Laboratory research is all well and good, but what is all this interest in epigenetics saying about how we should behave now? "Given that epigenetics is so new, we don't have a lot of experience in how you deal with that information and apply it clinically," explains Andrew Feinberg, director of the Johns Hopkins University Center for Epigenetics in Common Human Disease. Likewise, we cannot soon expect changes to public-health recommendations based on the notion of regulating our gene expression to prevent disease. And, he says, we can never ignore the basic blueprint of our hard-coded DNA. "It's a mistake to leave the genes out," he says. (And there's still much to be discovered about the human genome; now that it has been mapped, scientists have realized that most diseases don't come down to a single gene or even a handful. Instead, genes interact with one another with seemingly infinite complexity to cause illness.)
Indeed, the old rules of healthful living still apply, from getting regular physical activity to eating right and shunning tobacco. "Our work doesn't change those things," says Szyf. "It just provides an explanation" as to how they might provide a benefit. While Szyf suspects that critical epigenetic changes predisposing us to illness may occur in the womb and during early childhood, it's not clear whether it would be practical to reverse them. It's possible, he says, that some changes have accumulated in so many different places that it would be tough to reverse them all.
Yet some are optimistic that even though we will never be able to trump our own genes, we do have some control over how their influence plays out. The revelation from 30-odd years spent investigating what power an individual has over personal health, says Ornish, is that "our genes are a predisposition, but our genes are not our fate." In fact, he says, they "are much more dynamic than we'd once thought."
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