Prebiotic carbohydrates in human milk and formulas

Human milk oligosaccharides play an important role, as prebiotic soluble fibres, in the postnatal development of the intestnial flora. Infant formulas are virtually free of prebiotic oligosaccharides. As a consequence, formula-fed infants develop an intestinal flora significantly different to the flora of breastfed infants. Due to the complexity of human milk oligosaccharides, it is necessary to use alternative sources of prebiotic ingredients as components of infant formulas. The present review summarizes the data of experimental research and clinical studies with a prebiotic mixture containing 90% short-chain galacto-oligosaccharides and 10% long-chain fructo-oligosacchrides are summarized. The data demonstrate that, with this prebiotic mixture, the growth of bifidobacteria and lactobacilli can be stimulated, the faecal pH can be decreased, and the presence of pathogens can be reduced to levels similar to those of breastfed infants. Thus, prebiotic oligosaccharides such as the studied mixture provide beneficial effects for formula-fed infants.     

Galacto-oligosaccharides and long-chain fructo-oligosaccharides as prebiotics in infant formulas: A review

The present review summarizes clinical and experimental data concerning the possible effects of a prebiotic mixture of short-chain galacto-oligosaccharides and long-chain fructo-oligosaccharides. The results from several studies, made up of over 400 preterm and term infants, clearly demonstrate that the prebiotic mixture under examination specifically stimulates the growth of bifidobacteria and lactobacilli and reduces the growth of pathogens. As a consequence of the changed intestinal flora by the dietary galacto-oligosaccharides and fructo-oligosaccharides, the faecal pH values and the short-chain fatty acid pattern were similar to those found in breastfed infants. In addition, the stool consistency was the same as in breastfed infants. In vitro experiments have demonstrated that the specific short-chain fatty acid pattern, at a pH similar to that found in faecal samples of breastfed infants, reduces the growth of pathogens in a dose-dependent manner but does not influence the growth of bifidobacteria and lactobacilli. In an animal vaccination model, the prebiotic mixture improved the response to vaccination. In an allergy model (sensitization by ovalbumin), the allergic reaction was reduced by the prebiotic mixture. The data obtained from animal experiments are in agreement with preliminary data from clinical trials which indicate a reduced allergic response (reduced plasma IgE/IgG4 ratio) and reduced episodes of upper airway infection during the first year of life.
Conclusion: Experimental evidence demonstrates that the prebiotic mixture employed in these studies modulates the intestinal flora and modulates the immune system as human milk does. There are sufficient experimental data to put forward the hypothesis that substances like the prebiotic mixture under study will substantially contribute to the improvement of the protective properties of infant formulas.     

Galacto-oligosaccharides and long-chain fructo-oligosaccharides as prebiotics in infant formulas: a review

The present review summarizes clinical and experimental data concerning the possible effects of a prebiotic mixture of short-chain galacto-oligosaccharides and long-chain fructo-oligosaccharides. The results from several studies, made up of over 400 preterm and term infants, clearly demonstrate that the prebiotic mixture under examination specifically stimulates the growth of bifidobacteria and lactobacilli and reduces the growth of pathogens. As a consequence of the changed intestinal flora by the dietary galacto-oligosaccharides and fructo-oligosaccharides, the faecal pH values and the short-chain fatty acid pattern were similar to those found in breastfed infants. In addition, the stool consistency was the same as in breastfed infants. In vitro experiments have demonstrated that the specific short-chain fatty acid pattern, at a pH similar to that found in faecal samples of breastfed infants, reduces the growth of pathogens in a dose-dependent manner but does not influence the growth of bifidobacteria and lactobacilli. In an animal vaccination model, the prebiotic mixture improved the response to vaccination. In an allergy model (sensitization by ovalbumin), the allergic reaction was reduced by the prebiotic mixture. The data obtained from animal experiments are in agreement with preliminary data from clinical trials which indicate a reduced allergic response (reduced plasma IgE/IgG4 ratio) and reduced episodes of upper airway infection during the first year of life. CONCLUSION: Experimental evidence demonstrates that the prebiotic mixture employed in these studies modulates the intestinal flora and modulates the immune system as human milk does. There are sufficient experimental data to put forward the hypothesis that substances like the prebiotic mixture under study will substantially contribute to the improvement of the protective properties of infant formulas.     

Dietary prebiotic oligosaccharides are detectable in the faeces of formula-fed infants

Human milk oligosaccharides are not digested during intestinal passage and can be detected in stools. In this study it was investigated whether a prebiotic mixture of low-molecular-weight galacto-oligosaccharides (GOS) and high-molecular-weight fructo-oligosaccharides (FOS) can be detected in stool samples of formula-fed infants. The test formula was supplemented with 0.8 g/dl oligosaccharides (GOS+FOS). In the control formula, maltodextrins were used as placebo. Fecal flora was assessed at the beginning (day 1) and at the end of a 28-d feeding period (day 2). At day 2 the content of galacto- and fructo-oligosaccharides in the stool samples were measured. On study day 1, the number of bifidobacteria was not different among the groups (supplemented group: 7.7 (6.2) CFU/g; placebo group: 8.0 (6.0) CFU/g). At the end of the 28-d feeding period, the number of bifidobacteria was significantly higher in the group fed the supplemented formula when compared to placebo (supplemented group: 9.8 (0.7) CFU/g stool; placebo group: 7.1 (4.7) CFU/g stool; p<0.001). In all infants fed the supplemented formula, GOS and FOS could be identified in the stool samples. That was not the case in infants fed the non-supplemented formula. CONCLUSION: The present data confirm the bifidogenicity of oligosaccharides and indicate that dietary galacto-oligosaccharides and long chain fructo-oligosaccharides remain during the whole passage in the lumen of the gastrointestinal tract, similarly to human milk oligosaccharides.     

Dietary prebiotic oligosaccharides are detectable in the faeces of formula-fed infants

Human milk oligosaccharides are not digested during intestinal passage and can be detected in stools. In this study it was investigated whether a prebiotic mixture of low-molecular-weight galacto-oligosaccharides (GOS) and high-molecular-weight fructo-oligosaccharides (FOS) can be detected in stool samples of formula-fed infants. The test formula was supplemented with 0.8 g/dl oligosaccharides (GOS+FOS). In the control formula, maltodextrins were used as placebo. Fecal flora was assessed at the beginning (day 1) and at the end of a 28-d feeding period (day 2). At day 2 the content of galacto- and fructo-oligosaccharides in the stool samples were measured. On study day 1, the number of bifidobacteria was not different among the groups (supplemented group: 7.7 (6.2) CFU/g; placebo group: 8.0 (6.0) CFU/g). At the end of the 28-d feeding period, the number of bifidobacteria was significantly higher in the group fed the supplemented formula when compared to placebo (supplemented group: 9.8 (0.7) CFU/g stool; placebo group: 7.1 (4.7) CFU/g stool; p <0.001). In all infants fed the supplemented formula, GOS and FOS could be identified in the stool samples. That was not the case in infants fed the non-supplemented formula.
Conclusion: The present data confirm the bifidogenicity of oligosaccharides and indicate that dietary galacto-oligosaccharides and long chain fructo-oligosaccharides remain during the whole passage in the lumen of the gastrointestinal tract, similarly to human milk oligosaccharides.     

Reproducing the bifidogenic effect of human milk in formula-fed infants: Why and how?

Awareness of the key role of the intestinal microflora in the generation of the immunophysiological regulation and in the defence against pathogenic agents has attracted our interest in ways of manipulating the microbiota to improve health. Dietary modulation of the intestinal microflora is today one of the main topics of interest in the nutritional sciences. Performing this modulation in the neonatal or early infancy period, when immunological programming takes place, is a relatively new concept. Fructo-oligosaccharides (FOS) and galacto-oligosaccharides (GOS) are prebiotics whose bifidogenic activity has been proven in adults. However, only recently have they been combined in infant formulas to reproduce the prebiotic effect of human milk oligosaccharides. In two consecutive trials, it has been demonstrated that supplementation of infant formulas with a mixture of GOS and FOS modified the fecal flora of term and preterm infants, stimulating the growth of Bifidobacteria. In the trial with term infants, the bifidogenic effect of the prebiotic mixture was dose dependent and there was also a significant increase in the number of Lactobacilli in the supplemented group. These findings offer a promising horizon for the early prevention of allergy and infections in infants.     

Reproducing the bifidogenic effect of human milk in formula-fed infants: why and how?

Awareness of the key role of the intestinal microflora in the generation of the immunophysiological regulation and in the defence against pathogenic agents has attracted our interest in ways of manipulating the microbiota to improve health. Dietary modulation of the intestinal microflora is today one of the main topics of interest in the nutritional sciences. Performing this modulation in the neonatal or early infancy period, when immunological programming takes place, is a relatively new concept. Fructo-oligosaccharides (FOS) and galacto-oligosaccharides (GOS) are prebiotics whose bifidogenic activity has been proven in adults. However, only recently have they been combined in infant formulas to reproduce the prebiotic effect of human milk oligosaccharides. In two consecutive trials, it has been demonstrated that supplementation of infant formulas with a mixture of GOS and FOS modified the fecal flora of term and preterm infants, stimulating the growth of Bifidobacteria. In the trial with term infants, the bifidogenic effect of the prebiotic mixture was dose dependent and there was also a significant increase in the number of Lactobacilli in the supplemented group. These findings offer a promising horizon for the early prevention of allergy and infections in infants.     

Prebiotics in infant milk formulas: new perspectives

In recent years it has become accepted that healthy human intestinal microflora may play an important part in priming the infants' systemic and mucosal immunity. Dietary modulation of the gut microbiota is a topical area of nutritional sciences and the main focus of many current functional foods such as non-digestible oligosaccharides (NDOs). Fructo-oligosaccharides (FOS) and trans-beta-galacto-oligosaccharides (TOS) have been claimed to benefit the health of the colon by selectively stimulating the growth of bifidobacteria and lactobacilli (prebiotic effect). It could be of clinical interest to manipulate colonic flora because it is supposed that specific bacteria in the gut microbial microflora could promote potentially antiallergenic processes and play a key part in atopic disease prevention. Supporting this view is the finding that analysis of the composition of the intestinal bacterial populations showed different microbial patterns between healthy and allergic individuals. Assuming that non-digestible TOS and FOS can affect the intestinal ecosystem beneficially, the opportunity for gut flora manipulation arises in bottle-fed infants. New preterm and term infant milk formulas, supplemented with a mixture of TOS and FOS as prebiotic ingredients induced a significantly higher colonization of bifidobacteria and lactobacilli. In the future, selective manipulation of the intestinal microbiota might be an approach to novel prophylactic and therapeutic intervention strategies of atopy, by redirecting allergic Th-2 responses in favour of Th-1 responses.     

Prebiotics in infant milk formulas: new perspectives

In recent years it has become accepted that healthy human intestinal microflora may play an important part in priming the infants' systemic and mucosal immunity. Dietary modulation of the gut microbiota is a topical area of nutritional sciences and the main focus of many current functional foods such as non-digestible oligosaccharides (NDOs). Fructo-oligosaccharides (FOS) and trans-β-galacto-oligosaccharides (TOS) have been claimed to benefit the health of the colon by selectively stimulating the growth of bifidobacteria and lactobacilli (prebiotic effect). It could be of clinical interest to manipulate colonic flora because it is supposed that specific bacteria in the gut microbial microflora could promote potentially antiallergenic processes and play a key part in atopic disease prevention. Supporting this view is the finding that analysis of the composition of the intestinal bacterial populations showed different microbial patterns between healthy and allergic individuals. Assuming that non-digestible TOS and FOS can affect the intestinal ecosystem beneficially, the opportunity for gut flora manipulation arises in bottle-fed infants. New preterm and term infant milk formulas, supplemented with a mixture of TOS and FOS as prebiotic ingredients induced a significantly higher colonization of bifidobacteria and lactobacilli. In the future, selective manipulation of the intestinal microbiota might be an approach to novel prophylactic and therapeutic intervention strategies of atopy, by redirecting allergic Th-2 responses in favour of Th-1 responses.     

Prebiotic concept for infant nutrition

In the neonatal period, the intestine is colonised in a stepwise process that depends on mode of delivery, environmental factors, bacterial interactions, and the host itself resulting in a colonisation with a complex heterogeneous bacterial flora. Oligosaccharides have been identified as an important prebiotic factor of human milk As long as analogues of human milk oligosaccharides are not available now and in the near future it is aimed to resemble the prebiotic effect of human milk by oligosaccharides from available sources. In the present study in preterm infants, a mixture of 90% galacto-oligosaccharides and 10% fructo-oligosaccharides has been tested. The mixture of GOS/FOS was composed to mimic the molecule size distribution of human milk oligosaccharides. Microbiological analysis of the faces was performed before and 7, 14, and 28 days after start of supplementation and stool characteristics have been recorded. Maltodextrin was used as placebo and infants fed human milk have been used as reference. After a 28 days feeding period, the number of bifidobacteria of the group fed the oligosaccharide supplemented formula was in the upper range of the reference group whereas the numbers of the group fed the formula supplemented with the placebo were in the lower range of the reference group (placebo: 7.9 ± 0.83 and GOS/FOS mixture: 10,0 ± 2.05 log 10 CFU/g wet stool; reference (M ± SD): 7.14-10.7 log 10 CFU/g wet stool). Stool characteristics in the group fed the supplemented formula were close to those found in the human milk fed infants. In summary, supplementation of a preterm formula with a mixture of galacto- and fructo-oligosaccharides has a stimulating effect on the growth of bifidobacteria in the intestine and results in more frequent produced and softer stools. Thus, prebiotic mixtures such like the studied oligosaccharide mixture might help in improving intestinal tolerance to enteral feeding in preterm infants.     

Increase of faecal bifidobacteria due to dietary oligosaccharides induces a reduction of clinically relevant pathogen germs in the faeces of formula-fed preterm infants

In a previous study on formula-fed preterm infants, we were able to demonstrate that dietary oligosaccharides (a mixture of 90% galacto-oligosaccharides and 10% fructo-oligosaccharides in a concentration of 1 g/dl) stimulate the growth of faecal bifidobacteria. In the present explorative analysis of this study, we focus on the effect of the dominance of bifidobacteria on the presence of clinically relevant pathogens ( Staphylococcus aureus, Staphylococcus epidermidis, Staphylococcus haemolyticus, Pseudomonas aeruginosa, Enterobacter, Klebsiella, Proteus, Streptococcus group B, Clostridium difficile, Bacillus subtilis and Acinetobacter ).
Conclusion : The data demonstrate that stimulation of bifidobacteria by prebiotic oligosaccharides reduces the presence of clinically relevant pathogens in the faecal flora, indicating that prebiotic substances might have the capacity to protect against enteral infections.     

Increase of faecal bifidobacteria due to dietary oligosaccharides induces a reduction of clinically relevant pathogen germs in the faeces of formula-fed preterm infants

In a previous study on formula-fed preterm infants, we were able to demonstrate that dietary oligosaccharides (a mixture of 90% galacto-oligosaccharides and 10% fructo-oligosaccharides in a concentration of 1 g/dl) stimulate the growth of faecal bifidobacteria. In the present explorative analysis of this study, we focus on the effect of the dominance of bifidobacteria on the presence of clinically relevant pathogens (Staphylococcus aureus, Staphylococcus epidermidis, Staphylococcus haemolyticus, Pseudomonas aeruginosa, Enterobacter, Klebsiella, Proteus, Streptococcus group B, Clostridium difficile, Bacillus subtilis and Acinetobacter). CONCLUSION: The data demonstrate that stimulation of bifidobacteria by prebiotic oligosaccharides reduces the presence of clinically relevant pathogens in the faecal flora, indicating that prebiotic substances might have the capacity to protect against enteral infections.     

Influence of two infant formulas and human milk on the development of the faecal flora in newborn infants

The establishment of the faecal flora of 39 full-term infants fed exclusively on breast milk (n = 20) or with two different modern adapted cow's milk formulas (n = 19) was studied during the first 3 months of life. One formula investigated was based on 100% bovine casein as the protein source whereas the other formula contained bovine milk proteins with a whey/casein ratio of 60:40. A faecal flora rich in bifidobacteria was found in all study groups; the growth of putrefactive bacteria (especially Bacteroides spp.), however, was limited. In formula-fed infants, significantly higher bacterial counts of enterococci and Clostridia were detected compared to breast milk-fed infants. Similarities and differences due to the feeding regimen were particularly reflected in the pattern of the anaerobic bacterial species. Bifidobacterium bifidum, B. infantis and B. breve constituted the majority of the bifidobacterial flora independent of the type of milk feeding. Other bifidobacterial species such as B. longum, B. adolescentis, B. parabifidum and B. pseudo-catenulatum were detected in high numbers and at low frequencies in breastfed infants. The latter three were observed in infants fed the whey/casein formula as well. It seems that infants fed a casein formula develop a faecal flora more like that of breastfed infants concerning Lactobacillus spp. (especially L. fermentum and L. brevis).     

Neural maturation of breastfed and formula-fed infants

Background: Human milk provides infants with a full complement of all polyunsaturated fatty acids, including docosahexaenoic acid (DHA) and arachidonic acid (AA). Formula milks only contain the precursors of DHA, AA and linoleic acid, and hence formula-fed infants must synthesize their own DHA and AA. Aim: To evaluate the effect of feeding—whether breastfeeding or formula-feeding—in early infancy upon subsequent neurodevelopment and achievement of optimum brain function. Subjects and methods: The study included 53 normal, healthy infants (30 exclusively breastfed infants and 23 exclusively formula-fed infants) at the age of 1 y (±1 mo). Each infant was subjected to a full physical and neurological examination together with neurophysiological studies including flash visual evoked potential (FVEP), brainstem auditory evoked potential (BAEP) and somatosensory evoked potential (SSEP). Results: There was significant prolongation of P ₁₀₀ wave latency of FVEP in formula-fed infants, together with significant prolongation of absolute latency of waves I, III and V of BAEP in formula-fed infants compared with breastfed infants. There was significant prolongation in inter-peak latencies between cortical and Erb's components in formula-fed infants compared with breastfed infants.

Conclusion: We can conclude that VEP, BAEP and SSEP are more mature in breastfed infants relative to formula-fed infants at 1 y of age, and thus breast milk helps earlier development and maturation of some aspects of the nervous system than milk formulas.     

Prebiotic concept for infant nutrition

In the neonatal period, the intestine is colonised in a stepwise process that depends on mode of delivery, environmental factors, bacterial interactions, and the host itself resulting in a colonisation with a complex heterogeneous bacterial flora. Oligosaccharides have been identified as an important prebiotic factor of human milk As long as analogues of human milk oligosaccharides are not available now and in the near future it is aimed to resemble the prebiotic effect of human milk by oligosaccharides from available sources. In the present study in preterm infants, a mixture of 90% galacto-oligosaccharides and 10% fructo-oligosaccharides has been tested. The mixture of GOS/FOS was composed to mimic the molecule size distribution of human milk oligosaccharides. Microbiological analysis of the faces was performed before and 7, 14, and 28 days after start of supplementation and stool characteristics have been recorded. Maltodextrin was used as placebo and infants fed human milk have been used as reference. After a 28 days feeding period, the number of bifidobacteria of the group fed the oligosaccharide supplemented formula was in the upper range of the reference group whereas the numbers of the group fed the formula supplemented with the placebo were in the lower range of the reference group (placebo: 7.9 +/- 0.83 and GOS/FOS mixture: 10,0 +/- 2.05 log 10 CFU/g wet stool; reference (M +/- SD): 7.14-10.7 log 10 CFU/g wet stool). Stool characteristics in the group fed the supplemented formula were close to those found in the human milk fed infants. In summary, supplementation of a preterm formula with a mixture of galacto- and fructo-oligosaccharides has a stimulating effect on the growth of bifidobacteria in the intestine and results in more frequent produced and softer stools. Thus, prebiotic mixtures such like the studied oligosaccharide mixture might help in improving intestinal tolerance to enteral feeding in preterm infants.     

Factors controlling the bacterial colonization of the intestine in breastfed infants

This article summarizes the published data on the intestinal microflora in breastfed infants published during the last 15 y. Enterobacteria and enterococci are found in high numbers in most infants during the first week of life. Bifidobacteria and Bacteroides spp. are found in increasing numbers at the following weeks. The intestinal microflora in breastfed infants can also be followed by different biochemical parameters. Acetic acid is found in higher concentrations in breastfed than in formula-fed infants. Degradation of mucin starts later in breastfed than in formula-fed infants. The conversion of cholesterol to coprostanol is also delayed by breastfeeding. Geographical differences in the composition of the intestinal microflora in infants have been reported, i.e. enterobacteria, enterococci, bifidobacteria, lactobacilli and bacteroides show different occurrences in developed and developing countries. There are minor differences in the infant's intestinal microflora due to breastfeeding or/and formula feeding.     

Factors controlling the bacterial colonization of the intestine in breastfed infants

This article summarizes the published data on the intestinal microflora in breastfed infants published during the last 15 y. Enterobacteria and enterococci are found in high numbers in most infants during the first week of life. Bifidobacteria and Bacteroides spp. are found in increasing numbers at the following weeks. The intestinal microflora in breastfed infants can also be followed by different biochemical parameters. Acetic acid is found in higher concentrations in breastfed than in formula-fed infants. Degradation of mucin starts later in breastfed than in formula-fed infants. The conversion of cholesterol to coprostanol is also delayed by breastfeeding. Geographical differences in the composition of the intestinal microflora in infants have been reported, i.e. enterobacteria, enterococci, bifidobacteria, lactobacilli and bacteroides show different occurrences in developed and developing countries. There are minor differences in the infant's intestinal microflora due to breastfeeding or/and formula feeding.     

Effect of the specific infant formula mixture of oligosaccharides on local immunity and development of allergic and infectious disease in young children: randomized study

Aim

The aim of our open prospective randomized nutritional intervention study was to evaluate the effect of feeding with a standard infant formula enriched with the specific mixture of oligosaccharides on local digestive immunity system and further development of allergic and infectious diseases in young children.

Material and methods

Depending on the type of feeding the infants were divided into 3 groups (with random allocation to one of the formula feeding groups): 80 infants who were breastfed, 80 infants consuming the formula supplemented with oligosaccharides, 80 infants fed with a standard formula.

Results

Breastfed infants had the highest content of Bifidobacteria and Lactobacilli in feces (9.047 ± 1.075 and 7.26 ± 0.65 CFU/g accordingly). In infants fed with formula supplemented with scGOS/lcFOS fecal concentrations of Bifidobacteria and Lactobacilli were similar to those in breastfed infants (8.92 ± 1.011 and 7.22 ± 0.74 CFU/g accordingly). It was found that infants fed with breast milk and supplemented formula had significantly less allergic reactions to food products compared to the babies from the third group (3.92% and 4.84% vs. 16.98% accordingly; p < 0,05).

Conclusions

The mixture of prebiotic oligosaccharides (scGOS/lcFOS – 9:1; 8 g/L) has a similar to breast milk positive impact on the factors of local digestive immunity system in formula-fed infants. This effect may reduce the risk of allergic and infectious diseases in children aged up to 18 months of life, compared with babies fed with the standard formula without oligosaccharides.     

Infant formulas supplemented with prebiotics: intestinal microbiota and immune responses

It is well known that the type of feeding influences the composition of the gut microflora after birth. Human milk favours the growth of a 'bifidus flora' which, according to several evidences, may activate the immune system and defend from pathogens. Breast milk oligosaccharides, which are involved in many functional effects both at local and systemic level, are thought to stimulate the growth of health promoting microbes, such as bifidobacteria, and may ultimately influence the immune system. In accordance with this current working hypothesis, dietary modulation of the gut microbiota to obtain a 'bifidus flora' also in bottle-fed infants may be a useful way to stimulate immunological functions and to harbour a biological barrier against pathogens. In several clinical trials prebiotic oligosaccharides have been used to mimic the beneficial effects of breast milk oligosaccharides. A mixture of oligosaccharides has shown its efficacy in stimulating the establishment of a 'bifidus flora', with stools closer to those found in breast-fed infants. Several experimental data also indicate that oligosaccharides might modulate the immune system and contribute to the improvement of the protective properties of infant formulas.     

Leptin levels in breast-fed and formula-fed infants

Aim: Leptin, a hormone that regulates food intake and energy metabolism, is present in breast milk and thus may be involved in body composition differences between breastfed and formula-fed infants. The aim of this study was to evaluate whether diet and gender affect plasma leptin concentration in breastfed and formula-fed infants during the first months of life. Methods: Anthropometric and bioelectrical impedance measurements [total body water (TBW) calculated with the Fjeld equation] were made and venous blood plasma samples were analysed for leptin concentration in healthy, exclusively breastfed or formula-fed Italian infants in the first year of life. Infants were subdivided in two ways: three groups (periods) in relation to age, and five groups in relation to weight. Results: The average serum concentration of leptin was 7.35 ng ml -1 . Serum leptin values were higher in breastfed than in formula-fed infants. Breastfed infants in group 1 had a statistically higher serum leptin concentration (2500-3749 g). There were no significant differences in anthropometric measurements, body mass index or skinfold thickness between breastfed and formula-fed infants. In the periods I and II, breastfed infants had a significantly higher TBW than formula-fed infants. Males had a significantly higher TBW than females in periods I and II. Breastfed infants in group 2 (3750-4999 g) had a significantly higher TBW than formula-fed infants.

Conclusion: The data on TBW, weight and skinfold thickness suggest that the higher leptin concentration observed in breastfed infants in the first months of life may be due not only to adipose tissue production but also to human milk.