Epigenetics shows how social and physical environments influence genetic development
A version of this commentary appeared in the Huffington Post and the Guelph Mercury
We are not our genes.
The choices we make, from breakfast to bedtime, reshape our gene expression, moulding us into the people we are. Living an active life of purposeful activity with social support, eating nutritiously and sleeping well in a safe place to call home can reduce our risk of a host of diseases.
But more important than whether we make healthy choices is whether we can make them. Right now, many Canadians are struggling to make healthy choices for themselves and their families.
The late Clyde Hertzman, recipient of the Order of Canada for his groundbreaking work on early childhood development, said that much of childhood risk is preventable. At the anniversary of Hertzman’s death this month, we must remember the powerful legacy he left behind; namely, his constant belief that by caring for children we can change schools, neighbourhoods, communities and cities — we can change the world.
Each child is born with 100 billion neurons, neither branched nor connected, with time sensitive windows of optimal opportunity.
We are, as you read this, building brains in our communities.
We can build good brains or bad ones, and the experiences available in the first 1,000 days of life have an enormous impact. Hence the importance of the early years: cuddling, singing, reading and an early tuck in to bed every night. The building blocks also stack and form in middle childhood and adolescence.
The environment we are in turns our genes off or on. Epigenetics, the study of changes to our genes that our children, and their children, could inherit, shows us that genes capture information from environmental exposures.
If the DNA is the hard drive, epigenetics is the operating system.
Consider the stress hormone cortisol, which is bad for the brain in excessive amounts: it switches genes off or on through specific receptors, such as those in the memory and learning centre, the hippocampus. The stress hormone receptor turns on or off depending upon the quality of caregiving. When the cortisol is activated too often and there is no responsive adult to balance out that stress, it becomes toxic.
Poverty, neglect, family violence and substance abuse can expose children to toxic stress that changes their bodies and increases their likelihood of having many problems later in life, including early pregnancy, heart disease, asthma and cancer.
Researchers understand these processes well. The evidence that experience moulds our biology is undeniable, and prevention must occur in the homes of children, in the policies created in the halls of government and in society at large. But the paths to Queen’s Park and Parliament Hill, where decisions are made, do not often cross through Canada’s many impoverished neighbourhoods, such as Toronto’s Regent Park, Jane and Finch and Scarborough, where healthy food is often scarce, and safe, affordable housing is hard-won. Closer to the city’s borders, public transit is sorely lacking.
One in 2.9 Torontonians lives in a poverty postal code, according to the Toronto Community Foundation. These Canadians and others like them suffer from inadequate transit, safety, affordable housing and a lack of subsidized healthy food. For example, Regent Park didn’t even have a grocery store until a few years ago.
Clyde Hertzman once said that neuroscience has caught up with social epidemiology. Unfortunately, our social policies have not caught up with these powerful sources of evidence, which have shown us the bonds between environment and health.
There is a fundamental disconnect between the parents most in need, who struggle each day to build the brains of their children and to keep them fed, and the policymakers who decide how many building blocks to hand over for the task.
Canada invests too many resources into complex care — treating people once they’re already sick — and too few into the factors that keep them healthy in the first place, starting in the first years of their lives.
A civil society requires a safe, supportive and affordable life for families, for optimal parenting that gives every child a chance in life.
Dr. Elizabeth Lee Ford-Jones is an expert advisor with EvidenceNetwork.ca, a paediatrician specializing in social paediatrics and Project Investigator at SickKids and a professor in the Department of Paediatrics at the University of Toronto.
The above represent the opinions of Dr. Lee Ford-Jones and not necessarily the official positions of either The Hospital for Sick Children or the University of Toronto.
February 2014
See the two posters, 1 and 2 based on this commentary
This work is licensed under a Creative Commons Attribution 4.0 International License.
