Hibiscus, an easily accessible and popular herb, has been shown in a recent study to be very good for reducing blood pressure in hypertensive people.
Hibiscus flowers have been used historically to treat high blood pressure, liver disease, and fever. It now turns out that in addition to ascorbic and citric acid (vitamin C), they contain a number of important vasoactive alkaloids, anthocyanins and quercetin, which may lay behind this blood-pressure benefit.
The study referred to was designed to compare the blood pressure lowering effects of “Sour tea,” made from Hibiscus sabdariffa, with ordinary black tea (Camellia sinensis) in type II diabetics with mild high blood pressure. Sixty such patients, none of whom were taking antihypertensive or lipid-lowering medications, were randomly assigned to drink one cup of Sour tea or black tea twice daily for one month. Each infusion was to be made with one tea sachet weighing 2 gm, placed in a teapot with 240 ml boiling water, and steeped for 20–30 minutes. They were permitted to add one cube of sugar.
The average systolic blood pressure (SBP) in the Hibiscus group decreased from 134.4 ± 11.8 mmHg at baseline to 112.7 ± 5.7 mmHg after 1 month, a robust 16% reduction. Among the black tea drinkers, the average SBP actually increased over the month, from 118.6 ± 14.9 mmHg at baseline to 127.3 ± 8.7 mmHg, a 7.3% rise. There were no statistically significant changes in mean diastolic blood pressure in either group.
Overall, the interventions were deemed “effective” (i.e., producing significant decreases in systolic pressure) in 48% of the Sour tea patients but only 15% of the black tea patients. The study was written up in the Journal of Human Hypertension, 2009; 23: 48–54). The findings are highly supportive of Hibiscus as a remedy for mild blood pressure elevations, in which the risks and costs of drug therapy may not be outweighed by their expected benefits, or in cases where a patient does not want to begin pharmaceutical treatment.