Improper colonization of the infant gut, (altered gut microbiome) resulting when a substance other than breastmilk is introduced, delays the process of mucosal host defence provided by prebiotic oligosaccharides and probiotic bifidobacteria evolved over millions of years. This may result in increased susceptibility to newborn and infant infections and altered immune homeostasis leading to the expression of immune-mediated  and metabolic diseases with successive generations of manufactured formula use creating this world wide increase (slides 44-49). Human milk sialic acid conjugated oligosaccharides in the colon are essential components in ganglioside structure and are critical for brain development. This may be another link to understanding the IQ reduction seen in the formula fed infant and to concern for how evolution may be influenced.

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