The neonatal intestinal microbiota is a complex ecosystem composed of numerous genera, species and strains of bacteria. This enormous cell mass performs a variety of unique activities that affect both the colonic and systemic physiology. Its primary activities include nutritive, metabolic, immunological and protective functions. Most studies of infants have been based on faecal samples using the classical plating techniques with culturing on specific media. The limitations of these methods must be taken into account when evaluating the varying results of the different studies. The establishment of the gut microbial population is not strictly a succession in the ecological sense; it is rather a complex process influenced by microbial and host interactions and by external and internal factors. The climax intestinal flora is attained in successive stages. The foetal intestine is sterile and bathed in swallowed amniotic fluid. Following delivery, multiple different antigens challenge the intestine of the newborn. The maternal intestinal flora is a source of bacteria for the neonatal gut. The bacterial flora is usually heterogeneous during the first few days of life, independently of feeding habits. After the first week of life, a stable bacterial flora is usually established. In full‐term infants a diet of breast milk induces the development of a flora rich in Bifidobacterium spp. Other obligate anaerobes, such as Clostridium spp. and Bacteroides spp., are more rarely isolated and also enterobacteria and enterococci are relatively few. During the corresponding period, formula‐fed babies are often colonized by other anaerobes in addition to bifidobacteria and by facultatively anaerobic bacteria; the development of a “bifidus flora” is unusual. In other studies the presence of a consistent number of bifidobacteria in infants delivered in large urban hospitals has not been demonstrated, whether the babies were bottle fed or exclusively breastfed. The predominant faecal bacteria were coliforms and bacteroides. According to these studies, environmental factors may be more important than breastfeeding in gut colonization after delivery. Environmental factors are indeed extremely important for the intestinal colonization of infants born by caesarean section. In these infants, the establishment of a stable flora characterized by a low incidence of Bacteroides spp. and by the isolation of few other bacteria is consistently delayed. In extremely low‐birthweight infants, hospitalization in neonatal intensive care units, characterized by prolonged antibiotic therapy, parenteral nutrition, delayed oral feedings and intubation seems to affect the composition of the intestinal microbiota. The gut is colonized by a small number of bacterial species; Lactobacillus and Bifidobacteria spp. are seldom, if ever, identified. According to the few studies so far performed, the predominant species are Enterococcus faecalis, E. coli, Enterobacter cloacae, Klebsiella pneumoniae, Staphylococcus epidermidis and Staphylococcus haemolyticus. Hygie...

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 Bacteriodes 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.

There are no studies in vivo on the effects of insulin on androgens and sex hormone-binding globulin (SHBG) in men. We, therefore, investigated the effects of insulin suppression on testosterone and SHBG in two groups of eight nondiabetic adult obese men and six healthy normal weight men who underwent diazoxide treatment (100 mg, three times daily) for 7 days. Blood samples for hormone determination were obtained before the subjects had been selected for the study, immediately before diazoxide administration, and on the last day of treatment. A 24-h oral glucose tolerance test was also performed for glucose, insulin, and C-peptide determinations before and on the last day of treatment. Only one subject experienced significant side-effects, and no significant changes in mean body weight were found during the treatment. Diazoxide administration worsened glucose tolerance in several subjects and reduced fasting and glucose-stimulated insulin levels by approximately 50% in both control and obese subjects. No significant difference was present between historical and pretreatment hormone values in either group. Moreover, there were no differences in pretreatment gonadotropin and SHBG concentrations between the two groups, whereas testosterone (free and total) levels were lower in the obese than in the control subjects. After diazoxide administration, testosterone (free and total) decreased slightly, but significantly, whereas LH and SHBG significantly increased in both groups. Diazoxide treatment increased estradiol levels in controls, but not in obese men. In conclusion, these results indicate that in vivo, insulin is capable of stimulating testosterone production and, simultaneously, of inhibiting SHBG concentrations in both normal weight and obese men.

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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.