Oligosaccharides are the third most abundant solid constituent of human milk19,20 in which these are believed to play two major roles, i.e., defense agents by acting as receptor analogues to inhibit the binding of enteropathogens to the host cell receptors and bifidogenic factors. At least 21 different kinds of these oligosaccharides have already been identified that are either linear or branched, composed of simple sugars like galactose, or sugar derivatives like uronic acids or uronic esters, some being acidic other being neutral.21,22
There is substantial evidence that the oligosaccharides secretion in mother's milk is a complex, variable, and dynamic process.23 Not only does the amount of oli-gosaccharides in human milk change during lactation, but the composition of their mixture also varies among different samples, being influenced by many factors. The highest amount of oligosaccharides (i.e., 20/l) is reached on day four after birth,21,22 but at days 30 and 120 of lactation, that content falls by 20 and 40% respectively, and is compensated by an increase in lactose content.21,23
Based on these considerations, and as cow's milk is very poor in oligosaccharides, it has been hypothesized that supplementing infant formulas with oligosac-charides could improve the nutritional value of formulas and help mimic some of the effects of mother's milk, especially the bifidogenic effect. Although breast-fed and formula-fed infants have similar gastrointestinal flora on day three or four after birth when it is dominated by bifidobacteria and lactobacilli, there is a substantial difference in colonic flora after several weeks of life in relation to feeding.24 In order to improve formulas, either lactobacilli (probiotic) or oligosaccharides (synbi-otic/prebiotic) were added with the aim of obtaining the same effect on gastrointestinal colonization as that of mother's milk.25,26 The addition of lactobacilli to infant formula results in a gastrointestinal flora that is dominated by lactobacilli, comparable to the flora found in breast-fed infants, and the stools change accordingly.27 However, this approach has been regarded as "nonphysiological" because lactobacilli are, of course, not present in human milk.28 Moreover, the bacteria need to be administered in a viable form, necessitating specific guidelines of formula preparation. The addition of probiotics to infant formula has been shown to be associated with a decrease in the incidence and severity of episodes of infectious (rotavirus) diarrhea, in hospitalized children.29
By referencing the prebiotic concept, a mixture of long-chain inulin and galac-tooligosaccharides (10/90 w/w) has been added to an infant formula, and a series of studies show that like in breast-fed babies, the absolute number of bifidobacteria and lactobacilli or the proportion of bifidobacteria to the total number of anaerobic microorganisms increase in the prebiotic supplemented formula-fed infants (both preterm and term infants). Concomitantly, stool characteristics of the babies fed the supplemented formula were similar to those of the breast-fed babies.30-32
The growth and quality of growth of infants fed with the prebiotic formula containing D-palmitate and hydrolyzed proteins were similar to those seen in breastfed infants and current infant formulas.30,33 At first, the prebiotic approach seems more physiological, but the dynamic aspects of oligosaccharide content in mother's milk cannot be mimicked in an artificial feeding.
As it has been reported that differences in the gut microflora of neonates precede the development of atopy, suggesting a crucial role of the indigenous intestinal microflora for the maturation of human immunity,34 it can also be hypothesized that prebiotics may help reducing the risk of allergy in infants by improving the composition of the intestinal microflora early in life.
Even though breast feeding must remain the gold-standard and the common recommendation, supplementing infant formulas with inulin-type fructans and other prebiotics is a promising approach that is likely to help in improving the intestinal health and well-being of babies who are not breast-fed at all, breast-fed only for a short period, or are mixed-fed. As compared to the probiotics, the prebiotics stimulate the growth of indigenous bacteria (especially indigenous bifidobacteria strains) and are thus expected to maintain and favor a more natural and physiological microflora, creating the conditions for an optimum crosstalk between the prokaryotic and the eukaryotic worlds that live in symbiosis in the intestine. An optimum crosstalk situation such as this is more and more recognized as a condition for a healthy development during early life which contributes to good health throughout life.
Was this article helpful?
Once your pregnancy is over and done with, your baby is happily in your arms, and youre headed back home from the hospital, youll begin to realize that things have only just begun. Over the next few days, weeks, and months, youre going to increasingly notice that your entire life has changed in more ways than you could ever imagine.