Though it’s widely touted as a cholesterol buster, garlic has no effect on any plasma lipid, according to the surprising results of a major, NIH-funded study.
A research team at Stanford University’s School of Medicine recruited 192 volunteers ages 30-65 with moderately high LDL levels (130-190 mg/dL). The subjects were randomized to four groups for six months: raw garlic, powdered garlic supplement, aged garlic extract supplement, or placebo. All the garlic-product doses were equivalent to one medium-sized garlic clove, and each was consumed six days a week. To make the raw garlic palatable, it was crushed in a blender and used as a seasoning in sandwiches prepared under the researchers’ supervision. “Placebo” sandwiches with no garlic were served to the three groups not randomized to raw garlic.
At follow-up, the investigators found that none of the garlic varieties produced a statistically significant effect on LDL concentrations. The mean changes in LDL concentrations were +0.4 mg/dL for raw garlic, +3.2 mg/dL for powdered garlic, +0.2 mg/dL for aged extract, and -3.9 mg/dL for placebo. Nor did any garlic product produce a statistically significant effect on HDL, total cholesterol, or triglyceride levels.
Based on these and other recent findings, the investigators said that clinicians “can advise patients with moderately elevated LDL that garlic supplements or dietary garlic in reasonable doses are unlikely to produce lipid benefits” (Arch Intern Med. 2007;167:346-353). Nevertheless, the researchers say garlic at higher dosages than they used might still lower lipids in certain populations, such as those with high LDL levels. They also theorize that garlic might have the potential to produce other benefits, such as increased fibrinolysis, decreased atherosclerosis, or anti-carcinogenic properties.