Garlic May Not Lower Cholesterol
Study Shows No Improvement in Cholesterol Levels From Raw Garlic or Garlic Supplements
WebMD News Archive
The researchers included Stanford University's Christopher Gardner, PhD.
They gave participants sandwiches to eat and pills to take six days per week for six months.
Participants were split into four groups. One group got sandwiches that included four to six cloves of crushed raw garlic. They took sham supplements containing no garlic or other active ingredients (placebo pills).
Another group got garlic-free sandwiches and took Garlicin, a powdered garlic supplement.
The third group got garlic-free sandwiches and took Kyolic, an aged garlic supplement. The fourth group got garlic-free sandwiches and placebo pills.
Extensive tests show that all three forms of garlic contained comparable amounts of allicin, a compound studied for possible anticholesterol effects.
Participants had their cholesterol checked monthly throughout the six-month study.
None of the three forms of garlic affected participants' total cholesterol, LDL ("bad") cholesterol, HDL ("good") cholesterol, triglycerides, or other blood fats, the study shows.
"The lack of effect was compelling and clear," Gardner says in a Stanford news release. "The numbers just didn't move. There was no effect with any of these three products, even though fairly high doses were used."
He says the study was large enough and long enough to have detected any cholesterol changes.
"We even looked separately at the participants with the highest vs. the lowest LDL cholesterol levels at the start of the study, and the results were identical," Gardner says.
However, the researchers don't rule out the possibility that garlic has health benefits for other groups of people (such as those with higher LDL cholesterol levels) or requires higher doses.
The study's results "do not demonstrate that garlic has no usefulness in the prevention of cardiovascular disease," write the editorialists.
They included Marcus McFerren, MD, PhD, of the Center for Complementary and Integrative Medicine at New York's Weill Cornell Medical College.
Many factors affect heart disease, and allicin may not be the only compound in garlic that affects cholesterol, the editorialists suggest.
Garlic supplements are probably safe (no side effects were seen in the study), write McFerren and colleagues. "Do they prevent cardiovascular disease? The jury is still out," the editorialists write.
Gardner's team didn't set out to see if garlic prevented heart disease. The study only tracked cholesterol and other lipid levels.