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Dyslipidemia and Sour tea (Hibiscus sabdariffa)
Hibiscus sabdariffa, or sour tea, is a genus of the Malvaceae family. In Iran, it is typically known as sour tea, in English-speaking countries is it called Red Sorrel.
Originally from Angola, it is now cultivated throughout tropical regions, especially from Sudan, Egypt, Thailand, Mexico and China.
The calyces of H. sabdariffa are prolific in many modern commercial blends of cold and hot drinks due to it's pleasing taste. Approximately 15%-30% of the plant is made up of plant acids, including citric, malic, tartaric acids and allo-hydroxycitric acid lactone—i.e. hibiscus acid which is specific to this plant. Other chemical constituents are many, including alkaloids, L-ascorbic acid, anthocyanin, Beta-carotene, Beta-sitosterol, citric acid, polysaccharides arabins and arabinogalactans, quercetin, gossypetin and small amounts of galactose, arabinose, glucose, xylose, mannose and rhamnose. Historically, folk medicine has used H. sabdariffa for the treatment of high blood pressure, liver diseases and fevers. In large amounts, hibiscus tea acts as a mild laxative. In African folk medicine it has been used for its spasmolytic, antibacterial, cholagogic, diuretic and anthelmintic properties.
Scientific interest in Hibiscus has grown in the last several years with a small burst of published research studies, especially in the area of dyslipidemia and hypertension. Over twenty years ago, water extracts of hibiscus flowers were reported to have a relaxation effect on the uterus and to lower the blood pressure.[i] Studies in both animal[ii], [iii], [iv], [v] and human models have demonstrated that extracts or infusions affects atherosclerosis mechanisms, blood sugar, lipids and blood pressure [vi], [vii]
In 2007, a clinical trial showed that Hibiscus reduced cholesterol by 8.3% to 14.4% after just one month.[viii] A total of 42 subjects were randomized to 3 groups for the study, conducted in Taiwan. The hibiscus extract capsules contained 500 mg of dried herb by macerating 150 g of hibiscus flowers in 6 L of hot water for 2 hours and then drying and filtering the extract. Group 1 received 1 capsule of extract 3 times daily (1,500 mg/day), group 2 received 2 capsules 3 times daily (3,000 mg/day), and group 3 received 3 capsules 3 times daily (4,500 mg/day)
Overall, subjects in group 2 responded best to the hibiscus extract treatment. Groups 1 and 2, but not group 3, experienced a significant reduction in serum cholesterol levels at week 4, compared with baseline levels. In addition, group 2 experienced a significant reduction in serum cholesterol levels at week 2, compared with baseline levels. At week 2, there was a 42.9% responder rate in groups 1 and 3 and a 64.3% responder rate in group 2. By week 4, group 2 had a cholesterol reduction response from 71.4% of the subjects. In group 1, 50.0% were responders, and 42.9% subjects in group 3 were responders at week 4. It appeared that group 2, taking 1,000 mg taken three times daily was the optimum dose in achieving cholesterol reduction effects. While this study is small with a small number of subjects in each of the study groups, as well as a short duration of 4 weeks, there was indeed a clear effect with significant reductions in serum cholesterol seen as early as week 2, in the 1,000 mg tid group. Oddly enough, the responders in group 3, receiving the highest dose (4,500 mg/day), had the smallest response to the hibiscus extract with an average of 8.3% reduction at week 4. Group 1 received a 14.4% reduction at week 4.
In 2009, 60 Type 2 diabetics, mostly women, were given either Hibiscus tea from Saudi Arabia or black tea, 1 cup twice per day. [ix] Seven individuals withdrew from the study and after one month, mean HDL cholesterol increased significantly (48.2 mg/dL to 56.1 mg/dL) whereas apolipoprotein A1 and lipoprotein (a) were not significant. There was also a significant decrease in the mean of total cholesterol (236.2 to 218.6), LDL cholesterol (137.5 to 128.5), triglycerides (246.1 to 209.2) and Apo-B100 (80.0 to 77.3) in the Hibiscus group. Only HDLc showed a significant change in the black tea group (46.2 to 52.01). Something as simple as Hibiscus tea in a diabetic, is a welcomed intervention. Achieving a 7.6% decrease in total cholesterol, an 8.0% decrease in LDLc, a 14.9% decrease in triglycerides, a 3.4% decrease in Apo-B100, a 4.2% increase in Apo-A1 and a 16.7% increase in HDLc is no small accomplishment with merely two cups of tea per day.
Hibiscus extract was also studied in 222 patients some with and some without metabolic syndrome (MS).[x] A total daily dose of 100 mg Hibiscus sabdariffa extract powder (HSEP) was given for one month to men and women, 150 without MS and 72 with MS. They were randomly assigned to a preventive diet, HSEP treatment or diet combined with HSEP treatment. The MS patients receiving HSEP had significantly reduced glucose, total cholesterol and LDL-c and increased HDL-c. A triglyceride lowering effect was seen in all groups but was only significant in the control group that was treated with diet. The triglyceride/HDL-c ratio was also significantly reduced with HSEP in the control and MS groups, indicating an improvement in insulin resistance. It has been hypothesized that the anthocyanins regulate adipocyte function, which has definite and important implications for both preventing and treating metabolic syndrome. Due to both its hypolipidemic and hypotensive effects, Hibiscus extract would be an excellent option for individuals with metabolic syndrome.
A double-blind, placebo control, randomized trial in 69 subjects with elevated LDL and ho history of coronary heart disease did not appear to show a blood lipid lowering effect from Hibiscus extract. [xi] The treatment group received 1,000mg/day Hibiscus extract for 90 days in addition to dietary and physical activity. Body weight, serum LDL cholesterol and triglyceride levels decreased in both the extract and placebo groups, with no significant differences between the two. It is likely that the positive effects were due to dietary and exercise activity. One wonders why the results of this study were negative and the 3 previous studies above, showed positive results. The doses and product used in all four studies were different. One a tea, another used dried powdered flowers, another used a standardized extract powder of the sepals of the flowers, and this one, an ethyl alcohol/water extract, dried and then powder of the leaves. It is reasonable to consider that these different preparations would yield different results. With more consistent product selection and dosages used in larger randomized trials, we would hope that this would clarify the best intervention to use.
Practitioners should be encouraged about the modern research in Hibiscus, although more robust high quality randomized controlled trials would be welcomed and a worthy addition in our ability to help stem the tide of the impact of cardiovascular disease on the lives of men and women. For the ever growing number of patients who refuse and even loathe the aggressive prescribing of statins, Hibiscus can be an important tool especially in the context of comprehensive lifestyle changes and other nutraceutical/botanical interventions to reduce life threatening or debilitating cardiovascular disease
[i] Franz M, Franz G. Hibiscus sabdariffa. Phytotherapy 1988;9(2):63
[ii] Adegunloye B, Omoniyi J, Owolabi O, et al. Mechanisms of the blood pressure lowering effect of the calyx extract of Hibiscus sabdariffa in rats. Afr J Med Med Sci 1996; 25:235-238.
[iii] Ali M, Salih W, Mohamed A, Homeida A. Investigation of the antispasmodic potential of Hibiscus sabdariffa calyces. J Ethnopharmacol 1991;31:249-257.
[iv] Odigie I, Ettarh R, Adigun S. Chronic administration of aqueous extract of Hibiscus sabdariffa attenuates hypertension and reverses cardiac hypertrophy in 2K-1C hypertensive rats. J Ethnopharmacol 2003;86:181-185.
[v] Onyenekwe P, Ajani E, Ameh D, Gamaniel K. Antihypertensive effect of roselle calyx infusion in spontaneously hypertensive rats and a comparison of its toxicity with that in Wistar rats. Cell Biochem Funct 1999;17:199-206.
[vi] Chen C, Chou F, Ho W, et al. Inhibitory effects of Hibiscus sabdariffa L extact on low-density lipoprotein oxidation and anti-hyperlipidemia in fructose-fed and cholesterol-fed rats. J Sci food and agr 2004;84:1989-1996.
[vii] Herra-Arellano A, Flores-Romero S, Chavez-Soto M, Tortoriello J. Effectiveness and tolerability of a standardized extract from Hibiscus sabdariffa in patients with mild to moderate hypertension: a controlled and randomized clinical trial. Phytomedicine 2004;11:375-382.
[viii] Lin T, Lin H, Chen C, et al. Hibiscus sabdariffa extract reduces serum cholesterol in men and women. Nutr Res 2007;27:140-145.
[ix] Mozaffari-Khosravi H, Jalali-Khanabadi B, Afkhami-Ardehani M, Fatehi F. Effects of sour tea (Hibiscus sabdariffa) on lipid profile and lipoproteins in patients with Type II diabetes. J Altern and Comp Med 2009;15(8):899-903.
[x] Gurrola-Diaz C, Garcia-Lopez P, Sanchez-Enriquez S, et al. Effects of Hibiscus sabdariffa extract powder and preventive treatment (diet) on the lipid profiles of patients with metabolic syndrome (MeSy). Phytomedicine 2010;17:500-505.
[xi] Kuriyan R, Kumar D, Rajendran R, Kurpad A. An evaluation of the hypolipidemic effect of an extract of Hibiscus sabdariffa leaves in hyperlipdemic Indians: a double blind, placebo controlled trial. BMC Compl and Alt Med 2010;10:27
