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What effect does garlic have on cholesterol?

Stacy Wiegman, PharmD
Pharmacy Specialist

Although garlic does seem to have some cholesterol-lowering effect, research is inadequate to explain exactly how it accomplishes this goal. Garlic does not reduce cholesterol to as high a degree as a combined treatment of a low-fat diet and statins, cholesterol-lowering prescription drugs. This more conventional therapy is two to 10 times more effective than garlic. Garlic may present an attractive alternative or supplement to conventional treatment because of its low incidence of side effects.

Numerous studies have shown that garlic has a beneficial influence on cholesterol.

In a 12-week, randomized, controlled trial in men with moderately high cholesterol levels, 900 milligrams of garlic per day reduced total cholesterol levels by 12 percent, significantly improved their ratio of high-density cholesterol (HDL, the good cholesterol) to total cholesterol levels, and reduced blood pressure.

A double-blind, cross-over study found significant decreases in cholesterol levels and blood pressure in men with moderately elevated cholesterol levels who were taking 7.2 grams of aged garlic extract per day over six months.

In a large-scale, randomized, controlled trial in patients with elevated cholesterol or blood fats, taking 800 milligrams of standardized garlic powder per day resulted, on average, in a 12 percent drop in cholesterol and a 17 percent drop in levels of certain blood fats known as triglycerides.

Another study found that 600 milligrams per day of garlic powder protected low-density cholesterol (LDL, the bad cholesterol) against oxidation; oxidized LDL is damaging to the arterial walls.

In people with a tendency toward excessive blood clotting, taking 800 mg of powdered garlic in a form that passes the stomach intact (enteric-coated tablets) reduced unwanted clotting.

A quantitative review of 28 clinical studies on the effect of garlic preparations found evidence to suggest that garlic reduces total serum cholesterol. One-half to one clove of garlic per day or the equivalent supplement lowered cholesterol levels by a conservative average of 9 percent.

A review of a similar set of studies concluded that a daily dose of 600 to 900 milligrams of garlic powder would, on average, reduce serum cholesterol levels by about 10 percent and triglyceride levels by about 14 percent.

A quantitative summary study (meta-analysis) of 16 previous studies found an average 12 percent reduction of serum cholesterol among participants who all took the same dried garlic powder preparation. Although another study does not support this conclusion, the totality of evidence appears to favor a beneficial effect of garlic preparations on cholesterol levels.

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Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs.