Research has shown that humans respond differently to diets and, moreover, that they display varying predispositions to many diet-dependent metabolic and degenerative diseases. The focus of nutritional science is thus shifting from dietary guidelines for populations to individualized foods and diets. It is the aim of nutrigenomics to assign this human diversity in nutritional response to diet - as well as the subsequent consequences to human health - to specific genetic elements. At the same time, evidence suggests that diet itself is a critical determinant of human diversity. This publication focuses on the differences of humans as infants and children with respect to nutritional needs and responses to diet. For this purpose, four main points are discussed, namely 1) How do children differ in view of genetic diversity, environmental inputs, prior imprinting, and resident microflora; 2) What are the immediate and long-term consequences of these differences; 3) Can we accurately assess them; and 4) How can we act on these differences. Supplying answers to some crucial issues, as well as identifying directions for further research and practical applications by the food industry, this publication is an important source of information for all those involved in the subject of diet and individual responses.
205 - 222: Human Milk Oligosaccharides: Evolution, Structures and Bioselectivity as Substrates for Intestinal Bacteria Free
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Published:2008
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Subject Area: Further Areas , Gastroenterology , Genetics , Nutrition and Dietetics , Women's and Children's HealthBook Series: Nestlé Nutrition Institute Workshop Series
J. Bruce German, Samara L. Freeman, Carlito B. Lebrilla, David A. Mills, 2008. "Human Milk Oligosaccharides: Evolution, Structures and Bioselectivity as Substrates for Intestinal Bacteria", Personalized Nutrition for the Diverse Needs of Infants and Children: 62nd Nestlé Nutrition Workshop, Pediatric Program, Helsinki, September 2007, D.M. Bier, J.B. German, B. Lönnerdal
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Abstract
Human milk contains a high concentration of diverse soluble oligosaccharides, carbohydratepolymers formed from a small number of monosaccharides. Novel methods combiningliquid chromatography with high resolution mass spectrometry have identifiedapproximately 200 unique oligosaccharides structures varying from 3 to 22 sugars. Theincreasing complexity of oligosaccharides follows the general pattern of mammalian evolutionthough the concentration and diversity of these structures in homo sapiens arestrikingly. There is also diversity among human mothers in oligosaccharides. Milks fromrandomly selected mothers contain as few as 23 and as many as 130 different oligosaccharides.The functional implications of this diversity are not known. Despite the role ofmilk to serve as a sole nutrient source for mammalian infants, the oligosaccharides in milkare not digestible by human infants. This apparent paradox raises questions about thefunctions of these oligosaccharides and how their diverse molecular structures affecttheir functions. The nutritional function most attributed to milk oligosaccharides is toserve as prebiotics - a form of indigestible carbohydrate that is selectively fermented bydesirable gut microflora. This function was tested by purifying human milk oligosaccharidesand providing these as the sole carbon source to various intestinal bacteria. Indeed,the selectively of providing the complex mixture of oligosaccharides pooled from humanmilk samples is remarkable. Among a variety of Bifidobacteria tested only Bifidobacterialongum biovar infantis was able to grow extensively on human milk oligosaccharides assole carbon source. The genomic sequence of this strain revealed approximately 700genes that are unique to infantis, including a variety of co-regulated glycosidases, relativeto other Bifidobacteria, implying a co-evolution of human milk oligosaccharides and thegenetic capability of select intestinal bacteria to utilize them. The goal of ongoingresearch is to assign specific functions to the combined oligosaccharide-bacteria-hostinteractions that emerged from this evolutionary pressure.
