Warning sounded on herbal tea

Even the most innocuous-sounding beverages- such as herbal tea- can pack an unwanted and dangerous punch, a case study from Canada demonstrates.

Writing in the Canadian Medical Association Journal, Jean-Pierre Falet, Arielle Elkrief and Laurence Green, all of McGill University in Montreal, detail the travails of an elderly man who presented himself at a hospital because he was having, the doctors explain, “a hypertensive emergency”.

The man, 84, had been experiencing extremely elevated blood pressure for a week before seeking help – by which point his symptoms had extended to include headache, painful sensitivity to light, chest pain and fatigue. He was admitted immediately.

The patient had a history of high blood pressure and diabetes, but extensive tests taken four months previously showed that everything was well-managed and under control. The cause of the sudden, potentially lethal, spike was a mystery.

Initial blood tests revealed an elevated level of bicarbonate and very low amounts of potassium. The doctors administered a range of medications, and brought the most severe symptoms under control within 24 hours. Others resolved over the following few days.

Interviews with the man uncovered the cause of his distress: liquorice juice. It turned out that during the previous two weeks he had been making a type of cordial containing liquorice juice, known as erk sous, and consuming one or two glasses of it each day.

Erk sous is a traditional Egyptian drink, made by combining liquorice root and baking soda in a cloth, then slowly adding water. Making any quantity takes several hours. It is particularly popular during the month of Ramadan.

Unfortunately, the authors explain, its main ingredient “is well known to exacerbate high blood pressure in patients with hypertension”.

“Treatment of liquorice-induced hypertensive crisis involves supportive measures aimed at reducing blood pressure until the effect of the liquorice wears off,” they add.

The link between liquorice and high blood pressure is well established, with many countries requiring products to carry warning texts. However, there are significant differences regarding calculations for safe maximum dose.

The 84-year-old man did not consider that his consumption was dangerous.

Nevertheless, Falet, Elkrief and Green credit his recovery, at least in part, to the fact that he did not drink any erk sous during his stay in hospital. Follow-up tests revealed that the man’s blood pressure levels had returned to normal. He has not consumed liquorice since.

Related reading: Gut bacteria could be the link between salt and high blood pressure

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