Epigenetics is the study of all non-genetic factors that interfere in the determination of ontogeny or in the development of an organism from fertilization to senescence. Such factors are involved in the heritable regulation of gene expression via methylation, acetylation and phosphorylation of DNA rather than alteration of the nucleotide sequence. The concept of epigenetics was coined by Conrad Waddington in 1953 and gained importance after the human genome project in 2003 [23, 24]. Living in urban areas, resulting in greater exposure to chemicals, reduced green spaces, and the consequent limited presence of flora, fauna and microbial life, is associated with immune dysfunction in humans. Reduced contact with nature and environmental microbiota appears to be related to a range of diseases including allergy and type 1 diabetes [25, 26]. Alterations in intestinal flora influence the development of not only asthma and allergies but also other chronic and recurring inflammatory disorders, such as type 1 diabetes, inflammatory bowel disease, obesity, and even psychiatric disorders . Epigenetics has transformed our understanding of the impact of the environment on our genes and health, which in turn will potentially streamline many lines of research in psychoneuroimmunology seeking to explain how environmental cues are transduced into the genome [28, 29]. In turn, the psychosocial environment can substantially change behavior and alter nervous, endocrine and immune functions.