It’s the heart of the Primal Blueprint : understanding that our lifestyle factors direct influence the expression of our genetic code. While the DNA itself is set, the structure fixed, that’s hardly the end of the story – our story. How we live – even where we live  – holds significant sway over the final picture. And by picture I mean, of course, the picture of our genes’ activity: when proteins are produced (and how much), when or whether certain genes are turned on or off. This activity, researchers are increasingly finding, is key in the development – or avoidance – of any number of conditions like Parkinson’s, Alzheimer’s and cancer. Rather than a predetermined formula simply set in motion in the womb, our genes demonstrate a much more complex, nuanced interplay. The sum of all our daily choices and exposures direct our epigenetic signaling and the course laid out by that ongoing sequence of gene activity. As I’ve said  many a time, our original genetic heritage doesn’t design our physiological fate. How we live determines how our genes play out their hand. No doubt a powerful concept, the comprehension can take us by surprise. The quickly expanding field of epigenetics has, indeed, rewritten old school genetics. It’s even ruffled a few feathers here and there, but isn’t that always the case with new breakthroughs?
As scientists study the physical principles (e.g. methylation, etc.) behind gene expression, they’re also able to examine what in the environment incites the switch flipping, so to speak. Of course, our bodies are in constant interaction with any number of influences in our environment. We take in air, food, and water – as well as the extraneous substances contained in them. We use medications and personal hygiene products. We lick the adhesive to seal an envelope. The list goes on and on. A few months ago members of the National Academies met for a workshop entitled “Use of Emerging Science and Technologies to Explore Epigenetic Mechanisms Underlying the Developmental Basis for Disease.” (Check out the full program online  for yourself.) The workshop was part of the Emerging Science for Environmental Health Decisions initiative and standing committee within the National Academies. In a nutshell, the group focused on the demonstrated influence environmental toxins exhibit on gene expression as well as the impact this evidence should have on public education and regulation of these substances.
Compounds that may not appear dramatically or immediately harmful on a cellular level nonetheless trigger significant havoc on an epigenetic level, throwing off normal methylization patterns and causing the dysregulation of microRNAs, which direct gene expression. Among the implicated substances presenters highlighted were tobacco carcinogens, asbestos, ionizing radiation, arsenic, nickel, cadmium, benzene and polycyclic aromatic hydrocarbons (PAHs – components of common air pollution). Early/in utero exposure to these chemicals appears most destructive. As one presenter noted  (PDF), in utero exposure to PAHs, for example, has been identified as a significant “risk factor” for childhood asthma. Although in utero exposure has been identified as a particularly “critical period” for epigenetic impact, it doesn’t mean we’re out of the woods as soon as we’re out of the womb. Researchers are examining the possibility of other “critical periods” and emphasize  (PDF) the ongoing vulnerability to epigenetic alteration throughout life. The real problem with exposure to many of these substances isn’t the immediate impact on cells but the previously unseen changes to genes’ subsequent activity throughout an individual’s lifetime. Genes are silenced and lose their ability to manage the production of proteins for ongoing cell function and repair. Others are activated when they shouldn’t be. The resulting complement of abnormal down-regulation and overexpression can set the stage for cancer, metabolic disease and neurological impairment. Researchers have already begun to identify epigenetic changes that foretell cancer development .
It will be interesting to follow how this conversation continues to unfold in the scientific and public policy arenas. Although these issues aren’t exactly at the forefront of the mainstream media or public classrooms, the information is out there. Individual knowledge is personal power. While scientists continue their research and officials from every sphere wrangle over the public implications of these findings, we can start making decisions in the here and now. Just as negative experiences and exposures have the ability to instigate damaging epigenetic changes, our positive efforts can support normal epigenetic patterns by providing the healthy conditions our bodies expect and by counteracting the environmental challenges our modern bodies encounter each day in traffic, in our food supply, in the stress of work, and so on. Eating a clean diet , minimizing emotional tension , exercising smartly , and supplementing wisely  can go a long way to reducing our exposure to modern toxins  and offsetting their influence.
Let me know what you think. Send your comments and questions. Thanks for reading.