Effects of Dill Extract on Blood Lipid Levels (TC, TG, LDL and HDL): A Systematic Review and Meta-Analysis

Background and Objective: In recent years,there has been a growing trend  towards the use of herbal medicine in the treatment and prevention of diseases. Blood lipid-lowering drugs have many side effects. On the other hand, various studies have reported the effect of dill (Anethum graveolens) on the reduction of blood lipids in different ways. This study aimed to evaluate the effect of dill on reducing the blood lipid levels. Materials and Methods: In this systematic review, 12 papers that evaluated the effect of dill on blood lipid levels up to the end of 2018 were studied using valid key words such as Lipid Profile, Dill (Anethum graveolens), and Hyperlipidemia in Pubmed, Medlib, Scopus, Sciencedirect, Embase, Google Scholar, Magiran, IranMedex, and SID. The results of the studies were combined using the random effects method of meta-analysis. The heterogeneity of studies was investigated using Q statistics and I2 Index. Results: In 12 studies, the weighted mean differences (WMDs) of cholesterol reduction (TC) before and after intervention were estimated to be WMD = -19.22 mg / dl (95% CI: -30.68, -7.77), triglyceride, WMD = -25.47 mg / dl (95% CI: -49.28, -1.66) and low density lipoprotein (LDL), WMD = -14.01 mg / dl (95% CI: -22.14, -5.89) which were statistically significant (p = 0.001). Meta-analysis after intervention in the case and placebo groups were (SMD=-2.71, 95% CI:-3.28,-1.06), for TC (SMD=-1.77, 95%CI:-2.71,-0.82) for TG and (SMD=-2.64, 95%CI:-3.88,-1.41)for LDL which indicated statistically significant reduction. Conclusion: Dill reduces cholesterol, triglyceride and low-density lipoprotein, but does not have a significant effect on high-density lipoprotein levels.