Is blood pressure commonly raised by moderate consumption of liquorice?

It is well known that excessive liquorice intake can induce sodium and fluid retention, hypokalaemia, hypertension and inhibition of the renin-angiotensin system. We tested whether regular moderate liquorice consumption (50 g and 100 g daily) raises blood pressure (BP) in a normotensive population. Ingestion of 100 g of liquorice daily (n = 30) caused a significant rise in systolic blood pressure (SBP) by a mean of 6.5 mm Hg (P < 0.001) and a fall in plasma potassium by 0.24 mmol/l (P < 0.001); the highest rise in SBP observed was 19 mm Hg. In a subgroup of 13 women the consumption of 50 g of liquorice daily also caused a significant rise in SBP of 5.6 mm Hg (P < 0.001) and DBP of 3.4 mm Hg (P = 0.002). A significant change in the cortisol/cortisone ratio in urine was observed during 100 g liquorice consumption indicating inhibition of 11 beta-hydroxysteroid dehydrogenase in kidneys. The results indicate that liquorice-induced hypertension might be more common than has been appreciated and it important for medical doctors to be on the alert for this effect in both the prevention and treatment of hypertension.