Eating 100g of pure liquorice a week could affect a child's development
Pregnant women who eat large amounts of liquorice could negatively affect their child's intelligence and behaviour, according to research.
Experts from Edinburgh and Helsinki universities studied eight-year-olds born in Finland, where consumption of liquorice among young women is common.
The children of women who ate a lot of liquorice when pregnant did not perform as well as other youngsters in tests.
Researchers said a component in liquorice may impair the placenta.
They said the component - glycyrrhizin - may allow stress hormones to cross from the mother to the baby.
High levels of such hormones, known as glucocorticoids, are thought to affect foetal brain development and have been linked to behavioural disorders in children in previous studies.
Of the children who took part in the Finnish study, 64 were exposed to high levels of glycyrrhizin in liquorice, 46 to moderate levels and 211 to low levels.
They were tested on a range of cognitive functions including vocabulary, memory and spatial awareness.
Behaviour was assessed using an in-depth questionnaire completed by the mother.
The results suggested that women who ate more than 500mg of glycyrrhizin per week - found in the equivalent of 100g of pure liquorice - were more likely to have children with lower intelligence levels and more behavioural problems.
The eight-year-olds were more likely to have poor attention spans and show disruptive behaviour such as attention deficit hyperactivity disorder (ADHD), the researchers said.
Professor Jonathan Seckl, from Edinburgh University's centre for cardiovascular science, said: "This shows that eating liquorice during pregnancy may affect a child's behaviour or IQ and suggests the importance of the placenta in preventing stress hormones that may affect cognitive development getting through to the baby."
The research comes after a study which suggested that liquorice consumption was also linked to shorter pregnancies.
The results of the study are published in the American Journal of Epidemiology.