Holding babies affects their genes

01 February 2018
Woman holding a baby

The amount of close and comforting contact between infants and their caregivers can affect children at the molecular level for up to four years, new research has found.

The University of British Columbia study showed that distressed infants who had received less physical contact were found to have an undeveloped molecular profile in their cells meaning that they were potentially lagging biologically.

This is first study in humans to show that the simple act of touching could have deeply-rooted and potentially lifelong consequences on the epigenome (the range of biochemical changes that affect gene expression).

Researcher, Professor of Medical Genetics, Dr Michael Kobor says: “In children, we think slower epigenetic aging could reflect less favorable developmental progress.”

The study, published in Development and Psychopathology, involved 94 healthy children in British Columbia.

Researchers asked parents of five-week-old babies to keep a diary of their infants’ behaviour (such as sleeping, fussing, crying or feeding) as well as the duration of caregiving that involved bodily contact. When the children were about 4 ½ 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 occurs, 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 are not yet known.

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. 

A discrepancy between epigenetic age and chronological age has been linked to poor health in some recent studies.

“We plan to follow up on whether the ‘biological immaturity’ we saw in these children carries broader implications for their health, especially their psychological development,” says lead author Sarah Moore, a postdoctoral fellow.

“If further research confirms this initial finding, it will underscore the importance of providing physical contact, especially for distressed infants.”

You can read the full article here.