ABSTRACT
This chapter considers the evidence that many medical conditions associated with chronic inflammatory states caused by failing regulation of the immune system are more prevalent in urban settings, and that this is at least partly a consequence of the deviation of the microbiota of the urban environment from that of the natural environment in which humans evolved. Animal experiments have shown that there is a window of opportunity in the first months of life when an appropriate microbiota must be present in the gut for healthy development of the immune and metabolic systems. While transmission of microbiota from mother to infant may be similar in urban and rural communities, the mother is not the only source of data inputs and microbiota. The prevalence of inflammatory bowel disease increases rapidly as societies modernize. Autoimmune disorders, another type of ‘forbidden target’ immunoregulatory problem, are also more prevalent in urban settings.
