Transgenerational Impact of Nutrition on Disease Risk

Abstract Although the evidence for transgenerational epigenetic inheritance from animal experiments is strong, there is very little evidence from human studies. The few studies in human populations that have been able to investigate several generations seem to suggest that transgenerational epigenetic inheritance occurs in humans as well and that this may occur both through the maternal and through the paternal line. We are only beginning to appreciate the generation‐spanning effects of poor environmental conditions during early life, which may be particularly relevant to populations in transition between traditional and Western lifestyles. This may shed light on the epidemic of diabetes, obesity and cardiovascular disease. Public health strategies that focus on improved nutrition during critical periods of growth and development may provide a means of promoting cardiovascular and metabolic health and ultimately benefit generations to come. However, the full impact of the strategies may not be apparent for decades. Key Concepts: A popular definition of epigenetics states that it concerns the study of mitotically and/or meiotically heritable changes in gene expression that occur without a change in DNA sequence. Under this definition, epigenetic regulation has a role at two levels. First, it is involved in development, leading to the differentiation of cells in different tissues and organs and assuring the faithful inheritance of their differentiated state over mitotic cell divisions. Second, epigenetic states can be inherited meiotically, from one generation to the next. Transgenerational effects refer to effects being transmitted from one generation to another. Although some biologists consider all effects that concern both parents and offspring to be transgenerational, the author would like to distinguish transgenerational effects from parental and grandparental effects. In addition to contributing their DNA, parents can influence their offspring in many ways, for example, by contributing bioactive molecules in the egg and sperm cytoplasm, by providing nutrients and hormonal information during embryogenesis and by provisioning and taking care of offspring after birth. Many of these parental and grandparental effects will not have an epigenetic basis. In a pregnant woman, for instance, not only are the mother and foetus exposed to the environmental stimuli but also are exposed the foetus' primordial germ cells, which will eventually produce the grandoffspring. Transgenerational epigenetics is defined here as the study of the transfer of nongenetic information between organisms, setting it apart from the transfer of epigenetic information between cells of the same organism.