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A Radical NotionDung Hoang

A Radical Notion (continued)

ANIMAL STUDIES HAVE SHOWN that a number of environmental triggers, such as poor nutrition or exposure to bisphenol A (a chemical found in plastic), alter the protein production of genes at critical times by turning them on, off, up or down; and that these “epigenetic” changes get passed down from mother to baby and even into the next generation. A striking example involves research using mice that, despite being genetically identical, are either small and brown, or obese and yellow (and prone to diabetes and cancer as adults), depending on whether or not a particular gene is activated by a simple change in their mother’s diet. Exposures in the womb get biologically embedded just when the developing nervous, immune and metabolic systems are most susceptible to being modified, essentially programming these systems early on.

These signals from the environment apparently echo far into the future, “which is why we’ve got to take seriously the public health aspects of food choices by girls and women,” says David Barker whose 1995 paper, “Fetal Origins of Coronary Disease” in the British Medical Journal, gave rise to the Barker Hypothesis.

A physician and professor at the University of Southampton Medical School in the U.K. and at the Oregon Health and Science University in Portland, Barker offers up a body of research suggesting that hundreds of millions of people need not have type 2 diabetes, for instance; that this and other chronic disease epidemics can be traced back to the placenta and are, he says, “unnecessary.” Prevention is simple but not easy, he explains: It requires improvement in the nutrition of girls and young women.

“Chronic disease isn’t about abnormal things happening to adults who then need fixing,” Barker says. “It’s about variations in key systems during development, which in turn cause wide variations in how well a baby is nourished. The ability of a mother to nourish her baby in the womb reflects her own lifetime nutrition, beginning when she herself was in the womb. To say ‘don’t drink, don’t smoke,’ is not enough. We’ve done that; we need to move on from merely limiting damage to building better people.”

Using good nutrition to build healthy people is hardly a new idea. (The Bloomberg School’s David Paige—decades before he taught Wang when she was a doctoral student here—developed a food voucher program in Baltimore that later served as the model for WIC.) What is news: the extent to which a developing baby’s or young child’s environment plays a role in chronic disease by silencing or activating genes. That’s why the heavy emphasis by Barker and his acolytes on birth weight: In addition to being a measure of pregnancy outcome, it’s an indicator of fetal nutrition, of whether an individual’s in utero experience was harsh or benign. Birth size implies potential in terms of metabolism, cognition and endocrine function.

If the early-origins framework that Barker built still rankles some scientists, it’s because the mechanisms remain elusive. Associating a prenatal exposure with the heart disease of a middle-aged man is one thing; directly linking the two is quite another. Lots of other potentially culpable stuff also happens in the intervening decades, muddying up the path between cause and effect. Which is why Wang is collaborating with a vast network of scientists and clinicians around the world as she leads comprehensive long-term studies into the early life precursors for pediatric and adult diseases including preterm birth, food allergy, obesity and metabolic syndrome. In Wang’s purview, the futile nature-versus-nurture debate morphs into verifiable questions with measurable answers: What environmental and social factors consort with which genetic factors; how, when and to what degree?  Is the net effect a risk for disease—or resilience?

Of many adverse influences that can pull a trigger cocked by genetics, poor nutrition is a biggie. But brutal neighborhoods also belong on that list, according to Wang, as well as vicious domestic situations: “Violence is to mental health as cigarette smoking is to cancer,” says Barry Zuckerman, MD, chief of pediatrics at the Boston Medical Center and a mentor of Wang’s since she was a resident there in the late 1990s. While Zuckerman and his protégé are focused on discovering those factors contributing to low birth weight, they also are keen to identify biologic interventions and social strategies that could preempt or at least buffer the detrimental effects of environmental influences. Zuckerman’s Reach Out and Read program, for instance, goes beyond the scope of conventional pediatric practice, using literacy as “medicine” to immunize kids against the power of poverty and violence; he says that primary care practitioners must encourage parents to read aloud to babies and preschoolers.

Comments

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  • Graciela Bernardo

    Neuquén- Argentina 05/29/2012 06:54:22 PM

    Congratulations! I´m a midwife and work for the healths of mothers and their babies. I´m very happy with you investigation.. Continue Best wishes!!

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