From Society to Cells

Recent research has discovered that the environment shapes the way genes are activated and expressed. Early childhood is a very sensitive period in human development; it is during the first two to three years that the brain and, especially, the circuitry that governs attention, emotion, self-control and stress are formed.

In November 2014 the Royal College of Physicians and Surgeons of Canada (RCPSC) warned that Canada is not spending enough on early childhood care and learning. Citing a recent OECD (Organization of Economic Co-operation and Development) study in which Canada trailed most other rich countries, the College recommended that the Federal government boost its current spending on early childhood care and learning from 0.6 percent of GDP to the OECD-recommended one percent of GDP, and far from the Nordic countries which spend close to two percent of GDP on early childhood development.

A 2006 OECD report placed Canada last in spending on early childhood programs, leading to a study initiated by the Senate Committee on Social Affairs Science and Technology and , culminating in the 2009 report “Early Childhood Education and Care: The Next Steps”. The report recommended that the Government of Canada collaborate with the provinces and territories to “create an adequately funded, robust system of data collection, evaluation and research, promoting all aspects of quality human development and in early childhood programming including the development of curricula, program evaluation and child outcome measures”.

While Canada’s commitment has progressed since 2006, the recent RCPSC recommendation is made in light of compelling evidence that chronic diseases often have their roots in the early years of childhood.

“We do know today that something happens to the development of the children who have been exposed to adversity in the form of abuse, violence, toxic stress or simply day-to-day neglect in their early childhood. The exposure to significant stress—either prenatal or postnatal, can have long term consequences seen decades later, including higher rates of metabolic syndrome (hypertension, cardiovascular diseases, diabetes), mental health issues or even cancer”, says pediatrician Dr. Paul Roumeliotis, Medical Officer of Health and CEO for Eastern Ontario Heath Unit and author of the newly released book Baby Comes Home: A Parent's Guide to a Healthy and Well First 18 Months. “So something is obviously going on”, adds Roumeliotis. 

This ‘something’ can today be explained from a biological and neurological perspective. Exposure to toxic or chronic stress, i.e. “non-physical” environmental factors, influences the heritable state in gene expression without altering the DNA sequence. These are called epigenetic changes. Close to 20,000 human genes have been identified. Cells use a system that regulates how genes are expressed, with ‘switches’ that turn genes on and off. It is believed that this genetic control system determines what a cell can do, and can potentially shape what diseases an individual may be prone to. Changes in gene expression can manifest themselves as disease later on in life, but can initially go undetected. Furthermore, these epigenetic changes can be passed on from one generation to another.

In addition to epigenetic changes, exposure to adverse events during early brain development and sculpting can affect the body’s sophisticated hormonal control system (Hypothalamic-Pituitary-Axis - HPA). The primary hormonal mediators of stress responses have both protective and potentially damaging effects on the body. These “stress” hormones are essential for adaptation, maintenance of homeostasis, and survival in the short run. However, if the HPA is mis-developed due to external adverse events, such as lack of bonding and nurturing during infancy, the stress hormone response will be abnormal. The presence of these abnormally regulated and consistently high stress hormones represents an “allostatic load” that can accelerate disease process in the long run. Allostasis due to aberrent brain responses to environmental stress factors can affect the body at the tissue level, resulting in the generation of various chronic diseases.

If a baby is exposed to negative environmental factors in the form of violence, poverty, lack of adequate housing, hunger and inadequate food  (also see the interview with Dr. Lynn McIntyre in this issue) this increases stress hormones and the overburden of steroid, cortisone, and adrenaline, leading the cells to turn off the system’s building blocks – the proteins. This alteration of DNA-binding and regulatory proteins can be passed on from one generation to the next.

“The long-term allostatic load effects and epigenetic changes actually originate during a neglected baby’s first sensitive years,” says Dr.Roumeliotis. “A negative environment will not only impact their learning ability and academic success, as their neural network will not develop properly, with the risk of failing in school and later in life. But notwithstanding the psychological effects, we now understand that early exposure to negative environments also has long-term biological adverse effects on humans.” <>

By Jostein Algroy