Effect of Anethum graveolens L. (Dill)Consumption on Serum Lipids: A Systematic Review and Meta-analysis

Background: Anethum graveolens L. (dill) has been used as traditional medicinal plant for abdominal discomfort, colic, sleep disprders and for promoting digestion since ancient times. Recently, lipid-lowering effect of dill has been noticed. Aim of the study: We conducted a meta-analysis to evaluate the effect of dill supplementation on human serum lipid profile. Methods: A systematic search for English published randomized controlled trials (RCTs) was performed up to December 2019 covering PubMed, EMBASE, Scopus and Coherence library. Inclusion criteria were RCT study design, at least one of lipid profile components (triglyceride, total cholesterol, LDL-C and HDL-C) levels measured before dill use and also reported as result. The pooled weighted mean difference (MD) and its 95% confidence interval (CI) were calculated and pooled using a random-effects model. Results: Pooled data of six RCTs involving 171 intervention cases indicated that dill supplementation was associated with a significant reduction in mean serum total cholesterol (MD 95% CI=-3.71 (-5.71,-1.70); p < 0.001), low-density lipoprotein cholesterol (LDL-C) (MD 95% CI=-1.51 (-2.65,-0.47); p=0.005), triglycerides (MD 95% CI=-2.48 (-3.98,-0.98); p=0.001) and interestingly high-density lipoprotein cholesterol level (HDL-C) (MD 95% CI=-2.19 (-3.58,-0.81); p=0.002). Subgroup analysis showed that dill use was more effective in lowering triglyceride in both hyperlipidemic patients, MD 95% CI=-3.54 (-6.49,-0.60); p=0.02) and type 2 diabetes (MD 95% CI=-3.64 (-5.69,-1.58); p=0.001). Dill use reduced the LDL levels more effectively in patients with type 2 diabetes (MD 95% CI=-3.54 (-6.49,-0.60); p=0.03). Conclusion: Dill supplementation significantly improved LDL-C, TG and TC levels but not HDL-C. Further high quality controlled clinical trials on human is needed for more accurate and confirm conclusion.