In a growing world population in which chronic inflammatory diseases are on the rise and allergies and asthma affect 30-40% of the population, there is a pressing need to understand underlying mechanisms to develop successful preventive strategies for these diseases. Raw cow’s milk consumption in early life has been associated in epidemiological studies with a significant decrease in the prevalence of allergies and asthma. In this thesis we investigated the effect of components present in raw cow’s milk on maintenance of mucosal immune functioning in the gut and discussed their implications for respiratory health. We thereby give novel insights into the underlying mechanisms by which raw cow’s milk components display their immunomodulatory capacity and may contribute to regulation of mucosal immune responses. Future studies should further investigate the effects of these components in in vivo allergy and respiratory infection models, to better understand the link between diet and respiratory health.