3.2. | Characteristics of included studies
The characteristics of included studies were abstracted in Table 2 . Selected eligible trials enrolled 549 participants with age ranging from 30.7 to 59.4 years old and were conducted on both genders. All trials were conducted in Italy, which involved 549 patients with dyslipidemic patients and overweight [5] euglycemic with statins at high doses and overweight [7] dyslipidemic and euglycemic with statins at high doses and overweight [6], type 2 diabetes mellitus [9], type 1 diabetic [42]. Publication dates ranged from 2013 and 2016. All of the included studies had parallel designs. The participants of all studies were of both genders. All studies used berberis aristata/silybum marianum for intervention. The cases received a daily dose of berberis aristata from 1176 mg/day plus silybum marianum from 210 mg/day except Guarino study with dose of BBR-aristata from 1000 mg/day plus silybum marianum from 300 mg/day [9] and the control group received a placebo. The intervention duration was from 12 to 24 weeks.
3.3. | Effect of BBR and silymarin on liver enzymes The effect of BBR-silymarin on serum ALT and AST was reported in all studies. The combined supplementation was found to not significantly reduce in ALT (WMD: −0.39 mg/dl; 95% CI: −1.67 to 0.89, P=0.55) (I2=39.3%, P<0.001) (Figure 2) and AST (WMD: −0.44 mg/dl; 95% CI: −2.02 to 1.14, P=0.58) (I2=35.9%, P<0.001) (Figure 3).