THE INFLUENCE OF DIFFERENT FORMULAS ON TH E INTESTINAL MICROFLORA OF INFANTS

The intestinal microflora of humans is composed of a huge variety of a naerob and aerob growing microbes, consisting mainly of Eubacteria, Ba cteroides, anaerobic cocci, Bifidobacteria, Fusobacteria as well as Pr opioni- and Lactobacilli. The numeric composition of all intestinal ge rms that can be cultivated from stool specimens of an individual are o verall constant. The intestinal microbes react on different nutritiona l components by changes in their enzymatic activity rather then by cha nges in their cell count. Mother's milk feeding of infants brings abou t the phenomenon of the dominating bifidobacterial intestinal flora. B ifidobacteria produce acetic and lactic acid by fermentation of lactos e and oligosaccharides. In this manner the pH of colonic chyme is adju sted to an acid range. This results in a drastic numeric reduction of the accompanying potential pathogenic germs. The principle of the bifi dogenic effect of mother's milk - though having been intensively inves tigated on for almost 100 years - is not yet understood in detail. Esp ecially all attempts to minic the bifidogenic principles of infant for mulas to that of human milk have not been successful to this day. At p resent, there is agreement that a dominating bifidobacterial flora can not be obtained by adding single growth factors to regular infant form ulas. This effect is rather brought about by the interaction of a broa d variety of nutritional factors. We consider a low concentration of h igh-grade and antigen-reduced protein, a high concentration of lactose and a moderate concentration of microbially available polymeric carbo hydrates as well as a low concentration of iron and other substrates w hich stimulate the growth of competing intestinal bacteria to be the m ost important prepositions when creating bifidogenic infant formulas.