Garlic reduces TC to a modest extent , an effect driven mostly by the modest reductions in TAG , without appreciable LDL lowering or HDL elevation .
Higher baseline line TC levels and the use of dietary modification may alter the effect of garlic on these parameters .
In order to determine the impact of  garlic on total cholesterol ( TC ) , TAG levels , as well as LDL and HDL  , and establish if any variables have an impact on the magnitude of this effect , a meta- analysis was conducted .
Effect of raw garlic vs commercial garlic supplements on plasma lipid concentrations in adults with moderate hypercholesterolemia: a randomized clinical trial.
BACKGROUND Garlic is widely promoted as a cholesterol-lowering agent , but efficacy studies have produced conflicting results . Garlic supplements differ in bioavailability of key phytochemicals . We evaluated the effect of raw garlic and 2 commonly used garlic supplements on cholesterol concentrations in adults with moderate hypercholesterolemia . METHODS In this parallel- design trial , 192 adults with low-density lipoprotein cholesterol ( LDL-C ) concentrations of 130 to 190 mg/dL ( 3.36 - 4.91 mmol/L ) were r and omly assigned to 1 of the following 4 treatment arms : raw garlic , powdered garlic supplement , aged garlic extract supplement , or placebo . Garlic product doses equivalent to an average-sized garlic clove were consumed 6 d/wk for 6 months . The primary study outcome was LDL-C concentration . Fasting plasma lipid concentrations were assessed monthly . Extensive chemical characterization of study material s was conducted throughout the trial . RESULTS Retention was 87 % to 90 % in all 4 treatment arms , and chemical stability of study material s was high throughout the trial . There were no statistically significant effects of the 3 forms of garlic on LDL-C concentrations . The 6-month mean ( SD ) changes in LDL-C concentrations were + 0.4 ( 19.3 ) mg/dL ( + 0.01 [ 0.50 ] mmol/L ) , + 3.2 ( 17.2 ) mg/dL ( + 0.08 [ 0.44 ] mmol/L ) , + 0.2 ( 17.8 ) mg/dL ( + 0.005 [ 0.46 ] mmol/L ) , and -3.9 ( 16.5 ) mg/dL ( -0.10 [ 0.43 ] mmol/L ) for raw garlic , powdered supplement , aged extract supplement , and placebo , respectively . There were no statistically significant effects on high-density lipoprotein cholesterol , triglyceride levels , or total cholesterol-high-density lipoprotein cholesterol ratio . CONCLUSIONS None of the forms of garlic used in this study , including raw garlic , when given at an approximate dose of a 4-g clove per day , 6 d/wk for 6 months , had statistically or clinical ly significant effects on LDL-C or other plasma lipid concentrations in adults with moderate hypercholesterolemia
Garlic reduces TC to a modest extent , an effect driven mostly by the modest reductions in TAG , without appreciable LDL lowering or HDL elevation .
Higher baseline line TC levels and the use of dietary modification may alter the effect of garlic on these parameters .
In order to determine the impact of  garlic on total cholesterol ( TC ) , TAG levels , as well as LDL and HDL  , and establish if any variables have an impact on the magnitude of this effect , a meta- analysis was conducted .