New Study Supports Cholesterol-Lowering Effects of Garlic

A recent study supports previous findings that suggest garlic may reduce cholesterol.

Garlic is a culinary herb that is widely used for the treatment and prevention of cardiovascular disease and cancer. Numerous studies have examined the effects of garlic on cholesterol. Long-term effects on lipids or cardiovascular morbidity and mortality remain unknown. Other preparations (such as enteric-coated or raw garlic) have not been well studied.

Multiple previous studies in humans have reported that garlic may slightly reduce total blood cholesterol and low-density lipoproteins (LDL, or “bad cholesterol”) over short periods of time (4-12 weeks). Effects on high-density lipoproteins (HDL, or “good cholesterol”) are unclear. This remains an area of controversy.

In a new study, researchers analyzed data from 26 well-designed clinical trials to evaluate the effects of garlic on cholesterol levels. Overall, the researchers found that garlic was more effective than placebo in reducing cholesterol. The authors noted that when compared to control groups, garlic significantly reduced both total cholesterol and triglyceride levels. The benefits of garlic were more pronounced when used as a long-term treatment, and in individuals who started treatment with higher total cholesterol levels. Garlic did not appear to have any significant effects on other lipid levels, including HDL and LDL.

The authors concluded that garlic may reduce total cholesterol and triglyceride levels and may be considered for individuals at risk for heart disease.

In addition to garlic, several other integrative therapies, including red yeast rice and fish oil, may reduce cholesterol levels.

Since the 1970s, human studies have reported that red yeast lowers blood levels of total cholesterol, LDL and triglycerides. Products containing red yeast rice extract can still be purchased, mostly over the Internet. However, these products may not be standardized and effects are not predictable. For lowering cholesterol, there is better evidence for using prescription drugs such as lovastatin.

There is strong scientific evidence from human trials that omega-3 fatty acids from fish or fish oil supplements significantly reduce blood triglyceride levels. Benefits appear to be dose-dependent. Fish oil supplements also appear to cause small improvements in HDL cholesterol. However, increases in (worsening of) LDL cholesterol levels have also been observed. It is not clear if alpha-linolenic acid significantly affects triglyceride levels, and there is conflicting evidence in this area. The American Heart Association has published recommendations for docosahexaenoic acid (DHA) plus eicosapentaenoic acid (EPA). Because of the risk of bleeding from omega-3 fatty acids, a qualified healthcare provider should be consulted prior to starting treatment with supplements.

For more information about integrative therapies for high cholesterol, please visit Natural Standard’s Comparative Effectiveness Database.

For more information about garlic, please visit Natural Standard’s Foods, Herbs & Supplements Database.

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Zeng T, Guo FF, Zhang CL, et al. A meta-analysis of randomized, double-blind, placebo-controlled trials for the effects of garlic on serum lipid profiles. J Sci Food Agric. 2012 Jan 10.