Research from the fall of 2017 out of the University of British Columbia and BC Children’s Hospital Research Institute found that “the amount of close and comforting contact between infants and their caregivers can affect children at the molecular level”1 and that effect is detectable four years later.
Children who had been more distressed as infants (like preemies) or who had received less physical contact, “had a molecular profile in their cells that was underdeveloped for their age.” In other words, they were biologically immature. And researchers believe that this slower epigenetic aging might indicate an inability to thrive.
While the implications of this aren’t totally understood, these findings build on similar work in rodents. However, this is the first study in humans to show that the act of touching, early in life, “has deeply-rooted and potentially lifelong consequences on genetic expression.”2)
Published in Development and Psychopathology, the study involved 94 healthy children in British Columbia:
- Researchers from UBC and BC Children’s Hospital asked parents of 5-week-old babies to keep a diary of their infants’ behavior (such as 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 children who experienced higher distress and received relatively little contact had an “epigenetic age” that was lower than would be expected, given their actual age. Such a discrepancy has been linked to poor health in several recent studies.
Lead author Sarah Moore, a postdoctoral fellow and her team plan to follow up to see if the ‘biological immaturity’ they saw in the children carried broad implications for their health and especially their psychological development. She said, “If further research confirms this initial finding, it will underscore the importance of providing physical contact, especially for distressed infants.”3