Garlic, touted as a natural way to reduce cholesterol levels, does not do so, Stanford University researchers reported Monday.
Whether it was raw garlic, aged garlic or garlic extract, the popular supplement had no effect on cholesterol levels in people with moderately high levels, according to the report in the Archives of Internal Medicine.
“It just doesn’t work,” said Christopher Gardner, a Stanford professor of medicine who led the study. “If garlic was going to work, in one form or another, then it would have worked in our study. The lack of effect was compelling and clear.”
The study does not rule out the possibility that garlic has other beneficial effects on the cardiovascular system, he said, but those potential effects need to be studied in similar trials.
Robert Borris, a botanical scientist at the Council for Responsible Nutrition, a trade group for supplement manufacturers, said the study was well designed but that the researchers erred in treating garlic like a drug rather than a supplement.
“In a multicomponent natural substance, you have to look at all the effects taken together as opposed to each one taken by itself,” he said.
In an editorial accompanying the paper in the journal, Dr. Mary Charlson and Dr. Marcus McFerren, of the Weill Cornell Medical College in New York City, wrote that the authors “convincingly demonstrate that raw garlic and two popularly used supplements do not reduce cholesterol. … Do they prevent cardiovascular disease? The jury is still out.”
Garlic has been used for a variety of medical purposes, perhaps because of its unique and powerful odor.
Recent studies have shown that allicin, the active ingredient of garlic, can block the synthesis of cholesterol in test tubes and animals. But limited trials in humans have shown mixed results.