Early Changes in the Human Microbiome Alter Immune Function and Immunologically Mediated Disorders

Recent evidence from a number of studies suggest that early changes in the human Microbiome may play an important role in regulating immune function. As the human gastrointestinal tract is not dissimilar from that of many other non-ruminants, such as pigs, human studies may well have some relevance to nonruminant animal nutrition. During the past hundred years, humans have seen a marked increase in the incidence of disorders of immune regulation including allergy, and autoimmune diseases such as inflammatory bowel disease, type I diabetes, rheumatoid arthritis, and celiac disease. In the case of allergy, it has been noted that there is an association between the end incidence of allergy and children raised in a clean urban environment relative to farm raised controls. Close exposure to farm animals appears to be a factor. The revised hygiene hypothesis proposes that early changes in microbial colonization might ultimately direct the immune system to react differently later in life affecting the incidence of these disorders. Early colonization with increased numbers of lactobacilli and bifidobacterium appear to be advantageous. Studies have shown differences in certain microbial populations earlier in life with later development of allergy and type I diabetes. Dietary and environmental factors appear to have a major effect on the gut Microbiome. Administration of antibiotics to pregnant mothers or infants, or other factors which alter early colonization such cesarean section or breast-feeding appear to affect the incidence of disorders of immune regulation such as allergy or autoimmune disease. Recent studies utilizing probiotics given early in life to alter microbial colonization appear to influence not only the incidence of allergy to foods such as cow milk but also to stimulate the development of immune tolerance early in life. When taken as a whole, this body of data suggests efforts to optimize microbial colonization of the gut early in life might reward us with more effective immune function. In all likelihood, the same could well be true with other non-ruminants species including pigs.