Pregnant women who eat liquorice are exposed to glycyrrhizic acid, which may have adverse health effects for fetuses and longterm effects on children. The data are too uncertain to determine a level for how much liquorice it is safe to eat by pregnant women.
This is the main message in an assessment made by the Norwegian Scientific Committee for Food and Environment (VKM) of possible negative health effects associated with glycyrrhizic acid. Glycyrrhizic acid is a natural sweet substance from the plant liquorice root that gives the typical liquorice flavour.In this assessment, the term glycyrrhizin is used as a more general term denoting glycyrrhizic acid and its metabolite glycyrrhetic acid in liquorice.
Finnish studies have reported that intake of licorice-containing confectionary during pregnancy is related to negative effects on the fetus and long-term adverse effects on the child.
High glycyrrhizin exposure was significantly associated with shorter gestational duration, and more than twofold increased risk of preterm (<37 weeks) delivery.
Effects on children's development
When the children reached a mean age of 8.1 years, they were reported to have poorer cognitive performance, more externalising symptoms and attention problems after high glycyrrhizin exposure. They also had higher salivary cortisol levels in various tests. Increased cortisol may potentially have negative effects on children’s development.
At mean age 12.5 years, girls, but not boys, were taller, heavier and had higher body mass index for age, were closer to adult height and had more advanced pubertal development. Both girls and boys scored lower on tests of intelligence quotient, had poorer memory and had higher odds of attention deficit/hyperactivity disorder problems.
In these studies, high glycyrrhizin intake was defined as ≥500 mg of glycyrrhizin per week, corresponding to approximately 250 g licorice-containing confectionary per week.
500 milligrams per week of glycyrrhizin, i.e. approximately 71 milligrams per day, is the lowest dose with observed negative effects in these human studies. It is lower than what has previously been suggested as a safe level, which is 100 milligrams per day.
Uncertainties in the studies
The level of 500 mg per week is uncertain due to several weaknesses in the studies.
VKM concludes that because of the large uncertainty associated with the relationship between the exposure dose and the observed adverse effects, a safe level cannot be established with certainty for glycyrrhizic acid or for the amount of licorice-containing confectionary that the pregnant mothers can consume without causing negative effects on the fetus or child.
VKM's Scientific Panel on Food Additives, Flavourings, Processing Aids, Materials in Contact with Food and Cosmetics is responsible for the assessment.