After decades of exploring the damage that alcohol causes to human fetuses, Susan M. Smith PhD’87, a professor of nutritional science, is finally growing hopeful that the biggest cause of preventable brain damage among American newborns may be tamed.
Fetal alcohol spectrum disorder (FASD), the current name for alcohol’s ravages on the developing brain, impairs both behavior and intelligence in children. While the severity of FASD typically increases with heavier drinking during pregnancy, even a few drinks can create damage in a developing baby.
Smith’s optimism does not reflect any reduction in the rate of FASD, which affects 2 to 5 percent of American newborns. Rather it emerges from the growing understanding of exactly how a mother’s drinking causes the cells in her child’s brain to commit suicide during a period when they should be growing and networking.
In the latest of many landmark studies to emerge from Smith’s lab, graduate student Echoleah Rufer has found that in rats, the combination of alcohol and a low level of iron multiplies the damage expected from either factor alone. Although the iron level in the study was not low enough to constitute anemia, it is found in 22 percent of American women of child-bearing age.
Smith says she began to wonder if iron was implicated in fetal alcohol problems several years ago. “We noticed that FASD often grows more severe with successive pregnancies, and we realized it sounded as if the women were being depleted of a protective factor.” Iron was a key suspect, because women lose so much iron during menstruation and pregnancy. Iron deficiencies also cause learning and behavioral problems in children.
In 2007, Smith won a Merit Award from the National Institutes of Health, which gave her 10 years of research support and a perfect opportunity to explore the link further. The recent research found that either alcohol exposure or iron deficiency alone could impede learning, but the combination caused a significant increase in brain cell death, which resulted in a five-fold decrease in the learning ability of the newborn rats. The destructive synergy could reflect the need for iron in chemicals that carry signals among nerve cells or in the reactions that cells use to process energy.
If the findings are supported by further research, Smith says screening for subtle iron deficiencies could become a standard part of prenatal care. “If an adequate level of iron is essential to brain development in all developing children, then we should identify a strategy to ensure that all pregnant women have this level of iron.” She adds that a nutritional approach would likely be more effective at mitigating FASD than the current alternative, which is urging women not to drink while pregnant. Reports in the press sometimes give the impression that moderate drinking during pregnancy can be safe, which makes abstinence an uphill battle, Smith says.
“We cannot say there is a safe limit, and we do not know who is more or less susceptible,” she says. “A woman is playing Russian roulette if she drinks during pregnancy.”