Welcome, my friends, to another Food-for-Thought Wednesday! We will delve further into the hot subject of epigenetics today. I was given this link by nutritionist Karla Maree in response to my previous post on epigenetics, and found the implications mind-blowing:
Can you believe this:
– Animal studies and a smattering of human data suggest prenatal effects could reach farther down the family tree: The vices, virtues, inadvertent actions and accidental exposures of a pregnant mother may pose health consequences for her grandchildren and great-grandchildren, and perhaps even their offspring.
– While hormonal or diet exposures in the womb don’t directly change or damage DNA (like ionizing radiation would, for example) those sorts of exposures can induce scribblings in the genome’s margins that can also be passed down.
– The resulting health effects are not produced by altering DNA itself. Rather they stem from changes in chemical tags on DNA or its associated proteins, or to actions by RNA, another type of genetic molecule. All of these are exactly the types of changes that scientists have always assumed cannot be inherited. Their very name, epigenetic, literally means “over and above” or “beyond” genetics.
– Until fairly recently, scientists have thought that every new generation starts with its own freshly printed genome, devoid of epigenetic embellishments. But then scientists began to document cases in which inheritance of a particular trait did not follow the usual rules of genetics, hinting that at least some epigenetic marks may be carried on to new generations.
I find this paradigm shift in our understanding of how traits are passed down fascinating and yet another indication of how amazingly complex our biology is! (Side note: this is why I proclaim that the focus on GMO’s is PURE HUBRIS. We assume we can slice and dice plant and animal DNA – the basis of life! – and get what we want without serious unintended consequences. We don’t even understand the complexities of our own biology, what really happens when we digest food, how our bodies adapt to situations, etc. so how could we mess with the DNA that nature has evolved in a balanced fashion over millennia without seriously screwing up ourselves and the planet? That’s all. Just a simple question.)
But wait, there’s more:
– Researchers showed that exposing a pregnant rat to chemicals that disrupt the action of sex hormones could produce fertility problems that lasted at least to her great-great-grandchildren’s generation, as reported in Science in 2005. One implication of this finding is that epigenetic programming becomes permanent and gets passed along to future generations.
– Australian researchers showed that rat fathers that ate a high-fat diet and became obese before mating passed along a propensity to become diabetic to their daughters (but not their sons), as reported in Science in 2010. Something in the dads’ high-fat diet apparently caused a change in methyl tags on DNA in the fathers’ sperm that was then passed on to the daughters. It was direct evidence that diet or other environmental factors could influence epigenetic marks in sperm, escape the epigenetic reset at fertilization and affect the health of offspring.
Regarding results on people:
– Babies born to obese fathers had an altered epigenetic legacy, researchers reported February 6, 2013 in BMC Medicine. The children of 16 obese men had lower levels of methylation of the gene IGF2 compared with the kids of normal-weight dads.
– It is a possibility that epigenetic changes observed in grandchildren might stem from conditions encountered by fetal germ cells. It’s not until the great-grandchild generation that researchers can determine whether an epigenetic mark is truly inherited, because that is the first generation that had no contact with what the original pregnant mom encountered. Research on this topic continues.
– Washington State University researcher Michael Skinner thinks that epigenetics offers an organism a way to adjust the activity of genes rapidly in response to environmental cues. Epigenetic marks prepare future generations for the environment that they are likely to encounter, he contends. He even thinks that epigenetic changes may eventually become permanently inscribed in DNA, thus influencing the evolution of species. “I don’t want to suggest that genetics and DNA is not important — it’s just not the whole story,” he says.
Holy genome! This implies that the DNA we inherit from our parents is not a fixed quantity to be passed along, but something that can be subtly modified as a result of our life choices and then PASSED DOWN for 1, and possibly more, generations. The dangers of things like chemical exposure (e.g. even common ones like bisphenol A, pesticides, DEET), synthetic hormone exposure, eating pesticides, and obesity take on a whole new meaning. Those are not just bad for our organs, they are bad for our genes. Wow.
So riddle me this: do our future generations even have a chance at optimal mental and physical health if 70% of our population is overweight; if our food supply is contaminated with pesticides, fungicides, herbicides, and synthetic hormones; if babies are being fed GM soy formula; if kids are growing up on GM junk food, artificial sweeteners and bad fats? Junk bodies, indeed!
How about next time you want to reach for a bag of Cheetos/doughnuts/any awful junk, decide not to exercise, microwave your lunch in a plastic container, eat conventional foods (especially the Dirty Dozen), live in prolonged stressful circumstances…consider that you are not just messing with your own biology!