Editorial: Role of hormones and bioactive components in breast milk on development of metabolic, neural and behavioral systems in offspring

Abstract

Editorial on the Research TopicRole of hormones and bioactive components in breast milk on development of metabolic, neural and behavioral systems in offspring Early life experiences in mammals shape developmental processes in most physiological systems: in altricial mammals such as rodents and primates such experience interacts with genetic backround from the fetal stage to the first postnatal days (rodents) or months (humans). Although each species is unique and has its own developmental scheme, one can propose three critical periods of development during which external stimuliexperiencecan positively or negatively modify geneticallyprogrammed developmental processes through epigenetic mechanisms: the prenatal period, postnatal/pre-weaning period, and the juvenile/adolescence period. Among species, the timing and duration of these three main critical periods differ greatly. Moreover, different physiological systems (e.g., neural, metabolic, immune) often have distinct temporal windows of sensitivity within each of the critical periods.During pregnancy (prenatal intrauterine period) the effects of the environmental factors depend on the identity of the factor as well as the specific prenatal stage of exposure to that factor (germinal, embryonic, or fetal). For example, the neural tube develops into the nervous system during the fetal stage (in humans, from the ninth week until birth) and the neurons begin to migrate to their location and start establishing connections. Therefore, exposure to certain environmental factors during this period could positively or negatively affect the developing brain, depending on the nature of the factor. After birth, the immature infant advances to a new developmental phase where he/she receives nutrition from breastmilk and crucial sensory and social cues (primarily from the mother, but also from siblings, father and other conspecifics) that are necessary to achieve physiological independence [See (1, 2)].Breastmilk has attracted the scientific attention since the 1930´s, but studies have mainly focused on its nutritional function: the chemical structures of the macronutrients (carbohydrates, proteins, fats) and their functions on the growth and development of the Frontiers in Endocrinology frontiersin.org 01