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 .
A randomized trial of the effects of garlic oil upon coronary heart disease risk factors in trained male runners
Most trials of bulb garlic and garlic powder tablets indicate reduced  coronary heart disease ( CHD ) risk in elevated-risk subjects . Most persons taking garlic supplements lack overt risk of CHD . However , no trials have tested steam-distilled garlic oil ( GO ) capsules with healthy subjects . The objectives of the present r and omized , double-blind , placebo-controlled study were to determine whether GO capsules reduce CHD risk in trained male runners . Twenty-seven volunteers ( mean age , 28.8 years ) completed the study . Each took 12.3 mg/day GO ( or placebo ) capsules for 16 weeks . Main outcome measures were 95 % confidence intervals ( CIs ) between GO and placebo groups for differences in changes of blood pressure ( BP ) , plasma lipids , total antioxidant status ( TAS ) , low-density lipoprotein ( LDL ) composition and blood clotting factors . Principal results as mean differences ( 95 % CI ) between GO and placebo are : pulse , 2.9 beats/min ( −0.8 to 6.7 ) , P= 0.12 ; systolic BP , −4.5 mmHg ( −10.8 to 1.9 ) , P= 0.16 ; plasma total cholesterol , 0.01 mmol/l ( −0.34 to 0.37 ) , P= 0.95 ; plasma triglycerides , −0.20 mmol/l ( −0.43 to 0.03 ) , P= 0.09 ; plasma TAS , 45 μmol Trolox equivalent/l ( −35 to 124 ) , P= 0.26 ; LDL density , 0.0019 g/ml ( −0.0005 to 0.0043 ) , P= 0.12 ; LDL triglycerides/protein , −0.078 mg/mg ( −0.149 to −0.007 ) , P= 0.03 ; LDL cholesterol/protein , −0.24 mg/mg ( −0.69 to 0.22 ) , P= 0.3 ; LDL TAS/triglycerides , 29 nmol/mg ( 11 , 68 ) , P= 0.15 ; prothrombin time , 0.99 s ( −0.36 to 2.35 ) , P= 0.14 ; partial thromboplastin time , 3.0 s ( −1.0 to 7.1 ) , P= 0.13 . Results were null statistically . Trends with GO were mostly towards lower CHD risk , and a larger study ( ~150 subjects ) is required to test their validity
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 .