The amount of close and comforting contact between infants and their caregivers can affect children at the molecular level, according to new research.
The study from the University of British Columbia and BC Children’s Hospital Research Institute involved 94 healthy children.
Researchers asked parents of 5 week old babies to keep a diary of their infants’ behavior (sleeping, fussing, crying or feeding) as well as the duration of caregiving that involved bodily contact.
When the children were about 4 1/2 years old, their DNA was sampled by swabbing the inside of their cheeks.
The team examined a biochemical modification called DNA methylation, in which some parts of the chromosome are tagged with small molecules made of carbon and hydrogen.
These molecules act as “dimmer switches” that help to control how active each gene is and thus affect how cells function.
The extent of methylation and where on the DNA it specifically happens, can be influenced by external conditions, especially in childhood. These epigenetic patterns also change in predictable ways as we age.
Scientists found consistent methylation differences between high-contact and low-contact children at five specific DNA sites.
Two of these sites fall within genes: one plays a role in the immune system and the other is involved in metabolism.
However, the downstream effects of these epigenetic changes on child development and health aren’t known yet.
The study of DNA methylation patterns showed that children who had been more distressed as infants and had received less physical contact had a molecular profile that was underdeveloped for their age.
Although the implications for childhood development and adult health have yet to be understood, this finding builds on similar work in rodents.
This is the first study to show in humans that the simple act of touching, early in life, has deeply-rooted and potentially lifelong consequences on genetic expression.
The amount of physical contact between infants and their caregivers can affect children at the molecular level. The study was published in journal Development and Psychopathology.