Vittorio Vigi

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.

Supplementation of an adapted formula with bovine lactoferrin: 1. Effect on the infant faecal flora

The development of the infant faecal flora was studied over the first three months of life in infants receiving breast milk, a modern adapted formula and adaptations of this formula. Breast‐fed infants developed a flora rich in Bifidobacterium sp. Facultative anaerobes were ubiquitous, but in relatively small numbers within the diet group. Other obligate anaerobes, such as Clostridium sp. and Bacteroides sp. were rarely isolated. Standard formula produced a flora rich in bifidobacteria, but the growth of facultative organisms was not suppressed by this diet. Clostridium sp. and Bacteroides sp. were more common in this feeding group. After the addition of lactoferrin at 10 mg/100 ml to the formula diet, a flora similar to that of the standard formula‐fed babies was achieved. Lactoferrin at 100 mg/100 ml was able to establish a “bifidus flora” in half of the babies given this formula, but only at age three months. Clostridium sp. and Bacteroides sp. were common faecal isolates from babies receiving both the lactoferrin diets.

Acidic oligosaccharides from pectin hydrolysate as new component for infant formulae : Effect on intestinal flora, stool characteristics, and pH

Objectives: To come even closer to the functional composition of human milk, acidic oligosaccharides (AOS) from pectin were added to well known neutral prebiotics (galacto-oligosaccharides (GOS) and long-chain fructo-oligosaccharides (FOS)). The effect of AOS and GOS/FOS/AOS on intestinal flora, stool characteristics as well as acceptance and tolerance was investigated. Methods: Human milk contains 75% to 85% neutral and 15% to 25% acidic oligosaccharides. In this prospective, randomized, double blind study, a mixture of 80% neutral oligosaccharides (from long-chain galacto- and long-chain fructo-oligosaccharides) with 20% acidic oligosaccharides derived from pectin hydrolysis was investigated. Forty-six term infants were fed a standard formula supplemented with either maltodextrin as control (n = 15), or with 0.2 g acidic oligosaccharides (n = 16), or with the latter plus 0.6 g neutral oligosaccharides (mixture of galacto- and fructo-oligosaccharides; n = 15). Fecal flora using plating technique and pH were measured. Stool characteristics and possible side effects (crying, vomiting, and regurgitation) were recorded. Results: There was no difference in the bifidobacteria counts between the control and the group supplemented with acidic oligosaccharides alone (8.75 ± 0.50 vs. 8.58 ± 0.94 log colony forming units [CFU]/g stool). In infants fed the combination of acidic and neutral oligosaccharides, bifidobacteria were increased (9.61 ± 0.70 log CFU/g stool; P < 0.01). The same pattern was observed with lactobacilli. Stool consistency was softest in infants fed the complete oligosaccharide mixture, but also in those fed formula supplemented with acidic oligosaccharides alone, the stool consistency was significantly softer compared with the control group. Fecal pH increased in the controls, remained constant in acidic oligosaccharides alone, and decreased in the complete mixture of oligosaccharides group. Conclusion: There was no difference in growth, crying, vomiting, and regurgitation patterns between the groups. In summary, acidic oligosaccharides from pectin hydrolysate are well tolerated as ingredient in infant formulae but do not affect intestinal microecology.

Galacto-oligosaccharides are bifidogenic and safe at weaning: a double-blind randomized multicenter study.

Objectives: The primary objective of this study was to determine the bifidogenic effect of galacto-oligosaccharides (GOS) in a follow-on formula and the effects on other intestinal bacteria. Secondary objectives were the effects on stool characteristics, growth, and general well-being. Participants and Methods: In a multicenter, double-blind study, 159 healthy infants, formula-fed at enrollment (at 4–6 months), were randomized to an experimental follow-on formula supplemented with 5 g/L (GOS) (77 infants), or to a standard follow-on formula (control, 82 infants). Infants were evaluated at enrollment (study day 1 = sd1), after 6 weeks (study day 2 = sd2), and after an additional 12 weeks (study day 3 = sd3). At each study day, a fresh stool sample for the bacterial counts was collected, and the growth parameters were measured. At sd2, urinary specimens were collected for the evaluation of urinary osmolarity. Results: At sd2 and sd3, the GOS group had a higher median number (colony-forming units per gram of stool) of bifidobacteria than did the control group (sd2 GOS 9.2 × 109 vs control 4.4 × 109, P = 0.012); (sd3 GOS 7.2 × 109 vs control 2.4 × 109, P = 0.027). Other bacteria did not show any significant differences between the 2 groups at all study days. The GOS produced softer stools but had no effect on stool frequency. The urinary osmolarity (mOsm/L) at sd2 was comparable in both groups. Supplementation had no influence on the incidence of gastrointestinal side effects or on the growth of the infants. Conclusions: These data indicate that the addition of GOS (5 g/L) to a follow-on formula positively influences the bifidobacteria flora and the stool consistency in infants during the supplementation period at weaning. No local or systemic side effects were recorded.

Supplementation of an adapted formula with bovine lactoferrin. 2. Effects on serum iron, ferritin and zinc levels

Breast milk provides an excellent supply of most nutrients for newborn infants. Infant formulae should be nutritionally comparable to breast milk especially with regard to critical nutrients like iron and other trace elements. Infant formulae supplemented with various amounts of bovine lactoferrin were given to two groups of infants. These infants were compared with infants receiving unsupplemented formula and breast‐fed infants. The effects of these diets on levels of haemoglobin, haematocrit, serum iron, ferritin and zinc were examined for a study period of 150 days. At birth, concentrations of iron, haemoglobin, haematocrit and zinc were comparable in all four feeding groups. The fact that the serum zinc level was not altered by lactoferrin supplementation appears to rule out an in‐vivo effect of lactoferrin on zinc nutrition of infants. Ferritin levels of breast‐fed infants were significantly higher than in non‐supplemented formula‐fed infants at day 30 and day 90. This difference was seen only at day 30, when comparing breast‐fed infants to lactoferrin‐supplemented formula‐fed infants. Comparing the infants receiving formulae, the formula supplemented with the higher amount of bovine lactoferrin induced significantly higher serum ferritin levels compared to the unsupplemented formula at day 90 and day 150. These observations favour the idea that lactoferrin may be involved in iron absorption. Since this effect was pronounced only after 90 days, it has to be discussed as to whether this effect is a convincing argument for supplementing infant formulae with bovine lactoferrin.

Fecal flora measurements of breastfed infants using an integrated transport and culturing system

Sir, It is generally recognized that bacterial colonization of the intestine with indigenous flora is an important component in development of the intestinal mucosal barrier function in the human infant (1). There is accumulating evidence that the intestinal flora plays an important role in the postnatal development of the immune system (2) and promotes the absorption of nutrients in the colon (3). As a consequence, the artificial manipulation of the intestinal ecosystem by including preor probiotics in feeding formulas to generate a predominantly bifidobacterial flora even in bottle-fed infants has been attempted (4). Detailed knowledge of the microbial ecology of the human colon is essential to obtain reliable information on the effects of preor probiotics and on the influence of diet on the intestinal microflora. Technical difficulties are still a major barrier in studying the gut flora from stool samples and may represent a limiting factor in studies on the effect of early diet on the establishment of the intestinal bacterial ecosystem in the newborn infant. We therefore studied an integrated system of stool sampling, transporting and culturing in order to investigate the number of bifidobacteria and lactobacilli in stool samples of infants of up to 3 mo of age. Particular attention has been paid to the possible influence of storage time. Fifteen exclusively breastfed term infants were enrolled in the study. The Ethics Committee of the University Hospital approved the protocol of the study and informed parental consent was obtained for each infant before enrolment in the study. The infants were examined on the first day of full breastfeeding, i.e. 120 ml kg 1 d 1 (examination day 1; mean age: 5.3 2.4 d) and were re-examined after a 6 to 8-wk period of breastfeeding (examination day 2). On each examination day, the stool samples were collected in the hospital. Two samples were taken for evaluation of a possible influence by a circadian rhythm. When more than two stools were available for each infant, the first and second samples were collected at intervals of 12 h, the 24-h sampling period starting at 06.00 h. To account for data not normally distributed, the data on the microflora as well as stool frequency and consistency were described as medians and interquartile ranges (IQR, 25th–75th percentiles). The influence of the duration of feeding or the influence of duration of storage on these parameters was investigated using nonparametric tests. A linear regression analysis was performed to investigate the relationship between the two different samples from the same examination day. All tests were performed on an alpha-level of 5%. Pvalues 0.05 were considered as significant. The software used was StatView 5.0 (SAS Institute Inc.). On the second examination day, one stool of the first 5 infants was divided into four portions. Each portion was separately transferred to the transport medium, homogenized and stored at 80°C. The samples were analysed after different storage times. The first portion was analysed within 1 mo, the second after 3 mo, the third after 5 mo and the fourth portion after 8 mo. A portion of a fresh faecal sample (0.2 g) was

Z-score of weight for age of infants with atopic dermatitis and cow's milk allergy fed with a rice-hydrolysate formula during the first two years of life

BACKGROUND Recently, rice-based formulas have been widely used in hypoallergenic diets, but data on nutritional values are scarce. AIM To evaluate the growth of infants fed with a rice-based hydrolysate formula, compared to those infants fed with a soy formula or an extensively hydrolysed casein formula, in the first 2 y of life. METHODS A total of 88 infants were enrolled between March 2002 and March 2004. Fifty-eight infants with atopic dermatitis (AD) and cows milk allergy (CMA), confirmed by open challenge, were enrolled as study group: 15 were fed with a rice-based hydrolysate formula (RHF), 17 with a soy-based formula (SF) and 26 with an extensively hydrolysed casein formula (eHCF). Thirty infants with AD without cows milk allergy were recruited as a control group (CG) and fed with a free diet. Weight was recorded on enrolment and at 3-monthly intervals in the first year of life, and at 6-monthly intervals in the second year. Infants were weighed naked, before feeding, by means of an electronic integrating scale. The z-scores of weight for age were calculated. STATISTICS One-way analysis of variance and Students t-test were used for statistical comparison. Significance was set at p<0.05. RESULTS No significant differences between the RHF, SF and eHCF groups were observed for the z-score of weight for age during the first 2 y of life, but a significantly lower difference was seen in the RHF group compared to the control group in the intervals 9 mo-1 y (p=0.025) and 1-1.5 y (p=0.020) of age. In contrast, the SF and eHCF groups were comparable to the control group, but the eHCF group was significantly lower (p=0) in the first trimester of life. CONCLUSION Even if our findings show no significant difference between RHF and control, low weight observed in infants fed with RHF raises doubts about the nutritional adequacy of rice-hydrolysate formulas.

Different pre-term formulas for different pre-term infants

Optimal nutrition is one of the most important aspects in the care of pre-term infants, especially for the gestationally youngest ones. These infants should receive a supply of nutrients that can sustain growth similar to that of a third trimester normal foetus. Traditional pre-term formulas do not ensure an optimal protein supply except when fed at high volumes, with an excess of fat and carbohydrates. Formulas with a protein content of 2-2.5 g 100ml(-1) and a protein/energy (P:E) ratio of less than 3g 100 kcal(-1) are not the best choice for the very low birth weight (VLBW) infants. We have tested a new formulation designed for the nutrition of the VLBW infants that is characterised by a protein content of 2.9 g 100ml(-1) and a P:E ratio of 3.5 g 100 kcal(-1). The milk formula was well tolerated and associated with better weight gain compared with fortified breast milk (18.1 vs. 15.2 g kg(-1)day(-1); p=0.0015). These results were obtained with a noticeably lower fluid supply (157 vs. 177 ml kg day(-1); p<0.0001) and lower energy intake (130 vs. 151 kcal kg(-1)day(-1); p<0.0001). Infant length and head circumference did not differ significantly between groups. Currently, the use of a formula with a P:E ratio of 3.5 g 100 kcal(-1) appears to be safe and to represent the best choice available for the gestationally youngest infants.

Experimental milk formulae with reduced protein content and desialylated milk proteins: influence on the faecal flora and the growth of term newborn infants

We have assessed the growth, tolerance and the faecal flora composition in healthy infants on different feeding regimens. Four groups of infants were fed exclusively on mothers milk, a standard formula and two experimental formulae. The first experimental formula consisted of a milk with a reduced protein content (1.2 g/100 ml), the second in a formula with the same protein content and with milk proteins desialylated by mild acid hydrolysis. The aim of the study was to test whether lowering the protein content and/or modifying the proteins by desialylation would favour the development of a bifidus flora. A bifidus flora was detected in 60% of breastfed infants at 1 month of life. All formulae employed during the study failed to induce a prevalence of colonization with bifidobacteria at 1 month of age. The two experimental milk formulae were well tolerated, but the infant growth rate was slightly lower as compared to the breastfed infants and the infants fed the standard formula. The presence in milk formulae of pre‐digested and desialylated proteins can offer some advantages in term of digestibility and mimic a physiological intestinal mechanism of the infant.

Complementary feeding practices in preterm infants: an observational study in a cohort of Italian infants.

Background: There are no evidence-based guidelines for weaning preterm infants, and the timing of weaning and the diet offered tend to reflect tradition and marketing rather than medical advice. Procedures: In a survey of complementary feeding practices in preterm infants conducted at the University Hospital of Ferrara, Italy, we evaluated the effect of sex, gestational age (GA), birth weight (BW), and milk feeding, and of the mothers age, education, and professional status, on weaning. Results: Complete data were available for 156 infants. Solid food was introduced, on average, 22.2 weeks after birth and 15.1 weeks after term; 6.5% of infants (considering chronological age) and 60.9% (considering corrected age) were weaned before 4 months; 18% of infants weighed <5 kg at weaning (most had low GA and BW). Among maternal factors, only age significantly influenced the weaning schedule. Milk feeding did not affect initiation of weaning; however, formula-fed infants, most of whom had lower GA and BW, were lighter and younger (from term) than were their counterparts. The first solid food was mashed fruit in 46.8% of cases. Meat and gluten were offered 5 and 7 weeks (average) after the initiation of weaning. Conclusions: A matter of concern emerging from our study is that in almost 50% of cases, the first solid food offered to infants is low in energy density, and its protein, iron, and zinc content is negligible. It is evident that despite the lack of a general consensus, mothers of preterm babies should receive customized instructions from family pediatricians and health caregivers about weaning.