Hibiscus sabdariffa (roselle, red sorrel, Jamaica sorrel) is an annual plant that can grow to about two meters in height and is widely grown and used as tea in (sub)tropical areas. The flowers are not only tasty but also appear to have a blood pressure lowering effect. People in countries such as Mexico, the Caribbean, Iran, Egypt, Sudan, Nigeria, Thailand, India and China eat the red fleshy calyxes as a vegetable (raw or cooked), process it in sauce or jam (the calyx is rich in citric acid and pectin ) or use the dried calyxes to make herbal tea, wine or soft drinks (with sugar and ginger). Red dye (anthocyanidins or E163) is also extracted from the calyxes for the food industry.
Various parts of the plant (flowers, leaves, roots) have traditionally had medicinal uses. Hibiscus tea from the flowers is used in folk medicine for high blood pressure, high cholesterol levels, arteriosclerosis, as a diuretic, for fever, liver disease, cancer, wounds and abscesses and as a tonic for the stomach and intestines (it promotes peristalsis and bile release, has a mild laxative effect, but can also help with diarrhea).
Hibiscus tea against high blood pressure
A regular herbal tea that combats high blood pressure as well as the regular medicine captopril; this is remarkable. The Mexican research that demonstrates this and was published in the scientific journal Phytomedicine confirms results from previous clinical research and animal studies and shows that the traditional use of hibiscus tea for (essential) hypertension is far from nonsense. The result of the research was Noteworthy: hibiscus tea reduced the average systolic blood pressure from 139 to 124 mm Hg and the average diastolic blood pressure from 91 to 80 mm Hg, making it as effective as the standard therapy captopril. There was no significant difference between the results of both treatments. Diastolic blood pressure decreased by an average of 12.3% when using hibiscus tea. Hibiscus tea increased the excretion of sodium in the urine, while the excretion of chloride and potassium and the acidity of the urine remained unchanged.
Also an Iranian study with 54 patients with essential hypertension (systolic blood pressure above 160 mm Hg and/or diastolic blood pressure above 100 mm Hg) lasted only 12 days and the average systolic pressure fell from 158 to 140 mm Hg (decrease of 11.2%). , the average negative pressure from 101 to 90 mm Hg (decrease of 10.7%).6 In this study, participants took two teaspoons of hibiscus flower (or regular tea) and steeped them in boiled water. Blood pressure was significantly reduced by drinking hibiscus tea compared to the control tea. Side effects were not observed. After stopping drinking the tea, systolic blood pressure increased again after three days by an average of 5.6% and diastolic blood pressure by 6.2%.
Possible influence on fat metabolism (overweight), liver protective…
But there is more: in vitro and animal studies show that red hibiscus tea improves fat metabolism, may counteract arteriosclerosis and obesity, protects the liver and has a powerful antioxidant activity and anticarcinogenic effect. The (pro)anthocyanidins and other polyphenols in hibiscus are mainly responsible for these effects. Hibiscus tea may be of great benefit to people with metabolic syndrome. This is good news, also because hibiscus tea has no side effects, has extremely low toxicity, is easily available and is also cheap.