Ácidos graxos de cadeia curta e imunidade intestinal : a repercussão dos oligossacarídeos do leite humano na saúde infantil

Abstract

The importance of breastfeeding is already proven by several scientific studies, due to its numerous benefits, such as immune development and protective effect against numerous pathologies. Breast milk is nutritionally complete and also contains bioactive compounds, such as human milk oligosaccharides (HMOs), carbohydrates derived from the combination of different monosaccharides: glucose (Glc), galactose (Gal), N-acetylglucosamine (GlcNAc), fucose (Fuc) or sialic acid (Neu5Ac), abundant in breast milk and with variable concentration and composition among women. The human organism does not have enzymes for the degradation of these oligosaccharides, being 1 to 3% absorbed through the paracellular pathway and the vast majority passing intact through the upper gastrointestinal tract and reaching the large intestine, where they will be fermented by anaerobic bacteria, such as Bacteroids and Bifidobacteria, present in the cecum and colon microbiota, giving rise to organic acids such as short-chain fatty acids (SFCASs) and other fermentation products. Considering the above, the objective was to review the role of EHRs, their impact on child health and the role of shortchain fatty acids in the development of intestinal immunity. The search for the articles took place from December 2020 to February 2021 in the following databases: PubMed Central (PMC), Medline, Scientific Electronic Library Online (SciELO), Cochrane Library, Web of Science, Latin American and Caribbean Literature in Health Sciences (LILACS) and Excerpta Medica database (EMBASE), through the search strategy: (“Human milk oligosaccharides” OR HMO OR “Nutritional Fiber” OR Prebiotic) AND (“Bacterial short-chain fatty acid” OR “Short-chain fatty acid” OR SCFA OR Butyrate OR “Propionic acid” OR “Acetic acid”) AND (“Intestinal Barrier” OR “Immunity”) AND (“Gut microbiome” OR Probiotic OR Bifidobacterium OR “Infant microbiota”). Other articles were included in the research through specific reference searches on topics of interest and from the references of previously read articles. EHRs have a direct action on the infant's intestinal and systemic immunity, protecting them from pathogens and acting as prebiotics, shaping the baby's intestinal microbiome. Likewise, butyrate, acetate and propionate, considered the most abundant SCFAs in the human body, have a fundamental role in the development of the intestinal mucosa, influencing the functioning of this organ as they are the preferred source of energy for your cells and thus contribute to the maintenance of intestinal homeostasis. In addition, its role in intestinal immunity involves several effects and mechanisms, of which we can mention the protection of the intestinal barrier, alteration of the intestinal pH, antioxidant, anticarcinogenic and antiinflammatory action. This guarantees the newborn protection against diseases such as necrotizing enterocolitis, prevents various infections, giving intestinal cells the fullness of their immunological and absorptive functions, which are important for child growth and development.