Anemia, defined as a hemoglobin (Hb) serum concentration of <11.0 g/dL at sea level, is usually caused by low intake and absorption of dietary iron. Anemia currently affects roughly 67.6% of the population in Africa, many of whom are concurrently exposed to malaria. In Tanzania, hibiscus (Hibiscus sabdariffa, Malvaceae) flower and calyx infusions or juices are among several natural products used for anemia. Hibiscus contains several minerals, including iron, and ascorbic acid, which is known to increase iron absorption. In vivo, an aqueous extract of hibiscus significantly increased hematocrit (Hct) and Hb levels. Clinical trials have evaluated its use in lowering cholesterol, reducing hypertension, and controlling type 2 diabetes; however, none have examined its effect on iron deficiency. Therefore, these authors conducted a randomized clinical trial to measure the effect of hibiscus extract on iron status in patients with anemia.
Hibiscus calyxes were collected from local farms in March 2014, with a voucher specimen deposited in the herbarium of the Botany Department, University of Dar es Salaam, Tanzania. An aqueous extract optimized for both ascorbic acid and iron extraction was prepared to contain 0.831 mg/g L-ascorbic acid and 0.078 mg/g iron. The extract was issued to patients in 10-day dose packs with instructions.
Of the 202 individuals screened, 130 who were eligible (aged 18-50 years, Hb between 8.0-12.9 g/dL for men and 8.0-11.9 g/dL for women [anemic], no use of vitamin or mineral supplements for 30 days before enrollment, no organ impairment, no chronic illness, no blood given or received in prior 6 months, not pregnant or nursing, residents of study area, no history of serious medical conditions, and no participation in any investigational trial for 90 days before the study) were randomly assigned into 4 groups with similar proportions of key characteristics (e.g., gender, age, and Hb levels) in each.
Patients in group D1 (n=35) drank 1 L of the product daily; those in D2 (n=34), 1500 mL; and those in D3(n=32), 2 L. Patients in D4 (control; n=29) took 200 mg ferrous sulphate yielding 65 mg ferrous iron daily. The primary endpoint was changed in iron status indicators (Hb level, serum ferritin [Fer], and Hct parameters [mean corpuscular hemoglobin (MCH), mean corpuscular volume (MCV), and red cell distribution width (RDW)]) between baseline and end of follow-up. Vital signs, laboratory tests, and questionnaires were used at baseline and at clinic visits every 10th day. Tests included complete blood count, renal and liver function tests, and hematology. Adverse events were assessed and classified as mild, medium, or severe. Compliance was monitored through home visits by village health workers in addition to clinic visits.
Patients, from 8 villages in Mkuranga District, Tanzania, had a mean age of 37 ± 11.8 years; 79 (60.8%) were women. About 20% had been ill in the 12 months before baseline, with urinary tract infections most common (41.7%). About 34% were using antibiotics at baseline; 32.7%, analgesics. “A significant proportion” of patients with no reported illness was taking medicine. There were no significant differences among groups in red blood cell characteristics, nutrition, or inflammatory markers at baseline (P>0.05 for all). After 4 weeks, 82 patients remained in the study—18 in group D1, 24 in D2, 21 in D3, and 19 in D4. A total of 37 were lost to follow-up for unknown reasons; others, for medical reasons or by moving away. Malaria (58 cases) did not cause any cited dropouts. Baseline data on malaria status are not provided.
In this study, the hibiscus treatment was not effective in treating anemia, but showed potential for improving hematological parameters. Fer levels rose significantly in D4 (control; P=0.0014) compared to baseline; in other groups, nonsignificantly (P>0.05). RDW fell, although nonsignificantly, in all groups compared to baseline, most noticeably in D3 (P=0.2754). There was a significant decrease in MCH in D1, D2, and D4 compared to baseline (P<0.05 for all); in D3, there was a nonsignificant decrease in MCH (P=0.0571). In D1 and D4, significant declines in Hb were seen compared to baseline (P=0.0123 and P=0.0219, respectively). [Note: In the article text, the value for D1 is given as P=0.123.]
The authors call for studies with larger populations. Findings differ from a study of hibiscus and pineapple (Ananas comosus, Bromeliaceae) juice, with an average increase in Hb after 9 days that exceeded conventional anemia treatment (+2 g/dL in 3 weeks). Additional studies are also needed to examine the complex comorbidities of anemia and malaria. A recent study in Tanzania found that “iron deficiency appears to protect against both malaria infection and mortality.”1,2
1Richards S. Iron deficiency protective against malaria. The Scientist website. Available at: http://www.the-scientist.com/?articles.view/articleNo/31974/title/Iron-Deficiency-Protective-Against-Malaria/. Published April 13, 2012. Accessed October 4, 2017.
2Gwamaka M, Kurtis JD, Sorensen BE, et al. Iron deficiency protects against severe Plasmodium falciparum malaria and death in young children. Clin Infect Dis. April 15, 2012;54(8):1137-1144.
Peter EL, Rumisha SF, Mashoto KO, Minzi OMS, Mfinanga S. Efficacy of standardized extract of Hibiscus sabdariffa L. (Malvaceae) in improving the iron status of adults in malaria endemic area: a randomized controlled trial. J Ethnopharmacol. September 14, 2017;209:288-293.