Liquorice is a popular sweetener found in many soft drinks, food products, snacks and herbal medicines. It has a rich history as an old remedy that was used by ancient Egyptians and Assyrians made into a sweet liquid drink. There is a traditional belief that liquorice is a healthy natural substance without side effects driving its liberal consumption that can occasionally be hazardous.
If you have followed this blog for a while you might remember that we have covered the good and the bad of liquorice before. Now we also cover the ugly.
Liquorice is extracted from the roots of the plant Glycyrrhiza glabra, a member of the pea family. Most liquorice roots are wild-harvested with collection occurring mainly in Central Asia (Iran, Turkmenistan, Afghanistan and China). Liquorice extract is produced by boiling liquorice root and subsequently evaporating most of the water. Large-scale extraction is limited to China and Iran. Glycyrrhizin, that is 50 times sweeter than sugar, is the main active component in liquorice extract and apart from sweetness also provides the desirable liquorice flavour. Moderate consumption of liquorice is associated with several health benefits in that it can quickly soothe sore throats and coughs among some other positive effects.
Unfortunately, it has long been known that excessive and prolonged consumption of glycyrrhizin intensifies the effects of the stress hormone cortisol by inhibiting the enzyme that inactivates cortisol and may interfere with the sodium and potassium balance. High levels may increase hypertension. Thus, it has been suggested to limit consumption of glycyrrhizin to 100 mg per day, the approximate amount found in 60–70 g of liquorice candy. However, it is not that easy to estimate intake of glycyrrhizin as various forms of candies, beverages, supplements and extracts contain very different amounts of the active components.
Recently new warnings were issued by the Finnish National Institute for Health and Welfare to women to avoid consuming large amounts of liquorice during pregnancy as it can have long-term harmful effects on the development of the foetus. A new Finnish study had shown that youths previously exposed to large amounts of liquorice in the womb performed less well than others in cognitive reasoning tests carried out by a psychologist. The difference was equivalent to approximately seven IQ points.
Those exposed to liquorice also performed less well in tasks measuring memory capacity, and according to parental estimates, they had more ADHD-type problems than others. With girls, puberty had started earlier and advanced further.
In this study a large amount was defined as daily consumption of more than 70 mg and compared to consumption of less than 35 mg glycyrrhizin.
Although cortisol is essential to the development of a foetus, large increases initiated by excessive consumption of liquorice can be detrimental.