Here’s an interesting new study for readers who pick up garlic or garlic supplements when shopping for organic food: Three forms of garlic—including raw garlic and two types of commercial garlic supplements—did not significantly reduce low-density lipoprotein (LDL, or “bad” cholesterol) during a six-month trial, according to results published in the Feb. 26 issue of Archives of Internal Medicine.

“Garlic supplements, many of which seek to package the benefits of raw garlic in more palatable forms, are promoted as cholesterol-lowering agents and are among the top-selling herbal supplements,” the authors write as background information in the article. Crushing garlic triggers the formation of a compound known as allicin, which has been shown to prevent the formation of cholesterol in the laboratory. But clinical trials on garlic as a cholesterol-lowering agent in humans have been inconsistent.

Christopher D. Gardner, PhD, of Stanford University Medical School, and colleagues enrolled 192 adults ages 30 to 65 who had moderately high LDL levels. Forty-nine participants were randomly assigned to receive raw garlic, 47 to take a powdered garlic supplement, 48 to take an aged garlic supplement and 48 to take a placebo. The amount of garlic consumed in the three garlic groups was the equivalent of an average-sized garlic clove each day, six days per week. Cholesterol levels were assessed monthly, and the chemical composition of the supplements was checked regularly; 169 adults completed the study.

“There were no statistically significant effects of the three forms of garlic on LDL cholesterol concentrations,” the authors write. Levels of other types of cholesterol—including high-density lipoprotein (HDL, or “good” cholesterol), triglycerides and total cholesterol also remained the same. No serious adverse events occurred, although bad body and breath odor were reported to occur often or almost always by 57% of people in the raw garlic group.

“The results of this trial should not be generalized to other populations or health effects,” the authors write. “Garlic might lower LDL in specific subpopulations, such as those with higher LDL concentrations, or may have other beneficial health effects. Based on our results and those of other recent trials, physicians can advise patients with moderately elevated LDL cholesterol concentrations that garlic supplements or dietary garlic in reasonable doses are unlikely to produce lipid benefits.”

Tune in tomorrow for another take on this topic.

Book Pick of the Day: Controlling Cholesterol for Dummies