The environmental advocacy group Environmental Defense Fund (EDF) on June 15 released a study about dietary lead exposure, with a focus on food intended for babies and young children.
Using a Federal Drug Administration (FDA) database of food samples, EDF reported some pretty worrying numbers, most remarkably in fruit juice samples intended for children. For example, 89 percent of the baby food grape juice samples had detectable levels of lead in them.
As researchers who served as independent reviewers on the EDF report, we think it raises important concerns about the safety of our food supply. Since EDF primarily focused on exposure (whether lead was detectable or not), we were interested to see if we could get a better sense of the magnitude of risk. Specifically, we examined potential IQ loss and the percentage of samples with high lead concentrations.
Why is lead in our food and beverages?
But food is a source of lead exposure most of us probably aren’t thinking about. Soil contamination is a known source of lead in food, but the EDF report also raised the possibility of contamination occurring via the use of lead-containing materials during food processing.
Eating lead-contaminated food increases the level of lead in the blood. Chronic, low-level exposure to lead during childhood can harm mental and physical development. For each microgram (µg) per day of dietary lead intake, blood lead levels increase by about .16 micrograms per deciliter (µg/dL), though there is individual variation in how much lead is absorbed through the gastroinestical tract. A microgram is one millionth of a gram – a very small unit of measure.
There is no known level of lead exposure that is considered safe. Even low blood lead levels can harm child development and behavior. In 2012, the Centers for Disease Control and Prevention (CDC) reduced the definition of elevated blood levels in children from 10 to 5 μg/dL.
This revised definition reflects findings from a 2012 National Toxicology Program Report that concluded a wide range of adverse health effects are associated with blood lead levels less than 5 μg/dL. These included “decreased academic achievement, IQ, and specific cognitive measures; increased incidence of attention-related behaviors and problem behaviors.”
The FDA has set limits for lead in the form of maximum parts per billion (ppb) for certain foods. The FDA reports that these differences in limits are due to what is considered achievable after food processing. The American Academy of Pediatrics has the lowest recommended limit at 1 ppb for school drinking water.