Garlic may work wonders in your next vegetable lasagna, but don't count on it to lower your cholesterol. New research shows that the herb—widely promoted as a cholesterol-lowering agent—has no effect on low-density lipoprotein (LDL) levels, or "bad" cholesterol, in people with moderately high cholesterol.
The study, published in the Feb. 26 issue of the Archives of Internal Medicine, looked at the LDL-lowering efficacy of three forms of garlic: raw garlic and two popular supplements, Garlicin and Kyolic. In the study, 192 participants with LDL concentrations of 130 to 190 mg/dL were randomly assigned to one of the following treatments: one clove of garlic six days a week, the equivalent amount of garlic in either pill or powder form, or placebo. After six months, none of the participants' LDL levels went down.
Christopher Gardner, Ph.D., co-author of the study, said the research was well designed. "If we had a wish list of all the things we wanted to do, we did them all," he said. In addition to looking at the participants' reaction to the garlic for six months, Gardner and his colleagues took blood samples every month to pick up on transient or delayed effects, and they targeted people who were most likely to see an improvement in their cholesterol levels. "Nothing worked," said Gardner. "We thought if anything was going to work, the real garlic would."
While experts agree that the study findings are significant due to the well-designed and well-funded trial—the Stanford University Medical School researchers received more than $1.5 million from the National Institutes of Health, among other government agencies—they warn against losing all hope in garlic because of its other proven health-boosting benefits.
"This is one study that looked at a very specific question, and as the researchers appropriately pointed out in their paper, garlic may have other benefits," said Steven Dentali, Ph.D., vice president of scientific and technical affairs at the American Herbal Products Association. "They bet on one horse and that horse didn't come in, but that doesn't negate garlic's other possible benefits."
Dentali also noted that more thought needs to be given to the approach researchers take when studying botanicals. "We have a very simple, science-based way of finding out if a drug works," he said. "But that approach doesn't always work when you're testing herbs. This study essentially set out to find out if garlic acts as a cholesterol-?lowering drug. We're barking up the wrong tree if we assume that the beneficial effects offered by botanical extracts are going to work by the same mechanisms as drugs."
Mark Blumenthal, founder and exec?utive director of the American Botanical Council, agreed that similar research is necessary to determine garlic's other cardio?vascular effects.
"We're dealing with a product that has numerous health benefits, only one of which has been dealt a fairly heavy blow in this study," said Blumenthal. "Consumers should take this not with a grain of salt, but with a massive grain of salt—with a salt shaker! In six clinical trials in the last decade, garlic has been shown to lower and in some cases actually reverse levels of arterial plaque. This needs to be confirmed in larger trials, but it could be a more significant cardiac benefit than the fact that we thought garlic lowered cholesterol."
Gardner agreed: "We shouldn't write off the other possible benefits," he said. "And it still tastes great. Garlic certainly isn't bad for you, and I bet if you have a veggie stir fry that you like more because it has garlic in it, you'll probably lower your cholesterol because you had a low-fat, high-fiber meal."
Charlie Fox, sales adviser to Kyolic, said he disagrees with the study's conclusions. "There are over 550 articles in peer-reviewed medical journals that show Kyolic aged garlic extract has many health benefits, including reduction and prevention of arterial plaque formation, improved circulation and lowering blood pressure."
Natural Foods Merchandiser volume XXVIII/number 4/p.12