The Roles of Garlic on the Lipid Parameters: A Systematic Review of the Literature

Abstract

Garlic has long been the focus of experimental and clinical attentions due to its promising lipid-lowering effects. Numerous animal studies as well as in vitro ones have demonstrated the hypolipidemic effects of garlic, while clinical trials are highly inconsistent. Based on some double-blind, randomized, placebo-controlled clinical trials which denied the hypolipidemic effects of garlic, some meta-analysis concluded that garlic did not possess beneficial effects for hyperlipidemia. However, we should not ignore the abundant supporting data in the literature. It should be noted that the doses of garlic used in clinical trials were usually far lower than those used in animal studies, which might cover its potential effects. The type of the garlic products may be another important factor responsible for the conflicting outcomes, as different garlic products are composed of different organosulfur compounds. In addition, the biological availability of garlic products is of importance, which was omitted in many studies. Moreover, some studies indicated that different people might have a different response to garlic, and thus garlic may be more beneficial for some specific groups. Collectively, it may be inappropriate to draw a conclusion that garlic does not benefit for hyperlipidemia. Future studies with larger samples are needed to further clarify the effects of garlic used at higher but non-toxic doses on specific groups.

Keywords:

• garlic
• hyperlipidemia
• lipid
• cardiovascular disease
• LDL oxidation

ACKNOWLEDGEMENT

This work was supported by the Scientific and Technological Cooperation Project of Shandong Province (2008GG2NS02012).