More on Cholesterol Lowering Benefits From Garlic

Garlic's Impact on Blood Cholesterol Levels

You've probably seen advertisements for garlic supplements and debated whether you should eat more garlic to improve your heart's health. Perhaps you've wondered if it's worth the odor or if it's only good for keeping vampires at bay. Does garlic really promote heart health, and if so, how?


Research on animals and humans in the 1980s and early 1990s seemed to indicate that garlic had much promise for lowering cholesterol
. It appeared that garlic was able to lower total blood cholesterol in those who had high blood cholesterol (levels of 200 mg/dL or more). However, many of the studies included small numbers of patients and were short term, lasting just three months or less.

A number of more recent studies have tempered the initial enthusiasm about garlic's cholesterol-lowering effects. The National Center for Complementary and Alternative Medicine, a division of the National Institutes of Health (NIH), requested a thorough review of human studies that investigated garlic's ability to control cholesterol levels.

The NIH released a paper in 2000 that concluded garlic did not alter HDL, but that it could significantly lower LDL cholesterol and triglycerides in the short term. Researchers determined that garlic had the greatest cholesterol-lowering effect in the first one to three months of garlic therapy. After six months, no further lipid reductions occurred.

Elevated cholesterol levels, however, contribute to heart disease over a long period of time. So based on this newer research, it would appear that although garlic may be a helpful addition to a cholesterol-lowering diet, it can't be relied on as the sole solution to high blood cholesterol levels.

Still, it's obvious that more research is needed. Indeed, the NIH statement in 2000 encouraged longer-term studies, as well as consideration of the type of garlic used.

For example, there is some evidence that garlic must be cut or crushed to activate its health-promoting components. But the products tested in the various studies were not consistent. Some used raw garlic, while others used dried garlic or garlic oil; sometimes the raw garlic was cut, sometimes it was minced, and sometimes it was used whole.

When dried garlic was used, it often was made into a powder and formed into tablets. It's also unknown whether garlic just stops being effective after several months or whether other factors in these studies influenced the findings.


The Bottom Line: Garlic and Cholesterol

Although garlic may not be the blood-cholesterol miracle cure it was once promoted to be, and there are still plenty of questions that require answers, garlic does appear to have a healing role to play.

A 2005 Mayo Clinic report gives garlic a grade of "B" for small reductions in blood cholesterol and LDL cholesterol over short periods of time (4 to 12 weeks). A "B" grade means there is good scientific evidence to support its use for that purpose. The Mayo Clinic reported the following findings from multiple studies:

Garlic may not be a magic bullet against cholesterol, but it can have significant, positive effects.
Garlic may not be a magic bullet against
cholesterol, but it can have significant,
positive effects.

  • Supplements of nonenteric-coated tablets containing dehydrated garlic powder (standardized to 1.3 percent alliin) may reduce total cholesterol by up to 20 mg/dL for 4 to 12 weeks. The effects are unclear beyond 20 weeks.

  • LDL may decrease by up to 10 mg/dL.

  • Triglycerides may decrease by up to 20 mg/dL.

  • HDL cholesterol levels are not significantly affected.

Mayo's report concluded that well-designed studies of longer duration and including more people might provide stronger evidence of garlic's cholesterol-reducing benefits. In the meantime, however, garlic is not likely to take the place of medications prescribed by a physician to lower blood cholesterol levels.


On the other hand, doctors often recommend that patients try lifestyle changes to lower cholesterol levels before or even along with drug therapy. Drugs often come with their own side effects -- some merely unpleasant, others downright dangerous -- and postponing or minimizing drug therapy with lifestyle changes can cut the risks of such side effects.

Garlic's main drawback seems to be the odor it gives your breath and perspiration. Although garlic should never take the place of prescribed medications, including it more often in a cholesterol-lowering diet is easy, inexpensive, and enhances the flavor of your meals -- especially those that are low in fat and sodium.

Cholesterol isn't the only risk to your heart floating in the blood. On the next page you'll learn how garlic helps prevent harmful oxidation, too.

Different Forms of Garlic Yield Different Results
One of the difficulties in comparing studies of garlic's effectiveness in humans is that there are many different forms of garlic used in the studies. One may contain more of an active ingredient than another. For example:
  • Fresh cloves of garlic -- chopped or chewed: These may impart the highest amount of allicin, but they have not been well studied yet.

  • Fresh cloves of garlic -- swallowed whole: These showed no therapeutic value in a limited number of studies that have been done.

  • Dehydrated garlic powder -- made into tablets or capsules: This form often provided some therapeutic value, but allicin content of these products varies within and among brands.

  • Enteric-coated garlic tablets: These are treated so they do not dissolve until they reach your intestines, rather than your stomach. Some studies show that enteric-coated tablets don't dissolve soon enough to release the allicin they contain. This type of tablet usually prevents garlic odor on the breath.

  • Nonenteric-coated garlic tablets: Tablets effective in studies were standardized to contain 1.3 percent allicin (more about the content of garlic supplements later). These may be more effective than the enteric-coated tablets, but they do cause garlic breath.

  • Aged garlic extract: The active compound in this form is ajoene, among others. There have been conflicting results in studies of health benefits.

  • Garlic oil: Shows little therapeutic value in studies.


Want more information about garlic? Try:

  • Vegetable Recipes: Find delicious recipes that feature garlic.
  • Nutrition: Find out how garlic fits in with your overall nutrition plans.
  • Vegetable Gardens: Grow a full harvest of great vegetables this year.
  • Gardening: We answer your questions about all things that come from the garden.

This information is solely for informational purposes. IT IS NOT INTENDED TO PROVIDE MEDICAL ADVICE. Neither the Editors of Consumer Guide (R), Publications International, Ltd., the author nor publisher take responsibility for any possible consequences from any treatment, procedure, exercise, dietary modification, action or application of medication which results from reading or following the information contained in this information. The publication of this information does not constitute the practice of medicine, and this information does not replace the advice of your physician or other health care provider. Before undertaking any course of treatment, the reader must seek the advice of their physician or other health care provider.