The original superfood.
Milk is a mammalian innovation, and breast milk is the complete food for infants as a result of thousands of years of tweaking by natural selection on the mammalian lactation process. Milk provides complete nourishment and protection for an infant's immediate state of health and for its initial physiological, anatomical, and psychological development.
This natural process of breast milk synthesis has selected for a milk source that totally and completely satisfies the needs of the human infant on multiple levels. I am going to focus this article on one of those levels, as much has been written about the superior nutritional qualities of breast milk. This level involves the inclusion of an energy-intensive, high-diversity class of molecules: oligosaccharides. This molecule is largely indigestible to the human infant and the adult human. Researchers have discovered that these oligosaccharides instead act as a food source for the specific bacterium, Bifidobacterium longum subspecies infantis or B. infantis, which can be an initial colonizer of the gastrointestinal tract of a breastfed newborn. These oligosaccharides work to nourish and feed B. infantis of the infant. Due to this evolutionary oligosaccharide development, we can describe a new syndrome called Milk-Oriented Microbiome (MOM) that results from exclusive breastfeeding. I believe this is one important component of the multiple studies that say breastfeeding helps children to achieve a superior immunological, gastrointestinal, emotional, and intellectual status over non-breastfed infants. (1)
Oligosaccharides are complex sugars composed of a variable number of monosaccharide units and are among the most biologically diverse and important carbohydrates in biological systems. The aim of the UC-Davis Foods for Health Institute's research on oligosaccharides is to identify and chemically characterize the numerous oligosaccharides present in various mammalian milks, especially human milk. Over 200 human milk oligosaccharides or HMOs have so far been identified. These HMOs are the third largest constituent of human milk after lactose and fats. Breast milk also has five times as many HMOs as cow's milk. (2)
These HMOs should be a rich source of energy for growing babies, but functional studies have shown that these molecules are able to act as indigestible prebiotics which encourage the growth of a protective microbiota for the infant. (3)
A study that was published in the journal Applied and Environmental Microbiology by David A. Mills et al demonstrated that B. infantis did not grow on the milk protein fraction but did demonstrate that the oligosaccharide portion of the milk provided the key substrate for its growth. However, the ability to viably grow on HMOs is variable and importantly does not extend to all bifidobacteria! species. (4,6) This capability to grow vigorously on HMOs appears to be most common in the B. infantis strains, whereas isolates of B. longum subsp. longum and B. breve show less robust growth and B. adolescentis and B. animales lack this ability altogether. (7) The ironically named Bifidobacterium lactis, a common fixture in probiotic yogurts, doesn't grow at all on HMOs. B. infantis, on the other hand, is a true HMOvore! It devours every last oligosaccharide available. Unsurprisingly, it is the dominant microbe in the Gl tract of breastfed infants.
Oligosaccharides can also inhibit the binding of pathogenic bacteria to intestinal cells. Bacteria have binding sites on their surfaces for oligosaccharides. (8-9) Various oligosaccharides in milk can act as decoys and bind to the bacteria at these sites, which would prevent the bacteria from binding to the gastrointestinal epithelium and initiating symptoms. This would help to explain the decreased gastrointestinal illnesses in breastfed babies. (10,11) This anti-binding activity of free HMOs has been described for Streptococcus pneumonia, (12) enterpathogenic E. coli, (13,14) Listeria monocytogenes, (15) and Vibrio cholerae, (16) HMOs have also been implicated in protective mechanisms against pathogens such as Pseudomonas aeruginosa," noroviruses, (18) cholera and shiga toxins, (19) and rotavirus. (20) Newburg and coworkers have shown that HMOs inhibit binding of Campylobactor jejuni to human intestinal mucosa. (21) This large diversity of oligosaccharides in breast milk is likely responsible for the broad range of bacteria and bacterial toxins that are inhibited from causing Gl disease in the newborn.
In addition to inhibition of pathogens, milk oligosaccharides also appear to stimulate the growth of various other bifidobacteria which are quite commonly found in the feces of breastfed infants. (22-24) Numerous studies have shown a large bifidobacteria! species in the feces of breastfed infants, and these species are more prominent in the breastfed infant microbiome in relation to a common adult or non-breastfed microbiome. (25,26)
Mothers then are not only creating food in their breast milk for their infant but also for a specific species of intestinal bacteria that assists in the successful development of that infant in its initial time on this earth. As a result, mothers aren't just eating for themselves and their baby. They are actually eating for their own intestinal microbiome as well as their infant! (27)
Possible Brain Growth
Glucose, galactose, N-acetlyglucosamine, fucose, and sialic acid are the constituent parts of oligosaccharides. Human milk thus contains large amounts of sialylated oligosaccharides that are not found in cow's milk or formula. Human neuronal cell membranes have the highest concentration of sialic acid compared to other membranes throughout the body. The majority of sialic acid in the brain is bound to gangliosides. Sialic acid is an essential component of brain gangliosides that impact cell to cell communication in the nervous system. Brain gangliosides play a crucial role in cell-to-cell interactions, modification of synaptic connectivity, and memory formation. (28)
These findings support the hypothesis that the sialic acid in human milk may contribute significantly to greater concentrations of gangliosides in the brains of breastfed infants and to the observed neurological and intellectual advantages of breastfeeding over formula feeding. (29) Human milk contains large numbers of sialylated oligo-saccharides that are not found in significant amounts in cow's milk or infant formulas. One of nature's richest sources of sialic acid, a vital component of brain gangliosides and the building block of polysialic acid (PSA) on neural cell adhesion molecule (NCAM), is found in human breast mil
Another of the important health-protective effects of probiotics in the intestinal mucosa is to strengthen the epithelial tight junctions, which protect the mucosal barrier in the baby's Gl tract. Probiotics induce synthesis and assembly of tight junction proteins. They also prevent disruption of the newly zipped tight junctions by preventing the initiation of a leaky gut and the myriad problems that can result from antigenic molecules entering the circulation of the newborn. (30)
In addition, probiotic bacteria trigger activation of various cell signaling pathways that lead to strengthening of tight junctions and their barrier function. One group of metabolic products released by probiotics is short-chain fatty acids. Short-chain fatty acids/SCFAs enhance the intestinal epithelial barrier by regulating the expression and assembly of tight junction proteins. (31) Oral administration of these SCFA's from B. infantis reduced colonic permeability in a mouse model of colitis. (32)
Interestingly, weaning results in an immediate change in the infant microbiome. Weaning is also associated with an increased risk of a variety of intestine-related diseases. (33,34) This might lead to an interesting study to see what the effects of a prolonged breastfeeding regimen would have on the microbiome of the developing child.
Microbial ecosystems contain a complex array of microorganisms competing to maintain their respective niches. In the human intestine, we decide--mostly through our diets and the amount of antimicrobials we take or don't take--what type of environmental conditions will exist and whether a pathogenic or probiotic flora will predominate. Because of this fact, we humans have the unique opportunity to either strongly positively or strongly negatively affect our microbiome, which in turn affects our overall health in either a plus or minus way. As scientists gain an ever increasingly more detailed description of this microbial system and its influence on human health, the opportunities to positively influence it in the newborn, infant, and adult populations will become increasingly easier and more effective. (35)
(1.) Sela DA, Chapman J, Adeuya A, et al. The genome sequence of Bifidobacterium longum subsp infantis reveals adaptations for milk utilization within the infant microbiome. Proc Natl Acad Sei. 2008; 105:18964-18969.
(2.) German JB, et al. Human milk glycobiome and its impact on the infant gastrointestinal microbiota. Proc Natl Acad Sei USA. 2011 Mar 15; 108(Suppl 1): 4653-4658.
(4.) LoCascio RG, et al. A versatile and scalable strategy for glycoprofiling bifidobacteria! consumption of human milk oligosaccharides. Microb Biotechnol. 2009; 2: 333-342.
(5.) LoCascio RG, et al. Glycoprofiling of bifidobacteria! consumption of human milk oligosaccharides demonstrates strain specific, preferential consumption of small chain glycans secreted in early human lactation. J Agrie Food Chem. 2007; 55: 8914-8919.
(6.) Ward RE, Ninonuevo M, Mills DA, Lebrilla CB, German JB. In vitro fermentability of human milk oligosaccharides by several strains of bifidobacteria. Mol Nutr Food Res. 2007; 51:1398-1405.
(7.) LoCascio RG, et al. A versatile and scalable strategy for glycoprofiling bifidobacteria! consumption of human milk oligosaccharides. Microb Biotechnol. 2009; 2 :333-342.
(8.) Martin M, Sela DA. Infant gut microbiota: developmental influences and health outcomes. In: Clancy KBH, Hinde K, Rutherford JN, editors. Primate Developmental Trajectories in Proximate and Ultimate Perspectives. New York; Springer.
(9.) Boehm G, Moro G. Structural and functional aspects of prebiotics used in infant nutrition. J Nutr. 2008; 138:1818S-1828S.
(10.) Newburg DS. Oligosaccharides in human milk and bacterial colonization. J Pediatr Gastroenterol Nutr. 2000; 30(Suppl 2):S8-S17.
(11.) Newburg DS, Ruiz-Palacios GM, Morrow AL. Human milk glycans protect infants against enteric pathogens. Annu Rev Nutr. 2005; 25:37-58.
(12.) Andersson B, Porras O, Hanson LA, Lagergard T, Svanborg-Eden C. Inhibition of attachment of Streptococcus pneumoniae and Haemophilus influenzae by human milk and receptor oligosaccharides. J Infect Dis. 1986, 153: 232-237.
(13.) Angeloni S, et al. Glycoprofiling with micro-arrays of glycoconjugates and lectins. Glycobioiogy. 2005; 15: 31-41.
(14.) Coppa GV, et al. Human milk oligosaccharides inhibit the adhesion to Caco-2 cells of diarrheal pathogens: Escherichia coli, Vibrio cholerae, and Salmonella fyris. Pediatr Res. 2006; 59:377-382.
(15.) Coppa GV, et al. Oligosaccharides of human milk inhibit the adhesion of Listeria monocytogenes to Caco-2 cells. ItalJ Pediatr. 2003; 29:61-68.
(16.) Coppa GV, Zampini L, Galeazzi T, Gabrielli O. Prebiotics in human milk: A review. Dig Liver Dis. 2006; 38(Suppl 2):S291-S294.
(17.) Lesman-Movshovich E, Lerrer B, Gilboa-Garber N. Blocking of Pseudomonas aeruginosa lectins by human milk glycans. Can J Microbiol. 2003; 49:230-235.
(18.) Jiang X, et al. Human milk contains elements that block binding of noroviruses to human histoblood group antigens in saliva. J Infect Dis. 2004; 190:1850-1859.
(19.) Idota T, Kawakami H, Murakami Y, Sugawara M. Inhibition of cholera toxin by human milk fractions and sialyllactose. Biosci Biotechnol Biochem. 1995; 59:417-419.
(20.) Yolken RH, et al. Human milk mucin inhibits rotavirus replication and prevents experimental gastroenteritis. J Clin Invest. 1992; 90:1984-1991.
(21.) Ruiz-Palacios GM, Cervantes LE, Ramos P, Chavez-Munguia B, Newburg DS. Campylobacter jejuni binds intestinal H(O) antigen (Fuc alpha 1, 2Gal beta 1, 4GlcNAc), and fucosyloligosaccharides of human milk inhibit its binding and infection. J Biol Chem. 2003; 278:14112-14120.
(22.) Biavati B, Mattarelli P. The family Bifidobacteriaceae. Prokaryotes. 2006; 3:322-382.
(23.) Haarman M, Knol J. Quantitative real-time PCR assays to identify and quantify fecal Bifidobacterium species in infants receiving a prebiotic infant formula. Appi Environ Microbiol. 2005; 71: 2318-2324.
(24.) Matsuki T, Watanabe K, Tanaka R, Fukuda M, Oyaizu H. Distribution of bifidobacteria! species in human intestinal microflora examined with 16S rRNA-gene-targeted species-specific primers. Appi Environ Microbiol. 1999; 65: 4506-4512.
(25.) Mariat D, et al. The Firmicutes/Bacteroidetes ratio of the human microbiota changes with age. BMC Microbiol. 2009; 9:123.
(26.) Hinde K, German JB. Food in an Evolutionary Context: Insights from Mother's Milk. J Sei Food Agrie. 2012 Aug 30; 92(11): 10.1002/jsfa.5720.
(28.) Ward RE et al. In vitro fermentability of human milk oligosaccharides by several strains of bifidobacteria!. Mol. Nutr. Food Res. 2007; 51:1398-1405.
(29.) Wang B. Sialic acid is an essential nutrient for brain development and cognition. Annu Rev Nutr. 2009; 29:177-22.
(30.) Rao RK, Samak G. Protection and Restitution of Gut Barrier by Probiotics: Nutritional and Clinical Implications. Curr Nutr Food Sei. 2013 May 1; 9(2): 99-107.
(31.) Peng L, et al. Butyrate enhances the intestinal barrier by facilitating tight junction assembly via activation of AMP-activated protein kinase in Caco-2 cell monolayers. J Nutr. 2009; 139(9):1619-25.
(32.) Segawa S, et al. Probiotic-derived polyphosphate enhances the epithelial barrier function and maintains intestinal homeostasis through integrin-p38 MAPK pathway. PLoS One. 2011; 6(8):e23278.
(33.) Edwards CA, Parrett AM. Intestinal flora during the first months of life: New perspectives. Br J Nutr. 2002; 88(Suppl 1):S11-S18.
(34.) Victora CG, et al. Evidence for protection by breast-feeding against infant deaths from infectious diseases in Brazil. Lancet. 1987; 2:319-322.
(35.) Dethlefsen L, Huse S, Sogin ML, Relman DA. The pervasive effects of an antibiotic on the human gut microbiota, as revealed by deep 16S rRNA sequencing. PLoS Biol. 2008; 6:e280.
by Jim Cross, ND, LAc
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|Date:||Apr 1, 2017|
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