Physiological and bifidogenic effects of prebiotic supplements in infant formulae.

OBJECTIVES: This randomized controlled trial involving 110 healthy neonates studied physiological and bifidogenic effects of galactooligosaccharides (GOS), oligofructose, and long-chain inulin (fructooligosaccharides, FOS) in formula. METHODS: Subjects were randomized to Orafti Synergy1 (50 oligofructose:50 FOS) 0.4 g/dL or 0.8 g/dL, GOS:FOS (90:10) 0.8 g/dL, or a standard formula according to Good Clinical Practice guidelines. A breast-fed group was included for comparison. Outcome parameters were weight, length, intake, stool characteristics, crying, regurgitation, vomiting, adverse events, and fecal bacterial population counts. Statistical analyses used nonparametric tests. RESULTS: During the first month of life, weight, length, intake, and crying increased significantly in all of the groups. Regurgitation and vomiting scores were low and similar. Stool frequency decreased significantly and similarly in all of the formula groups but was lower than in the breast-fed group. All of the prebiotic groups maintained soft stools, only slightly harder than those of breast-fed infants. The standard group had significantly harder stools at weeks 2 and 4 compared with 1 (P < 0.001 and P = 0.0279). The total number of fecal bacteria increased in all of the prebiotic groups (9.82, 9.73, and 9.91 to 10.34, 10.38, and 10.37, respectively, log10 cells/g feces, P = 0.2298) and more closely resembled the breast-fed pattern. Numbers of lactic acid bacteria, bacteroides, and clostridia were comparable. In the SYN1 0.8 g/dL and GOS:FOS groups, Bifidobacterium counts were significantly higher at D14 and 28 compared with D3 and were comparable with the breast-fed group. Tolerance and growth were normal. CONCLUSIONS: Stool consistency and bacterial composition of infants taking SYN1 0.8 g/dL or GOS:FOS-supplemented formula were closer to the breast-fed pattern. There was no risk of dehydration.

Novel approaches for analysing gut microbes and dietary polyphenols: challenges and opportunities.

Polyphenols, ubiquitously present in the food we consume, may modify the gut microbial composition and/or activity, and moreover, may be converted by the colonic microbiota to bioactive compounds that influence host health. The polyphenol content of fruit and vegetables and derived products is implicated in some of the health benefits bestowed on eating fruit and vegetables. Elucidating the mechanisms behind polyphenol metabolism is an important step in understanding their health effects. Yet, this is no trivial assignment due to the diversity encountered in both polyphenols and the gut microbial composition, which is further confounded by the interactions with the host. Only a limited number of studies have investigated the impact of dietary polyphenols on the complex human gut microbiota and these were mainly focused on single polyphenol molecules and selected bacterial populations. Our knowledge of gut microbial genes and pathways for polyphenol bioconversion and interactions is poor. Application of specific in vitro or in vivo models mimicking the human gut environment is required to analyse these diverse interactions. A particular benefit can now be gained from next-generation analytical tools such as metagenomics and metatranscriptomics allowing a wider, more holistic approach to the analysis of polyphenol metabolism. Understanding the polyphenol-gut microbiota interactions and gut microbial bioconversion capacity will facilitate studies on bioavailability of polyphenols in the host, provide more insight into the health effects of polyphenols and potentially open avenues for modulation of polyphenol bioactivity for host health.