Featured Research

UNC Researcher Shares The Ironies of Iron During Pregnancy

August 17, 2017

Iron is listed by the American Academy of Pediatrics as one of the most essential nutrients for healthy fetal development. But Susan Smith, PhD, deputy director of science at the UNC Nutrition Research Institute on the NC Research Campus, points out that 22 percent of U.S. women in their childbearing years are iron deficient.

The catch, according to Smith’s research, is that just consuming more iron either through diet or supplements does not always guarantee the mother will have enough iron to support both her growing fetus and herself. For almost 30 years, Smith has studied many different genetic, environmental and lifestyle factors that affect prenatal development, and she has some insights for women to consider.

Diet or Supplements

A mother’s iron consumption directly impacts development of the fetal brain. Iron also prevents anemia, low birth weight, and premature delivery. Iron levels can be increased by eating more beef, poultry, shellfish, lentils, beans, and spinach, or by taking supplements. Part of Smith’s research studies how to optimize iron delivery for the pregnant mother and her fetus.

Some women have trouble consuming enough iron because iron-rich foods can be expensive. And while lentils, beans, and spinach are more affordable, Smith emphasizes, they have a different kind of iron than meat and shellfish – nonheme iron – which is absorbed less efficiently.

Supplements are a good option, but even when doctors prescribe them, Smith says, it can be hard to take them regularly because some supplements can cause gut irritation or constipation. For a pregnant woman who is already experiencing uncomfortable changes in her body, this discomfort may keep her from obtaining the iron that her fetus needs.

Smith and her research team are looking for a solution by studying optimal forms of iron, either from natural sources or in a supplement, to help mother and fetus.

Smith and her research team are looking for a solution by testing optimal forms of iron, either from natural sources or in a supplement, to help mother and fetus.

The additional challenge, adds Smith, is that “we can feed mothers all the iron we want, but is the fetus using it effectively?”

Iron and Alcohol

One lifestyle choice made by women that affects how a fetus uses iron is drinking alcohol. “The parallels between alcohol exposure and iron deficiency are striking,” Smith explained. “Both cause similar growth reductions and behavioral deficits in the child.” Smith’s 2016 study published in the Journal of Nutrition showed that alcohol disrupts how a fetus uses iron.

Exposure to the mother’s alcohol causes inflammation that puts fetal cells into alert status, which results in iron being stowed away in the liver. “One of the body’s defenses against infection is to put iron into storage,” Smith explained. “In this case though, the mother doesn’t have an infection. She’s drinking alcohol. But the body doesn’t know the difference.”

Smith emphasizes that when iron is stockpiled in the liver, it is virtually useless because alcohol prevents other organs from using it. Meanwhile, the fetal brain is stunted by the lack of iron, which can result in changes in behavior and cognitive function that can have negative consequences throughout a person’s life.

In an October 2017 review of recent findings, Smith and co-authors discussed how iron deficiency in pregnant mothers increases the risk of adverse outcomes for the fetus, especially when the fetus is also exposed to alcohol. Prenatal exposure to alcohol (PAE) causes neurodevelopmental problems in many parts of the brain also affected by iron-deficiency, and each condition seems to make the other worse. Based on findings explained in the review, Smith believes that alcohol-exposed, iron-deficient pregnancies “contribute to the severe end of the FASD spectrum.”

The Take Home

Smith acknowledges that the specific effects of alcohol exposure during pregnancy vary for each woman and that many factors determine the health of a pregnant woman and her baby. Still, she cautions that drinking during pregnancy is risky, especially since no form of iron can resist the effects of alcohol, at least none that Smith has found so far.

For Smith, what is most important is for women to be aware that when they are pregnant they should increase their iron intake and think twice about drinking alcohol. “Alcohol prevents a baby’s healthy development. It may also prevent the baby from using nutrients efficiently,” she explains. “Our work strives to understand and address that problem. This way, we can give women the best scientific advice to help them make the best decisions for their health and for their family’s health.”

Learn more about the UNC Nutrition Research Institute at www.uncnri.org.