Cholesterol Lowering Benefits From Garlic

Cholesterol is closely related to heart disease. When your body makes too much of it, it can clog up the bloodstream, which naturally leads to problems at the pump. Therefore, anything that is effective against cholesterol will also help lower the risk of heart disease. Garlic is one such agent.

The tiny garlic clove may play a big role in reducing the risk of heart disease, heart attacks, and stroke. How could such a simple herb have such powerful, far-reaching effects? To explore the answer and gain some appreciation for garlic's labors on our behalf, it's important to have a basic understanding of how the heart functions in sickness and in health.

Heart disease is the number one killer of Americans. The most common form of heart disease occurs when the arteries that deliver oxygen- and nutrient-rich blood to the heart become narrowed or clogged and lose their elasticity. Blood flow to the heart diminishes or may be cut off completely, starving the organ of oxygen. Without adequate oxygen, the heart can no longer work properly and heart cells begin to die.

Cholesterol and other debris in the blood causes plaque, which can restrict blood flow and even lead to a heart attack or stroke.

Healthy arteries are similar to flexible tubes, wide open and able to contract and expand slightly as blood surges through with each heartbeat. When there is any injury to the inner lining of these vital tubes -- such as damage caused by high blood cholesterol and triglyceride levels, high blood pressure, tobacco smoke, diabetes, and the aging process -- the body tries to protect and heal the wounded area by producing a sticky substance to cover the damage.

This process is similar to the way we might use spackle to patch a small hole in drywall. But the sticky spackle the body produces to heal the wound causes fatty substances (including cholesterol), proteins, calcium, inflammatory cells, and other "debris" in the blood to stick to the vessel walls, forming plaque.

As the plaque accumulates on the inner walls of the arteries, the arteries become less elastic, which leaves them vulnerable to even more injury. The gradual buildup of plaque also slowly narrows the inner diameter of the artery, and blood flow is hampered.

In addition, the plaque itself can crack, or bits of plaque can become dislodged. The body responds by sending platelets (particles in the blood that aid clotting) to form a clot around the plaque, further narrowing the artery.

In some cases, the blood clot may completely block the flow of blood through the artery. Cells beyond the blockage that depend on a steady flow of oxygen from the blood can die. When this occurs in an artery that feeds the heart muscle (known as a coronary artery), it's called a heart attack. If this happens in a vessel that feeds the brain, the result is a stroke.

Cholesterol's Role in Heart Disease

Some cholesterol is necessary for normal body processes -- it is a vital part of cell membranes, transports nutrients into and waste products out of cells, and is part of the structure of many hormones, among other functions -- but too much of the wrong kind leads to trouble. A quick review of cholesterol will help you appreciate the beneficial role garlic might play in your heart's health.

Dietary cholesterol is a fatty substance, or lipid. When you eat cholesterol in food, as in meat, eggs, and cheese, your body breaks it down to digest it, then turns some of it back into cholesterol. Your body also makes cholesterol out of the solid fats (saturated fat and trans fat) in your diet.

Heredity also plays a role in the amount of cholesterol your body produces. Genetics determine whether your body makes a little or a lot of cholesterol from the fats you eat. If you have a family history of high blood cholesterol, your body may make large amounts of the substance regardless of your eating and activity habits.

All this cholesterol is transported throughout your body via your internal highway -- the bloodstream. There are several types of blood cholesterol. The most significant are:

Target Cholesterol Numbes Here are the optimal blood lipid levels from the National Heart, Lung, and Blood Institute (as of 2005): Total cholesterol: 200 milligrams of cholesterol per deciliter of blood (mg/dL) or less LDL cholesterol: 100 mg/dL or less HDL cholesterol: 40 mg/dL or more Triglycerides: 150 mg/dL or less Note: Cholesterol levels are just one of several risk factors, including family history and smoking, that add up to determine your risk of heart disease. If you have one or more risk factors, you may need to aim for lipid levels lower than the standard ones listed here. Check with your health-care provider.

LDL cholesterol. LDL stands for low-density lipoprotein. LDL is nicknamed "bad" cholesterol because as it flows through your arteries it has a tendency to stick to the artery walls and form plaque. As the plaque builds up, it narrows the arteries. Arteries lined with plaque are no longer flexible and elastic. Instead, they are inflexible and "hard," which makes it more difficult for the heart to pump blood throughout the body, increasing your blood pressure. The more clogged the artery, the harder it is for blood to flow and deliver oxygen and nutrients to every part of the body.

HDL cholesterol. HDL stands for high-density lipoprotein. HDL carries the nickname "good" cholesterol because it works to eliminate excess blood cholesterol so it doesn't collect in the arteries and increase your risk for heart attacks and strokes. HDL carries cholesterol to the liver, where it is metabolized and then eliminated from the body. The higher your HDL level, the lower your chance of getting heart disease.

Triglycerides. Triglycerides are another form of lipid. Although they are not cholesterol, they do adversely affect your heart's health if you have too many in your blood. They can contribute to the thickening of artery walls. Your body manufactures triglycerides, and they are also present in food.

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.

• 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 ResultsOne 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.
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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.