Pregnant moms who crave black licorice may want to think twice. A recent study from Finland finds that kids born to mothers who ate a lot of licorice while they were pregnant scored lower on IQ tests, had poorer memory and had higher odds of attention deficit/hyperactivity disorder symptoms. Among the girls, tests showed that they had also started puberty earlier than normal.
In the study, scientists at the University of Helsinki suggest that there are long-term health effects for the fetus if they’re exposed to too much licorice in the womb, and that “it appears no safe exposure during human pregnancy exists.”
First, an important note: In Finland, licorice tends to be black, hard and salty. It’s made with real licorice root extract. In the U.S., what Americans know as “licorice” tends to be red, tacky and sweet, and made with a whole variety of flavors that don’t usually include real licorice root. So if Red Vines are what you crave during pregnancy, there’s no need to worry, even as a precaution, that they may cause harm your child.
In northern Europe, however, licorice made from the licorice root is a popular candy. The average northern European eats about 4.5 pounds of licorice a year. In 2016, Finland issued an official recommendation that pregnant women keep licorice consumption low because animal studies suggested it could make stress hormones from the mother pass more easily to the developing fetus.
So how exactly could a piece of candy be linked to such serious cognitive and physical health deficits? Scientists suspect it may have to do with the licorice root compound glycyrrhizin, which gives licorice candy its distinctive sweet taste and is sometimes used as a sweetener in teas, drinks and other foods. In the U.S., glycyrrhizin is also found in dietary supplements for digestion issues, menopause symptoms and infections.
Glycyrrhizin blocks an enzyme that the body uses to deactivate the stress hormone cortisol, causing cortisol levels to rise. Past research in humans has linked high cortisol levels in the womb to a higher risk of mood disorders, a heightened response to stress and an increased risk of premature births or low birth weights, but the findings are still inconsistent.
Other scientists say the findings in the University of Helsinki study are preliminary, too, and that more research needs to be done before definitively concluding that black licorice harms fetuses.
The Study Details
The Finnish study, published in the American Journal of Epidemiology, assessed 378 13 year-olds and divided them into two groups: those whose moms reported eating “large amounts” of licorice per week (about 250 grams of licorice) during their pregnancies, and those whose mothers ate little or no licorice during their pregnancy.
To avoid skewing the results, the study surveyed only healthy children and excluded twins, children in special education classes or kids with a general estimated IQ of less than 70 (the threshold for cognitive deficiency).
They found that kids whose mothers ate large amounts of licorice scored seven points lower on intelligence quotient tests. Kids in the high-exposure group also had more than triple the odds of having ADHD symptoms, compared to those whose mothers ate only a little licorice during their pregnancies.
Based on the range of cognitive deficits the high-exposure kids showed, their limbic systems may have been damaged by excess cortisol from the licorice their mothers ate when they were fetuses, researchers wrote. The limbic system, a group of structures in the brain in charge of emotion, behavior and processing information, is especially sensitive to fluctuating cortisol levels, according to previous research on animals.
And Now For Some Caveats
There were some limitations to the University of Helsinki study, however. Scientists could only estimate how much glycyrrhizin women consumed based on how much of the actual candy they remembered eating, as different brands can contain different amounts of the compound. And while researchers were able to control for things like maternal intelligence and parental background, some hidden food or behavioral factor could confound the results.
Finally, because Finnish people eat so much licorice, the researchers aren’t sure how meaningful these results are for women in other countries — although they note that glycyrrhizin is used in many American foods, tobacco and medicine.
In commentary published alongside the study, Katherine Keyes, an epidemiologist at Columbia University, praised the “intriguing and suggestive” study and said more research should be given high priority to confirm a potential causal relationship.
In the meantime, however, she cautioned that these results should still be considered preliminary. She pointed out that there’s incomplete information about most of the women who initially participated in the study. Also, because the women who fell in the “none to low” licorice consumption category ranged from those who had consumed absolutely no licorice to those who ate up to 249 milligrams of glycyrrhizin per week, the participant group was too diverse to draw any strong conclusions about the relationship between licorice consumption and cognitive effects in children.
“The authors suggest that as a public health community we should advocate for avoiding licorice consumption during pregnancy at the same level on which we advocate against heavy alcohol consumption during pregnancy,” Keyes wrote. “We believe that such calibration of messages is unwarranted. Licorice and closely related substances have been used as herbal medicines for thousands of years, and they may have a variety of health effects, some of which may be positive.”