Nutrients and gene expression in development

Development encompasses the formation of a complex organism starting from a unicellular zygote. This process requires finely tuned changes in gene expression across several cells and tissues, which may be regulated by a combination of stable and dynamic epigenetic modifications that make the DNA more or less accessible to transcriptional regulators. Diverse interdependent epigenetic mechanisms have been described, including DNA and histone methylation, histone acetylation, and silencing by micro RNAs. In the developing embryo or fetus, the epigenetic status is influenced by diverse environmental conditions, including maternal nutrition. Depending on the stage of pregnancy, gestational nutritional inadequacies may lead to congenital embryonic defects, suboptimal fetal growth, and/or reprogramming of tissues, which may determine different phenotypes or predispose individuals to chronic diseases later in life. During early pregnancy, abnormal methylation of certain genes resulting from nutritional inadequacies has been shown to increase the risk for congenital malformations that lead to perinatal death or postnatal disabilities. During mid to late pregnancy, maternal malnutrition, both undernutrition and overnutrition, has been shown to promote adaptive epigenetic changes in different organs that allow the embryo or fetus to cope with the intrauterine environment but that persist throughout life and may increase susceptibility to chronic diseases. Preconceptional nutrition in the mother, and paternal nutrition, also influence the epigenetic marks in the embryo. Nutrition seems to use epigenetics to tailor diversity and susceptibility to disease in animals and humans. Understanding nutrigenomics may be useful to understand evolution and promote health in future generations.