and feeding in infants

BACKGROUND: Data on hormonal feeding control in infants in the first months of life according to the kind of feeding are scanty. AIM: To evaluate whether serum ghrelin could be involved in feeding behaviour control of breast-fed (BF) and formula fed (FF) infants. METHODS: We studied 50 AGA healthy term infants aged 1-6 months of age. Serum ghrelin concentration was determined by RIA. Fasting time (measured as the difference between the time of the last meal and the time of blood collection) and number of meals were recorded. RESULTS: A positive correlation between serum ghrelin levels and fasting time emerged in FF infants (r = 0.752; p <0.001) but not in BF infants (r = 0.345; p = 0.072). CONCLUSIONS: Circulating ghrelin concentration correlates positively with fasting time in FF infants; these infants have higher serum ghrelin concentration, longer fasting time and fewer meals than BF infants. These observations suggest a possible influence of early feeding on mechanisms regulating satiety and feeding behaviour.