Lead is a heavy metal that has been linked to a number of health problems, most notably, neurological conditions. According to the Centers for Disease Control (CDC), in at least four million households, children are being exposed to high levels of lead. And yet, no safe blood level in children has been identified, which means that even at low exposure there are health risks.

In a recent study published in the Public Library of Sciences ONE journal, researchers found that even very low lead levels were associated with obesity in mice whose mothers had been exposed to it.

“The data support the obesogen hypothesis that toxicant exposures in the womb contribute to the higher rate of obesity,” noted Dana Dolinoy, PhD, lead researcher.

Until now, lead has not been thought of as an obesogen, or a compound that alters metabolic processes and predisposes some people to weight gain. Common obesogens are endocrine disrupting chemicals such as bisphenol A and phthalates. But this study shows that a mother’s exposure—even before pregnancy—plays a role on her offspring’s obesity risk. Notably, males were more affected than females in the study.

Christopher Faulk, PhD, lead researcher, was surprised by the results. “To see that the level I and others have considered very low has such statistical significance in this study is alarming. There is no minimum safe level for lead. Our study really supports this,” he stated.

Lead still exists in older homes, as the CDC research illustrates. It is also found in air, water, soil, food, and in some consumer products. For ways to reduce your child’s lead exposure, read this.