Pregnant women may want to avoid licorice, which may affect the cognitive abilities of their children, a study suggests.
Licorice contains glycyrrhizin, a sweetener derived from the root of the licorice plant, and is used to flavor candies, soft drinks, herbal teas and other products. Pills and supplements containing concentrated licorice are also a popular herbal remedy for respiratory ailments and other ills.
The analysis, in the American Journal of Epidemiology, included 1,049 mothers and their healthy infants born in Finland in 1998. Eleven percent of the mothers consumed more than 500 milligrams of glycyrrhizin a week, the amount found in about 8.8 ounces of pure licorice (many licorice candies and foods contain anise flavorings and only small amounts of glycyrrhizin).
At age 13, compared with those whose mothers ate the least licorice, those whose mothers consumed the most averaged seven points lower on I.Q. tests and had triple the risk for attention deficit disorder problems. Girls in the high-consumption group also tended to reach puberty earlier and have a higher body mass index.
Glycyrrhizin increases levels of cortisol, the stress hormone, which may affect development of the fetal nervous system.
“We know that there are limitations in observational studies like this,” said the lead author, Katri Raikkonen, of the University of Helsinki. “But we have tried to account for numerous variables, and we know from animal studies that there are detrimental consequences for offspring of mothers who consume glycyrrhizin. Insofar as you can avoid it during pregnancy, you should do so.”