Researchers from Shandong University report that, compared with placebo groups, garlic consumption is associated with a 5.4% reduction in cholesterol levels and a 6.5% reduction in triglyceride levels.
“Compared with the conventional methods for lipid-lowering, the estimated reduction of garlic obtained from this meta-analysis is unimpressive,” wrote the researchers in the Journal of the Science of Food and Agriculture.
“Although the size of the effect is modest, garlic therapy should benefit patients with risk of cardiovascular diseases, as garlic may also reduce blood pressure, decrease plasma viscosity, etc.”
Garlic (Allium sativum) has been suggested to exhibit several health benefits, including inhibiting enzymes involved in lipid synthesis, decreasing platelet aggregation, preventing lipid peroxidation, and increasing antioxidant status.
The Chinese scientists identified 26 studies that compared powder with garlic in different forms, incuding garlic powder (doses ranging from 600 to 900 mg per day), garlic oil (8.2 to 15 mg per day), or aged garlic extract (1.8 to 7.2 mg per day).
“The 0.28 mmol/L reduction of serum total cholesterol and 0.13 mmol/L reduction of serum triglycerides attributable to garlic were modest in size, and approximate to a 5.4% reduction in a patient with baseline total cholesterol level of 5 mmol/L and to a 6.5% reduction in a patient with baseline triglycerides level of 2 mmol/L,” wrote the researchers.
The most pronounced cholesterol-lowering effects were observed for garlic powder, they added, while garlic oil produced the best triglyceride-lowering effects.
Commenting on the potential mechanism, the researchers said that this may be linked to inhibition of certain enzymes that play a role in the absorption of dietary fat and the production of cholesterol.
“Future studies should be conducted to illustrate the active compounds in garlic responsible for the hypolipidemic effects, to explore the influence of gender on garlic’s effects, and to compare the efficiency between garlic and regular lipid-lowering drugs such as statins and fibrates,” concluded the researchers.
Source: Journal of the Science of Food and Agriculture
Published online ahead of print, doi: 10.1002/jsfa.5557
“A meta-analysis of randomized, double-blind, placebo-controlled trials for the effects of garlic on serum lipid profiles”
Authors: T. Zeng, F-F. Guo, C-L. Zhang, F-Y. Song, X-L. Zhao, K-Q. Xie