A study from Stanford University casts doubt on the effectiveness of garlic to lower LDL (low density lipoprotein) cholesterol levels in adults with moderately high cholesterol. LDL cholesterol is widely known as «bad cholesterol,» and is believed to be a leading contributor to heart disease.
Christopher Gardner, Ph.D., and colleagues conducted a randomized, placebo-controlled trial studying whether three different formulations of garlic could lower LDL cholesterol. The study participants were randomly divided into four groups to receive raw garlic, a powdered garlic supplement, an aged extract supplement, or a placebo.
The 169 participants who completed the study had their cholesterol levels checked monthly for the duration of the 6-month trial. None of the formulations of garlic had a statistically significant effect on the LDL cholesterol levels.
The authors caution that these results should not be generalized for all populations or all health effects. An accompanying editorial in the journal Archives of Internal Medicine points out that LDL cholesterol levels are only one factor contributing to heart disease, and that this trial did not investigate garlic's effects on other risk factors, such as high blood pressure.
Gardner CD, Lawson LD, Block E, et al. Effect of raw garlic vs. commercial garlic supplements on plasma lipid concentrations in adults with moderate hypercholesterolemia: a randomized clinical trial. Archives of Internal Medicine.; 167(4):346–353.2007