Effect of sumac (Rhus Coriaria) on blood lipids: A systematic review and meta-analysis

Cardiovascular diseases (CVD) are the prominent cause of mortality worldwide. Hypercholesterolemia is a chief risk factor for the progress of atherosclerotic vascular disease. Complementary and alternative medicine (CAM) such as herbal interventions has received much attention in literature. Rhus Coriaria (RC) with the general name Sumac is a medicinal spice, especially in Middle Eastern countries which is well known as an anti-lipid spice. This study aimed to summarize the existing findings regarding the effect of RC on the lipid profile. In this review randomized controlled trials (RCTs) assessing the effect of RC on blood lipids were included. Electronic searches using the MeSH terms were conducted in the following databases: Medline, Embase, Scopus, Web of Science and The Cochrane Library. The effect of RC on serum lipid concentration were measured as standardized mean difference (SMD) and 95% confidence intervals (CI) by the random-effects model. The initial search extracted 119 potentially relevant articles. After studying these publications, 4 were potentially eligible and retrieved in full text (four RCTs). Based on the results of the systematic review, RC has positive effects on different indices of the lipid profile including increasing Apo A-I and HDL; decreasing Apo B, Apo B/ Apo A1 ratio, total cholesterol, LDL and triglyceride. However the meta-analysis conducted on three studies on total cholesterol, HDL, LDL and triglyceride individually did not show any significant difference between intervention and control groups. No definite conclusion could be made on the effect of RC on serum blood lipids due to lack of sufficient clinical trials and variable inconsistency. Future trials with desirable designs that would eliminate the limitations in the current evidence are needed before conclusive claims can be made about the effect of RC on the lipid profile.