This review describes the mechanisms by which polyunsaturated fatty acids regulate the activity of the nuclear transcription factors, peroxisome proliferator-activated receptor and sterol regulatory element binding protein-1, and it describes the role that the peroxisome proliferator-activated receptor and sterol regulatory element binding protein-1 play in coordinating the regulation of lipid synthesis, lipid oxidation, and thermogenesis. Finally, the requirement for dietary polyunsaturated fatty acids, particularly n-3 fatty acids, is defined in terms of the effects polyunsaturated fatty acids exert on gene expression and the role that these effects play in overall energy balance.

The objective of this study was to systematically assess the bifidogenic effect of three commonly used prebiotic products using in vitro cultures of infant fecal samples. Fresh stool samples collected from six term infants, each exclusively fed human milk (n ‫؍‬ 3) or infant formula (n ‫؍‬ 3), at 28 days of age were used as inocula. The following prebiotic products were added at concentrations applicable to infant formula: Vivinal IN). The growth of total bacteria, Bifidobacterium, Bacteroides, Bifidobacterium longum, and Escherichia coli was quantified using specific quantitative PCR (qPCR). Bifidobacterium was also enumerated on selective Beerens agar plates, with representative colonies identified by sequencing of their 16S rRNA genes. Volatile fatty acids (VFA) and pH in the cultures were also determined. Irrespective of the feeding methods, the GOS product, either alone or in combination with Beneo HP, resulted in substantially higher growth of total bifidobacteria, and much of this growth was attributed to growth of B. longum. Beneo Synergy 1 also increased the abundance of total bifidobacteria and B. longum. Corresponding to the increases in these two bacterial groups, acetic acid concentrations were higher, while there was a trend of lower E. coli levels and pH. The lower pH and higher acetic acid concentration might be directly responsible for the lower E. coli population. At the concentrations studied, the GOS product was more bifidogenic and potent in inhibiting E. coli than the other products tested. These results suggest that supplementation of infant formula with GOS may increase intestinal bifidobacteria and benefit infant health. It is generally accepted that human milk-fed infants and formulafed infants can have different gut microbiomes. The demonstrated differences in the gut microbiomes include a greater abundance of Bifidobacterium and a lower abundance of clostridia and enteric bacteria in human milk-fed infants than in formula-fed infants (1, 2). Such differences in gut microbiomes are believed to contribute to the benefits associated with human milk feeding, such as protection against infection and allergy (3-5), as well as long-term health and neurodevelopment (5-7). Human milk contains high levels of more than 200 structures of nondigestible oligosaccharides (8, 9), whereas cow milk contains virtually no oligosaccharides (10). Therefore, without supplementation, oligosaccharides are nearly absent in cow milk-based infant formulas. The difference in nondigestible oligosaccharides between human milk and infant formula is believed to be a main reason for the observed differences in intestinal microbiomes between infants receiving these two types of feeding (9, 11).Nondigestible oligosaccharides can be added to infant formula as prebiotics to increase its oligosaccharide content (12). However, the prebiotics commercially available for inclusion in infant formula are limited in variety, and the nondigestible oligosaccharides contained in most prebiotic products are much simpler in structu...

In this clinical study, milk-based term infant formula (Similac Advance) with 4 g GOS/L was well-tolerated in terms of stool consistency and additional measures of gastrointestinal tolerance by newborn infants through the first 4 months of life.